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
13 static atomic_t rxrpc_txbuf_debug_ids;
14 atomic_t rxrpc_nr_txbuf;
15
16 /*
17 * Allocate and partially initialise a data transmission buffer.
18 */
19 struct 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_wire_header *whdr;
23 struct rxrpc_txbuf *txb;
24 size_t total, hoff;
25 void *buf;
26
27 txb = kmalloc(sizeof(*txb), gfp);
28 if (!txb)
29 return NULL;
30
31 hoff = round_up(sizeof(*whdr), data_align) - sizeof(*whdr);
32 total = hoff + sizeof(*whdr) + data_size;
33
34 data_align = umax(data_align, L1_CACHE_BYTES);
35 mutex_lock(&call->conn->tx_data_alloc_lock);
36 buf = page_frag_alloc_align(&call->conn->tx_data_alloc, total, gfp,
37 data_align);
38 mutex_unlock(&call->conn->tx_data_alloc_lock);
39 if (!buf) {
40 kfree(txb);
41 return NULL;
42 }
43
44 whdr = buf + hoff;
45
46 INIT_LIST_HEAD(&txb->call_link);
47 INIT_LIST_HEAD(&txb->tx_link);
48 refcount_set(&txb->ref, 1);
49 txb->last_sent = KTIME_MIN;
50 txb->call_debug_id = call->debug_id;
51 txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids);
52 txb->space = data_size;
53 txb->len = 0;
54 txb->offset = sizeof(*whdr);
55 txb->flags = call->conn->out_clientflag;
56 txb->ack_why = 0;
57 txb->seq = call->tx_prepared + 1;
58 txb->serial = 0;
59 txb->cksum = 0;
60 txb->nr_kvec = 1;
61 txb->kvec[0].iov_base = whdr;
62 txb->kvec[0].iov_len = sizeof(*whdr);
63
64 whdr->epoch = htonl(call->conn->proto.epoch);
65 whdr->cid = htonl(call->cid);
66 whdr->callNumber = htonl(call->call_id);
67 whdr->seq = htonl(txb->seq);
68 whdr->type = RXRPC_PACKET_TYPE_DATA;
69 whdr->flags = 0;
70 whdr->userStatus = 0;
71 whdr->securityIndex = call->security_ix;
72 whdr->_rsvd = 0;
73 whdr->serviceId = htons(call->dest_srx.srx_service);
74
75 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 1,
76 rxrpc_txbuf_alloc_data);
77
78 atomic_inc(&rxrpc_nr_txbuf);
79 return txb;
80 }
81
82 /*
83 * Allocate and partially initialise an ACK packet.
84 */
85 struct rxrpc_txbuf *rxrpc_alloc_ack_txbuf(struct rxrpc_call *call, size_t sack_size)
86 {
87 struct rxrpc_wire_header *whdr;
88 struct rxrpc_acktrailer *trailer;
89 struct rxrpc_ackpacket *ack;
90 struct rxrpc_txbuf *txb;
91 gfp_t gfp = rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS;
92 void *buf, *buf2 = NULL;
93 u8 *filler;
94
95 txb = kmalloc(sizeof(*txb), gfp);
96 if (!txb)
97 return NULL;
98
99 buf = page_frag_alloc(&call->local->tx_alloc,
100 sizeof(*whdr) + sizeof(*ack) + 1 + 3 + sizeof(*trailer), gfp);
101 if (!buf) {
102 kfree(txb);
103 return NULL;
104 }
105
106 if (sack_size) {
107 buf2 = page_frag_alloc(&call->local->tx_alloc, sack_size, gfp);
108 if (!buf2) {
109 page_frag_free(buf);
110 kfree(txb);
111 return NULL;
112 }
113 }
114
115 whdr = buf;
116 ack = buf + sizeof(*whdr);
117 filler = buf + sizeof(*whdr) + sizeof(*ack) + 1;
118 trailer = buf + sizeof(*whdr) + sizeof(*ack) + 1 + 3;
119
120 INIT_LIST_HEAD(&txb->call_link);
121 INIT_LIST_HEAD(&txb->tx_link);
122 refcount_set(&txb->ref, 1);
123 txb->call_debug_id = call->debug_id;
124 txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids);
125 txb->space = 0;
126 txb->len = sizeof(*whdr) + sizeof(*ack) + 3 + sizeof(*trailer);
127 txb->offset = 0;
