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
37 #include "rds.h"
38 #include "tcp.h"
39
40 static struct kmem_cache *rds_tcp_incoming_slab;
41
rds_tcp_inc_purge(struct rds_incoming * inc)42 static void rds_tcp_inc_purge(struct rds_incoming *inc)
43 {
44 struct rds_tcp_incoming *tinc;
45 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
46 rdsdebug("purging tinc %p inc %p\n", tinc, inc);
47 skb_queue_purge(&tinc->ti_skb_list);
48 }
49
rds_tcp_inc_free(struct rds_incoming * inc)50 void rds_tcp_inc_free(struct rds_incoming *inc)
51 {
52 struct rds_tcp_incoming *tinc;
53 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
54 rds_tcp_inc_purge(inc);
55 rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
56 kmem_cache_free(rds_tcp_incoming_slab, tinc);
57 }
58
59 /*
60 * this is pretty lame, but, whatever.
61 */
rds_tcp_inc_copy_to_user(struct rds_incoming * inc,struct iov_iter * to)62 int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
63 {
64 struct rds_tcp_incoming *tinc;
65 struct sk_buff *skb;
66 int ret = 0;
67
68 if (!iov_iter_count(to))
69 goto out;
70
71 tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
72
73 skb_queue_walk(&tinc->ti_skb_list, skb) {
74 unsigned long to_copy, skb_off;
75 for (skb_off = 0; skb_off < skb->len; skb_off += to_copy) {
76 to_copy = iov_iter_count(to);
77 to_copy = min(to_copy, skb->len - skb_off);
78
79 if (skb_copy_datagram_iter(skb, skb_off, to, to_copy))
80 return -EFAULT;
81
82 rds_stats_add(s_copy_to_user, to_copy);
83 ret += to_copy;
84
85 if (!iov_iter_count(to))
86 goto out;
87 }
88 }
89 out:
90 return ret;
91 }
92
93 /*
94 * We have a series of skbs that have fragmented pieces of the congestion
95 * bitmap. They must add up to the exact size of the congestion bitmap. We
96 * use the skb helpers to copy those into the pages that make up the in-memory
97 * congestion bitmap for the remote address of this connection. We then tell
98 * the congestion core that the bitmap has been changed so that it can wake up
99 * sleepers.
100 *
101 * This is racing with sending paths which are using test_bit to see if the
102 * bitmap indicates that their recipient is congested.
103 */
104
rds_tcp_cong_recv(struct rds_connection * conn,struct rds_tcp_incoming * tinc)105 static void rds_tcp_cong_recv(struct rds_connection *conn,
106 struct rds_tcp_incoming *tinc)
107 {
108 struct sk_buff *skb;
109 unsigned int to_copy, skb_off;
110 unsigned int map_off;
111 unsigned int map_page;
112 struct rds_cong_map *map;
113 int ret;
114
115 /* catch completely corrupt packets */
116 if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
117 return;
118
119 map_page = 0;
120 map_off = 0;
121 map = conn->c_fcong;
122
123 skb_queue_walk(&tinc->ti_skb_list, skb) {
124 skb_off = 0;
125 while (skb_off < skb->len) {
126 to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
127 skb->len - skb_off);
128
129 BUG_ON(map_page >= RDS_CONG_MAP_PAGES);
130
131 /* only returns 0 or -error */
132 ret = skb_copy_bits(skb, skb_off,
133 (void *)map->m_page_addrs[map_page] + map_off,
134 to_copy);
135 BUG_ON(ret != 0);
136
137 skb_off += to_copy;
138 map_off += to_copy;
139 if (map_off == PAGE_SIZE) {
140 map_off = 0;
141 map_page++;
142 }
143 }
144 }
145
146 rds_cong_map_updated(map, ~(u64) 0);
147 }
148
149 struct rds_tcp_desc_arg {
150 struct rds_conn_path *conn_path;
151 gfp_t gfp;
152 };
153
rds_tcp_data_recv(read_descriptor_t * desc,struct sk_buff * skb,unsigned int offset,size_t len)154 static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
155 unsigned int offset, size_t len)
156 {
157 struct rds_tcp_desc_arg *arg = desc->arg.data;
158 struct rds_conn_path *cp = arg->conn_path;
159 struct rds_tcp_connection *tc = cp->cp_transport_data;
160 struct rds_tcp_incoming *tinc = tc->t_tinc;
161 struct sk_buff *clone;
162 size_t left = len, to_copy;
163
164 rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
165 len);
166
167 /*
168 * tcp_read_sock() interprets partial progress as an indication to stop
169 * processing.
170 */
171 while (left) {
172 if (!tinc) {
173 tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
174 arg->gfp);
175 if (!tinc) {
176 desc->error = -ENOMEM;
177 goto out;
178 }
179 tc->t_tinc = tinc;
180 rdsdebug("allocated tinc %p\n", tinc);
181 rds_inc_path_init(&tinc->ti_inc, cp,
182 &cp->cp_conn->c_faddr);
183 tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
184 local_clock();
185
186 /*
187 * XXX * we might be able to use the __ variants when
188 * we've already serialized at a higher level.
