net/xdp/xsk.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* XDP sockets
   3  *
   4  * AF_XDP sockets allows a channel between XDP programs and userspace
   5  * applications.
   6  * Copyright(c) 2018 Intel Corporation.
   7  *
   8  * Author(s): Björn Töpel <bjorn.topel@intel.com>
   9  *            Magnus Karlsson <magnus.karlsson@intel.com>
  10  */
  11
  12 #define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
  13
  14 #include <linux/if_xdp.h>
  15 #include <linux/init.h>
  16 #include <linux/sched/mm.h>
  17 #include <linux/sched/signal.h>
  18 #include <linux/sched/task.h>
  19 #include <linux/socket.h>
  20 #include <linux/file.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/net.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/rculist.h>
  25 #include <net/xdp_sock_drv.h>
  26 #include <net/busy_poll.h>
  27 #include <net/xdp.h>
  28
  29 #include "xsk_queue.h"
  30 #include "xdp_umem.h"
  31 #include "xsk.h"
  32
  33 #define TX_BATCH_SIZE 16
  34
  35 static DEFINE_PER_CPU(struct list_head, xskmap_flush_list);
  36
  37 void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool)
  38 {
  39         if (pool->cached_need_wakeup & XDP_WAKEUP_RX)
  40                 return;
  41
  42         pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP;
  43         pool->cached_need_wakeup |= XDP_WAKEUP_RX;
  44 }
  45 EXPORT_SYMBOL(xsk_set_rx_need_wakeup);
  46
  47 void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool)
  48 {
  49         struct xdp_sock *xs;
  50
  51         if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
  52                 return;
  53
  54         rcu_read_lock();
  55         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
  56                 xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
  57         }
  58         rcu_read_unlock();
  59
  60         pool->cached_need_wakeup |= XDP_WAKEUP_TX;
  61 }
  62 EXPORT_SYMBOL(xsk_set_tx_need_wakeup);
  63
  64 void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool)
  65 {
  66         if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX))
  67                 return;
  68
  69         pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP;
  70         pool->cached_need_wakeup &= ~XDP_WAKEUP_RX;
  71 }
  72 EXPORT_SYMBOL(xsk_clear_rx_need_wakeup);
  73
  74 void xsk_clear_tx_need_wakeup(struct xsk_buff_pool *pool)
  75 {
  76         struct xdp_sock *xs;
  77
  78         if (!(pool->cached_need_wakeup & XDP_WAKEUP_TX))
  79                 return;
  80
  81         rcu_read_lock();
  82         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
  83                 xs->tx->ring->flags &= ~XDP_RING_NEED_WAKEUP;
  84         }
  85         rcu_read_unlock();
  86
  87         pool->cached_need_wakeup &= ~XDP_WAKEUP_TX;
  88 }
  89 EXPORT_SYMBOL(xsk_clear_tx_need_wakeup);
  90
  91 bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool)
  92 {
  93         return pool->uses_need_wakeup;
  94 }
  95 EXPORT_SYMBOL(xsk_uses_need_wakeup);
  96
  97 struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
  98                                             u16 queue_id)
  99 {
 100         if (queue_id < dev->real_num_rx_queues)
 101                 return dev->_rx[queue_id].pool;
 102         if (queue_id < dev->real_num_tx_queues)
 103                 return dev->_tx[queue_id].pool;
 104
 105         return NULL;
 106 }
 107 EXPORT_SYMBOL(xsk_get_pool_from_qid);
 108
 109 void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
 110 {
 111         if (queue_id < dev->real_num_rx_queues)
 112                 dev->_rx[queue_id].pool = NULL;
 113         if (queue_id < dev->real_num_tx_queues)
 114                 dev->_tx[queue_id].pool = NULL;
 115 }
 116
 117 /* The buffer pool is stored both in the _rx struct and the _tx struct as we do
 118  * not know if the device has more tx queues than rx, or the opposite.
 119  * This might also change during run time.
