1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* RDMA Transport Layer
4	*
5	* Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
6	* Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
7	* Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
8	*/
9
10	#undef pr_fmt
11	#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
12
13	#include <linux/module.h>
14	#include <linux/rculist.h>
15	#include <linux/random.h>
16
17	#include "rtrs-clt.h"
18	#include "rtrs-log.h"
19	#include "rtrs-clt-trace.h"
20
21	#define RTRS_CONNECT_TIMEOUT_MS 30000
22	/*
23	* Wait a bit before trying to reconnect after a failure
24	* in order to give server time to finish clean up which
25	* leads to "false positives" failed reconnect attempts
26	*/
27	#define RTRS_RECONNECT_BACKOFF 1000
28	/*
29	* Wait for additional random time between 0 and 8 seconds
30	* before starting to reconnect to avoid clients reconnecting
31	* all at once in case of a major network outage
32	*/
33	#define RTRS_RECONNECT_SEED 8
34
35	#define FIRST_CONN 0x01
36	/* limit to 128 * 4k = 512k max IO */
37	#define RTRS_MAX_SEGMENTS 128
38
39	MODULE_DESCRIPTION("RDMA Transport Client");
40	MODULE_LICENSE("GPL");
41
42	static const struct rtrs_rdma_dev_pd_ops dev_pd_ops;
43	static struct rtrs_rdma_dev_pd dev_pd = {
44	.ops = &dev_pd_ops
45	};
46
47	static struct workqueue_struct *rtrs_wq;
48	static const struct class rtrs_clt_dev_class = {
49	.name = "rtrs-client",
50	};
51
52	static inline bool rtrs_clt_is_connected(const struct rtrs_clt_sess *clt)
53	{
54	struct rtrs_clt_path *clt_path;
55	bool connected = false;
56
57	rcu_read_lock();
58	list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry)
59	if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED) {
60	connected = true;
61	break;
62	}
63	rcu_read_unlock();
64
65	return connected;
66	}
67
68	static struct rtrs_permit *
69	__rtrs_get_permit(struct rtrs_clt_sess *clt, enum rtrs_clt_con_type con_type)
70	{
71	size_t max_depth = clt->queue_depth;
72	struct rtrs_permit *permit;
73	int bit;
74
75	/*
76	* Adapted from null_blk get_tag(). Callers from different cpus may
77	* grab the same bit, since find_first_zero_bit is not atomic.
78	* But then the test_and_set_bit_lock will fail for all the
79	* callers but one, so that they will loop again.
80	* This way an explicit spinlock is not required.
81	*/
82	do {
83	bit = find_first_zero_bit(addr: clt->permits_map, size: max_depth);
84	if (bit >= max_depth)
85	return NULL;
86	} while (test_and_set_bit_lock(nr: bit, addr: clt->permits_map));
87
88	permit = get_permit(clt, idx: bit);
89	WARN_ON(permit->mem_id != bit);
90	permit->cpu_id = raw_smp_processor_id();
91	permit->con_type = con_type;
92
93	return permit;
94	}
95
96	static inline void __rtrs_put_permit(struct rtrs_clt_sess *clt,
97	struct rtrs_permit *permit)
98	{
99	clear_bit_unlock(nr: permit->mem_id, addr: clt->permits_map);
100	}
101
102	/**
103	* rtrs_clt_get_permit() - allocates permit for future RDMA operation
104	* @clt: Current session
105	* @con_type: Type of connection to use with the permit
106	* @can_wait: Wait type
107	*
108	* Description:
109	* Allocates permit for the following RDMA operation. Permit is used
110	* to preallocate all resources and to propagate memory pressure
111	* up earlier.
112	*
113	* Context:
114	* Can sleep if @wait == RTRS_PERMIT_WAIT
115	*/
116	struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt_sess *clt,
117	enum rtrs_clt_con_type con_type,
118	enum wait_type can_wait)
119	{
120	struct rtrs_permit *permit;
121	DEFINE_WAIT(wait);
122
123	permit = __rtrs_get_permit(clt, con_type);
124	if (permit || !can_wait)
125	return permit;
126
127	do {
128	prepare_to_wait(wq_head: &clt->permits_wait, wq_entry: &wait,
129	TASK_UNINTERRUPTIBLE);
130	permit = __rtrs_get_permit(clt, con_type);
131	if (permit)
132	break;
133
134	io_schedule();
135	} while (1);
136
137	finish_wait(wq_head: &clt->permits_wait, wq_entry: &wait);
138
139	return permit;
140	}
141	EXPORT_SYMBOL(rtrs_clt_get_permit);
142
143	/**
144	* rtrs_clt_put_permit() - puts allocated permit
145	* @clt: Current session
146	* @permit: Permit to be freed
147	*
148	* Context:
149	* Does not matter
150	*/
151	void rtrs_clt_put_permit(struct rtrs_clt_sess *clt,
152	struct rtrs_permit *permit)
153	{
154	if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map)))
155	return;
156
157	__rtrs_put_permit(clt, permit);
158
159	/*
160	* rtrs_clt_get_permit() adds itself to the &clt->permits_wait list
161	* before calling schedule(). So if rtrs_clt_get_permit() is sleeping
162	* it must have added itself to &clt->permits_wait before
163	* __rtrs_put_permit() finished.
164	* Hence it is safe to guard wake_up() with a waitqueue_active() test.
165	*/
166	if (waitqueue_active(wq_head: &clt->permits_wait))
167	wake_up(&clt->permits_wait);
168	}
169	EXPORT_SYMBOL(rtrs_clt_put_permit);
170
171	/**
172	* rtrs_permit_to_clt_con() - returns RDMA connection pointer by the permit
173	* @clt_path: client path pointer
174	* @permit: permit for the allocation of the RDMA buffer
175	* Note:
176	* IO connection starts from 1.
177	* 0 connection is for user messages.
178	*/
179	static
180	struct rtrs_clt_con *rtrs_permit_to_clt_con(struct rtrs_clt_path *clt_path,
181	struct rtrs_permit *permit)
182	{
183	int id = 0;
184
185	if (permit->con_type == RTRS_IO_CON)
186	id = (permit->cpu_id % (clt_path->s.irq_con_num - 1)) + 1;
187
188	return to_clt_con(c: clt_path->s.con[id]);
189	}
190
191	/**
192	* rtrs_clt_change_state() - change the session state through session state
193	* machine.
194	*
195	* @clt_path: client path to change the state of.
196	* @new_state: state to change to.
197	*
198	* returns true if sess's state is changed to new state, otherwise return false.
199	*
200	* Locks:
201	* state_wq lock must be hold.
202	*/
203	static bool rtrs_clt_change_state(struct rtrs_clt_path *clt_path,
204	enum rtrs_clt_state new_state)
205	{
206	enum rtrs_clt_state old_state;
207	bool changed = false;
208
209	lockdep_assert_held(&clt_path->state_wq.lock);
210
211	old_state = clt_path->state;
212	switch (new_state) {
213	case RTRS_CLT_CONNECTING:
214	switch (old_state) {
215	case RTRS_CLT_RECONNECTING:
216	changed = true;
217	fallthrough;
218	default:
219	break;
220	}
221	break;
222	case RTRS_CLT_RECONNECTING:
223	switch (old_state) {
224	case RTRS_CLT_CONNECTED:
225	case RTRS_CLT_CONNECTING_ERR:
226	case RTRS_CLT_CLOSED:
227	changed = true;
228	fallthrough;
229	default:
230	break;
231	}
232	break;
233	case RTRS_CLT_CONNECTED:
234	switch (old_state) {
235	case RTRS_CLT_CONNECTING:
236	changed = true;
237	fallthrough;
238	default:
239	break;
240	}
241	break;
242	case RTRS_CLT_CONNECTING_ERR:
243	switch (old_state) {
244	case RTRS_CLT_CONNECTING:
245	changed = true;
246	fallthrough;
247	default:
248	break;
249	}
250	break;
251	case RTRS_CLT_CLOSING:
252	switch (old_state) {
253	case RTRS_CLT_CONNECTING:
254	case RTRS_CLT_CONNECTING_ERR:
255	case RTRS_CLT_RECONNECTING:
256	case RTRS_CLT_CONNECTED:
257	changed = true;
258	fallthrough;
259	default:
260	break;
261	}
262	break;
263	case RTRS_CLT_CLOSED:
264	switch (old_state) {
265	case RTRS_CLT_CLOSING:
266	changed = true;
267	fallthrough;
268	default:
269	break;
270	}
271	break;
272	case RTRS_CLT_DEAD:
273	switch (old_state) {
274	case RTRS_CLT_CLOSED:
275	changed = true;
276	fallthrough;
277	default:
278	break;
279	}
280	break;
281	default:
282	break;
283	}
284	if (changed) {
285	clt_path->state = new_state;
286	wake_up_locked(&clt_path->state_wq);
287	}
288
289	return changed;
290	}
291
292	static bool rtrs_clt_change_state_from_to(struct rtrs_clt_path *clt_path,
293	enum rtrs_clt_state old_state,
294	enum rtrs_clt_state new_state)
295	{
296	bool changed = false;
297
298	spin_lock_irq(lock: &clt_path->state_wq.lock);
299	if (clt_path->state == old_state)
300	changed = rtrs_clt_change_state(clt_path, new_state);
301	spin_unlock_irq(lock: &clt_path->state_wq.lock);
302
303	return changed;
304	}
305
306	static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path);
307	static void rtrs_rdma_error_recovery(struct rtrs_clt_con *con)
308	{
309	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
310
311	trace_rtrs_rdma_error_recovery(clt_path);
312
313	if (rtrs_clt_change_state_from_to(clt_path,
314	old_state: RTRS_CLT_CONNECTED,
315	new_state: RTRS_CLT_RECONNECTING)) {
316	queue_work(wq: rtrs_wq, work: &clt_path->err_recovery_work);
317	} else {
318	/*
319	* Error can happen just on establishing new connection,
320	* so notify waiter with error state, waiter is responsible
321	* for cleaning the rest and reconnect if needed.
322	*/
323	rtrs_clt_change_state_from_to(clt_path,
324	old_state: RTRS_CLT_CONNECTING,
325	new_state: RTRS_CLT_CONNECTING_ERR);
326	}
327	}
328
329	static void rtrs_clt_fast_reg_done(struct ib_cq *cq, struct ib_wc *wc)
330	{
331	struct rtrs_clt_con *con = to_clt_con(c: wc->qp->qp_context);
332
333	if (wc->status != IB_WC_SUCCESS) {
334	rtrs_err_rl(con->c.path, "Failed IB_WR_REG_MR: %s\n",
335	ib_wc_status_msg(wc->status));
336	rtrs_rdma_error_recovery(con);
337	}
338	}
339
340	static struct ib_cqe fast_reg_cqe = {
341	.done = rtrs_clt_fast_reg_done
342	};
343
344	static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
345	bool notify, bool can_wait);
346
347	static void rtrs_clt_inv_rkey_done(struct ib_cq *cq, struct ib_wc *wc)
348	{
349	struct rtrs_clt_io_req *req =
350	container_of(wc->wr_cqe, typeof(*req), inv_cqe);
351	struct rtrs_clt_con *con = to_clt_con(c: wc->qp->qp_context);
352
353	if (wc->status != IB_WC_SUCCESS) {
354	rtrs_err_rl(con->c.path, "Failed IB_WR_LOCAL_INV: %s\n",
355	ib_wc_status_msg(wc->status));
356	rtrs_rdma_error_recovery(con);
357	}
358	req->mr->need_inval = false;
359	if (req->need_inv_comp)
360	complete(&req->inv_comp);
361	else
362	/* Complete request from INV callback */
363	complete_rdma_req(req, errno: req->inv_errno, notify: true, can_wait: false);
364	}
365
366	static int rtrs_inv_rkey(struct rtrs_clt_io_req *req)
367	{
368	struct rtrs_clt_con *con = req->con;
369	struct ib_send_wr wr = {
370	.opcode = IB_WR_LOCAL_INV,
371	.wr_cqe = &req->inv_cqe,
372	.send_flags = IB_SEND_SIGNALED,
373	.ex.invalidate_rkey = req->mr->rkey,
374	};
375	req->inv_cqe.done = rtrs_clt_inv_rkey_done;
376
377	return ib_post_send(qp: con->c.qp, send_wr: &wr, NULL);
378	}
379
380	static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
381	bool notify, bool can_wait)
382	{
383	struct rtrs_clt_con *con = req->con;
384	struct rtrs_clt_path *clt_path;
385	int err;
386
387	if (!req->in_use)
388	return;
389	if (WARN_ON(!req->con))
390	return;
391	clt_path = to_clt_path(s: con->c.path);
392
393	if (req->sg_cnt) {
394	if (req->mr->need_inval) {
395	/*
396	* We are here to invalidate read/write requests
397	* ourselves. In normal scenario server should
398	* send INV for all read requests, we do local
399	* invalidate for write requests ourselves, but
400	* we are here, thus three things could happen:
401	*
402	* 1. this is failover, when errno != 0
403	* and can_wait == 1,
404	*
405	* 2. something totally bad happened and
406	* server forgot to send INV, so we
407	* should do that ourselves.
408	*
409	* 3. write request finishes, we need to do local
410	* invalidate
411	*/
412
413	if (can_wait) {
414	req->need_inv_comp = true;
415	} else {
416	/* This should be IO path, so always notify */
417	WARN_ON(!notify);
418	/* Save errno for INV callback */
419	req->inv_errno = errno;
420	}
421
422	refcount_inc(r: &req->ref);
423	err = rtrs_inv_rkey(req);
424	if (err) {
425	rtrs_err_rl(con->c.path, "Send INV WR key=%#x: %d\n",
426	req->mr->rkey, err);
427	} else if (can_wait) {
428	wait_for_completion(&req->inv_comp);
429	}
430	if (!refcount_dec_and_test(r: &req->ref))
431	return;
432	}
433	ib_dma_unmap_sg(dev: clt_path->s.dev->ib_dev, sg: req->sglist,
434	nents: req->sg_cnt, direction: req->dir);
435	}
436	if (!refcount_dec_and_test(r: &req->ref))
437	return;
438	if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
439	atomic_dec(v: &clt_path->stats->inflight);
440
441	req->in_use = false;
442	req->con = NULL;
443
444	if (errno) {
445	rtrs_err_rl(con->c.path,
446	"IO %s request failed: error=%d path=%s [%s:%u] notify=%d\n",
447	req->dir == DMA_TO_DEVICE ? "write" : "read", errno,
448	kobject_name(&clt_path->kobj), clt_path->hca_name,
449	clt_path->hca_port, notify);
450	}
451
452	if (notify)
453	req->conf(req->priv, errno);
454	}
455
456	static int rtrs_post_send_rdma(struct rtrs_clt_con *con,
457	struct rtrs_clt_io_req *req,
458	struct rtrs_rbuf *rbuf, u32 off,
459	u32 imm, struct ib_send_wr *wr)
460	{
461	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
462	enum ib_send_flags flags;
463	struct ib_sge sge;
464
465	if (!req->sg_size) {
466	rtrs_wrn(con->c.path,
467	"Doing RDMA Write failed, no data supplied\n");
468	return -EINVAL;
469	}
470
471	/* user data and user message in the first list element */
472	sge.addr = req->iu->dma_addr;
473	sge.length = req->sg_size;
474	sge.lkey = clt_path->s.dev->ib_pd->local_dma_lkey;
475
476	/*
477	* From time to time we have to post signalled sends,
478	* or send queue will fill up and only QP reset can help.
