1// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2/*
3 * Copyright (c) 2017, Mellanox Technologies inc. All rights reserved.
4 */
5#include <rdma/uverbs_ioctl.h>
6#include <rdma/rdma_user_ioctl.h>
7#include <linux/bitops.h>
8#include "rdma_core.h"
9#include "uverbs.h"
10
11static int ib_uverbs_notsupp(struct uverbs_attr_bundle *attrs)
12{
13 return -EOPNOTSUPP;
14}
15
16static void *uapi_add_elm(struct uverbs_api *uapi, u32 key, size_t alloc_size)
17{
18 void *elm;
19 int rc;
20
21 if (key == UVERBS_API_KEY_ERR)
22 return ERR_PTR(error: -EOVERFLOW);
23
24 elm = kzalloc(size: alloc_size, GFP_KERNEL);
25 if (!elm)
26 return ERR_PTR(error: -ENOMEM);
27 rc = radix_tree_insert(&uapi->radix, index: key, elm);
28 if (rc) {
29 kfree(objp: elm);
30 return ERR_PTR(error: rc);
31 }
32
33 return elm;
34}
35
36static void *uapi_add_get_elm(struct uverbs_api *uapi, u32 key,
37 size_t alloc_size, bool *exists)
38{
39 void *elm;
40
41 elm = uapi_add_elm(uapi, key, alloc_size);
42 if (!IS_ERR(ptr: elm)) {
43 *exists = false;
44 return elm;
45 }
46
47 if (elm != ERR_PTR(error: -EEXIST))
48 return elm;
49
50 elm = radix_tree_lookup(&uapi->radix, key);
51 if (WARN_ON(!elm))
52 return ERR_PTR(error: -EINVAL);
53 *exists = true;
54 return elm;
55}
56
57static int uapi_create_write(struct uverbs_api *uapi,
58 struct ib_device *ibdev,
59 const struct uapi_definition *def,
60 u32 obj_key,
61 u32 *cur_method_key)
62{
63 struct uverbs_api_write_method *method_elm;
64 u32 method_key = obj_key;
65 bool exists;
66
67 if (def->write.is_ex)
68 method_key |= uapi_key_write_ex_method(id: def->write.command_num);
69 else
70 method_key |= uapi_key_write_method(id: def->write.command_num);
71
72 method_elm = uapi_add_get_elm(uapi, key: method_key, alloc_size: sizeof(*method_elm),
73 exists: &exists);
74 if (IS_ERR(ptr: method_elm))
75 return PTR_ERR(ptr: method_elm);
76
77 if (WARN_ON(exists && (def->write.is_ex != method_elm->is_ex)))
78 return -EINVAL;
79
80 method_elm->is_ex = def->write.is_ex;
81 method_elm->handler = def->func_write;
82 if (!def->write.is_ex)
83 method_elm->disabled = !(ibdev->uverbs_cmd_mask &
84 BIT_ULL(def->write.command_num));
85
86 if (!def->write.is_ex && def->func_write) {
87 method_elm->has_udata = def->write.has_udata;
88 method_elm->has_resp = def->write.has_resp;
89 method_elm->req_size = def->write.req_size;
90 method_elm->resp_size = def->write.resp_size;
91 }
92
93 *cur_method_key = method_key;
94 return 0;
95}
96
97static int uapi_merge_method(struct uverbs_api *uapi,
98 struct uverbs_api_object *obj_elm, u32 obj_key,
99 const struct uverbs_method_def *method,
100 bool is_driver)
101{
102 u32 method_key = obj_key | uapi_key_ioctl_method(id: method->id);
103 struct uverbs_api_ioctl_method *method_elm;
104 unsigned int i;
105 bool exists;
106
107 if (!method->attrs)
108 return 0;
109
110 method_elm = uapi_add_get_elm(uapi, key: method_key, alloc_size: sizeof(*method_elm),
111 exists: &exists);
112 if (IS_ERR(ptr: method_elm))
113 return PTR_ERR(ptr: method_elm);
114 if (exists) {
115 /*
116 * This occurs when a driver uses ADD_UVERBS_ATTRIBUTES_SIMPLE
117 */
118 if (WARN_ON(method->handler))
119 return -EINVAL;
120 } else {
121 WARN_ON(!method->handler);
122 rcu_assign_pointer(method_elm->handler, method->handler);
123 if (method->handler != uverbs_destroy_def_handler)
124 method_elm->driver_method = is_driver;
125 }
126
127 for (i = 0; i != method->num_attrs; i++) {
128 const struct uverbs_attr_def *attr = (*method->attrs)[i];
129 struct uverbs_api_attr *attr_slot;
130
131 if (!attr)
132 continue;
133
134 /*
135 * ENUM_IN contains the 'ids' pointer to the driver's .rodata,
136 * so if it is specified by a driver then it always makes this
137 * into a driver method.