 120  */
 121 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
 122                         u16 queue_id)
 123 {
 124         if (queue_id >= max_t(unsigned int,
 125                               dev->real_num_rx_queues,
 126                               dev->real_num_tx_queues))
 127                 return -EINVAL;
 128
 129         if (queue_id < dev->real_num_rx_queues)
 130                 dev->_rx[queue_id].pool = pool;
 131         if (queue_id < dev->real_num_tx_queues)
 132                 dev->_tx[queue_id].pool = pool;
 133
 134         return 0;
 135 }
 136
 137 void xp_release(struct xdp_buff_xsk *xskb)
 138 {
 139         xskb->pool->free_heads[xskb->pool->free_heads_cnt++] = xskb;
 140 }
 141
 142 static u64 xp_get_handle(struct xdp_buff_xsk *xskb)
 143 {
 144         u64 offset = xskb->xdp.data - xskb->xdp.data_hard_start;
 145
 146         offset += xskb->pool->headroom;
 147         if (!xskb->pool->unaligned)
 148                 return xskb->orig_addr + offset;
 149         return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
 150 }
 151
 152 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 153 {
 154         struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
 155         u64 addr;
 156         int err;
 157
 158         addr = xp_get_handle(xskb);
 159         err = xskq_prod_reserve_desc(xs->rx, addr, len);
 160         if (err) {
 161                 xs->rx_queue_full++;
 162                 return err;
 163         }
 164
 165         xp_release(xskb);
 166         return 0;
 167 }
 168
 169 static void xsk_copy_xdp(struct xdp_buff *to, struct xdp_buff *from, u32 len)
 170 {
 171         void *from_buf, *to_buf;
 172         u32 metalen;
 173
 174         if (unlikely(xdp_data_meta_unsupported(from))) {
 175                 from_buf = from->data;
 176                 to_buf = to->data;
 177                 metalen = 0;
 178         } else {
 179                 from_buf = from->data_meta;
 180                 metalen = from->data - from->data_meta;
 181                 to_buf = to->data - metalen;
 182         }
 183
 184         memcpy(to_buf, from_buf, len + metalen);
 185 }
 186
 187 static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len,
 188                      bool explicit_free)
 189 {
 190         struct xdp_buff *xsk_xdp;
 191         int err;
 192
 193         if (len > xsk_pool_get_rx_frame_size(xs->pool)) {
 194                 xs->rx_dropped++;
 195                 return -ENOSPC;
 196         }
 197
 198         xsk_xdp = xsk_buff_alloc(xs->pool);
 199         if (!xsk_xdp) {
 200                 xs->rx_dropped++;
 201                 return -ENOSPC;
 202         }
 203
 204         xsk_copy_xdp(xsk_xdp, xdp, len);
 205         err = __xsk_rcv_zc(xs, xsk_xdp, len);
 206         if (err) {
 207                 xsk_buff_free(xsk_xdp);
 208                 return err;
 209         }
 210         if (explicit_free)
 211                 xdp_return_buff(xdp);
 212         return 0;
 213 }
 214
 215 static bool xsk_tx_writeable(struct xdp_sock *xs)
 216 {
 217         if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2)
 218                 return false;
 219
 220         return true;
 221 }
 222
 223 static bool xsk_is_bound(struct xdp_sock *xs)
 224 {
 225         if (READ_ONCE(xs->state) == XSK_BOUND) {
 226                 /* Matches smp_wmb() in bind(). */
 227                 smp_rmb();
 228                 return true;
 229         }
 230         return false;
 231 }
 232
 233 static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp,
 234                    bool explicit_free)
 235 {
 236         u32 len;
 237
 238         if (!xsk_is_bound(xs))
 239                 return -EINVAL;
 240
 241         if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
 242                 return -EINVAL;
 243
 244         sk_mark_napi_id_once_xdp(&xs->sk, xdp);
 245         len = xdp->data_end - xdp->data;
 246
 247         return xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL ?