479	*/
480	flags = atomic_inc_return(v: &con->c.wr_cnt) % clt_path->s.signal_interval ?
481	0 : IB_SEND_SIGNALED;
482
483	ib_dma_sync_single_for_device(dev: clt_path->s.dev->ib_dev,
484	addr: req->iu->dma_addr,
485	size: req->sg_size, dir: DMA_TO_DEVICE);
486
487	return rtrs_iu_post_rdma_write_imm(con: &con->c, iu: req->iu, sge: &sge, num_sge: 1,
488	rkey: rbuf->rkey, rdma_addr: rbuf->addr + off,
489	imm_data: imm, flags, head: wr, NULL);
490	}
491
492	static void process_io_rsp(struct rtrs_clt_path *clt_path, u32 msg_id,
493	s16 errno, bool w_inval)
494	{
495	struct rtrs_clt_io_req *req;
496
497	if (WARN_ON(msg_id >= clt_path->queue_depth))
498	return;
499
500	req = &clt_path->reqs[msg_id];
501	/* Drop need_inv if server responded with send with invalidation */
502	req->mr->need_inval &= !w_inval;
503	complete_rdma_req(req, errno, notify: true, can_wait: false);
504	}
505
506	static void rtrs_clt_recv_done(struct rtrs_clt_con *con, struct ib_wc *wc)
507	{
508	struct rtrs_iu *iu;
509	int err;
510	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
511
512	WARN_ON((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0);
513	iu = container_of(wc->wr_cqe, struct rtrs_iu,
514	cqe);
515	err = rtrs_iu_post_recv(con: &con->c, iu);
516	if (err) {
517	rtrs_err(con->c.path, "post iu failed %d\n", err);
518	rtrs_rdma_error_recovery(con);
519	}
520	}
521
522	static void rtrs_clt_rkey_rsp_done(struct rtrs_clt_con *con, struct ib_wc *wc)
523	{
524	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
525	struct rtrs_msg_rkey_rsp *msg;
526	u32 imm_type, imm_payload;
527	bool w_inval = false;
528	struct rtrs_iu *iu;
529	u32 buf_id;
530	int err;
531
532	WARN_ON((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0);
533
534	iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
535
536	if (wc->byte_len < sizeof(*msg)) {
537	rtrs_err(con->c.path, "rkey response is malformed: size %d\n",
538	wc->byte_len);
539	goto out;
540	}
541	ib_dma_sync_single_for_cpu(dev: clt_path->s.dev->ib_dev, addr: iu->dma_addr,
542	size: iu->size, dir: DMA_FROM_DEVICE);
543	msg = iu->buf;
544	if (le16_to_cpu(msg->type) != RTRS_MSG_RKEY_RSP) {
545	rtrs_err(clt_path->clt,
546	"rkey response is malformed: type %d\n",
547	le16_to_cpu(msg->type));
548	goto out;
549	}
550	buf_id = le16_to_cpu(msg->buf_id);
551	if (WARN_ON(buf_id >= clt_path->queue_depth))
552	goto out;
553
554	rtrs_from_imm(be32_to_cpu(wc->ex.imm_data), type: &imm_type, payload: &imm_payload);
555	if (imm_type == RTRS_IO_RSP_IMM ||
556	imm_type == RTRS_IO_RSP_W_INV_IMM) {
557	u32 msg_id;
558
559	w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
560	rtrs_from_io_rsp_imm(payload: imm_payload, msg_id: &msg_id, errno: &err);
561
562	if (WARN_ON(buf_id != msg_id))
563	goto out;
564	clt_path->rbufs[buf_id].rkey = le32_to_cpu(msg->rkey);
565	process_io_rsp(clt_path, msg_id, errno: err, w_inval);
566	}
567	ib_dma_sync_single_for_device(dev: clt_path->s.dev->ib_dev, addr: iu->dma_addr,
568	size: iu->size, dir: DMA_FROM_DEVICE);
569	return rtrs_clt_recv_done(con, wc);
570	out:
571	rtrs_rdma_error_recovery(con);
572	}
573
574	static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc);
575
576	static struct ib_cqe io_comp_cqe = {
577	.done = rtrs_clt_rdma_done
578	};
579
580	/*
581	* Post x2 empty WRs: first is for this RDMA with IMM,
582	* second is for RECV with INV, which happened earlier.
583	*/
584	static int rtrs_post_recv_empty_x2(struct rtrs_con *con, struct ib_cqe *cqe)
585	{
586	struct ib_recv_wr wr_arr[2], *wr;
587	int i;
588
589	memset(wr_arr, 0, sizeof(wr_arr));
590	for (i = 0; i < ARRAY_SIZE(wr_arr); i++) {
591	wr = &wr_arr[i];
592	wr->wr_cqe = cqe;
593	if (i)
594	/* Chain backwards */
595	wr->next = &wr_arr[i - 1];
596	}
597
598	return ib_post_recv(qp: con->qp, recv_wr: wr, NULL);
599	}
600
601	static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
602	{
603	struct rtrs_clt_con *con = to_clt_con(c: wc->qp->qp_context);
604	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
605	u32 imm_type, imm_payload;
606	bool w_inval = false;
607	int err;
608
609	if (wc->status != IB_WC_SUCCESS) {
610	if (wc->status != IB_WC_WR_FLUSH_ERR) {
611	rtrs_err(clt_path->clt, "RDMA failed: %s\n",
612	ib_wc_status_msg(wc->status));
613	rtrs_rdma_error_recovery(con);
614	}
615	return;
616	}
617	rtrs_clt_update_wc_stats(con);
618
619	switch (wc->opcode) {
620	case IB_WC_RECV_RDMA_WITH_IMM:
621	/*
622	* post_recv() RDMA write completions of IO reqs (read/write)
623	* and hb
624	*/
625	if (WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done))
626	return;
627	clt_path->s.hb_missed_cnt = 0;
628	rtrs_from_imm(be32_to_cpu(wc->ex.imm_data),
629	type: &imm_type, payload: &imm_payload);
630	if (imm_type == RTRS_IO_RSP_IMM ||
631	imm_type == RTRS_IO_RSP_W_INV_IMM) {
632	u32 msg_id;
633
634	w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
635	rtrs_from_io_rsp_imm(payload: imm_payload, msg_id: &msg_id, errno: &err);
636
637	process_io_rsp(clt_path, msg_id, errno: err, w_inval);
638	} else if (imm_type == RTRS_HB_MSG_IMM) {
639	WARN_ON(con->c.cid);
640	rtrs_send_hb_ack(path: &clt_path->s);
641	if (clt_path->flags & RTRS_MSG_NEW_RKEY_F)
642	return rtrs_clt_recv_done(con, wc);
643	} else if (imm_type == RTRS_HB_ACK_IMM) {
644	WARN_ON(con->c.cid);
645	clt_path->s.hb_cur_latency =
646	ktime_sub(ktime_get(), clt_path->s.hb_last_sent);
647	if (clt_path->flags & RTRS_MSG_NEW_RKEY_F)
648	return rtrs_clt_recv_done(con, wc);
649	} else {
650	rtrs_wrn(con->c.path, "Unknown IMM type %u\n",
651	imm_type);
652	}
653	if (w_inval)
654	/*
655	* Post x2 empty WRs: first is for this RDMA with IMM,
656	* second is for RECV with INV, which happened earlier.
657	*/
658	err = rtrs_post_recv_empty_x2(con: &con->c, cqe: &io_comp_cqe);
659	else
660	err = rtrs_post_recv_empty(con: &con->c, cqe: &io_comp_cqe);
661	if (err) {
662	rtrs_err(con->c.path, "rtrs_post_recv_empty(): %d\n",
663	err);
664	rtrs_rdma_error_recovery(con);
665	}
666	break;
667	case IB_WC_RECV:
668	/*
669	* Key invalidations from server side
670	*/
671	clt_path->s.hb_missed_cnt = 0;
672	WARN_ON(!(wc->wc_flags & IB_WC_WITH_INVALIDATE ||
673	wc->wc_flags & IB_WC_WITH_IMM));
674	WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done);
675	if (clt_path->flags & RTRS_MSG_NEW_RKEY_F) {
676	if (wc->wc_flags & IB_WC_WITH_INVALIDATE)
677	return rtrs_clt_recv_done(con, wc);
678
679	return rtrs_clt_rkey_rsp_done(con, wc);
680	}
681	break;
682	case IB_WC_RDMA_WRITE:
683	/*
684	* post_send() RDMA write completions of IO reqs (read/write)
685	* and hb.
686	*/
687	break;
688
689	default:
690	rtrs_wrn(clt_path->clt, "Unexpected WC type: %d\n", wc->opcode);
691	return;
692	}
693	}
694
695	static int post_recv_io(struct rtrs_clt_con *con, size_t q_size)
696	{
697	int err, i;
698	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
699
700	for (i = 0; i < q_size; i++) {
701	if (clt_path->flags & RTRS_MSG_NEW_RKEY_F) {
702	struct rtrs_iu *iu = &con->rsp_ius[i];
703
704	err = rtrs_iu_post_recv(con: &con->c, iu);
705	} else {
706	err = rtrs_post_recv_empty(con: &con->c, cqe: &io_comp_cqe);
707	}
708	if (err)
709	return err;
710	}
711
712	return 0;
713	}
714
715	static int post_recv_path(struct rtrs_clt_path *clt_path)
716	{
717	size_t q_size = 0;
718	int err, cid;
719
720	for (cid = 0; cid < clt_path->s.con_num; cid++) {
721	if (cid == 0)
722	q_size = SERVICE_CON_QUEUE_DEPTH;
723	else
724	q_size = clt_path->queue_depth;
725
726	/*
727	* x2 for RDMA read responses + FR key invalidations,
728	* RDMA writes do not require any FR registrations.
729	*/
730	q_size *= 2;
731
732	err = post_recv_io(con: to_clt_con(c: clt_path->s.con[cid]), q_size);
733	if (err) {
734	rtrs_err(clt_path->clt, "post_recv_io(), err: %d\n",
735	err);
736	return err;
737	}
738	}
739
740	return 0;
741	}
742
743	struct path_it {
744	int i;
745	struct list_head skip_list;
746	struct rtrs_clt_sess *clt;
747	struct rtrs_clt_path *(*next_path)(struct path_it *it);
748	};
749
750	/*
751	* rtrs_clt_get_next_path_or_null - get clt path from the list or return NULL
752	* @head: the head for the list.
753	* @clt_path: The element to take the next clt_path from.
754	*
755	* Next clt path returned in round-robin fashion, i.e. head will be skipped,
756	* but if list is observed as empty, NULL will be returned.
757	*
758	* This function may safely run concurrently with the _rcu list-mutation
759	* primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
760	*/
761	static inline struct rtrs_clt_path *
762	rtrs_clt_get_next_path_or_null(struct list_head *head, struct rtrs_clt_path *clt_path)
763	{
764	return list_next_or_null_rcu(head, &clt_path->s.entry, typeof(*clt_path), s.entry) ?:
765	list_next_or_null_rcu(head,
766	READ_ONCE((&clt_path->s.entry)->next),
767	typeof(*clt_path), s.entry);
768	}
769
770	/**
771	* get_next_path_rr() - Returns path in round-robin fashion.
772	* @it: the path pointer
773	*
774	* Related to @MP_POLICY_RR
775	*
776	* Locks:
777	* rcu_read_lock() must be held.
778	*/
779	static struct rtrs_clt_path *get_next_path_rr(struct path_it *it)
780	{
781	struct rtrs_clt_path __rcu **ppcpu_path;
782	struct rtrs_clt_path *path;
783	struct rtrs_clt_sess *clt;
784
785	/*
786	* Assert that rcu lock must be held
787	*/
788	RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "no rcu read lock held");
789
790	clt = it->clt;
791
792	/*
793	* Here we use two RCU objects: @paths_list and @pcpu_path
794	* pointer. See rtrs_clt_remove_path_from_arr() for details
795	* how that is handled.
796	*/
797
798	ppcpu_path = this_cpu_ptr(clt->pcpu_path);
799	path = rcu_dereference(*ppcpu_path);
800	if (!path)
801	path = list_first_or_null_rcu(&clt->paths_list,
802	typeof(*path), s.entry);
803	else
804	path = rtrs_clt_get_next_path_or_null(head: &clt->paths_list, clt_path: path);
805
806	rcu_assign_pointer(*ppcpu_path, path);
807
808	return path;
809	}
810
811	/**
812	* get_next_path_min_inflight() - Returns path with minimal inflight count.
813	* @it: the path pointer
814	*
815	* Related to @MP_POLICY_MIN_INFLIGHT
816	*
817	* Locks:
818	* rcu_read_lock() must be hold.
819	*/
820	static struct rtrs_clt_path *get_next_path_min_inflight(struct path_it *it)
821	{
822	struct rtrs_clt_path *min_path = NULL;
823	struct rtrs_clt_sess *clt = it->clt;
824	struct rtrs_clt_path *clt_path;
825	int min_inflight = INT_MAX;
826	int inflight;
827
828	list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
829	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
830	continue;
831
832	if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
833	continue;
834
835	inflight = atomic_read(v: &clt_path->stats->inflight);
836
837	if (inflight < min_inflight) {
838	min_inflight = inflight;
839	min_path = clt_path;
840	}
841	}
842
843	/*
844	* add the path to the skip list, so that next time we can get
845	* a different one
846	*/
847	if (min_path)
848	list_add(raw_cpu_ptr(min_path->mp_skip_entry), head: &it->skip_list);
849
850	return min_path;
851	}
852
853	/**
854	* get_next_path_min_latency() - Returns path with minimal latency.
855	* @it: the path pointer
856	*
857	* Return: a path with the lowest latency or NULL if all paths are tried
858	*
859	* Locks:
860	* rcu_read_lock() must be hold.
861	*
862	* Related to @MP_POLICY_MIN_LATENCY
863	*
864	* This DOES skip an already-tried path.
865	* There is a skip-list to skip a path if the path has tried but failed.
866	* It will try the minimum latency path and then the second minimum latency
867	* path and so on. Finally it will return NULL if all paths are tried.
868	* Therefore the caller MUST check the returned
869	* path is NULL and trigger the IO error.
870	*/
871	static struct rtrs_clt_path *get_next_path_min_latency(struct path_it *it)
872	{
873	struct rtrs_clt_path *min_path = NULL;
874	struct rtrs_clt_sess *clt = it->clt;
875	struct rtrs_clt_path *clt_path;
876	ktime_t min_latency = KTIME_MAX;
877	ktime_t latency;
878
879	list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
880	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
881	continue;
882
883	if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
884	continue;
885
886	latency = clt_path->s.hb_cur_latency;
887
888	if (latency < min_latency) {
889	min_latency = latency;
890	min_path = clt_path;
891	}
892	}
893
894	/*
895	* add the path to the skip list, so that next time we can get
896	* a different one
897	*/
898	if (min_path)
899	list_add(raw_cpu_ptr(min_path->mp_skip_entry), head: &it->skip_list);
900
901	return min_path;
902	}
903
904	static inline void path_it_init(struct path_it *it, struct rtrs_clt_sess *clt)
905	{
906	INIT_LIST_HEAD(list: &it->skip_list);
907	it->clt = clt;
908	it->i = 0;
909
910	if (clt->mp_policy == MP_POLICY_RR)
911	it->next_path = get_next_path_rr;
912	else if (clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
913	it->next_path = get_next_path_min_inflight;
914	else
915	it->next_path = get_next_path_min_latency;
916	}
917
918	static inline void path_it_deinit(struct path_it *it)
919	{
920	struct list_head *skip, *tmp;
921	/*
922	* The skip_list is used only for the MIN_INFLIGHT and MIN_LATENCY policies.