138 */
139 if (attr->attr.type == UVERBS_ATTR_TYPE_ENUM_IN)
140 method_elm->driver_method |= is_driver;
141
142 /*
143 * Like other uobject based things we only support a single
144 * uobject being NEW'd or DESTROY'd
145 */
146 if (attr->attr.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {
147 u8 access = attr->attr.u2.objs_arr.access;
148
149 if (WARN_ON(access == UVERBS_ACCESS_NEW ||
150 access == UVERBS_ACCESS_DESTROY))
151 return -EINVAL;
152 }
153
154 attr_slot =
155 uapi_add_elm(uapi, key: method_key | uapi_key_attr(id: attr->id),
156 alloc_size: sizeof(*attr_slot));
157 /* Attributes are not allowed to be modified by drivers */
158 if (IS_ERR(ptr: attr_slot))
159 return PTR_ERR(ptr: attr_slot);
160
161 attr_slot->spec = attr->attr;
162 }
163
164 return 0;
165}
166
167static int uapi_merge_obj_tree(struct uverbs_api *uapi,
168 const struct uverbs_object_def *obj,
169 bool is_driver)
170{
171 struct uverbs_api_object *obj_elm;
172 unsigned int i;
173 u32 obj_key;
174 bool exists;
175 int rc;
176
177 obj_key = uapi_key_obj(id: obj->id);
178 obj_elm = uapi_add_get_elm(uapi, key: obj_key, alloc_size: sizeof(*obj_elm), exists: &exists);
179 if (IS_ERR(ptr: obj_elm))
180 return PTR_ERR(ptr: obj_elm);
181
182 if (obj->type_attrs) {
183 if (WARN_ON(obj_elm->type_attrs))
184 return -EINVAL;
185
186 obj_elm->id = obj->id;
187 obj_elm->type_attrs = obj->type_attrs;
188 obj_elm->type_class = obj->type_attrs->type_class;
189 /*
190 * Today drivers are only permitted to use idr_class and
191 * fd_class types. We can revoke the IDR types during
192 * disassociation, and the FD types require the driver to use
193 * struct file_operations.owner to prevent the driver module
194 * code from unloading while the file is open. This provides
195 * enough safety that uverbs_uobject_fd_release() will
196 * continue to work. Drivers using FD are responsible to
197 * handle disassociation of the device on their own.
198 */
199 if (WARN_ON(is_driver &&
200 obj->type_attrs->type_class != &uverbs_idr_class &&
201 obj->type_attrs->type_class != &uverbs_fd_class))
202 return -EINVAL;
203 }
204
205 if (!obj->methods)
206 return 0;
207
208 for (i = 0; i != obj->num_methods; i++) {
209 const struct uverbs_method_def *method = (*obj->methods)[i];
210
211 if (!method)
212 continue;
213
214 rc = uapi_merge_method(uapi, obj_elm, obj_key, method,
215 is_driver);
216 if (rc)
217 return rc;
218 }
219
220 return 0;
221}
222
223static int uapi_disable_elm(struct uverbs_api *uapi,
224 const struct uapi_definition *def,
225 u32 obj_key,
226 u32 method_key)
227{
228 bool exists;
229
230 if (def->scope == UAPI_SCOPE_OBJECT) {
231 struct uverbs_api_object *obj_elm;
232
233 obj_elm = uapi_add_get_elm(
234 uapi, key: obj_key, alloc_size: sizeof(*obj_elm), exists: &exists);
235 if (IS_ERR(ptr: obj_elm))
236 return PTR_ERR(ptr: obj_elm);
237 obj_elm->disabled = 1;
238 return 0;
239 }
240
241 if (def->scope == UAPI_SCOPE_METHOD &&
242 uapi_key_is_ioctl_method(key: method_key)) {
243 struct uverbs_api_ioctl_method *method_elm;
244
245 method_elm = uapi_add_get_elm(uapi, key: method_key,
246 alloc_size: sizeof(*method_elm), exists: &exists);
247 if (IS_ERR(ptr: method_elm))
248 return PTR_ERR(ptr: method_elm);
249 method_elm->disabled = 1;
250 return 0;
251 }
252
253 if (def->scope == UAPI_SCOPE_METHOD &&
254 (uapi_key_is_write_method(key: method_key) ||
255 uapi_key_is_write_ex_method(key: method_key))) {
256 struct uverbs_api_write_method *write_elm;
257
258 write_elm = uapi_add_get_elm(uapi, key: method_key,