128 txb->flags = call->conn->out_clientflag;
129 txb->ack_rwind = 0;
130 txb->seq = 0;
131 txb->serial = 0;
132 txb->cksum = 0;
133 txb->nr_kvec = 3;
134 txb->kvec[0].iov_base = whdr;
135 txb->kvec[0].iov_len = sizeof(*whdr) + sizeof(*ack);
136 txb->kvec[1].iov_base = buf2;
137 txb->kvec[1].iov_len = sack_size;
138 txb->kvec[2].iov_base = filler;
139 txb->kvec[2].iov_len = 3 + sizeof(*trailer);
140
141 whdr->epoch = htonl(call->conn->proto.epoch);
142 whdr->cid = htonl(call->cid);
143 whdr->callNumber = htonl(call->call_id);
144 whdr->seq = 0;
145 whdr->type = RXRPC_PACKET_TYPE_ACK;
146 whdr->flags = 0;
147 whdr->userStatus = 0;
148 whdr->securityIndex = call->security_ix;
149 whdr->_rsvd = 0;
150 whdr->serviceId = htons(call->dest_srx.srx_service);
151
152 get_page(virt_to_head_page(trailer));
153
154 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 1,
155 rxrpc_txbuf_alloc_ack);
156 atomic_inc(&rxrpc_nr_txbuf);
157 return txb;
158 }
159
160 void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
161 {
162 int r;
163
164 __refcount_inc(&txb->ref, &r);
165 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r + 1, what);
166 }
167
168 void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
169 {
170 int r = refcount_read(&txb->ref);
171
172 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r, what);
173 }
174
175 static void rxrpc_free_txbuf(struct rxrpc_txbuf *txb)
176 {
177 int i;
178
179 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 0,
180 rxrpc_txbuf_free);
181 for (i = 0; i < txb->nr_kvec; i++)
182 if (txb->kvec[i].iov_base)
183 page_frag_free(txb->kvec[i].iov_base);
184 kfree(txb);
185 atomic_dec(&rxrpc_nr_txbuf);
186 }
187
188 void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
189 {
190 unsigned int debug_id, call_debug_id;
191 rxrpc_seq_t seq;
192 bool dead;
193 int r;
194
195 if (txb) {
196 debug_id = txb->debug_id;
197 call_debug_id = txb->call_debug_id;
198 seq = txb->seq;
199 dead = __refcount_dec_and_test(&txb->ref, &r);
200 trace_rxrpc_txbuf(debug_id, call_debug_id, seq, r - 1, what);
201 if (dead)
202 rxrpc_free_txbuf(txb);
203 }
204 }
205
206 /*
207 * Shrink the transmit buffer.
208 */
209 void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call)
210 {
211 struct rxrpc_txbuf *txb;
212 rxrpc_seq_t hard_ack = smp_load_acquire(&call->acks_hard_ack);
213 bool wake = false;
214
215 _enter("%x/%x/%x", call->tx_bottom, call->acks_hard_ack, call->tx_top);
216
217 while ((txb = list_first_entry_or_null(&call->tx_buffer,
218 struct rxrpc_txbuf, call_link))) {
219 hard_ack = smp_load_acquire(&call->acks_hard_ack);
220 if (before(hard_ack, txb->seq))
221 break;
222
223 if (txb->seq != call->tx_bottom + 1)
224 rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step);
225 ASSERTCMP(txb->seq, ==, call->tx_bottom + 1);
226 smp_store_release(&call->tx_bottom, call->tx_bottom + 1);
227 list_del_rcu(&txb->call_link);
228
229 trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);
230
231 rxrpc_put_txbuf(txb, rxrpc_txbuf_put_rotated);
232 if (after(call->acks_hard_ack, call->tx_bottom + 128))
233 wake = true;
234 }
235
236 if (wake)
237 wake_up(&call->waitq);
238 }
239
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.