923	* We need to remove paths from it, so that next IO can insert
924	* paths (->mp_skip_entry) into a skip_list again.
925	*/
926	list_for_each_safe(skip, tmp, &it->skip_list)
927	list_del_init(entry: skip);
928	}
929
930	/**
931	* rtrs_clt_init_req() - Initialize an rtrs_clt_io_req holding information
932	* about an inflight IO.
933	* The user buffer holding user control message (not data) is copied into
934	* the corresponding buffer of rtrs_iu (req->iu->buf), which later on will
935	* also hold the control message of rtrs.
936	* @req: an io request holding information about IO.
937	* @clt_path: client path
938	* @conf: conformation callback function to notify upper layer.
939	* @permit: permit for allocation of RDMA remote buffer
940	* @priv: private pointer
941	* @vec: kernel vector containing control message
942	* @usr_len: length of the user message
943	* @sg: scater list for IO data
944	* @sg_cnt: number of scater list entries
945	* @data_len: length of the IO data
946	* @dir: direction of the IO.
947	*/
948	static void rtrs_clt_init_req(struct rtrs_clt_io_req *req,
949	struct rtrs_clt_path *clt_path,
950	void (*conf)(void *priv, int errno),
951	struct rtrs_permit *permit, void *priv,
952	const struct kvec *vec, size_t usr_len,
953	struct scatterlist *sg, size_t sg_cnt,
954	size_t data_len, int dir)
955	{
956	struct iov_iter iter;
957	size_t len;
958
959	req->permit = permit;
960	req->in_use = true;
961	req->usr_len = usr_len;
962	req->data_len = data_len;
963	req->sglist = sg;
964	req->sg_cnt = sg_cnt;
965	req->priv = priv;
966	req->dir = dir;
967	req->con = rtrs_permit_to_clt_con(clt_path, permit);
968	req->conf = conf;
969	req->mr->need_inval = false;
970	req->need_inv_comp = false;
971	req->inv_errno = 0;
972	refcount_set(r: &req->ref, n: 1);
973	req->mp_policy = clt_path->clt->mp_policy;
974
975	iov_iter_kvec(i: &iter, ITER_SOURCE, kvec: vec, nr_segs: 1, count: usr_len);
976	len = _copy_from_iter(addr: req->iu->buf, bytes: usr_len, i: &iter);
977	WARN_ON(len != usr_len);
978
979	reinit_completion(x: &req->inv_comp);
980	}
981
982	static struct rtrs_clt_io_req *
983	rtrs_clt_get_req(struct rtrs_clt_path *clt_path,
984	void (*conf)(void *priv, int errno),
985	struct rtrs_permit *permit, void *priv,
986	const struct kvec *vec, size_t usr_len,
987	struct scatterlist *sg, size_t sg_cnt,
988	size_t data_len, int dir)
989	{
990	struct rtrs_clt_io_req *req;
991
992	req = &clt_path->reqs[permit->mem_id];
993	rtrs_clt_init_req(req, clt_path, conf, permit, priv, vec, usr_len,
994	sg, sg_cnt, data_len, dir);
995	return req;
996	}
997
998	static struct rtrs_clt_io_req *
999	rtrs_clt_get_copy_req(struct rtrs_clt_path *alive_path,
1000	struct rtrs_clt_io_req *fail_req)
1001	{
1002	struct rtrs_clt_io_req *req;
1003	struct kvec vec = {
1004	.iov_base = fail_req->iu->buf,
1005	.iov_len = fail_req->usr_len
1006	};
1007
1008	req = &alive_path->reqs[fail_req->permit->mem_id];
1009	rtrs_clt_init_req(req, clt_path: alive_path, conf: fail_req->conf, permit: fail_req->permit,
1010	priv: fail_req->priv, vec: &vec, usr_len: fail_req->usr_len,
1011	sg: fail_req->sglist, sg_cnt: fail_req->sg_cnt,
1012	data_len: fail_req->data_len, dir: fail_req->dir);
1013	return req;
1014	}
1015
1016	static int rtrs_post_rdma_write_sg(struct rtrs_clt_con *con,
1017	struct rtrs_clt_io_req *req,
1018	struct rtrs_rbuf *rbuf, bool fr_en,
1019	u32 count, u32 size, u32 imm,
1020	struct ib_send_wr *wr,
1021	struct ib_send_wr *tail)
1022	{
1023	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1024	struct ib_sge *sge = req->sge;
1025	enum ib_send_flags flags;
1026	struct scatterlist *sg;
1027	size_t num_sge;
1028	int i;
1029	struct ib_send_wr *ptail = NULL;
1030
1031	if (fr_en) {
1032	i = 0;
1033	sge[i].addr = req->mr->iova;
1034	sge[i].length = req->mr->length;
1035	sge[i].lkey = req->mr->lkey;
1036	i++;
1037	num_sge = 2;
1038	ptail = tail;
1039	} else {
1040	for_each_sg(req->sglist, sg, count, i) {
1041	sge[i].addr = sg_dma_address(sg);
1042	sge[i].length = sg_dma_len(sg);
1043	sge[i].lkey = clt_path->s.dev->ib_pd->local_dma_lkey;
1044	}
1045	num_sge = 1 + count;
1046	}
1047	sge[i].addr = req->iu->dma_addr;
1048	sge[i].length = size;
1049	sge[i].lkey = clt_path->s.dev->ib_pd->local_dma_lkey;
1050
1051	/*
1052	* From time to time we have to post signalled sends,
1053	* or send queue will fill up and only QP reset can help.
1054	*/
1055	flags = atomic_inc_return(v: &con->c.wr_cnt) % clt_path->s.signal_interval ?
1056	0 : IB_SEND_SIGNALED;
1057
1058	ib_dma_sync_single_for_device(dev: clt_path->s.dev->ib_dev,
1059	addr: req->iu->dma_addr,
1060	size, dir: DMA_TO_DEVICE);
1061
1062	return rtrs_iu_post_rdma_write_imm(con: &con->c, iu: req->iu, sge, num_sge,
1063	rkey: rbuf->rkey, rdma_addr: rbuf->addr, imm_data: imm,
1064	flags, head: wr, tail: ptail);
1065	}
1066
1067	static int rtrs_map_sg_fr(struct rtrs_clt_io_req *req, size_t count)
1068	{
1069	int nr;
1070
1071	/* Align the MR to a 4K page size to match the block virt boundary */
1072	nr = ib_map_mr_sg(mr: req->mr, sg: req->sglist, sg_nents: count, NULL, SZ_4K);
1073	if (nr != count)
1074	return nr < 0 ? nr : -EINVAL;
1075	ib_update_fast_reg_key(mr: req->mr, newkey: ib_inc_rkey(rkey: req->mr->rkey));
1076
1077	return nr;
1078	}
1079
1080	static int rtrs_clt_write_req(struct rtrs_clt_io_req *req)
1081	{
1082	struct rtrs_clt_con *con = req->con;
1083	struct rtrs_path *s = con->c.path;
1084	struct rtrs_clt_path *clt_path = to_clt_path(s);
1085	struct rtrs_msg_rdma_write *msg;
1086
1087	struct rtrs_rbuf *rbuf;
1088	int ret, count = 0;
1089	u32 imm, buf_id;
1090	struct ib_reg_wr rwr;
1091	struct ib_send_wr *wr = NULL;
1092	bool fr_en = false;
1093
1094	const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1095
1096	if (tsize > clt_path->chunk_size) {
1097	rtrs_wrn(s, "Write request failed, size too big %zu > %d\n",
1098	tsize, clt_path->chunk_size);
1099	return -EMSGSIZE;
1100	}
1101	if (req->sg_cnt) {
1102	count = ib_dma_map_sg(dev: clt_path->s.dev->ib_dev, sg: req->sglist,
1103	nents: req->sg_cnt, direction: req->dir);
1104	if (!count) {
1105	rtrs_wrn(s, "Write request failed, map failed\n");
1106	return -EINVAL;
1107	}
1108	}
1109	/* put rtrs msg after sg and user message */
1110	msg = req->iu->buf + req->usr_len;
1111	msg->type = cpu_to_le16(RTRS_MSG_WRITE);
1112	msg->usr_len = cpu_to_le16(req->usr_len);
1113
1114	/* rtrs message on server side will be after user data and message */
1115	imm = req->permit->mem_off + req->data_len + req->usr_len;
1116	imm = rtrs_to_io_req_imm(addr: imm);
1117	buf_id = req->permit->mem_id;
1118	req->sg_size = tsize;
1119	rbuf = &clt_path->rbufs[buf_id];
1120
1121	if (count) {
1122	ret = rtrs_map_sg_fr(req, count);
1123	if (ret < 0) {
1124	rtrs_err_rl(s,
1125	"Write request failed, failed to map fast reg. data, err: %d\n",
1126	ret);
1127	ib_dma_unmap_sg(dev: clt_path->s.dev->ib_dev, sg: req->sglist,
1128	nents: req->sg_cnt, direction: req->dir);
1129	return ret;
1130	}
1131	rwr = (struct ib_reg_wr) {
1132	.wr.opcode = IB_WR_REG_MR,
1133	.wr.wr_cqe = &fast_reg_cqe,
1134	.mr = req->mr,
1135	.key = req->mr->rkey,
1136	.access = (IB_ACCESS_LOCAL_WRITE),
1137	};
1138	wr = &rwr.wr;
1139	fr_en = true;
1140	req->mr->need_inval = true;
1141	}
1142	/*
1143	* Update stats now, after request is successfully sent it is not
1144	* safe anymore to touch it.
1145	*/
1146	rtrs_clt_update_all_stats(req, WRITE);
1147
1148	ret = rtrs_post_rdma_write_sg(con: req->con, req, rbuf, fr_en, count,
1149	size: req->usr_len + sizeof(*msg),
1150	imm, wr, NULL);
1151	if (ret) {
1152	rtrs_err_rl(s,
1153	"Write request failed: error=%d path=%s [%s:%u]\n",
1154	ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1155	clt_path->hca_port);
1156	if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1157	atomic_dec(v: &clt_path->stats->inflight);
1158	if (req->mr->need_inval) {
1159	req->mr->need_inval = false;
1160	refcount_dec(r: &req->ref);
1161	}
1162	if (req->sg_cnt)
1163	ib_dma_unmap_sg(dev: clt_path->s.dev->ib_dev, sg: req->sglist,
1164	nents: req->sg_cnt, direction: req->dir);
1165	}
1166
1167	return ret;
1168	}
1169
1170	static int rtrs_clt_read_req(struct rtrs_clt_io_req *req)
1171	{
1172	struct rtrs_clt_con *con = req->con;
1173	struct rtrs_path *s = con->c.path;
1174	struct rtrs_clt_path *clt_path = to_clt_path(s);
1175	struct rtrs_msg_rdma_read *msg;
1176	struct rtrs_ib_dev *dev = clt_path->s.dev;
1177
1178	struct ib_reg_wr rwr;
1179	struct ib_send_wr *wr = NULL;
1180
1181	int ret, count = 0;
1182	u32 imm, buf_id;
1183
1184	const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1185
1186	if (tsize > clt_path->chunk_size) {
1187	rtrs_wrn(s,
1188	"Read request failed, message size is %zu, bigger than CHUNK_SIZE %d\n",
1189	tsize, clt_path->chunk_size);
1190	return -EMSGSIZE;
1191	}
1192
1193	if (req->sg_cnt) {
1194	count = ib_dma_map_sg(dev: dev->ib_dev, sg: req->sglist, nents: req->sg_cnt,
1195	direction: req->dir);
1196	if (!count) {
1197	rtrs_wrn(s,
1198	"Read request failed, dma map failed\n");
1199	return -EINVAL;
1200	}
1201	}
1202	/* put our message into req->buf after user message*/
1203	msg = req->iu->buf + req->usr_len;
1204	msg->type = cpu_to_le16(RTRS_MSG_READ);
1205	msg->usr_len = cpu_to_le16(req->usr_len);
1206
1207	if (count) {
1208	ret = rtrs_map_sg_fr(req, count);
1209	if (ret < 0) {
1210	rtrs_err_rl(s,
1211	"Read request failed, failed to map fast reg. data, err: %d\n",
1212	ret);
1213	ib_dma_unmap_sg(dev: dev->ib_dev, sg: req->sglist, nents: req->sg_cnt,
1214	direction: req->dir);
1215	return ret;
1216	}
1217	rwr = (struct ib_reg_wr) {
1218	.wr.opcode = IB_WR_REG_MR,
1219	.wr.wr_cqe = &fast_reg_cqe,
1220	.mr = req->mr,
1221	.key = req->mr->rkey,
1222	.access = (IB_ACCESS_LOCAL_WRITE |
1223	IB_ACCESS_REMOTE_WRITE),
1224	};
1225	wr = &rwr.wr;
1226
1227	msg->sg_cnt = cpu_to_le16(1);
1228	msg->flags = cpu_to_le16(RTRS_MSG_NEED_INVAL_F);
1229
1230	msg->desc[0].addr = cpu_to_le64(req->mr->iova);
1231	msg->desc[0].key = cpu_to_le32(req->mr->rkey);
1232	msg->desc[0].len = cpu_to_le32(req->mr->length);
1233
1234	/* Further invalidation is required */
1235	req->mr->need_inval = !!RTRS_MSG_NEED_INVAL_F;
1236
1237	} else {
1238	msg->sg_cnt = 0;
1239	msg->flags = 0;
1240	}
1241	/*
1242	* rtrs message will be after the space reserved for disk data and
1243	* user message
1244	*/
1245	imm = req->permit->mem_off + req->data_len + req->usr_len;
1246	imm = rtrs_to_io_req_imm(addr: imm);
1247	buf_id = req->permit->mem_id;
1248
1249	req->sg_size = sizeof(*msg);
1250	req->sg_size += le16_to_cpu(msg->sg_cnt) * sizeof(struct rtrs_sg_desc);
1251	req->sg_size += req->usr_len;
1252
1253	/*
1254	* Update stats now, after request is successfully sent it is not
1255	* safe anymore to touch it.
1256	*/
1257	rtrs_clt_update_all_stats(req, READ);
1258
1259	ret = rtrs_post_send_rdma(con: req->con, req, rbuf: &clt_path->rbufs[buf_id],
1260	off: req->data_len, imm, wr);
1261	if (ret) {
1262	rtrs_err_rl(s,
1263	"Read request failed: error=%d path=%s [%s:%u]\n",
1264	ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1265	clt_path->hca_port);
1266	if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1267	atomic_dec(v: &clt_path->stats->inflight);
1268	req->mr->need_inval = false;
1269	if (req->sg_cnt)
1270	ib_dma_unmap_sg(dev: dev->ib_dev, sg: req->sglist,
1271	nents: req->sg_cnt, direction: req->dir);
1272	}
1273
1274	return ret;
1275	}
1276
1277	/**
1278	* rtrs_clt_failover_req() - Try to find an active path for a failed request
1279	* @clt: clt context
1280	* @fail_req: a failed io request.
