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 41static struct kmem_cache *rds_tcp_incoming_slab; 42 43static 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 51void 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 */ 63int 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 } 90out: 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 106static 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 150struct rds_tcp_desc_arg { 151 struct rds_conn_path *conn_path; 152 gfp_t gfp; 153}; 154 155static 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 } 255out: 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 */ 263static 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 */ 291int 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 307void 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 } 333out: 334 read_unlock_bh(&sk->sk_callback_lock); 335 ready(sk); 336} 337 338int rds_tcp_recv_init(void) 339{ 340 rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming", 341 sizeof(struct rds_tcp_incoming), 342 0, 0, NULL); 343 if (!rds_tcp_incoming_slab) 344 return -ENOMEM; 345 return 0; 346} 347 348void rds_tcp_recv_exit(void) 349{ 350 kmem_cache_destroy(rds_tcp_incoming_slab); 351} 352