259 alloc_size: sizeof(*write_elm), exists: &exists);
260 if (IS_ERR(ptr: write_elm))
261 return PTR_ERR(ptr: write_elm);
262 write_elm->disabled = 1;
263 return 0;
264 }
265
266 WARN_ON(true);
267 return -EINVAL;
268}
269
270static int uapi_merge_def(struct uverbs_api *uapi, struct ib_device *ibdev,
271 const struct uapi_definition *def_list,
272 bool is_driver)
273{
274 const struct uapi_definition *def = def_list;
275 u32 cur_obj_key = UVERBS_API_KEY_ERR;
276 u32 cur_method_key = UVERBS_API_KEY_ERR;
277 bool exists;
278 int rc;
279
280 if (!def_list)
281 return 0;
282
283 for (;; def++) {
284 switch ((enum uapi_definition_kind)def->kind) {
285 case UAPI_DEF_CHAIN:
286 rc = uapi_merge_def(uapi, ibdev, def_list: def->chain, is_driver);
287 if (rc)
288 return rc;
289 continue;
290
291 case UAPI_DEF_CHAIN_OBJ_TREE:
292 if (WARN_ON(def->object_start.object_id !=
293 def->chain_obj_tree->id))
294 return -EINVAL;
295
296 cur_obj_key = uapi_key_obj(id: def->object_start.object_id);
297 rc = uapi_merge_obj_tree(uapi, obj: def->chain_obj_tree,
298 is_driver);
299 if (rc)
300 return rc;
301 continue;
302
303 case UAPI_DEF_END:
304 return 0;
305
306 case UAPI_DEF_IS_SUPPORTED_DEV_FN: {
307 void **ibdev_fn =
308 (void *)(&ibdev->ops) + def->needs_fn_offset;
309
310 if (*ibdev_fn)
311 continue;
312 rc = uapi_disable_elm(
313 uapi, def, obj_key: cur_obj_key, method_key: cur_method_key);
314 if (rc)
315 return rc;
316 continue;
317 }
318
319 case UAPI_DEF_IS_SUPPORTED_FUNC:
320 if (def->func_is_supported(ibdev))
321 continue;
322 rc = uapi_disable_elm(
323 uapi, def, obj_key: cur_obj_key, method_key: cur_method_key);
324 if (rc)
325 return rc;
326 continue;
327
328 case UAPI_DEF_OBJECT_START: {
329 struct uverbs_api_object *obj_elm;
330
331 cur_obj_key = uapi_key_obj(id: def->object_start.object_id);
332 obj_elm = uapi_add_get_elm(uapi, key: cur_obj_key,
333 alloc_size: sizeof(*obj_elm), exists: &exists);
334 if (IS_ERR(ptr: obj_elm))
335 return PTR_ERR(ptr: obj_elm);
336 continue;
337 }
338
339 case UAPI_DEF_WRITE:
340 rc = uapi_create_write(
341 uapi, ibdev, def, obj_key: cur_obj_key, cur_method_key: &cur_method_key);
342 if (rc)
343 return rc;
344 continue;
345 }
346 WARN_ON(true);
347 return -EINVAL;
348 }
349}
350
351static int
352uapi_finalize_ioctl_method(struct uverbs_api *uapi,
353 struct uverbs_api_ioctl_method *method_elm,
354 u32 method_key)
355{
356 struct radix_tree_iter iter;
357 unsigned int num_attrs = 0;
358 unsigned int max_bkey = 0;
359 bool single_uobj = false;
360 void __rcu **slot;
361
362 method_elm->destroy_bkey = UVERBS_API_ATTR_BKEY_LEN;
363 radix_tree_for_each_slot (slot, &uapi->radix, &iter,
364 uapi_key_attrs_start(method_key)) {
365 struct uverbs_api_attr *elm =
366 rcu_dereference_protected(*slot, true);
367 u32 attr_key = iter.index & UVERBS_API_ATTR_KEY_MASK;
368 u32 attr_bkey = uapi_bkey_attr(attr_key);
369 u8 type = elm->spec.type;
370
371 if (uapi_key_attr_to_ioctl_method(attr_key: iter.index) !=
372 uapi_key_attr_to_ioctl_method(attr_key: method_key))
373 break;
374
375 if (elm->spec.mandatory)
376 __set_bit(attr_bkey, method_elm->attr_mandatory);
377
378 if (elm->spec.is_udata)
379 method_elm->has_udata = true;
380
381 if (type == UVERBS_ATTR_TYPE_IDR ||
382 type == UVERBS_ATTR_TYPE_FD) {
383 u8 access = elm->spec.u.obj.access;
384
385 /*
386 * Verbs specs may only have one NEW/DESTROY, we don't
387 * have the infrastructure to abort multiple NEW's or
388 * cope with multiple DESTROY failure.
