1// SPDX-License-Identifier: GPL-2.0-or-later
2/* RxRPC Tx data buffering.
3 *
4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/slab.h>
11#include "ar-internal.h"
12
13static atomic_t rxrpc_txbuf_debug_ids;
14atomic_t rxrpc_nr_txbuf;
15
16/*
17 * Allocate and partially initialise a data transmission buffer.
18 */
19struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_size,
20 size_t data_align, gfp_t gfp)
21{
22 struct rxrpc_txbuf *txb;
23 size_t total, doff, jsize = sizeof(struct rxrpc_jumbo_header);
24 void *buf;
25
26 txb = kzalloc(sizeof(*txb), gfp);
27 if (!txb)
28 return NULL;
29
30 /* We put a jumbo header in the buffer, but not a full wire header to
31 * avoid delayed-corruption problems with zerocopy.
32 */
33 doff = round_up(jsize, data_align);
34 total = doff + data_size;
35
36 data_align = umax(data_align, L1_CACHE_BYTES);
37 mutex_lock(&call->conn->tx_data_alloc_lock);
38 buf = page_frag_alloc_align(nc: &call->conn->tx_data_alloc, fragsz: total, gfp_mask: gfp,
39 align: data_align);
40 mutex_unlock(lock: &call->conn->tx_data_alloc_lock);
41 if (!buf) {
42 kfree(objp: txb);
43 return NULL;
44 }
45
46 refcount_set(r: &txb->ref, n: 1);
47 txb->call_debug_id = call->debug_id;
48 txb->debug_id = atomic_inc_return(v: &rxrpc_txbuf_debug_ids);
49 txb->alloc_size = data_size;
50 txb->space = data_size;
51 txb->offset = 0;
52 txb->flags = call->conn->out_clientflag;
53 txb->seq = call->send_top + 1;
54 txb->data = buf + doff;
55
56 trace_rxrpc_txbuf(debug_id: txb->debug_id, call_debug_id: txb->call_debug_id, seq: txb->seq, ref: 1,
57 what: rxrpc_txbuf_alloc_data);
58
59 atomic_inc(v: &rxrpc_nr_txbuf);
60 return txb;
61}
62
63void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
64{
65 int r = refcount_read(r: &txb->ref);
66
67 trace_rxrpc_txbuf(debug_id: txb->debug_id, call_debug_id: txb->call_debug_id, seq: txb->seq, ref: r, what);
68}
69
70static void rxrpc_free_txbuf(struct rxrpc_txbuf *txb)
71{
72 trace_rxrpc_txbuf(debug_id: txb->debug_id, call_debug_id: txb->call_debug_id, seq: txb->seq, ref: 0,
73 what: rxrpc_txbuf_free);
74 if (txb->data)
75 page_frag_free(addr: txb->data);
76 kfree(objp: txb);
77 atomic_dec(v: &rxrpc_nr_txbuf);
78}
79
80void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
81{
82 unsigned int debug_id, call_debug_id;
83 rxrpc_seq_t seq;
84 bool dead;
85 int r;
86
87 if (txb) {
88 debug_id = txb->debug_id;
89 call_debug_id = txb->call_debug_id;
90 seq = txb->seq;
91 dead = __refcount_dec_and_test(r: &txb->ref, oldp: &r);
92 trace_rxrpc_txbuf(debug_id, call_debug_id, seq, ref: r - 1, what);
93 if (dead)
94 rxrpc_free_txbuf(txb);
95 }
96}
97

source code of linux/net/rxrpc/txbuf.c