1281	*/
1282	static int rtrs_clt_failover_req(struct rtrs_clt_sess *clt,
1283	struct rtrs_clt_io_req *fail_req)
1284	{
1285	struct rtrs_clt_path *alive_path;
1286	struct rtrs_clt_io_req *req;
1287	int err = -ECONNABORTED;
1288	struct path_it it;
1289
1290	rcu_read_lock();
1291	for (path_it_init(it: &it, clt);
1292	(alive_path = it.next_path(&it)) && it.i < it.clt->paths_num;
1293	it.i++) {
1294	if (READ_ONCE(alive_path->state) != RTRS_CLT_CONNECTED)
1295	continue;
1296	req = rtrs_clt_get_copy_req(alive_path, fail_req);
1297	if (req->dir == DMA_TO_DEVICE)
1298	err = rtrs_clt_write_req(req);
1299	else
1300	err = rtrs_clt_read_req(req);
1301	if (err) {
1302	req->in_use = false;
1303	continue;
1304	}
1305	/* Success path */
1306	rtrs_clt_inc_failover_cnt(s: alive_path->stats);
1307	break;
1308	}
1309	path_it_deinit(it: &it);
1310	rcu_read_unlock();
1311
1312	return err;
1313	}
1314
1315	static void fail_all_outstanding_reqs(struct rtrs_clt_path *clt_path)
1316	{
1317	struct rtrs_clt_sess *clt = clt_path->clt;
1318	struct rtrs_clt_io_req *req;
1319	int i, err;
1320
1321	if (!clt_path->reqs)
1322	return;
1323	for (i = 0; i < clt_path->queue_depth; ++i) {
1324	req = &clt_path->reqs[i];
1325	if (!req->in_use)
1326	continue;
1327
1328	/*
1329	* Safely (without notification) complete failed request.
1330	* After completion this request is still useble and can
1331	* be failovered to another path.
1332	*/
1333	complete_rdma_req(req, errno: -ECONNABORTED, notify: false, can_wait: true);
1334
1335	err = rtrs_clt_failover_req(clt, fail_req: req);
1336	if (err)
1337	/* Failover failed, notify anyway */
1338	req->conf(req->priv, err);
1339	}
1340	}
1341
1342	static void free_path_reqs(struct rtrs_clt_path *clt_path)
1343	{
1344	struct rtrs_clt_io_req *req;
1345	int i;
1346
1347	if (!clt_path->reqs)
1348	return;
1349	for (i = 0; i < clt_path->queue_depth; ++i) {
1350	req = &clt_path->reqs[i];
1351	if (req->mr)
1352	ib_dereg_mr(mr: req->mr);
1353	kfree(objp: req->sge);
1354	rtrs_iu_free(iu: req->iu, dev: clt_path->s.dev->ib_dev, queue_num: 1);
1355	}
1356	kfree(objp: clt_path->reqs);
1357	clt_path->reqs = NULL;
1358	}
1359
1360	static int alloc_path_reqs(struct rtrs_clt_path *clt_path)
1361	{
1362	struct rtrs_clt_io_req *req;
1363	int i, err = -ENOMEM;
1364
1365	clt_path->reqs = kcalloc(clt_path->queue_depth,
1366	sizeof(*clt_path->reqs),
1367	GFP_KERNEL);
1368	if (!clt_path->reqs)
1369	return -ENOMEM;
1370
1371	for (i = 0; i < clt_path->queue_depth; ++i) {
1372	req = &clt_path->reqs[i];
1373	req->iu = rtrs_iu_alloc(queue_num: 1, size: clt_path->max_hdr_size, GFP_KERNEL,
1374	dev: clt_path->s.dev->ib_dev,
1375	DMA_TO_DEVICE,
1376	done: rtrs_clt_rdma_done);
1377	if (!req->iu)
1378	goto out;
1379
1380	req->sge = kcalloc(2, sizeof(*req->sge), GFP_KERNEL);
1381	if (!req->sge)
1382	goto out;
1383
1384	req->mr = ib_alloc_mr(pd: clt_path->s.dev->ib_pd,
1385	mr_type: IB_MR_TYPE_MEM_REG,
1386	max_num_sg: clt_path->max_pages_per_mr);
1387	if (IS_ERR(ptr: req->mr)) {
1388	err = PTR_ERR(ptr: req->mr);
1389	pr_err("Failed to alloc clt_path->max_pages_per_mr %d: %pe\n",
1390	clt_path->max_pages_per_mr, req->mr);
1391	req->mr = NULL;
1392	goto out;
1393	}
1394
1395	init_completion(x: &req->inv_comp);
1396	}
1397
1398	return 0;
1399
1400	out:
1401	free_path_reqs(clt_path);
1402
1403	return err;
1404	}
1405
1406	static int alloc_permits(struct rtrs_clt_sess *clt)
1407	{
1408	unsigned int chunk_bits;
1409	int err, i;
1410
1411	clt->permits_map = bitmap_zalloc(nbits: clt->queue_depth, GFP_KERNEL);
1412	if (!clt->permits_map) {
1413	err = -ENOMEM;
1414	goto out_err;
1415	}
1416	clt->permits = kcalloc(clt->queue_depth, permit_size(clt), GFP_KERNEL);
1417	if (!clt->permits) {
1418	err = -ENOMEM;
1419	goto err_map;
1420	}
1421	chunk_bits = ilog2(clt->queue_depth - 1) + 1;
1422	for (i = 0; i < clt->queue_depth; i++) {
1423	struct rtrs_permit *permit;
1424
1425	permit = get_permit(clt, idx: i);
1426	permit->mem_id = i;
1427	permit->mem_off = i << (MAX_IMM_PAYL_BITS - chunk_bits);
1428	}
1429
1430	return 0;
1431
1432	err_map:
1433	bitmap_free(bitmap: clt->permits_map);
1434	clt->permits_map = NULL;
1435	out_err:
1436	return err;
1437	}
1438
1439	static void free_permits(struct rtrs_clt_sess *clt)
1440	{
1441	if (clt->permits_map)
1442	wait_event(clt->permits_wait,
1443	bitmap_empty(clt->permits_map, clt->queue_depth));
1444
1445	bitmap_free(bitmap: clt->permits_map);
1446	clt->permits_map = NULL;
1447	kfree(objp: clt->permits);
1448	clt->permits = NULL;
1449	}
1450
1451	static void query_fast_reg_mode(struct rtrs_clt_path *clt_path)
1452	{
1453	struct ib_device *ib_dev;
1454	u64 max_pages_per_mr;
1455	int mr_page_shift;
1456
1457	ib_dev = clt_path->s.dev->ib_dev;
1458
1459	/*
1460	* Use the smallest page size supported by the HCA, down to a
1461	* minimum of 4096 bytes. We're unlikely to build large sglists
1462	* out of smaller entries.
1463	*/
1464	mr_page_shift = max(12, ffs(ib_dev->attrs.page_size_cap) - 1);
1465	max_pages_per_mr = ib_dev->attrs.max_mr_size;
1466	do_div(max_pages_per_mr, (1ull << mr_page_shift));
1467	max_pages_per_mr = min_not_zero((u32)max_pages_per_mr, U32_MAX);
1468	clt_path->max_pages_per_mr =
1469	min3(clt_path->max_pages_per_mr, (u32)max_pages_per_mr,
1470	ib_dev->attrs.max_fast_reg_page_list_len);
1471	clt_path->clt->max_segments =
1472	min(clt_path->max_pages_per_mr, clt_path->clt->max_segments);
1473	}
1474
1475	static bool rtrs_clt_change_state_get_old(struct rtrs_clt_path *clt_path,
1476	enum rtrs_clt_state new_state,
1477	enum rtrs_clt_state *old_state)
1478	{
1479	bool changed;
1480
1481	spin_lock_irq(lock: &clt_path->state_wq.lock);
1482	if (old_state)
1483	*old_state = clt_path->state;
1484	changed = rtrs_clt_change_state(clt_path, new_state);
1485	spin_unlock_irq(lock: &clt_path->state_wq.lock);
1486
1487	return changed;
1488	}
1489
1490	static void rtrs_clt_hb_err_handler(struct rtrs_con *c)
1491	{
1492	struct rtrs_clt_con *con = container_of(c, typeof(*con), c);
1493	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1494
1495	rtrs_err(con->c.path, "HB err handler for path=%s\n", kobject_name(&clt_path->kobj));
1496	rtrs_rdma_error_recovery(con);
1497	}
1498
1499	static void rtrs_clt_init_hb(struct rtrs_clt_path *clt_path)
1500	{
1501	rtrs_init_hb(path: &clt_path->s, cqe: &io_comp_cqe,
1502	interval_ms: RTRS_HB_INTERVAL_MS,
1503	missed_max: RTRS_HB_MISSED_MAX,
1504	err_handler: rtrs_clt_hb_err_handler,
1505	wq: rtrs_wq);
1506	}
1507
1508	static void rtrs_clt_reconnect_work(struct work_struct *work);
1509	static void rtrs_clt_close_work(struct work_struct *work);
1510
1511	static void rtrs_clt_err_recovery_work(struct work_struct *work)
1512	{
1513	struct rtrs_clt_path *clt_path;
1514	struct rtrs_clt_sess *clt;
1515	int delay_ms;
1516
1517	clt_path = container_of(work, struct rtrs_clt_path, err_recovery_work);
1518	clt = clt_path->clt;
1519	delay_ms = clt->reconnect_delay_sec * 1000;
1520	rtrs_clt_stop_and_destroy_conns(clt_path);
1521	queue_delayed_work(wq: rtrs_wq, dwork: &clt_path->reconnect_dwork,
1522	delay: msecs_to_jiffies(m: delay_ms +
1523	get_random_u32_below(RTRS_RECONNECT_SEED)));
1524	}
1525
1526	static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
1527	const struct rtrs_addr *path,
1528	size_t con_num, u32 nr_poll_queues)
1529	{
1530	struct rtrs_clt_path *clt_path;
1531	int err = -ENOMEM;
1532	int cpu;
1533	size_t total_con;
1534
1535	clt_path = kzalloc(sizeof(*clt_path), GFP_KERNEL);
1536	if (!clt_path)
1537	goto err;
1538
1539	/*
1540	* irqmode and poll
1541	* +1: Extra connection for user messages
1542	*/
1543	total_con = con_num + nr_poll_queues + 1;
1544	clt_path->s.con = kcalloc(total_con, sizeof(*clt_path->s.con),
1545	GFP_KERNEL);
1546	if (!clt_path->s.con)
1547	goto err_free_path;
1548
1549	clt_path->s.con_num = total_con;
1550	clt_path->s.irq_con_num = con_num + 1;
1551
1552	clt_path->stats = kzalloc(sizeof(*clt_path->stats), GFP_KERNEL);
1553	if (!clt_path->stats)
1554	goto err_free_con;
1555
1556	mutex_init(&clt_path->init_mutex);
1557	uuid_gen(u: &clt_path->s.uuid);
1558	memcpy(&clt_path->s.dst_addr, path->dst,
1559	rdma_addr_size((struct sockaddr *)path->dst));
1560
1561	/*
1562	* rdma_resolve_addr() passes src_addr to cma_bind_addr, which
1563	* checks the sa_family to be non-zero. If user passed src_addr=NULL
1564	* the sess->src_addr will contain only zeros, which is then fine.
1565	*/
1566	if (path->src)
1567	memcpy(&clt_path->s.src_addr, path->src,
1568	rdma_addr_size((struct sockaddr *)path->src));
1569	strscpy(clt_path->s.sessname, clt->sessname,
1570	sizeof(clt_path->s.sessname));
1571	clt_path->clt = clt;
1572	clt_path->max_pages_per_mr = RTRS_MAX_SEGMENTS;
1573	init_waitqueue_head(&clt_path->state_wq);
1574	clt_path->state = RTRS_CLT_CONNECTING;
1575	atomic_set(v: &clt_path->connected_cnt, i: 0);
1576	INIT_WORK(&clt_path->close_work, rtrs_clt_close_work);
1577	INIT_WORK(&clt_path->err_recovery_work, rtrs_clt_err_recovery_work);
1578	INIT_DELAYED_WORK(&clt_path->reconnect_dwork, rtrs_clt_reconnect_work);
1579	rtrs_clt_init_hb(clt_path);
1580
1581	clt_path->mp_skip_entry = alloc_percpu(typeof(*clt_path->mp_skip_entry));
1582	if (!clt_path->mp_skip_entry)
1583	goto err_free_stats;
1584
1585	for_each_possible_cpu(cpu)
1586	INIT_LIST_HEAD(per_cpu_ptr(clt_path->mp_skip_entry, cpu));
1587
1588	err = rtrs_clt_init_stats(stats: clt_path->stats);
1589	if (err)
1590	goto err_free_percpu;
1591
1592	return clt_path;
1593
1594	err_free_percpu:
1595	free_percpu(pdata: clt_path->mp_skip_entry);
1596	err_free_stats:
1597	kfree(objp: clt_path->stats);
1598	err_free_con:
1599	kfree(objp: clt_path->s.con);
1600	err_free_path:
1601	kfree(objp: clt_path);
1602	err:
1603	return ERR_PTR(error: err);
1604	}
1605
1606	void free_path(struct rtrs_clt_path *clt_path)
1607	{
1608	free_percpu(pdata: clt_path->mp_skip_entry);
1609	mutex_destroy(lock: &clt_path->init_mutex);
1610	kfree(objp: clt_path->s.con);
1611	kfree(objp: clt_path->rbufs);
1612	kfree(objp: clt_path);
1613	}
1614
1615	static int create_con(struct rtrs_clt_path *clt_path, unsigned int cid)
1616	{
1617	struct rtrs_clt_con *con;
1618
1619	con = kzalloc(sizeof(*con), GFP_KERNEL);
1620	if (!con)
1621	return -ENOMEM;
1622
1623	/* Map first two connections to the first CPU */
1624	con->cpu = (cid ? cid - 1 : 0) % nr_cpu_ids;
1625	con->c.cid = cid;
1626	con->c.path = &clt_path->s;
1627	/* Align with srv, init as 1 */
1628	atomic_set(v: &con->c.wr_cnt, i: 1);
1629	mutex_init(&con->con_mutex);
1630
1631	clt_path->s.con[cid] = &con->c;
1632
1633	return 0;
1634	}
1635
1636	static void destroy_con(struct rtrs_clt_con *con)
1637	{
1638	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1639
1640	clt_path->s.con[con->c.cid] = NULL;
1641	mutex_destroy(lock: &con->con_mutex);
1642	kfree(objp: con);
1643	}
1644
1645	static int create_con_cq_qp(struct rtrs_clt_con *con)
1646	{
1647	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1648	u32 max_send_wr, max_recv_wr, cq_num, max_send_sge, wr_limit;
1649	int err, cq_vector;
1650	struct rtrs_msg_rkey_rsp *rsp;
1651
1652	lockdep_assert_held(&con->con_mutex);
1653	if (con->c.cid == 0) {
1654	max_send_sge = 1;
1655	/* We must be the first here */
1656	if (WARN_ON(clt_path->s.dev))
1657	return -EINVAL;
1658
1659	/*
1660	* The whole session uses device from user connection.
1661	* Be careful not to close user connection before ib dev
1662	* is gracefully put.