389 */
390 if (access == UVERBS_ACCESS_NEW ||
391 access == UVERBS_ACCESS_DESTROY) {
392 if (WARN_ON(single_uobj))
393 return -EINVAL;
394
395 single_uobj = true;
396 if (WARN_ON(!elm->spec.mandatory))
397 return -EINVAL;
398 }
399
400 if (access == UVERBS_ACCESS_DESTROY)
401 method_elm->destroy_bkey = attr_bkey;
402 }
403
404 max_bkey = max(max_bkey, attr_bkey);
405 num_attrs++;
406 }
407
408 method_elm->key_bitmap_len = max_bkey + 1;
409 WARN_ON(method_elm->key_bitmap_len > UVERBS_API_ATTR_BKEY_LEN);
410
411 uapi_compute_bundle_size(method_elm, num_attrs);
412 return 0;
413}
414
415static int uapi_finalize(struct uverbs_api *uapi)
416{
417 const struct uverbs_api_write_method **data;
418 unsigned long max_write_ex = 0;
419 unsigned long max_write = 0;
420 struct radix_tree_iter iter;
421 void __rcu **slot;
422 int rc;
423 int i;
424
425 radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
426 struct uverbs_api_ioctl_method *method_elm =
427 rcu_dereference_protected(*slot, true);
428
429 if (uapi_key_is_ioctl_method(key: iter.index)) {
430 rc = uapi_finalize_ioctl_method(uapi, method_elm,
431 method_key: iter.index);
432 if (rc)
433 return rc;
434 }
435
436 if (uapi_key_is_write_method(key: iter.index))
437 max_write = max(max_write,
438 iter.index & UVERBS_API_ATTR_KEY_MASK);
439 if (uapi_key_is_write_ex_method(key: iter.index))
440 max_write_ex =
441 max(max_write_ex,
442 iter.index & UVERBS_API_ATTR_KEY_MASK);
443 }
444
445 uapi->notsupp_method.handler = ib_uverbs_notsupp;
446 uapi->num_write = max_write + 1;
447 uapi->num_write_ex = max_write_ex + 1;
448 data = kmalloc_array(n: uapi->num_write + uapi->num_write_ex,
449 size: sizeof(*uapi->write_methods), GFP_KERNEL);
450 if (!data)
451 return -ENOMEM;
452
453 for (i = 0; i != uapi->num_write + uapi->num_write_ex; i++)
454 data[i] = &uapi->notsupp_method;
455 uapi->write_methods = data;
456 uapi->write_ex_methods = data + uapi->num_write;
457
458 radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
459 if (uapi_key_is_write_method(key: iter.index))
460 uapi->write_methods[iter.index &
461 UVERBS_API_ATTR_KEY_MASK] =
462 rcu_dereference_protected(*slot, true);
463 if (uapi_key_is_write_ex_method(key: iter.index))
464 uapi->write_ex_methods[iter.index &
465 UVERBS_API_ATTR_KEY_MASK] =
466 rcu_dereference_protected(*slot, true);
467 }
468
469 return 0;
470}
471
472static void uapi_remove_range(struct uverbs_api *uapi, u32 start, u32 last)
473{
474 struct radix_tree_iter iter;
475 void __rcu **slot;
476
477 radix_tree_for_each_slot (slot, &uapi->radix, &iter, start) {
478 if (iter.index > last)
479 return;
480 kfree(rcu_dereference_protected(*slot, true));
481 radix_tree_iter_delete(&uapi->radix, iter: &iter, slot);
482 }
483}
484
