1 /*
2 * Copyright (c) 2006, 2017 Oracle and/or its affiliates. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <net/tcp.h>
36 #include <trace/events/sock.h>
37
38 #include "rds.h"
39 #include "tcp.h"
40
41 static struct kmem_cache *rds_tcp_incoming_slab;
42
43 static void rds_tcp_inc_purge(struct rds_incoming *inc)
44 {
45 struct rds_tcp_incoming *tinc;
46 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
47 rdsdebug("purging tinc %p inc %p\n", tinc, inc);
48 skb_queue_purge(&tinc->ti_skb_list);
49 }
50
51 void rds_tcp_inc_free(struct rds_incoming *inc)
52 {
53 struct rds_tcp_incoming *tinc;
54 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
55 rds_tcp_inc_purge(inc);
56 rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
57 kmem_cache_free(rds_tcp_incoming_slab, tinc);
58 }
59
60 /*
61 * this is pretty lame, but, whatever.
62 */
63 int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
64 {
65 struct rds_tcp_incoming *tinc;
66 struct sk_buff *skb;
67 int ret = 0;
68
69 if (!iov_iter_count(to))
70 goto out;
71
72 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
73
74 skb_queue_walk(&tinc->ti_skb_list, skb) {
75 unsigned long to_copy, skb_off;
76 for (skb_off = 0; skb_off < skb->len; skb_off += to_copy) {
77 to_copy = iov_iter_count(to);
78 to_copy = min(to_copy, skb->len - skb_off);
79
80 if (skb_copy_datagram_iter(skb, skb_off, to, to_copy))
81 return -EFAULT;
82
83 rds_stats_add(s_copy_to_user, to_copy);
84 ret += to_copy;
85
86 if (!iov_iter_count(to))
87 goto out;
88 }
89 }
90 out:
91 return ret;
92 }
93
94 /*
95 * We have a series of skbs that have fragmented pieces of the congestion
96 * bitmap. They must add up to the exact size of the congestion bitmap. We
97 * use the skb helpers to copy those into the pages that make up the in-memory
98 * congestion bitmap for the remote address of this connection. We then tell
99 * the congestion core that the bitmap has been changed so that it can wake up
100 * sleepers.
101 *
102 * This is racing with sending paths which are using test_bit to see if the
103 * bitmap indicates that their recipient is congested.
104 */
105
106 static void rds_tcp_cong_recv(struct rds_connection *conn,
107 struct rds_tcp_incoming *tinc)
108 {
109 struct sk_buff *skb;
110 unsigned int to_copy, skb_off;
111 unsigned int map_off;
112 unsigned int map_page;
113 struct rds_cong_map *map;
114 int ret;
115
116 /* catch completely corrupt packets */
117 if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
118 return;
119
120 map_page = 0;
121 map_off = 0;
122 map = conn->c_fcong;
123
124 skb_queue_walk(&tinc->ti_skb_list, skb) {
125 skb_off = 0;
126 while (skb_off < skb->len) {
127 to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
128 skb->len - skb_off);
129
130 BUG_ON(map_page >= RDS_CONG_MAP_PAGES);
131
132 /* only returns 0 or -error */
133 ret = skb_copy_bits(skb, skb_off,
134 (void *)map->m_page_addrs[map_page] + map_off,
135 to_copy);
136 BUG_ON(ret != 0);
137
138 skb_off += to_copy;
139 map_off += to_copy;
140 if (map_off == PAGE_SIZE) {
141 map_off = 0;
142 map_page++;
143 }
144 }
145 }
146
147 rds_cong_map_updated(map, ~(u64) 0);
148 }
149
150 struct rds_tcp_desc_arg {
151 struct rds_conn_path *conn_path;
152 gfp_t gfp;
153 };
154
155 static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
156 unsigned int offset, size_t len)
157 {
158 struct rds_tcp_desc_arg *arg = desc->arg.data;
159 struct rds_conn_path *cp = arg->conn_path;
160 struct rds_tcp_connection *tc = cp->cp_transport_data;
161 struct rds_tcp_incoming *tinc = tc->t_tinc;
162 struct sk_buff *clone;
163 size_t left = len, to_copy;
164
165 rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
166 len);
167
168 /*
169 * tcp_read_sock() interprets partial progress as an indication to stop
170 * processing.
171 */
172 while (left) {
173 if (!tinc) {
174 tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
175 arg->gfp);
176 if (!tinc) {
177 desc->error = -ENOMEM;
178 goto out;
179 }
180 tc->t_tinc = tinc;
181 rdsdebug("allocated tinc %p\n", tinc);
182 rds_inc_path_init(&tinc->ti_inc, cp,
183 &cp->cp_conn->c_faddr);
184 tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
185 local_clock();
186
187 /*
188 * XXX * we might be able to use the __ variants when
189 * we've already serialized at a higher level.