 248                 __xsk_rcv_zc(xs, xdp, len) :
 249                 __xsk_rcv(xs, xdp, len, explicit_free);
 250 }
 251
 252 static void xsk_flush(struct xdp_sock *xs)
 253 {
 254         xskq_prod_submit(xs->rx);
 255         __xskq_cons_release(xs->pool->fq);
 256         sock_def_readable(&xs->sk);
 257 }
 258
 259 int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 260 {
 261         int err;
 262
 263         spin_lock_bh(&xs->rx_lock);
 264         err = xsk_rcv(xs, xdp, false);
 265         xsk_flush(xs);
 266         spin_unlock_bh(&xs->rx_lock);
 267         return err;
 268 }
 269
 270 int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
 271 {
 272         struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
 273         int err;
 274
 275         err = xsk_rcv(xs, xdp, true);
 276         if (err)
 277                 return err;
 278
 279         if (!xs->flush_node.prev)
 280                 list_add(&xs->flush_node, flush_list);
 281
 282         return 0;
 283 }
 284
 285 void __xsk_map_flush(void)
 286 {
 287         struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
 288         struct xdp_sock *xs, *tmp;
 289
 290         list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
 291                 xsk_flush(xs);
 292                 __list_del_clearprev(&xs->flush_node);
 293         }
 294 }
 295
 296 void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries)
 297 {
 298         xskq_prod_submit_n(pool->cq, nb_entries);
 299 }
 300 EXPORT_SYMBOL(xsk_tx_completed);
 301
 302 void xsk_tx_release(struct xsk_buff_pool *pool)
 303 {
 304         struct xdp_sock *xs;
 305
 306         rcu_read_lock();
 307         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
 308                 __xskq_cons_release(xs->tx);
 309                 if (xsk_tx_writeable(xs))
 310                         xs->sk.sk_write_space(&xs->sk);
 311         }
 312         rcu_read_unlock();
 313 }
 314 EXPORT_SYMBOL(xsk_tx_release);
 315
 316 bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc)
 317 {
 318         struct xdp_sock *xs;
 319
 320         rcu_read_lock();
 321         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
 322                 if (!xskq_cons_peek_desc(xs->tx, desc, pool)) {
 323                         xs->tx->queue_empty_descs++;
 324                         continue;
 325                 }
 326
 327                 /* This is the backpressure mechanism for the Tx path.
 328                  * Reserve space in the completion queue and only proceed
 329                  * if there is space in it. This avoids having to implement
 330                  * any buffering in the Tx path.
 331                  */
 332                 if (xskq_prod_reserve_addr(pool->cq, desc->addr))
 333                         goto out;
 334
 335                 xskq_cons_release(xs->tx);
 336                 rcu_read_unlock();
 337                 return true;
 338         }
 339
 340 out:
 341         rcu_read_unlock();
 342         return false;
 343 }
 344 EXPORT_SYMBOL(xsk_tx_peek_desc);
 345
 346 static u32 xsk_tx_peek_release_fallback(struct xsk_buff_pool *pool, struct xdp_desc *descs,
 347                                         u32 max_entries)
 348 {
 349         u32 nb_pkts = 0;
 350
 351         while (nb_pkts < max_entries && xsk_tx_peek_desc(pool, &descs[nb_pkts]))
 352                 nb_pkts++;
 353
 354         xsk_tx_release(pool);
 355         return nb_pkts;
 356 }
 357
 358 u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, struct xdp_desc *descs,
 359                                    u32 max_entries)
 360 {
 361         struct xdp_sock *xs;
 362         u32 nb_pkts;
 363
 364         rcu_read_lock();
 365         if (!list_is_singular(&pool->xsk_tx_list)) {
 366                 /* Fallback to the non-batched version */
 367                 rcu_read_unlock();
 368                 return xsk_tx_peek_release_fallback(pool, descs, max_entries);
 369         }
 370
 371         xs = list_first_or_null_rcu(&pool->xsk_tx_list, struct xdp_sock, tx_list);
 372         if (!xs) {
 373                 nb_pkts = 0;
 374                 goto out;
 375         }
 376
 377         nb_pkts = xskq_cons_peek_desc_batch(xs->tx, descs, pool, max_entries);
 378         if (!nb_pkts) {
 379                 xs->tx->queue_empty_descs++;
 380                 goto out;
 381         }
 382
 383         /* This is the backpressure mechanism for the Tx path. Try to
 384          * reserve space in the completion queue for all packets, but
 385          * if there are fewer slots available, just process that many
 386          * packets. This avoids having to implement any buffering in
 387          * the Tx path.