485static void uapi_remove_object(struct uverbs_api *uapi, u32 obj_key)
486{
487 uapi_remove_range(uapi, start: obj_key,
488 last: obj_key | UVERBS_API_METHOD_KEY_MASK |
489 UVERBS_API_ATTR_KEY_MASK);
490}
491
492static void uapi_remove_method(struct uverbs_api *uapi, u32 method_key)
493{
494 uapi_remove_range(uapi, start: method_key,
495 last: method_key | UVERBS_API_ATTR_KEY_MASK);
496}
497
498
499static u32 uapi_get_obj_id(struct uverbs_attr_spec *spec)
500{
501 if (spec->type == UVERBS_ATTR_TYPE_IDR ||
502 spec->type == UVERBS_ATTR_TYPE_FD)
503 return spec->u.obj.obj_type;
504 if (spec->type == UVERBS_ATTR_TYPE_IDRS_ARRAY)
505 return spec->u2.objs_arr.obj_type;
506 return UVERBS_API_KEY_ERR;
507}
508
509static void uapi_key_okay(u32 key)
510{
511 unsigned int count = 0;
512
513 if (uapi_key_is_object(key))
514 count++;
515 if (uapi_key_is_ioctl_method(key))
516 count++;
517 if (uapi_key_is_write_method(key))
518 count++;
519 if (uapi_key_is_write_ex_method(key))
520 count++;
521 if (uapi_key_is_attr(key))
522 count++;
523 WARN(count != 1, "Bad count %u key=%x", count, key);
524}
525
526static void uapi_finalize_disable(struct uverbs_api *uapi)
527{
528 struct radix_tree_iter iter;
529 u32 starting_key = 0;
530 bool scan_again = false;
531 void __rcu **slot;
532
533again:
534 radix_tree_for_each_slot (slot, &uapi->radix, &iter, starting_key) {
535 uapi_key_okay(key: iter.index);
536
537 if (uapi_key_is_object(key: iter.index)) {
538 struct uverbs_api_object *obj_elm =
539 rcu_dereference_protected(*slot, true);
540
541 if (obj_elm->disabled) {
542 /* Have to check all the attrs again */
543 scan_again = true;
544 starting_key = iter.index;
545 uapi_remove_object(uapi, obj_key: iter.index);
546 goto again;
547 }
548 continue;
549 }
550
551 if (uapi_key_is_ioctl_method(key: iter.index)) {
552 struct uverbs_api_ioctl_method *method_elm =
553 rcu_dereference_protected(*slot, true);
554
555 if (method_elm->disabled) {
556 starting_key = iter.index;
557 uapi_remove_method(uapi, method_key: iter.index);
558 goto again;
559 }
560 continue;
561 }
562
563 if (uapi_key_is_write_method(key: iter.index) ||
564 uapi_key_is_write_ex_method(key: iter.index)) {
565 struct uverbs_api_write_method *method_elm =
566 rcu_dereference_protected(*slot, true);
567
568 if (method_elm->disabled) {
569 kfree(objp: method_elm);
570 radix_tree_iter_delete(&uapi->radix, iter: &iter, slot);
571 }
572 continue;
573 }
574
575 if (uapi_key_is_attr(key: iter.index)) {
576 struct uverbs_api_attr *attr_elm =
577 rcu_dereference_protected(*slot, true);
578 const struct uverbs_api_object *tmp_obj;
579 u32 obj_key;
580
581 /*
582 * If the method has a mandatory object handle
583 * attribute which relies on an object which is not
584 * present then the entire method is uncallable.