1663	*/
1664	clt_path->s.dev = rtrs_ib_dev_find_or_add(ib_dev: con->c.cm_id->device,
1665	pool: &dev_pd);
1666	if (!clt_path->s.dev) {
1667	rtrs_wrn(clt_path->clt,
1668	"rtrs_ib_dev_find_get_or_add(): no memory\n");
1669	return -ENOMEM;
1670	}
1671	clt_path->s.dev_ref = 1;
1672	query_fast_reg_mode(clt_path);
1673	wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1674	/*
1675	* Two (request + registration) completion for send
1676	* Two for recv if always_invalidate is set on server
1677	* or one for recv.
1678	* + 2 for drain and heartbeat
1679	* in case qp gets into error state.
1680	*/
1681	max_send_wr =
1682	min_t(int, wr_limit, SERVICE_CON_QUEUE_DEPTH * 2 + 2);
1683	max_recv_wr = max_send_wr;
1684	} else {
1685	/*
1686	* Here we assume that session members are correctly set.
1687	* This is always true if user connection (cid == 0) is
1688	* established first.
1689	*/
1690	if (WARN_ON(!clt_path->s.dev))
1691	return -EINVAL;
1692	if (WARN_ON(!clt_path->queue_depth))
1693	return -EINVAL;
1694
1695	wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1696	/* Shared between connections */
1697	clt_path->s.dev_ref++;
1698	max_send_wr = min_t(int, wr_limit,
1699	/* QD * (REQ + RSP + FR REGS or INVS) + drain */
1700	clt_path->queue_depth * 4 + 1);
1701	max_recv_wr = min_t(int, wr_limit,
1702	clt_path->queue_depth * 3 + 1);
1703	max_send_sge = 2;
1704	}
1705	atomic_set(v: &con->c.sq_wr_avail, i: max_send_wr);
1706	cq_num = max_send_wr + max_recv_wr;
1707	/* alloc iu to recv new rkey reply when server reports flags set */
1708	if (clt_path->flags & RTRS_MSG_NEW_RKEY_F || con->c.cid == 0) {
1709	con->rsp_ius = rtrs_iu_alloc(queue_num: cq_num, size: sizeof(*rsp),
1710	GFP_KERNEL,
1711	dev: clt_path->s.dev->ib_dev,
1712	DMA_FROM_DEVICE,
1713	done: rtrs_clt_rdma_done);
1714	if (!con->rsp_ius)
1715	return -ENOMEM;
1716	con->queue_num = cq_num;
1717	}
1718	cq_vector = con->cpu % clt_path->s.dev->ib_dev->num_comp_vectors;
1719	if (con->c.cid >= clt_path->s.irq_con_num)
1720	err = rtrs_cq_qp_create(path: &clt_path->s, con: &con->c, max_send_sge,
1721	cq_vector, nr_cqe: cq_num, max_send_wr,
1722	max_recv_wr, poll_ctx: IB_POLL_DIRECT);
1723	else
1724	err = rtrs_cq_qp_create(path: &clt_path->s, con: &con->c, max_send_sge,
1725	cq_vector, nr_cqe: cq_num, max_send_wr,
1726	max_recv_wr, poll_ctx: IB_POLL_SOFTIRQ);
1727	/*
1728	* In case of error we do not bother to clean previous allocations,
1729	* since destroy_con_cq_qp() must be called.
1730	*/
1731	return err;
1732	}
1733
1734	static void destroy_con_cq_qp(struct rtrs_clt_con *con)
1735	{
1736	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1737
1738	/*
1739	* Be careful here: destroy_con_cq_qp() can be called even
1740	* create_con_cq_qp() failed, see comments there.
1741	*/
1742	lockdep_assert_held(&con->con_mutex);
1743	rtrs_cq_qp_destroy(con: &con->c);
1744	if (con->rsp_ius) {
1745	rtrs_iu_free(iu: con->rsp_ius, dev: clt_path->s.dev->ib_dev,
1746	queue_num: con->queue_num);
1747	con->rsp_ius = NULL;
1748	con->queue_num = 0;
1749	}
1750	if (clt_path->s.dev_ref && !--clt_path->s.dev_ref) {
1751	rtrs_ib_dev_put(dev: clt_path->s.dev);
1752	clt_path->s.dev = NULL;
1753	}
1754	}
1755
1756	static void stop_cm(struct rtrs_clt_con *con)
1757	{
1758	rdma_disconnect(id: con->c.cm_id);
1759	if (con->c.qp)
1760	ib_drain_qp(qp: con->c.qp);
1761	}
1762
1763	static void destroy_cm(struct rtrs_clt_con *con)
1764	{
1765	rdma_destroy_id(id: con->c.cm_id);
1766	con->c.cm_id = NULL;
1767	}
1768
1769	static int rtrs_rdma_addr_resolved(struct rtrs_clt_con *con)
1770	{
1771	struct rtrs_path *s = con->c.path;
1772	int err;
1773
1774	mutex_lock(&con->con_mutex);
1775	err = create_con_cq_qp(con);
1776	mutex_unlock(lock: &con->con_mutex);
1777	if (err) {
1778	rtrs_err(s, "create_con_cq_qp(), err: %d\n", err);
1779	return err;
1780	}
1781	err = rdma_resolve_route(id: con->c.cm_id, RTRS_CONNECT_TIMEOUT_MS);
1782	if (err)
1783	rtrs_err(s, "Resolving route failed, err: %d\n", err);
1784
1785	return err;
1786	}
1787
1788	static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con)
1789	{
1790	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1791	struct rtrs_clt_sess *clt = clt_path->clt;
1792	struct rtrs_msg_conn_req msg;
1793	struct rdma_conn_param param;
1794
1795	int err;
1796
1797	param = (struct rdma_conn_param) {
1798	.retry_count = 7,
1799	.rnr_retry_count = 7,
1800	.private_data = &msg,
1801	.private_data_len = sizeof(msg),
1802	};
1803
1804	msg = (struct rtrs_msg_conn_req) {
1805	.magic = cpu_to_le16(RTRS_MAGIC),
1806	.version = cpu_to_le16(RTRS_PROTO_VER),
1807	.cid = cpu_to_le16(con->c.cid),
1808	.cid_num = cpu_to_le16(clt_path->s.con_num),
1809	.recon_cnt = cpu_to_le16(clt_path->s.recon_cnt),
1810	};
1811	msg.first_conn = clt_path->for_new_clt ? FIRST_CONN : 0;
1812	uuid_copy(dst: &msg.sess_uuid, src: &clt_path->s.uuid);
1813	uuid_copy(dst: &msg.paths_uuid, src: &clt->paths_uuid);
1814
1815	err = rdma_connect_locked(id: con->c.cm_id, conn_param: &param);
1816	if (err)
1817	rtrs_err(clt, "rdma_connect_locked(): %d\n", err);
1818
1819	return err;
1820	}
1821
1822	static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
1823	struct rdma_cm_event *ev)
1824	{
1825	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1826	struct rtrs_clt_sess *clt = clt_path->clt;
1827	const struct rtrs_msg_conn_rsp *msg;
1828	u16 version, queue_depth;
1829	int errno;
1830	u8 len;
1831
1832	msg = ev->param.conn.private_data;
1833	len = ev->param.conn.private_data_len;
1834	if (len < sizeof(*msg)) {
1835	rtrs_err(clt, "Invalid RTRS connection response\n");
1836	return -ECONNRESET;
1837	}
1838	if (le16_to_cpu(msg->magic) != RTRS_MAGIC) {
1839	rtrs_err(clt, "Invalid RTRS magic\n");
1840	return -ECONNRESET;
1841	}
1842	version = le16_to_cpu(msg->version);
1843	if (version >> 8 != RTRS_PROTO_VER_MAJOR) {
1844	rtrs_err(clt, "Unsupported major RTRS version: %d, expected %d\n",
1845	version >> 8, RTRS_PROTO_VER_MAJOR);
1846	return -ECONNRESET;
1847	}
1848	errno = le16_to_cpu(msg->errno);
1849	if (errno) {
1850	rtrs_err(clt, "Invalid RTRS message: errno %d\n",
1851	errno);
1852	return -ECONNRESET;
1853	}
1854	if (con->c.cid == 0) {
1855	queue_depth = le16_to_cpu(msg->queue_depth);
1856
1857	if (clt_path->queue_depth > 0 && queue_depth != clt_path->queue_depth) {
1858	rtrs_err(clt, "Error: queue depth changed\n");
1859
1860	/*
1861	* Stop any more reconnection attempts
1862	*/
1863	clt_path->reconnect_attempts = -1;
1864	rtrs_err(clt,
1865	"Disabling auto-reconnect. Trigger a manual reconnect after issue is resolved\n");
1866	return -ECONNRESET;
1867	}
1868
1869	if (!clt_path->rbufs) {
1870	clt_path->rbufs = kcalloc(queue_depth,
1871	sizeof(*clt_path->rbufs),
1872	GFP_KERNEL);
1873	if (!clt_path->rbufs)
1874	return -ENOMEM;
1875	}
1876	clt_path->queue_depth = queue_depth;
1877	clt_path->s.signal_interval = min_not_zero(queue_depth,
1878	(unsigned short) SERVICE_CON_QUEUE_DEPTH);
1879	clt_path->max_hdr_size = le32_to_cpu(msg->max_hdr_size);
1880	clt_path->max_io_size = le32_to_cpu(msg->max_io_size);
1881	clt_path->flags = le32_to_cpu(msg->flags);
1882	clt_path->chunk_size = clt_path->max_io_size + clt_path->max_hdr_size;
1883
1884	/*
1885	* Global IO size is always a minimum.
1886	* If while a reconnection server sends us a value a bit
1887	* higher - client does not care and uses cached minimum.
1888	*
1889	* Since we can have several sessions (paths) restablishing
1890	* connections in parallel, use lock.
1891	*/
1892	mutex_lock(&clt->paths_mutex);
1893	clt->queue_depth = clt_path->queue_depth;
1894	clt->max_io_size = min_not_zero(clt_path->max_io_size,
1895	clt->max_io_size);
1896	mutex_unlock(lock: &clt->paths_mutex);
1897
1898	/*
1899	* Cache the hca_port and hca_name for sysfs
1900	*/
1901	clt_path->hca_port = con->c.cm_id->port_num;
1902	scnprintf(buf: clt_path->hca_name, size: sizeof(clt_path->hca_name),
1903	fmt: clt_path->s.dev->ib_dev->name);
1904	clt_path->s.src_addr = con->c.cm_id->route.addr.src_addr;
1905	/* set for_new_clt, to allow future reconnect on any path */
1906	clt_path->for_new_clt = 1;
1907	}
1908
1909	return 0;
1910	}
1911
1912	static inline void flag_success_on_conn(struct rtrs_clt_con *con)
1913	{
1914	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
1915
1916	atomic_inc(v: &clt_path->connected_cnt);
1917	con->cm_err = 1;
1918	}
1919
1920	static int rtrs_rdma_conn_rejected(struct rtrs_clt_con *con,
1921	struct rdma_cm_event *ev)
1922	{
1923	struct rtrs_path *s = con->c.path;
1924	const struct rtrs_msg_conn_rsp *msg;
1925	const char *rej_msg;
1926	int status, errno;
1927	u8 data_len;
1928
1929	status = ev->status;
1930	rej_msg = rdma_reject_msg(id: con->c.cm_id, reason: status);
1931	msg = rdma_consumer_reject_data(id: con->c.cm_id, ev, data_len: &data_len);
1932
1933	if (msg && data_len >= sizeof(*msg)) {
1934	errno = (int16_t)le16_to_cpu(msg->errno);
1935	if (errno == -EBUSY)
1936	rtrs_err(s,
1937	"Previous session is still exists on the server, please reconnect later\n");
1938	else
1939	rtrs_err(s,
1940	"Connect rejected: status %d (%s), rtrs errno %d\n",
1941	status, rej_msg, errno);
1942	} else {
1943	rtrs_err(s,
1944	"Connect rejected but with malformed message: status %d (%s)\n",
1945	status, rej_msg);
1946	}
1947
1948	return -ECONNRESET;
1949	}
1950
1951	void rtrs_clt_close_conns(struct rtrs_clt_path *clt_path, bool wait)
1952	{
1953	trace_rtrs_clt_close_conns(clt_path);
1954
1955	if (rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_CLOSING, NULL))
1956	queue_work(wq: rtrs_wq, work: &clt_path->close_work);
1957	if (wait)
1958	flush_work(work: &clt_path->close_work);
1959	}
1960
1961	static inline void flag_error_on_conn(struct rtrs_clt_con *con, int cm_err)
1962	{
1963	if (con->cm_err == 1) {
1964	struct rtrs_clt_path *clt_path;
1965
1966	clt_path = to_clt_path(s: con->c.path);
1967	if (atomic_dec_and_test(v: &clt_path->connected_cnt))
1968
1969	wake_up(&clt_path->state_wq);
1970	}
1971	con->cm_err = cm_err;
1972	}
1973
1974	static int rtrs_clt_rdma_cm_handler(struct rdma_cm_id *cm_id,
1975	struct rdma_cm_event *ev)
1976	{
1977	struct rtrs_clt_con *con = cm_id->context;
1978	struct rtrs_path *s = con->c.path;
1979	struct rtrs_clt_path *clt_path = to_clt_path(s);
1980	int cm_err = 0;
1981
1982	switch (ev->event) {
1983	case RDMA_CM_EVENT_ADDR_RESOLVED:
1984	cm_err = rtrs_rdma_addr_resolved(con);
1985	break;
1986	case RDMA_CM_EVENT_ROUTE_RESOLVED:
1987	cm_err = rtrs_rdma_route_resolved(con);
1988	break;
1989	case RDMA_CM_EVENT_ESTABLISHED:
1990	cm_err = rtrs_rdma_conn_established(con, ev);
1991	if (!cm_err) {
1992	/*
1993	* Report success and wake up. Here we abuse state_wq,
1994	* i.e. wake up without state change, but we set cm_err.
1995	*/
1996	flag_success_on_conn(con);
1997	wake_up(&clt_path->state_wq);
1998	return 0;
1999	}
2000	break;
2001	case RDMA_CM_EVENT_REJECTED:
2002	cm_err = rtrs_rdma_conn_rejected(con, ev);
2003	break;
2004	case RDMA_CM_EVENT_DISCONNECTED:
2005	/* No message for disconnecting */
2006	cm_err = -ECONNRESET;
2007	break;
2008	case RDMA_CM_EVENT_CONNECT_ERROR:
2009	case RDMA_CM_EVENT_UNREACHABLE:
2010	case RDMA_CM_EVENT_ADDR_CHANGE:
2011	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2012	rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
2013	rdma_event_msg(ev->event), ev->status);
2014	cm_err = -ECONNRESET;
2015	break;
2016	case RDMA_CM_EVENT_ADDR_ERROR:
2017	case RDMA_CM_EVENT_ROUTE_ERROR:
2018	rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
2019	rdma_event_msg(ev->event), ev->status);
2020	cm_err = -EHOSTUNREACH;
2021	break;
2022	case RDMA_CM_EVENT_DEVICE_REMOVAL:
2023	/*
2024	* Device removal is a special case. Queue close and return 0.