 388          */
 389         nb_pkts = xskq_prod_reserve_addr_batch(pool->cq, descs, nb_pkts);
 390         if (!nb_pkts)
 391                 goto out;
 392
 393         xskq_cons_release_n(xs->tx, nb_pkts);
 394         __xskq_cons_release(xs->tx);
 395         xs->sk.sk_write_space(&xs->sk);
 396
 397 out:
 398         rcu_read_unlock();
 399         return nb_pkts;
 400 }
 401 EXPORT_SYMBOL(xsk_tx_peek_release_desc_batch);
 402
 403 static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
 404 {
 405         struct net_device *dev = xs->dev;
 406         int err;
 407
 408         rcu_read_lock();
 409         err = dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
 410         rcu_read_unlock();
 411
 412         return err;
 413 }
 414
 415 static int xsk_zc_xmit(struct xdp_sock *xs)
 416 {
 417         return xsk_wakeup(xs, XDP_WAKEUP_TX);
 418 }
 419
 420 static void xsk_destruct_skb(struct sk_buff *skb)
 421 {
 422         u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg;
 423         struct xdp_sock *xs = xdp_sk(skb->sk);
 424         unsigned long flags;
 425
 426         spin_lock_irqsave(&xs->tx_completion_lock, flags);
 427         xskq_prod_submit_addr(xs->pool->cq, addr);
 428         spin_unlock_irqrestore(&xs->tx_completion_lock, flags);
 429
 430         sock_wfree(skb);
 431 }
 432
 433 static int xsk_generic_xmit(struct sock *sk)
 434 {
 435         struct xdp_sock *xs = xdp_sk(sk);
 436         u32 max_batch = TX_BATCH_SIZE;
 437         bool sent_frame = false;
 438         struct xdp_desc desc;
 439         struct sk_buff *skb;
 440         int err = 0;
 441
 442         mutex_lock(&xs->mutex);
 443
 444         if (xs->queue_id >= xs->dev->real_num_tx_queues)
 445                 goto out;
 446
 447         while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) {
 448                 char *buffer;
 449                 u64 addr;
 450                 u32 len;
 451
 452                 if (max_batch-- == 0) {
 453                         err = -EAGAIN;
 454                         goto out;
 455                 }
 456
 457                 len = desc.len;
 458                 skb = sock_alloc_send_skb(sk, len, 1, &err);
 459                 if (unlikely(!skb))
 460                         goto out;
 461
 462                 skb_put(skb, len);
 463                 addr = desc.addr;
 464                 buffer = xsk_buff_raw_get_data(xs->pool, addr);
 465                 err = skb_store_bits(skb, 0, buffer, len);
 466                 /* This is the backpressure mechanism for the Tx path.
 467                  * Reserve space in the completion queue and only proceed
 468                  * if there is space in it. This avoids having to implement
 469                  * any buffering in the Tx path.
 470                  */
 471                 if (unlikely(err) || xskq_prod_reserve(xs->pool->cq)) {
 472                         kfree_skb(skb);
 473                         goto out;
 474                 }
 475
 476                 skb->dev = xs->dev;
 477                 skb->priority = sk->sk_priority;
 478                 skb->mark = sk->sk_mark;
 479                 skb_shinfo(skb)->destructor_arg = (void *)(long)desc.addr;
 480                 skb->destructor = xsk_destruct_skb;
 481
 482                 err = __dev_direct_xmit(skb, xs->queue_id);
 483                 if  (err == NETDEV_TX_BUSY) {
 484                         /* Tell user-space to retry the send */
 485                         skb->destructor = sock_wfree;
 486                         /* Free skb without triggering the perf drop trace */
 487                         consume_skb(skb);
 488                         err = -EAGAIN;
 489                         goto out;
 490                 }
 491
 492                 xskq_cons_release(xs->tx);
 493                 /* Ignore NET_XMIT_CN as packet might have been sent */
 494                 if (err == NET_XMIT_DROP) {
 495                         /* SKB completed but not sent */
 496                         err = -EBUSY;
 497                         goto out;
 498                 }
 499
 500                 sent_frame = true;
 501         }
 502
 503         xs->tx->queue_empty_descs++;
 504
 505 out:
 506         if (sent_frame)
 507                 if (xsk_tx_writeable(xs))
 508                         sk->sk_write_space(sk);
 509
 510         mutex_unlock(&xs->mutex);