190 */
191 skb_queue_head_init(&tinc->ti_skb_list);
192 }
193
194 if (left && tc->t_tinc_hdr_rem) {
195 to_copy = min(tc->t_tinc_hdr_rem, left);
196 rdsdebug("copying %zu header from skb %p\n", to_copy,
197 skb);
198 skb_copy_bits(skb, offset,
199 (char *)&tinc->ti_inc.i_hdr +
200 sizeof(struct rds_header) -
201 tc->t_tinc_hdr_rem,
202 to_copy);
203 tc->t_tinc_hdr_rem -= to_copy;
204 left -= to_copy;
205 offset += to_copy;
206
207 if (tc->t_tinc_hdr_rem == 0) {
208 /* could be 0 for a 0 len message */
209 tc->t_tinc_data_rem =
210 be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
211 tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
212 local_clock();
213 }
214 }
215
216 if (left && tc->t_tinc_data_rem) {
217 to_copy = min(tc->t_tinc_data_rem, left);
218
219 clone = pskb_extract(skb, offset, to_copy, arg->gfp);
220 if (!clone) {
221 desc->error = -ENOMEM;
222 goto out;
223 }
224
225 skb_queue_tail(&tinc->ti_skb_list, clone);
226
227 rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
228 "clone %p data %p len %d\n",
229 skb, skb->data, skb->len, offset, to_copy,
230 clone, clone->data, clone->len);
231
232 tc->t_tinc_data_rem -= to_copy;
233 left -= to_copy;
234 offset += to_copy;
235 }
236
237 if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
238 struct rds_connection *conn = cp->cp_conn;
239
240 if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
241 rds_tcp_cong_recv(conn, tinc);
242 else
243 rds_recv_incoming(conn, &conn->c_faddr,
244 &conn->c_laddr,
245 &tinc->ti_inc,
246 arg->gfp);
247
248 tc->t_tinc_hdr_rem = sizeof(struct rds_header);
249 tc->t_tinc_data_rem = 0;
250 tc->t_tinc = NULL;
251 rds_inc_put(&tinc->ti_inc);
252 tinc = NULL;
253 }
254 }
255 out:
256 rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
257 len, left, skb->len,
258 skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
259 return len - left;
260 }
261
262 /* the caller has to hold the sock lock */
263 static int rds_tcp_read_sock(struct rds_conn_path *cp, gfp_t gfp)
264 {
265 struct rds_tcp_connection *tc = cp->cp_transport_data;
266 struct socket *sock = tc->t_sock;
267 read_descriptor_t desc;
268 struct rds_tcp_desc_arg arg;
269
270 /* It's like glib in the kernel! */
271 arg.conn_path = cp;
272 arg.gfp = gfp;
273 desc.arg.data = &arg;
274 desc.error = 0;
275 desc.count = 1; /* give more than one skb per call */
276
277 tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
278 rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
279 desc.error);
280
281 return desc.error;
282 }
283
284 /*
285 * We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
286 * data_ready.
287 *
288 * if we fail to allocate we're in trouble.. blindly wait some time before
289 * trying again to see if the VM can free up something for us.
290 */
291 int rds_tcp_recv_path(struct rds_conn_path *cp)
292 {
293 struct rds_tcp_connection *tc = cp->cp_transport_data;
294 struct socket *sock = tc->t_sock;
295 int ret = 0;
296
297 rdsdebug("recv worker path [%d] tc %p sock %p\n",
298 cp->cp_index, tc, sock);
299
300 lock_sock(sock->sk);
301 ret = rds_tcp_read_sock(cp, GFP_KERNEL);
302 release_sock(sock->sk);
303
304 return ret;
305 }
306
307 void rds_tcp_data_ready(struct sock *sk)
308 {
309 void (*ready)(struct sock *sk);
310 struct rds_conn_path *cp;
311 struct rds_tcp_connection *tc;
312
313 trace_sk_data_ready(sk);
314 rdsdebug("data ready sk %p\n", sk);
315
316 read_lock_bh(&sk->sk_callback_lock);
317 cp = sk->sk_user_data;
318 if (!cp) { /* check for teardown race */
319 ready = sk->sk_data_ready;
320 goto out;
321 }
322
323 tc = cp->cp_transport_data;
324 ready = tc->t_orig_data_ready;
325 rds_tcp_stats_inc(s_tcp_data_ready_calls);
326
327 if (rds_tcp_read_sock(cp, GFP_ATOMIC) == -ENOMEM) {
328 rcu_read_lock();
329 if (!rds_destroy_pending(cp->cp_conn))
330 queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
331 rcu_read_unlock();
332 }
333 out:
334 read_unlock_bh(&sk->sk_callback_lock);
335 ready(sk);
336 }
337
338 int rds_tcp_recv_init(void)
339 {
340 rds_tcp_incoming_slab = KMEM_CACHE(rds_tcp_incoming, 0);
341 if (!rds_tcp_incoming_slab)
342 return -ENOMEM;
343 return 0;
344 }
345
346 void rds_tcp_recv_exit(void)
347 {
348 kmem_cache_destroy(rds_tcp_incoming_slab);
349 }
350
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