2025	*/
2026	rtrs_wrn_rl(s, "CM event: %s, status: %d\n", rdma_event_msg(ev->event),
2027	ev->status);
2028	rtrs_clt_close_conns(clt_path, wait: false);
2029	return 0;
2030	default:
2031	rtrs_err(s, "Unexpected RDMA CM error (CM event: %s, err: %d)\n",
2032	rdma_event_msg(ev->event), ev->status);
2033	cm_err = -ECONNRESET;
2034	break;
2035	}
2036
2037	if (cm_err) {
2038	/*
2039	* cm error makes sense only on connection establishing,
2040	* in other cases we rely on normal procedure of reconnecting.
2041	*/
2042	flag_error_on_conn(con, cm_err);
2043	rtrs_rdma_error_recovery(con);
2044	}
2045
2046	return 0;
2047	}
2048
2049	/* The caller should do the cleanup in case of error */
2050	static int create_cm(struct rtrs_clt_con *con)
2051	{
2052	struct rtrs_path *s = con->c.path;
2053	struct rtrs_clt_path *clt_path = to_clt_path(s);
2054	struct rdma_cm_id *cm_id;
2055	int err;
2056
2057	cm_id = rdma_create_id(&init_net, rtrs_clt_rdma_cm_handler, con,
2058	clt_path->s.dst_addr.ss_family == AF_IB ?
2059	RDMA_PS_IB : RDMA_PS_TCP, IB_QPT_RC);
2060	if (IS_ERR(ptr: cm_id)) {
2061	rtrs_err(s, "Failed to create CM ID, err: %pe\n", cm_id);
2062	return PTR_ERR(ptr: cm_id);
2063	}
2064	con->c.cm_id = cm_id;
2065	con->cm_err = 0;
2066	/* allow the port to be reused */
2067	err = rdma_set_reuseaddr(id: cm_id, reuse: 1);
2068	if (err != 0) {
2069	rtrs_err(s, "Set address reuse failed, err: %d\n", err);
2070	return err;
2071	}
2072	err = rdma_resolve_addr(id: cm_id, src_addr: (struct sockaddr *)&clt_path->s.src_addr,
2073	dst_addr: (struct sockaddr *)&clt_path->s.dst_addr,
2074	RTRS_CONNECT_TIMEOUT_MS);
2075	if (err) {
2076	rtrs_err(s, "Failed to resolve address, err: %d\n", err);
2077	return err;
2078	}
2079	/*
2080	* Combine connection status and session events. This is needed
2081	* for waiting two possible cases: cm_err has something meaningful
2082	* or session state was really changed to error by device removal.
2083	*/
2084	err = wait_event_interruptible_timeout(
2085	clt_path->state_wq,
2086	con->cm_err || clt_path->state != RTRS_CLT_CONNECTING,
2087	msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2088	if (err == 0 || err == -ERESTARTSYS) {
2089	if (err == 0)
2090	err = -ETIMEDOUT;
2091	/* Timedout or interrupted */
2092	return err;
2093	}
2094	if (con->cm_err < 0)
2095	return con->cm_err;
2096	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING)
2097	/* Device removal */
2098	return -ECONNABORTED;
2099
2100	return 0;
2101	}
2102
2103	static void rtrs_clt_path_up(struct rtrs_clt_path *clt_path)
2104	{
2105	struct rtrs_clt_sess *clt = clt_path->clt;
2106	int up;
2107
2108	/*
2109	* We can fire RECONNECTED event only when all paths were
2110	* connected on rtrs_clt_open(), then each was disconnected
2111	* and the first one connected again. That's why this nasty
2112	* game with counter value.
2113	*/
2114
2115	mutex_lock(&clt->paths_ev_mutex);
2116	up = ++clt->paths_up;
2117	/*
2118	* Here it is safe to access paths num directly since up counter
2119	* is greater than MAX_PATHS_NUM only while rtrs_clt_open() is
2120	* in progress, thus paths removals are impossible.
2121	*/
2122	if (up > MAX_PATHS_NUM && up == MAX_PATHS_NUM + clt->paths_num)
2123	clt->paths_up = clt->paths_num;
2124	else if (up == 1)
2125	clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_RECONNECTED);
2126	mutex_unlock(lock: &clt->paths_ev_mutex);
2127
2128	/* Mark session as established */
2129	clt_path->established = true;
2130	clt_path->reconnect_attempts = 0;
2131	clt_path->stats->reconnects.successful_cnt++;
2132	}
2133
2134	static void rtrs_clt_path_down(struct rtrs_clt_path *clt_path)
2135	{
2136	struct rtrs_clt_sess *clt = clt_path->clt;
2137
2138	if (!clt_path->established)
2139	return;
2140
2141	clt_path->established = false;
2142	mutex_lock(&clt->paths_ev_mutex);
2143	WARN_ON(!clt->paths_up);
2144	if (--clt->paths_up == 0)
2145	clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_DISCONNECTED);
2146	mutex_unlock(lock: &clt->paths_ev_mutex);
2147	}
2148
2149	static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path)
2150	{
2151	struct rtrs_clt_con *con;
2152	unsigned int cid;
2153
2154	WARN_ON(READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED);
2155
2156	/*
2157	* Possible race with rtrs_clt_open(), when DEVICE_REMOVAL comes
2158	* exactly in between. Start destroying after it finishes.
2159	*/
2160	mutex_lock(&clt_path->init_mutex);
2161	mutex_unlock(lock: &clt_path->init_mutex);
2162
2163	/*
2164	* All IO paths must observe !CONNECTED state before we
2165	* free everything.
2166	*/
2167	synchronize_rcu();
2168
2169	rtrs_stop_hb(path: &clt_path->s);
2170
2171	/*
2172	* The order it utterly crucial: firstly disconnect and complete all
2173	* rdma requests with error (thus set in_use=false for requests),
2174	* then fail outstanding requests checking in_use for each, and
2175	* eventually notify upper layer about session disconnection.
2176	*/
2177
2178	for (cid = 0; cid < clt_path->s.con_num; cid++) {
2179	if (!clt_path->s.con[cid])
2180	break;
2181	con = to_clt_con(c: clt_path->s.con[cid]);
2182	stop_cm(con);
2183	}
2184	fail_all_outstanding_reqs(clt_path);
2185	free_path_reqs(clt_path);
2186	rtrs_clt_path_down(clt_path);
2187
2188	/*
2189	* Wait for graceful shutdown, namely when peer side invokes
2190	* rdma_disconnect(). 'connected_cnt' is decremented only on
2191	* CM events, thus if other side had crashed and hb has detected
2192	* something is wrong, here we will stuck for exactly timeout ms,
2193	* since CM does not fire anything. That is fine, we are not in
2194	* hurry.
2195	*/
2196	wait_event_timeout(clt_path->state_wq,
2197	!atomic_read(&clt_path->connected_cnt),
2198	msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2199
2200	for (cid = 0; cid < clt_path->s.con_num; cid++) {
2201	if (!clt_path->s.con[cid])
2202	break;
2203	con = to_clt_con(c: clt_path->s.con[cid]);
2204	mutex_lock(&con->con_mutex);
2205	destroy_con_cq_qp(con);
2206	mutex_unlock(lock: &con->con_mutex);
2207	destroy_cm(con);
2208	destroy_con(con);
2209	}
2210	}
2211
2212	static void rtrs_clt_remove_path_from_arr(struct rtrs_clt_path *clt_path)
2213	{
2214	struct rtrs_clt_sess *clt = clt_path->clt;
2215	struct rtrs_clt_path *next;
2216	bool wait_for_grace = false;
2217	int cpu;
2218
2219	mutex_lock(&clt->paths_mutex);
2220	list_del_rcu(entry: &clt_path->s.entry);
2221
2222	/* Make sure everybody observes path removal. */
2223	synchronize_rcu();
2224
2225	/*
2226	* At this point nobody sees @sess in the list, but still we have
2227	* dangling pointer @pcpu_path which _can_ point to @sess. Since
2228	* nobody can observe @sess in the list, we guarantee that IO path
2229	* will not assign @sess to @pcpu_path, i.e. @pcpu_path can be equal
2230	* to @sess, but can never again become @sess.
2231	*/
2232
2233	/*
2234	* Decrement paths number only after grace period, because
2235	* caller of do_each_path() must firstly observe list without
2236	* path and only then decremented paths number.
2237	*
2238	* Otherwise there can be the following situation:
2239	* o Two paths exist and IO is coming.
2240	* o One path is removed:
2241	* CPU#0 CPU#1
2242	* do_each_path(): rtrs_clt_remove_path_from_arr():
2243	* path = get_next_path()
2244	* ^^^ list_del_rcu(path)
2245	* [!CONNECTED path] clt->paths_num--
2246	* ^^^^^^^^^
2247	* load clt->paths_num from 2 to 1
2248	* ^^^^^^^^^
2249	* sees 1
2250	*
2251	* path is observed as !CONNECTED, but do_each_path() loop
2252	* ends, because expression i < clt->paths_num is false.
2253	*/
2254	clt->paths_num--;
2255
2256	/*
2257	* Get @next connection from current @sess which is going to be
2258	* removed. If @sess is the last element, then @next is NULL.
2259	*/
2260	rcu_read_lock();
2261	next = rtrs_clt_get_next_path_or_null(head: &clt->paths_list, clt_path);
2262	rcu_read_unlock();
2263
2264	/*
2265	* @pcpu paths can still point to the path which is going to be
2266	* removed, so change the pointer manually.
2267	*/
2268	for_each_possible_cpu(cpu) {
2269	struct rtrs_clt_path __rcu **ppcpu_path;
2270
2271	ppcpu_path = per_cpu_ptr(clt->pcpu_path, cpu);
2272	if (rcu_dereference_protected(*ppcpu_path,
2273	lockdep_is_held(&clt->paths_mutex)) != clt_path)
2274	/*
2275	* synchronize_rcu() was called just after deleting
2276	* entry from the list, thus IO code path cannot
2277	* change pointer back to the pointer which is going
2278	* to be removed, we are safe here.
2279	*/
2280	continue;
2281
2282	/*
2283	* We race with IO code path, which also changes pointer,
2284	* thus we have to be careful not to overwrite it.
2285	*/
2286	if (try_cmpxchg((struct rtrs_clt_path **)ppcpu_path, &clt_path,
2287	next))
2288	/*
2289	* @ppcpu_path was successfully replaced with @next,
2290	* that means that someone could also pick up the
2291	* @sess and dereferencing it right now, so wait for
2292	* a grace period is required.
2293	*/
2294	wait_for_grace = true;
2295	}
2296	if (wait_for_grace)
2297	synchronize_rcu();
2298
2299	mutex_unlock(lock: &clt->paths_mutex);
2300	}
2301
2302	static void rtrs_clt_add_path_to_arr(struct rtrs_clt_path *clt_path)
2303	{
2304	struct rtrs_clt_sess *clt = clt_path->clt;
2305
2306	mutex_lock(&clt->paths_mutex);
2307	clt->paths_num++;
2308
2309	list_add_tail_rcu(new: &clt_path->s.entry, head: &clt->paths_list);
2310	mutex_unlock(lock: &clt->paths_mutex);
2311	}
2312
2313	static void rtrs_clt_close_work(struct work_struct *work)
2314	{
2315	struct rtrs_clt_path *clt_path;
2316
2317	clt_path = container_of(work, struct rtrs_clt_path, close_work);
2318
2319	cancel_work_sync(work: &clt_path->err_recovery_work);
2320	cancel_delayed_work_sync(dwork: &clt_path->reconnect_dwork);
2321	rtrs_clt_stop_and_destroy_conns(clt_path);
2322	rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_CLOSED, NULL);
2323	}
2324
2325	static int init_conns(struct rtrs_clt_path *clt_path)
2326	{
2327	unsigned int cid;
2328	int err, i;
2329
2330	/*
2331	* On every new session connections increase reconnect counter
2332	* to avoid clashes with previous sessions not yet closed
2333	* sessions on a server side.
2334	*/
2335	clt_path->s.recon_cnt++;
2336
2337	/* Establish all RDMA connections */
2338	for (cid = 0; cid < clt_path->s.con_num; cid++) {
2339	err = create_con(clt_path, cid);
2340	if (err)
2341	goto destroy;
2342
2343	err = create_cm(con: to_clt_con(c: clt_path->s.con[cid]));
2344	if (err)
2345	goto destroy;
2346	}
2347
2348	/*
2349	* Set the cid to con_num - 1, since if we fail later, we want to stay in bounds.
2350	*/
2351	cid = clt_path->s.con_num - 1;
2352
2353	err = alloc_path_reqs(clt_path);
2354	if (err)
2355	goto destroy;
2356
2357	return 0;
2358
2359	destroy:
2360	/* Make sure we do the cleanup in the order they are created */
2361	for (i = 0; i <= cid; i++) {
2362	struct rtrs_clt_con *con;
2363
2364	if (!clt_path->s.con[i])
2365	break;
2366
2367	con = to_clt_con(c: clt_path->s.con[i]);
2368	if (con->c.cm_id) {
2369	stop_cm(con);
2370	mutex_lock(&con->con_mutex);
2371	destroy_con_cq_qp(con);
2372	mutex_unlock(lock: &con->con_mutex);
2373	destroy_cm(con);
2374	}
2375	destroy_con(con);
2376	}
2377	/*
2378	* If we've never taken async path and got an error, say,
2379	* doing rdma_resolve_addr(), switch to CONNECTION_ERR state
2380	* manually to keep reconnecting.
2381	*/
2382	rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_CONNECTING_ERR, NULL);
2383
2384	return err;
2385	}
2386
2387	static void rtrs_clt_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
2388	{
2389	struct rtrs_clt_con *con = to_clt_con(c: wc->qp->qp_context);
2390	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
2391	struct rtrs_iu *iu;
2392
2393	iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2394	rtrs_iu_free(iu, dev: clt_path->s.dev->ib_dev, queue_num: 1);
2395
2396	if (wc->status != IB_WC_SUCCESS) {
2397	rtrs_err(clt_path->clt, "Path info request send failed: %s\n",
2398	ib_wc_status_msg(wc->status));
2399	rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_CONNECTING_ERR, NULL);
2400	return;
2401	}
2402
2403	rtrs_clt_update_wc_stats(con);
2404	}
2405
2406	static int process_info_rsp(struct rtrs_clt_path *clt_path,
2407	const struct rtrs_msg_info_rsp *msg)
2408	{
2409	unsigned int sg_cnt, total_len;
2410	int i, sgi;
2411
2412	sg_cnt = le16_to_cpu(msg->sg_cnt);
2413	if (!sg_cnt || (clt_path->queue_depth % sg_cnt)) {
2414	rtrs_err(clt_path->clt,
2415	"Incorrect sg_cnt %d, is not multiple\n",
2416	sg_cnt);
2417	return -EINVAL;
2418	}
2419
2420	/*
2421	* Check if IB immediate data size is enough to hold the mem_id and
2422	* the offset inside the memory chunk.