 511         return err;
 512 }
 513
 514 static int __xsk_sendmsg(struct sock *sk)
 515 {
 516         struct xdp_sock *xs = xdp_sk(sk);
 517
 518         if (unlikely(!(xs->dev->flags & IFF_UP)))
 519                 return -ENETDOWN;
 520         if (unlikely(!xs->tx))
 521                 return -ENOBUFS;
 522
 523         return xs->zc ? xsk_zc_xmit(xs) : xsk_generic_xmit(sk);
 524 }
 525
 526 static bool xsk_no_wakeup(struct sock *sk)
 527 {
 528 #ifdef CONFIG_NET_RX_BUSY_POLL
 529         /* Prefer busy-polling, skip the wakeup. */
 530         return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) &&
 531                 READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID;
 532 #else
 533         return false;
 534 #endif
 535 }
 536
 537 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 538 {
 539         bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
 540         struct sock *sk = sock->sk;
 541         struct xdp_sock *xs = xdp_sk(sk);
 542         struct xsk_buff_pool *pool;
 543
 544         if (unlikely(!xsk_is_bound(xs)))
 545                 return -ENXIO;
 546         if (unlikely(need_wait))
 547                 return -EOPNOTSUPP;
 548
 549         if (sk_can_busy_loop(sk))
 550                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 551
 552         if (xsk_no_wakeup(sk))
 553                 return 0;
 554
 555         pool = xs->pool;
 556         if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
 557                 return __xsk_sendmsg(sk);
 558         return 0;
 559 }
 560
 561 static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
 562 {
 563         bool need_wait = !(flags & MSG_DONTWAIT);
 564         struct sock *sk = sock->sk;
 565         struct xdp_sock *xs = xdp_sk(sk);
 566
 567         if (unlikely(!xsk_is_bound(xs)))
 568                 return -ENXIO;
 569         if (unlikely(!(xs->dev->flags & IFF_UP)))
 570                 return -ENETDOWN;
 571         if (unlikely(!xs->rx))
 572                 return -ENOBUFS;
 573         if (unlikely(need_wait))
 574                 return -EOPNOTSUPP;
 575
 576         if (sk_can_busy_loop(sk))
 577                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 578
 579         if (xsk_no_wakeup(sk))
 580                 return 0;
 581
 582         if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
 583                 return xsk_wakeup(xs, XDP_WAKEUP_RX);
 584         return 0;
 585 }
 586
 587 static __poll_t xsk_poll(struct file *file, struct socket *sock,
 588                              struct poll_table_struct *wait)
 589 {
 590         __poll_t mask = 0;
 591         struct sock *sk = sock->sk;
 592         struct xdp_sock *xs = xdp_sk(sk);
 593         struct xsk_buff_pool *pool;
 594
 595         sock_poll_wait(file, sock, wait);
 596
 597         if (unlikely(!xsk_is_bound(xs)))
 598                 return mask;
 599
 600         pool = xs->pool;
 601
 602         if (pool->cached_need_wakeup) {
 603                 if (xs->zc)
 604                         xsk_wakeup(xs, pool->cached_need_wakeup);
 605                 else
 606                         /* Poll needs to drive Tx also in copy mode */
 607                         __xsk_sendmsg(sk);
 608         }
 609
 610         if (xs->rx && !xskq_prod_is_empty(xs->rx))
 611                 mask |= EPOLLIN | EPOLLRDNORM;
 612         if (xs->tx && xsk_tx_writeable(xs))
 613                 mask |= EPOLLOUT | EPOLLWRNORM;
 614
 615         return mask;
 616 }
 617
 618 static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
 619                           bool umem_queue)
 620 {
 621         struct xsk_queue *q;
 622
 623         if (entries == 0 || *queue || !is_power_of_2(entries))
 624                 return -EINVAL;
 625
 626         q = xskq_create(entries, umem_queue);
 627         if (!q)
 628                 return -ENOMEM;
 629
 630         /* Make sure queue is ready before it can be seen by others */
 631         smp_wmb();
 632         WRITE_ONCE(*queue, q);
 633         return 0;
 634 }
 635
 636 static void xsk_unbind_dev(struct xdp_sock *xs)
 637 {
 638         struct net_device *dev = xs->dev;
 639
 640         if (xs->state != XSK_BOUND)
 641                 return;
 642         WRITE_ONCE(xs->state, XSK_UNBOUND);
 643
 644         /* Wait for driver to stop using the xdp socket. */
 645         xp_del_xsk(xs->pool, xs);