585 */
586 if (!attr_elm->spec.mandatory)
587 continue;
588 obj_key = uapi_get_obj_id(spec: &attr_elm->spec);
589 if (obj_key == UVERBS_API_KEY_ERR)
590 continue;
591 tmp_obj = uapi_get_object(uapi, object_id: obj_key);
592 if (IS_ERR(ptr: tmp_obj)) {
593 if (PTR_ERR(ptr: tmp_obj) == -ENOMSG)
594 continue;
595 } else {
596 if (!tmp_obj->disabled)
597 continue;
598 }
599
600 starting_key = iter.index;
601 uapi_remove_method(
602 uapi,
603 method_key: iter.index & (UVERBS_API_OBJ_KEY_MASK |
604 UVERBS_API_METHOD_KEY_MASK));
605 goto again;
606 }
607
608 WARN_ON(false);
609 }
610
611 if (!scan_again)
612 return;
613 scan_again = false;
614 starting_key = 0;
615 goto again;
616}
617
618void uverbs_destroy_api(struct uverbs_api *uapi)
619{
620 if (!uapi)
621 return;
622
623 uapi_remove_range(uapi, start: 0, U32_MAX);
624 kfree(objp: uapi->write_methods);
625 kfree(objp: uapi);
626}
627
628static const struct uapi_definition uverbs_core_api[] = {
629 UAPI_DEF_CHAIN(uverbs_def_obj_async_fd),
630 UAPI_DEF_CHAIN(uverbs_def_obj_counters),
631 UAPI_DEF_CHAIN(uverbs_def_obj_cq),
632 UAPI_DEF_CHAIN(uverbs_def_obj_device),
633 UAPI_DEF_CHAIN(uverbs_def_obj_dm),
634 UAPI_DEF_CHAIN(uverbs_def_obj_flow_action),
635 UAPI_DEF_CHAIN(uverbs_def_obj_intf),
636 UAPI_DEF_CHAIN(uverbs_def_obj_mr),
637 UAPI_DEF_CHAIN(uverbs_def_obj_qp),
638 UAPI_DEF_CHAIN(uverbs_def_obj_srq),
639 UAPI_DEF_CHAIN(uverbs_def_obj_wq),
640 UAPI_DEF_CHAIN(uverbs_def_write_intf),
641 {},
642};
643
644struct uverbs_api *uverbs_alloc_api(struct ib_device *ibdev)
645{
646 struct uverbs_api *uapi;
647 int rc;
648
649 uapi = kzalloc(size: sizeof(*uapi), GFP_KERNEL);
650 if (!uapi)
651 return ERR_PTR(error: -ENOMEM);
652
653 INIT_RADIX_TREE(&uapi->radix, GFP_KERNEL);
654 uapi->driver_id = ibdev->ops.driver_id;
655
656 rc = uapi_merge_def(uapi, ibdev, def_list: uverbs_core_api, is_driver: false);
657 if (rc)
658 goto err;
659 rc = uapi_merge_def(uapi, ibdev, def_list: ibdev->driver_def, is_driver: true);
660 if (rc)
661 goto err;
662
663 uapi_finalize_disable(uapi);
664 rc = uapi_finalize(uapi);
665 if (rc)
666 goto err;
667
668 return uapi;
669err:
670 if (rc != -ENOMEM)
671 dev_err(&ibdev->dev,
672 "Setup of uverbs_api failed, kernel parsing tree description is not valid (%d)??\n",
673 rc);
674
675 uverbs_destroy_api(uapi);
676 return ERR_PTR(error: rc);
677}
678
679/*
680 * The pre version is done before destroying the HW objects, it only blocks
681 * off method access. All methods that require the ib_dev or the module data
682 * must test one of these assignments prior to continuing.
683 */
684void uverbs_disassociate_api_pre(struct ib_uverbs_device *uverbs_dev)
685{
686 struct uverbs_api *uapi = uverbs_dev->uapi;
687 struct radix_tree_iter iter;
688 void __rcu **slot;
689
690 rcu_assign_pointer(uverbs_dev->ib_dev, NULL);
691
692 radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
693 if (uapi_key_is_ioctl_method(key: iter.index)) {
694 struct uverbs_api_ioctl_method *method_elm =
695 rcu_dereference_protected(*slot, true);
696
697 if (method_elm->driver_method)
698 rcu_assign_pointer(method_elm->handler, NULL);
699 }
700 }
701
702 synchronize_srcu(ssp: &uverbs_dev->disassociate_srcu);
703}
704
705/*
706 * Called when a driver disassociates from the ib_uverbs_device. The
707 * assumption is that the driver module will unload after. Replace everything
708 * related to the driver with NULL as a safety measure.
709 */
710void uverbs_disassociate_api(struct uverbs_api *uapi)
711{
712 struct radix_tree_iter iter;
713 void __rcu **slot;
714
715 radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
716 if (uapi_key_is_object(key: iter.index)) {
717 struct uverbs_api_object *object_elm =
718 rcu_dereference_protected(*slot, true);
719
720 /*
721 * Some type_attrs are in the driver module. We don't
722 * bother to keep track of which since there should be
723 * no use of this after disassociate.
724 */
725 object_elm->type_attrs = NULL;
726 } else if (uapi_key_is_attr(key: iter.index)) {
727 struct uverbs_api_attr *elm =
728 rcu_dereference_protected(*slot, true);
729
730 if (elm->spec.type == UVERBS_ATTR_TYPE_ENUM_IN)
731 elm->spec.u2.enum_def.ids = NULL;
732 }
733 }
734}
735

source code of linux/drivers/infiniband/core/uverbs_uapi.c