2423	*/
2424	if ((ilog2(sg_cnt - 1) + 1) + (ilog2(clt_path->chunk_size - 1) + 1) >
2425	MAX_IMM_PAYL_BITS) {
2426	rtrs_err(clt_path->clt,
2427	"RDMA immediate size (%db) not enough to encode %d buffers of size %dB\n",
2428	MAX_IMM_PAYL_BITS, sg_cnt, clt_path->chunk_size);
2429	return -EINVAL;
2430	}
2431	total_len = 0;
2432	for (sgi = 0, i = 0; sgi < sg_cnt && i < clt_path->queue_depth; sgi++) {
2433	const struct rtrs_sg_desc *desc = &msg->desc[sgi];
2434	u32 len, rkey;
2435	u64 addr;
2436
2437	addr = le64_to_cpu(desc->addr);
2438	rkey = le32_to_cpu(desc->key);
2439	len = le32_to_cpu(desc->len);
2440
2441	total_len += len;
2442
2443	if (!len || (len % clt_path->chunk_size)) {
2444	rtrs_err(clt_path->clt, "Incorrect [%d].len %d\n",
2445	sgi,
2446	len);
2447	return -EINVAL;
2448	}
2449	for ( ; len && i < clt_path->queue_depth; i++) {
2450	clt_path->rbufs[i].addr = addr;
2451	clt_path->rbufs[i].rkey = rkey;
2452
2453	len -= clt_path->chunk_size;
2454	addr += clt_path->chunk_size;
2455	}
2456	}
2457	/* Sanity check */
2458	if (sgi != sg_cnt || i != clt_path->queue_depth) {
2459	rtrs_err(clt_path->clt,
2460	"Incorrect sg vector, not fully mapped\n");
2461	return -EINVAL;
2462	}
2463	if (total_len != clt_path->chunk_size * clt_path->queue_depth) {
2464	rtrs_err(clt_path->clt, "Incorrect total_len %d\n", total_len);
2465	return -EINVAL;
2466	}
2467
2468	return 0;
2469	}
2470
2471	static void rtrs_clt_info_rsp_done(struct ib_cq *cq, struct ib_wc *wc)
2472	{
2473	struct rtrs_clt_con *con = to_clt_con(c: wc->qp->qp_context);
2474	struct rtrs_clt_path *clt_path = to_clt_path(s: con->c.path);
2475	struct rtrs_msg_info_rsp *msg;
2476	enum rtrs_clt_state state;
2477	struct rtrs_iu *iu;
2478	size_t rx_sz;
2479	int err;
2480
2481	state = RTRS_CLT_CONNECTING_ERR;
2482
2483	WARN_ON(con->c.cid);
2484	iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2485	if (wc->status != IB_WC_SUCCESS) {
2486	rtrs_err(clt_path->clt, "Path info response recv failed: %s\n",
2487	ib_wc_status_msg(wc->status));
2488	goto out;
2489	}
2490	WARN_ON(wc->opcode != IB_WC_RECV);
2491
2492	if (wc->byte_len < sizeof(*msg)) {
2493	rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2494	wc->byte_len);
2495	goto out;
2496	}
2497	ib_dma_sync_single_for_cpu(dev: clt_path->s.dev->ib_dev, addr: iu->dma_addr,
2498	size: iu->size, dir: DMA_FROM_DEVICE);
2499	msg = iu->buf;
2500	if (le16_to_cpu(msg->type) != RTRS_MSG_INFO_RSP) {
2501	rtrs_err(clt_path->clt, "Path info response is malformed: type %d\n",
2502	le16_to_cpu(msg->type));
2503	goto out;
2504	}
2505	rx_sz = sizeof(*msg);
2506	rx_sz += sizeof(msg->desc[0]) * le16_to_cpu(msg->sg_cnt);
2507	if (wc->byte_len < rx_sz) {
2508	rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2509	wc->byte_len);
2510	goto out;
2511	}
2512	err = process_info_rsp(clt_path, msg);
2513	if (err)
2514	goto out;
2515
2516	err = post_recv_path(clt_path);
2517	if (err)
2518	goto out;
2519
2520	state = RTRS_CLT_CONNECTED;
2521
2522	out:
2523	rtrs_clt_update_wc_stats(con);
2524	rtrs_iu_free(iu, dev: clt_path->s.dev->ib_dev, queue_num: 1);
2525	rtrs_clt_change_state_get_old(clt_path, new_state: state, NULL);
2526	}
2527
2528	static int rtrs_send_path_info(struct rtrs_clt_path *clt_path)
2529	{
2530	struct rtrs_clt_con *usr_con = to_clt_con(c: clt_path->s.con[0]);
2531	struct rtrs_msg_info_req *msg;
2532	struct rtrs_iu *tx_iu, *rx_iu;
2533	size_t rx_sz;
2534	int err;
2535
2536	rx_sz = sizeof(struct rtrs_msg_info_rsp);
2537	rx_sz += sizeof(struct rtrs_sg_desc) * clt_path->queue_depth;
2538
2539	tx_iu = rtrs_iu_alloc(queue_num: 1, size: sizeof(struct rtrs_msg_info_req), GFP_KERNEL,
2540	dev: clt_path->s.dev->ib_dev, DMA_TO_DEVICE,
2541	done: rtrs_clt_info_req_done);
2542	rx_iu = rtrs_iu_alloc(queue_num: 1, size: rx_sz, GFP_KERNEL, dev: clt_path->s.dev->ib_dev,
2543	DMA_FROM_DEVICE, done: rtrs_clt_info_rsp_done);
2544	if (!tx_iu || !rx_iu) {
2545	err = -ENOMEM;
2546	goto out;
2547	}
2548	/* Prepare for getting info response */
2549	err = rtrs_iu_post_recv(con: &usr_con->c, iu: rx_iu);
2550	if (err) {
2551	rtrs_err(clt_path->clt, "rtrs_iu_post_recv(), err: %d\n", err);
2552	goto out;
2553	}
2554	rx_iu = NULL;
2555
2556	msg = tx_iu->buf;
2557	msg->type = cpu_to_le16(RTRS_MSG_INFO_REQ);
2558	memcpy(msg->pathname, clt_path->s.sessname, sizeof(msg->pathname));
2559
2560	ib_dma_sync_single_for_device(dev: clt_path->s.dev->ib_dev,
2561	addr: tx_iu->dma_addr,
2562	size: tx_iu->size, dir: DMA_TO_DEVICE);
2563
2564	/* Send info request */
2565	err = rtrs_iu_post_send(con: &usr_con->c, iu: tx_iu, size: sizeof(*msg), NULL);
2566	if (err) {
2567	rtrs_err(clt_path->clt, "rtrs_iu_post_send(), err: %d\n", err);
2568	goto out;
2569	}
2570	tx_iu = NULL;
2571
2572	/* Wait for state change */
2573	wait_event_interruptible_timeout(clt_path->state_wq,
2574	clt_path->state != RTRS_CLT_CONNECTING,
2575	msecs_to_jiffies(
2576	RTRS_CONNECT_TIMEOUT_MS));
2577	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) {
2578	if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTING_ERR)
2579	err = -ECONNRESET;
2580	else
2581	err = -ETIMEDOUT;
2582	}
2583
2584	out:
2585	if (tx_iu)
2586	rtrs_iu_free(iu: tx_iu, dev: clt_path->s.dev->ib_dev, queue_num: 1);
2587	if (rx_iu)
2588	rtrs_iu_free(iu: rx_iu, dev: clt_path->s.dev->ib_dev, queue_num: 1);
2589	if (err)
2590	/* If we've never taken async path because of malloc problems */
2591	rtrs_clt_change_state_get_old(clt_path,
2592	new_state: RTRS_CLT_CONNECTING_ERR, NULL);
2593
2594	return err;
2595	}
2596
2597	/**
2598	* init_path() - establishes all path connections and does handshake
2599	* @clt_path: client path.
2600	* In case of error full close or reconnect procedure should be taken,
2601	* because reconnect or close async works can be started.
2602	*/
2603	static int init_path(struct rtrs_clt_path *clt_path)
2604	{
2605	int err;
2606	char str[NAME_MAX];
2607	struct rtrs_addr path = {
2608	.src = &clt_path->s.src_addr,
2609	.dst = &clt_path->s.dst_addr,
2610	};
2611
2612	rtrs_addr_to_str(addr: &path, buf: str, len: sizeof(str));
2613
2614	mutex_lock(&clt_path->init_mutex);
2615	err = init_conns(clt_path);
2616	if (err) {
2617	rtrs_err(clt_path->clt,
2618	"init_conns() failed: err=%d path=%s [%s:%u]\n", err,
2619	str, clt_path->hca_name, clt_path->hca_port);
2620	goto out;
2621	}
2622	err = rtrs_send_path_info(clt_path);
2623	if (err) {
2624	rtrs_err(clt_path->clt,
2625	"rtrs_send_path_info() failed: err=%d path=%s [%s:%u]\n",
2626	err, str, clt_path->hca_name, clt_path->hca_port);
2627	goto out;
2628	}
2629	rtrs_clt_path_up(clt_path);
2630	rtrs_start_hb(path: &clt_path->s);
2631	out:
2632	mutex_unlock(lock: &clt_path->init_mutex);
2633
2634	return err;
2635	}
2636
2637	static void rtrs_clt_reconnect_work(struct work_struct *work)
2638	{
2639	struct rtrs_clt_path *clt_path;
2640	struct rtrs_clt_sess *clt;
2641	int err;
2642
2643	clt_path = container_of(to_delayed_work(work), struct rtrs_clt_path,
2644	reconnect_dwork);
2645	clt = clt_path->clt;
2646
2647	trace_rtrs_clt_reconnect_work(clt_path);
2648
2649	if (READ_ONCE(clt_path->state) != RTRS_CLT_RECONNECTING)
2650	return;
2651
2652	if (clt_path->reconnect_attempts >= clt->max_reconnect_attempts) {
2653	/* Close a path completely if max attempts is reached */
2654	rtrs_clt_close_conns(clt_path, wait: false);
2655	return;
2656	}
2657	clt_path->reconnect_attempts++;
2658
2659	msleep(RTRS_RECONNECT_BACKOFF);
2660	if (rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_CONNECTING, NULL)) {
2661	err = init_path(clt_path);
2662	if (err)
2663	goto reconnect_again;
2664	}
2665
2666	return;
2667
2668	reconnect_again:
2669	if (rtrs_clt_change_state_get_old(clt_path, new_state: RTRS_CLT_RECONNECTING, NULL)) {
2670	clt_path->stats->reconnects.fail_cnt++;
2671	queue_work(wq: rtrs_wq, work: &clt_path->err_recovery_work);
2672	}
2673	}
2674
2675	static void rtrs_clt_dev_release(struct device *dev)
2676	{
2677	struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess,
2678	dev);
2679
2680	mutex_destroy(lock: &clt->paths_ev_mutex);
2681	mutex_destroy(lock: &clt->paths_mutex);
2682	kfree(objp: clt);
2683	}
2684
2685	static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
2686	u16 port, size_t pdu_sz, void *priv,
2687	void (*link_ev)(void *priv,
2688	enum rtrs_clt_link_ev ev),
2689	unsigned int reconnect_delay_sec,
2690	unsigned int max_reconnect_attempts)
2691	{
2692	struct rtrs_clt_sess *clt;
2693	int err;
2694
2695	if (!paths_num || paths_num > MAX_PATHS_NUM)
2696	return ERR_PTR(error: -EINVAL);
2697
2698	if (strlen(sessname) >= sizeof(clt->sessname))
2699	return ERR_PTR(error: -EINVAL);
2700
2701	clt = kzalloc(sizeof(*clt), GFP_KERNEL);
2702	if (!clt)
2703	return ERR_PTR(error: -ENOMEM);
2704
2705	clt->pcpu_path = alloc_percpu(typeof(*clt->pcpu_path));
2706	if (!clt->pcpu_path) {
2707	kfree(objp: clt);
2708	return ERR_PTR(error: -ENOMEM);
2709	}
2710
2711	clt->dev.class = &rtrs_clt_dev_class;
2712	clt->dev.release = rtrs_clt_dev_release;
2713	uuid_gen(u: &clt->paths_uuid);
2714	INIT_LIST_HEAD_RCU(list: &clt->paths_list);
2715	clt->paths_num = paths_num;
2716	clt->paths_up = MAX_PATHS_NUM;
2717	clt->port = port;
2718	clt->pdu_sz = pdu_sz;
2719	clt->max_segments = RTRS_MAX_SEGMENTS;
2720	clt->reconnect_delay_sec = reconnect_delay_sec;
2721	clt->max_reconnect_attempts = max_reconnect_attempts;
2722	clt->priv = priv;
2723	clt->link_ev = link_ev;
2724	clt->mp_policy = MP_POLICY_MIN_INFLIGHT;
2725	strscpy(clt->sessname, sessname, sizeof(clt->sessname));
2726	init_waitqueue_head(&clt->permits_wait);
2727	mutex_init(&clt->paths_ev_mutex);
2728	mutex_init(&clt->paths_mutex);
2729	device_initialize(dev: &clt->dev);
2730
2731	err = dev_set_name(dev: &clt->dev, name: "%s", sessname);
2732	if (err)
2733	goto err_put;
2734
2735	/*
2736	* Suppress user space notification until
2737	* sysfs files are created
2738	*/
2739	dev_set_uevent_suppress(dev: &clt->dev, val: true);
2740	err = device_add(dev: &clt->dev);
2741	if (err)
2742	goto err_put;
2743
2744	clt->kobj_paths = kobject_create_and_add(name: "paths", parent: &clt->dev.kobj);
2745	if (!clt->kobj_paths) {
2746	err = -ENOMEM;
2747	goto err_del;
2748	}
2749	err = rtrs_clt_create_sysfs_root_files(clt);
2750	if (err) {
2751	kobject_del(kobj: clt->kobj_paths);
2752	kobject_put(kobj: clt->kobj_paths);
2753	goto err_del;
2754	}
2755	dev_set_uevent_suppress(dev: &clt->dev, val: false);
2756	kobject_uevent(kobj: &clt->dev.kobj, action: KOBJ_ADD);
2757
2758	return clt;
2759	err_del:
2760	device_del(dev: &clt->dev);
2761	err_put:
2762	free_percpu(pdata: clt->pcpu_path);
2763	put_device(dev: &clt->dev);
2764	return ERR_PTR(error: err);
2765	}
2766
2767	static void free_clt(struct rtrs_clt_sess *clt)
2768	{
2769	free_percpu(pdata: clt->pcpu_path);
2770
2771	/*
2772	* release callback will free clt and destroy mutexes in last put
2773	*/
2774	device_unregister(dev: &clt->dev);
2775	}
2776
2777	/**
2778	* rtrs_clt_open() - Open a path to an RTRS server
2779	* @ops: holds the link event callback and the private pointer.
2780	* @pathname: name of the path to an RTRS server
2781	* @paths: Paths to be established defined by their src and dst addresses
2782	* @paths_num: Number of elements in the @paths array
2783	* @port: port to be used by the RTRS session
2784	* @pdu_sz: Size of extra payload which can be accessed after permit allocation.
2785	* @reconnect_delay_sec: time between reconnect tries
2786	* @max_reconnect_attempts: Number of times to reconnect on error before giving
2787	* up, 0 for * disabled, -1 for forever
2788	* @nr_poll_queues: number of polling mode connection using IB_POLL_DIRECT flag
2789	*
2790	* Starts session establishment with the rtrs_server. The function can block
2791	* up to ~2000ms before it returns.
2792	*
2793	* Return a valid pointer on success otherwise PTR_ERR.