189 */
190 skb_queue_head_init(&tinc->ti_skb_list);
191 }
192
193 if (left && tc->t_tinc_hdr_rem) {
194 to_copy = min(tc->t_tinc_hdr_rem, left);
195 rdsdebug("copying %zu header from skb %p\n", to_copy,
196 skb);
197 skb_copy_bits(skb, offset,
198 (char *)&tinc->ti_inc.i_hdr +
199 sizeof(struct rds_header) -
200 tc->t_tinc_hdr_rem,
201 to_copy);
202 tc->t_tinc_hdr_rem -= to_copy;
203 left -= to_copy;
204 offset += to_copy;
205
206 if (tc->t_tinc_hdr_rem == 0) {
207 /* could be 0 for a 0 len message */
208 tc->t_tinc_data_rem =
209 be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
210 tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
211 local_clock();
212 }
213 }
214
215 if (left && tc->t_tinc_data_rem) {
216 to_copy = min(tc->t_tinc_data_rem, left);
217
218 clone = pskb_extract(skb, offset, to_copy, arg->gfp);
219 if (!clone) {
220 desc->error = -ENOMEM;
221 goto out;
222 }
223
224 skb_queue_tail(&tinc->ti_skb_list, clone);
225
226 rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
227 "clone %p data %p len %d\n",
228 skb, skb->data, skb->len, offset, to_copy,
229 clone, clone->data, clone->len);
230
231 tc->t_tinc_data_rem -= to_copy;
232 left -= to_copy;
233 offset += to_copy;
234 }
235
236 if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
237 struct rds_connection *conn = cp->cp_conn;
238
239 if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
240 rds_tcp_cong_recv(conn, tinc);
241 else
242 rds_recv_incoming(conn, &conn->c_faddr,
243 &conn->c_laddr,
244 &tinc->ti_inc,
245 arg->gfp);
246
247 tc->t_tinc_hdr_rem = sizeof(struct rds_header);
248 tc->t_tinc_data_rem = 0;
249 tc->t_tinc = NULL;
250 rds_inc_put(&tinc->ti_inc);
251 tinc = NULL;
252 }
253 }
254 out:
255 rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
256 len, left, skb->len,
257 skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
258 return len - left;
259 }
260
261 /* the caller has to hold the sock lock */
rds_tcp_read_sock(struct rds_conn_path * cp,gfp_t gfp)262 static int rds_tcp_read_sock(struct rds_conn_path *cp, gfp_t gfp)
263 {
264 struct rds_tcp_connection *tc = cp->cp_transport_data;
265 struct socket *sock = tc->t_sock;
266 read_descriptor_t desc;
267 struct rds_tcp_desc_arg arg;
268
269 /* It's like glib in the kernel! */
270 arg.conn_path = cp;
271 arg.gfp = gfp;
272 desc.arg.data = &arg;
273 desc.error = 0;
274 desc.count = 1; /* give more than one skb per call */
275
276 tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
277 rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
278 desc.error);
279
280 return desc.error;
281 }
282
283 /*
284 * We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
285 * data_ready.
286 *
287 * if we fail to allocate we're in trouble.. blindly wait some time before
288 * trying again to see if the VM can free up something for us.
289 */
rds_tcp_recv_path(struct rds_conn_path * cp)290 int rds_tcp_recv_path(struct rds_conn_path *cp)
291 {
292 struct rds_tcp_connection *tc = cp->cp_transport_data;
293 struct socket *sock = tc->t_sock;
294 int ret = 0;
295
296 rdsdebug("recv worker path [%d] tc %p sock %p\n",
297 cp->cp_index, tc, sock);
298
299 lock_sock(sock->sk);
300 ret = rds_tcp_read_sock(cp, GFP_KERNEL);
301 release_sock(sock->sk);
302
303 return ret;
304 }
305
rds_tcp_data_ready(struct sock * sk)306 void rds_tcp_data_ready(struct sock *sk)
307 {
308 void (*ready)(struct sock *sk);
309 struct rds_conn_path *cp;
310 struct rds_tcp_connection *tc;
311
312 rdsdebug("data ready sk %p\n", sk);
313
314 read_lock_bh(&sk->sk_callback_lock);
315 cp = sk->sk_user_data;
316 if (!cp) { /* check for teardown race */
317 ready = sk->sk_data_ready;
318 goto out;
319 }
320
321 tc = cp->cp_transport_data;
322 ready = tc->t_orig_data_ready;
323 rds_tcp_stats_inc(s_tcp_data_ready_calls);
324
325 if (rds_tcp_read_sock(cp, GFP_ATOMIC) == -ENOMEM) {
326 rcu_read_lock();
327 if (!rds_destroy_pending(cp->cp_conn))
328 queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
329 rcu_read_unlock();
330 }
331 out:
332 read_unlock_bh(&sk->sk_callback_lock);
333 ready(sk);
334 }
335
rds_tcp_recv_init(void)336 int rds_tcp_recv_init(void)
337 {
338 rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
339 sizeof(struct rds_tcp_incoming),
340 0, 0, NULL);
341 if (!rds_tcp_incoming_slab)
342 return -ENOMEM;
343 return 0;
344 }
345
rds_tcp_recv_exit(void)346 void rds_tcp_recv_exit(void)
347 {
348 kmem_cache_destroy(rds_tcp_incoming_slab);
349 }
350