2794	*/
2795	struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops,
2796	const char *pathname,
2797	const struct rtrs_addr *paths,
2798	size_t paths_num, u16 port,
2799	size_t pdu_sz, u8 reconnect_delay_sec,
2800	s16 max_reconnect_attempts, u32 nr_poll_queues)
2801	{
2802	struct rtrs_clt_path *clt_path, *tmp;
2803	struct rtrs_clt_sess *clt;
2804	int err, i;
2805
2806	if (strchr(pathname, '/') || strchr(pathname, '.')) {
2807	pr_err("pathname cannot contain / and .\n");
2808	err = -EINVAL;
2809	goto out;
2810	}
2811
2812	clt = alloc_clt(sessname: pathname, paths_num, port, pdu_sz, priv: ops->priv,
2813	link_ev: ops->link_ev,
2814	reconnect_delay_sec,
2815	max_reconnect_attempts);
2816	if (IS_ERR(ptr: clt)) {
2817	err = PTR_ERR(ptr: clt);
2818	goto out;
2819	}
2820	for (i = 0; i < paths_num; i++) {
2821	struct rtrs_clt_path *clt_path;
2822
2823	clt_path = alloc_path(clt, path: &paths[i], con_num: nr_cpu_ids,
2824	nr_poll_queues);
2825	if (IS_ERR(ptr: clt_path)) {
2826	err = PTR_ERR(ptr: clt_path);
2827	goto close_all_path;
2828	}
2829	if (!i)
2830	clt_path->for_new_clt = 1;
2831	list_add_tail_rcu(new: &clt_path->s.entry, head: &clt->paths_list);
2832
2833	err = init_path(clt_path);
2834	if (err) {
2835	list_del_rcu(entry: &clt_path->s.entry);
2836	rtrs_clt_close_conns(clt_path, wait: true);
2837	free_percpu(pdata: clt_path->stats->pcpu_stats);
2838	kfree(objp: clt_path->stats);
2839	free_path(clt_path);
2840	goto close_all_path;
2841	}
2842
2843	err = rtrs_clt_create_path_files(clt_path);
2844	if (err) {
2845	list_del_rcu(entry: &clt_path->s.entry);
2846	rtrs_clt_close_conns(clt_path, wait: true);
2847	free_percpu(pdata: clt_path->stats->pcpu_stats);
2848	kfree(objp: clt_path->stats);
2849	free_path(clt_path);
2850	goto close_all_path;
2851	}
2852	}
2853	err = alloc_permits(clt);
2854	if (err)
2855	goto close_all_path;
2856
2857	return clt;
2858
2859	close_all_path:
2860	list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2861	rtrs_clt_destroy_path_files(clt_path, NULL);
2862	rtrs_clt_close_conns(clt_path, wait: true);
2863	kobject_put(kobj: &clt_path->kobj);
2864	}
2865	rtrs_clt_destroy_sysfs_root(clt);
2866	free_clt(clt);
2867
2868	out:
2869	return ERR_PTR(error: err);
2870	}
2871	EXPORT_SYMBOL(rtrs_clt_open);
2872
2873	/**
2874	* rtrs_clt_close() - Close a path
2875	* @clt: Session handle. Session is freed upon return.
2876	*/
2877	void rtrs_clt_close(struct rtrs_clt_sess *clt)
2878	{
2879	struct rtrs_clt_path *clt_path, *tmp;
2880
2881	/* Firstly forbid sysfs access */
2882	rtrs_clt_destroy_sysfs_root(clt);
2883
2884	/* Now it is safe to iterate over all paths without locks */
2885	list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2886	rtrs_clt_close_conns(clt_path, wait: true);
2887	rtrs_clt_destroy_path_files(clt_path, NULL);
2888	kobject_put(kobj: &clt_path->kobj);
2889	}
2890	free_permits(clt);
2891	free_clt(clt);
2892	}
2893	EXPORT_SYMBOL(rtrs_clt_close);
2894
2895	int rtrs_clt_reconnect_from_sysfs(struct rtrs_clt_path *clt_path)
2896	{
2897	enum rtrs_clt_state old_state;
2898	int err = -EBUSY;
2899	bool changed;
2900
2901	changed = rtrs_clt_change_state_get_old(clt_path,
2902	new_state: RTRS_CLT_RECONNECTING,
2903	old_state: &old_state);
2904	if (changed) {
2905	clt_path->reconnect_attempts = 0;
2906	rtrs_clt_stop_and_destroy_conns(clt_path);
2907	queue_delayed_work(wq: rtrs_wq, dwork: &clt_path->reconnect_dwork, delay: 0);
2908	}
2909	if (changed || old_state == RTRS_CLT_RECONNECTING) {
2910	/*
2911	* flush_delayed_work() queues pending work for immediate
2912	* execution, so do the flush if we have queued something
2913	* right now or work is pending.
2914	*/
2915	flush_delayed_work(dwork: &clt_path->reconnect_dwork);
2916	err = (READ_ONCE(clt_path->state) ==
2917	RTRS_CLT_CONNECTED ? 0 : -ENOTCONN);
2918	}
2919
2920	return err;
2921	}
2922
2923	int rtrs_clt_remove_path_from_sysfs(struct rtrs_clt_path *clt_path,
2924	const struct attribute *sysfs_self)
2925	{
2926	enum rtrs_clt_state old_state;
2927	bool changed;
2928
2929	/*
2930	* Continue stopping path till state was changed to DEAD or
2931	* state was observed as DEAD:
2932	* 1. State was changed to DEAD - we were fast and nobody
2933	* invoked rtrs_clt_reconnect(), which can again start
2934	* reconnecting.
2935	* 2. State was observed as DEAD - we have someone in parallel
2936	* removing the path.
2937	*/
2938	do {
2939	rtrs_clt_close_conns(clt_path, wait: true);
2940	changed = rtrs_clt_change_state_get_old(clt_path,
2941	new_state: RTRS_CLT_DEAD,
2942	old_state: &old_state);
2943	} while (!changed && old_state != RTRS_CLT_DEAD);
2944
2945	if (changed) {
2946	rtrs_clt_remove_path_from_arr(clt_path);
2947	rtrs_clt_destroy_path_files(clt_path, sysfs_self);
2948	kobject_put(kobj: &clt_path->kobj);
2949	}
2950
2951	return 0;
2952	}
2953
2954	void rtrs_clt_set_max_reconnect_attempts(struct rtrs_clt_sess *clt, int value)
2955	{
2956	clt->max_reconnect_attempts = (unsigned int)value;
2957	}
2958
2959	int rtrs_clt_get_max_reconnect_attempts(const struct rtrs_clt_sess *clt)
2960	{
2961	return (int)clt->max_reconnect_attempts;
2962	}
2963
2964	/**
2965	* rtrs_clt_request() - Request data transfer to/from server via RDMA.
2966	*
2967	* @dir: READ/WRITE
2968	* @ops: callback function to be called as confirmation, and the pointer.
2969	* @clt: Session
2970	* @permit: Preallocated permit
2971	* @vec: Message that is sent to server together with the request.
2972	* Sum of len of all @vec elements limited to <= IO_MSG_SIZE.
2973	* Since the msg is copied internally it can be allocated on stack.
2974	* @nr: Number of elements in @vec.
2975	* @data_len: length of data sent to/from server
2976	* @sg: Pages to be sent/received to/from server.
2977	* @sg_cnt: Number of elements in the @sg
2978	*
2979	* Return:
2980	* 0: Success
2981	* <0: Error
2982	*
2983	* On dir=READ rtrs client will request a data transfer from Server to client.
2984	* The data that the server will respond with will be stored in @sg when
2985	* the user receives an %RTRS_CLT_RDMA_EV_RDMA_REQUEST_WRITE_COMPL event.
2986	* On dir=WRITE rtrs client will rdma write data in sg to server side.
2987	*/
2988	int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
2989	struct rtrs_clt_sess *clt, struct rtrs_permit *permit,
2990	const struct kvec *vec, size_t nr, size_t data_len,
2991	struct scatterlist *sg, unsigned int sg_cnt)
2992	{
2993	struct rtrs_clt_io_req *req;
2994	struct rtrs_clt_path *clt_path;
2995
2996	enum dma_data_direction dma_dir;
2997	int err = -ECONNABORTED, i;
2998	size_t usr_len, hdr_len;
2999	struct path_it it;
3000
3001	/* Get kvec length */
3002	for (i = 0, usr_len = 0; i < nr; i++)
3003	usr_len += vec[i].iov_len;
3004
3005	if (dir == READ) {
3006	hdr_len = sizeof(struct rtrs_msg_rdma_read) +
3007	sg_cnt * sizeof(struct rtrs_sg_desc);
3008	dma_dir = DMA_FROM_DEVICE;
3009	} else {
3010	hdr_len = sizeof(struct rtrs_msg_rdma_write);
3011	dma_dir = DMA_TO_DEVICE;
3012	}
3013
3014	rcu_read_lock();
3015	for (path_it_init(it: &it, clt);
3016	(clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3017	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3018	continue;
3019
3020	if (usr_len + hdr_len > clt_path->max_hdr_size) {
3021	rtrs_wrn_rl(clt_path->clt,
3022	"%s request failed, user message size is %zu and header length %zu, but max size is %u\n",
3023	dir == READ ? "Read" : "Write",
3024	usr_len, hdr_len, clt_path->max_hdr_size);
3025	err = -EMSGSIZE;
3026	break;
3027	}
3028	req = rtrs_clt_get_req(clt_path, conf: ops->conf_fn, permit, priv: ops->priv,
3029	vec, usr_len, sg, sg_cnt, data_len,
3030	dir: dma_dir);
3031	if (dir == READ)
3032	err = rtrs_clt_read_req(req);
3033	else
3034	err = rtrs_clt_write_req(req);
3035	if (err) {
3036	req->in_use = false;
3037	continue;
3038	}
3039	/* Success path */
3040	break;
3041	}
3042	path_it_deinit(it: &it);
3043	rcu_read_unlock();
3044
3045	return err;
3046	}
3047	EXPORT_SYMBOL(rtrs_clt_request);
3048
3049	int rtrs_clt_rdma_cq_direct(struct rtrs_clt_sess *clt, unsigned int index)
3050	{
3051	/* If no path, return -1 for block layer not to try again */
3052	int cnt = -1;
3053	struct rtrs_con *con;
3054	struct rtrs_clt_path *clt_path;
3055	struct path_it it;
3056
3057	rcu_read_lock();
3058	for (path_it_init(it: &it, clt);
3059	(clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3060	if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3061	continue;
3062
3063	con = clt_path->s.con[index + 1];
3064	cnt = ib_process_cq_direct(cq: con->cq, budget: -1);
3065	if (cnt)
3066	break;
3067	}
3068	path_it_deinit(it: &it);
3069	rcu_read_unlock();
3070
3071	return cnt;
3072	}
3073	EXPORT_SYMBOL(rtrs_clt_rdma_cq_direct);
3074
3075	/**
3076	* rtrs_clt_query() - queries RTRS session attributes
3077	*@clt: session pointer
3078	*@attr: query results for session attributes.
3079	* Returns:
3080	* 0 on success
3081	* -ECOMM no connection to the server
3082	*/
3083	int rtrs_clt_query(struct rtrs_clt_sess *clt, struct rtrs_attrs *attr)
3084	{
3085	if (!rtrs_clt_is_connected(clt))
3086	return -ECOMM;
3087
3088	attr->queue_depth = clt->queue_depth;
3089	attr->max_segments = clt->max_segments;
3090	/* Cap max_io_size to min of remote buffer size and the fr pages */
3091	attr->max_io_size = min_t(int, clt->max_io_size,
3092	clt->max_segments * SZ_4K);
3093
3094	return 0;
3095	}
3096	EXPORT_SYMBOL(rtrs_clt_query);
3097
3098	int rtrs_clt_create_path_from_sysfs(struct rtrs_clt_sess *clt,
3099	struct rtrs_addr *addr)
3100	{
3101	struct rtrs_clt_path *clt_path;
3102	int err;
3103
3104	clt_path = alloc_path(clt, path: addr, con_num: nr_cpu_ids, nr_poll_queues: 0);
3105	if (IS_ERR(ptr: clt_path))
3106	return PTR_ERR(ptr: clt_path);
3107
3108	mutex_lock(&clt->paths_mutex);
3109	if (clt->paths_num == 0) {
3110	/*
3111	* When all the paths are removed for a session,
3112	* the addition of the first path is like a new session for
3113	* the storage server
3114	*/
3115	clt_path->for_new_clt = 1;
3116	}
3117
3118	mutex_unlock(lock: &clt->paths_mutex);
3119
3120	/*
3121	* It is totally safe to add path in CONNECTING state: coming
3122	* IO will never grab it. Also it is very important to add
3123	* path before init, since init fires LINK_CONNECTED event.
3124	*/
3125	rtrs_clt_add_path_to_arr(clt_path);
3126
3127	err = init_path(clt_path);
3128	if (err)
3129	goto close_path;
3130
3131	err = rtrs_clt_create_path_files(clt_path);
3132	if (err)
3133	goto close_path;
3134
3135	return 0;
3136
3137	close_path:
3138	rtrs_clt_remove_path_from_arr(clt_path);
3139	rtrs_clt_close_conns(clt_path, wait: true);
3140	free_percpu(pdata: clt_path->stats->pcpu_stats);
3141	kfree(objp: clt_path->stats);
3142	free_path(clt_path);
3143
3144	return err;
3145	}
3146
3147	void rtrs_clt_ib_event_handler(struct ib_event_handler *handler,
3148	struct ib_event *ibevent)
3149	{
3150	pr_info("Handling event: %s (%d).\n", ib_event_msg(ibevent->event),
3151	ibevent->event);
3152	}
3153
3154
3155	static int rtrs_clt_ib_dev_init(struct rtrs_ib_dev *dev)
3156	{
3157	INIT_IB_EVENT_HANDLER(&dev->event_handler, dev->ib_dev,
3158	rtrs_clt_ib_event_handler);
3159	ib_register_event_handler(event_handler: &dev->event_handler);
3160
3161	if (!(dev->ib_dev->attrs.device_cap_flags &
3162	IB_DEVICE_MEM_MGT_EXTENSIONS)) {
3163	pr_err("Memory registrations not supported.\n");
3164	return -ENOTSUPP;
3165	}
3166
3167	return 0;
3168	}
3169
3170	static void rtrs_clt_ib_dev_deinit(struct rtrs_ib_dev *dev)
3171	{
3172	ib_unregister_event_handler(event_handler: &dev->event_handler);
3173	}
3174
3175
3176	static const struct rtrs_rdma_dev_pd_ops dev_pd_ops = {
3177	.init = rtrs_clt_ib_dev_init,
3178	.deinit = rtrs_clt_ib_dev_deinit
3179	};
3180
3181	static int __init rtrs_client_init(void)
3182	{
3183	int ret = 0;
3184
3185	rtrs_rdma_dev_pd_init(pd_flags: 0, pool: &dev_pd);
3186	ret = class_register(class: &rtrs_clt_dev_class);
3187	if (ret) {
3188	pr_err("Failed to create rtrs-client dev class\n");
3189	return ret;
3190	}
3191	rtrs_wq = alloc_workqueue("rtrs_client_wq", 0, 0);
3192	if (!rtrs_wq) {
3193	class_unregister(class: &rtrs_clt_dev_class);
3194	return -ENOMEM;
3195	}
3196
3197	return 0;
3198	}
3199
3200	static void __exit rtrs_client_exit(void)
3201	{
3202	destroy_workqueue(wq: rtrs_wq);
3203	class_unregister(class: &rtrs_clt_dev_class);
3204	rtrs_rdma_dev_pd_deinit(pool: &dev_pd);
3205	}
3206
3207	module_init(rtrs_client_init);
3208	module_exit(rtrs_client_exit);
3209