 646         xs->dev = NULL;
 647         synchronize_net();
 648         dev_put(dev);
 649 }
 650
 651 static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs,
 652                                               struct xdp_sock ***map_entry)
 653 {
 654         struct xsk_map *map = NULL;
 655         struct xsk_map_node *node;
 656
 657         *map_entry = NULL;
 658
 659         spin_lock_bh(&xs->map_list_lock);
 660         node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node,
 661                                         node);
 662         if (node) {
 663                 bpf_map_inc(&node->map->map);
 664                 map = node->map;
 665                 *map_entry = node->map_entry;
 666         }
 667         spin_unlock_bh(&xs->map_list_lock);
 668         return map;
 669 }
 670
 671 static void xsk_delete_from_maps(struct xdp_sock *xs)
 672 {
 673         /* This function removes the current XDP socket from all the
 674          * maps it resides in. We need to take extra care here, due to
 675          * the two locks involved. Each map has a lock synchronizing
 676          * updates to the entries, and each socket has a lock that
 677          * synchronizes access to the list of maps (map_list). For
 678          * deadlock avoidance the locks need to be taken in the order
 679          * "map lock"->"socket map list lock". We start off by
 680          * accessing the socket map list, and take a reference to the
 681          * map to guarantee existence between the
 682          * xsk_get_map_list_entry() and xsk_map_try_sock_delete()
 683          * calls. Then we ask the map to remove the socket, which
 684          * tries to remove the socket from the map. Note that there
 685          * might be updates to the map between
 686          * xsk_get_map_list_entry() and xsk_map_try_sock_delete().
 687          */
 688         struct xdp_sock **map_entry = NULL;
 689         struct xsk_map *map;
 690
 691         while ((map = xsk_get_map_list_entry(xs, &map_entry))) {
 692                 xsk_map_try_sock_delete(map, xs, map_entry);
 693                 bpf_map_put(&map->map);
 694         }
 695 }
 696
 697 static int xsk_release(struct socket *sock)
 698 {
 699         struct sock *sk = sock->sk;
 700         struct xdp_sock *xs = xdp_sk(sk);
 701         struct net *net;
 702
 703         if (!sk)
 704                 return 0;
 705
 706         net = sock_net(sk);
 707
 708         mutex_lock(&net->xdp.lock);
 709         sk_del_node_init_rcu(sk);
 710         mutex_unlock(&net->xdp.lock);
 711
 712         local_bh_disable();
 713         sock_prot_inuse_add(net, sk->sk_prot, -1);
 714         local_bh_enable();
 715
 716         xsk_delete_from_maps(xs);
 717         mutex_lock(&xs->mutex);
 718         xsk_unbind_dev(xs);
 719         mutex_unlock(&xs->mutex);
 720
 721         xskq_destroy(xs->rx);
 722         xskq_destroy(xs->tx);
 723         xskq_destroy(xs->fq_tmp);
 724         xskq_destroy(xs->cq_tmp);
 725
 726         sock_orphan(sk);
 727         sock->sk = NULL;
 728
 729         sk_refcnt_debug_release(sk);
 730         sock_put(sk);
 731
 732         return 0;
 733 }
 734
 735 static struct socket *xsk_lookup_xsk_from_fd(int fd)
 736 {
 737         struct socket *sock;
 738         int err;
 739
 740         sock = sockfd_lookup(fd, &err);
 741         if (!sock)
 742                 return ERR_PTR(-ENOTSOCK);
 743
 744         if (sock->sk->sk_family != PF_XDP) {
 745                 sockfd_put(sock);
 746                 return ERR_PTR(-ENOPROTOOPT);
 747         }
 748
 749         return sock;
 750 }
 751
 752 static bool xsk_validate_queues(struct xdp_sock *xs)
 753 {
 754         return xs->fq_tmp && xs->cq_tmp;
 755 }
 756
 757 static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 758 {
 759         struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
 760         struct sock *sk = sock->sk;
 761         struct xdp_sock *xs = xdp_sk(sk);
 762         struct net_device *dev;
 763         u32 flags, qid;
 764         int err = 0;
 765
 766         if (addr_len < sizeof(struct sockaddr_xdp))
 767                 return -EINVAL;
 768         if (sxdp->sxdp_family != AF_XDP)
 769                 return -EINVAL;
 770
 771         flags = sxdp->sxdp_flags;
 772         if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY |
 773                       XDP_USE_NEED_WAKEUP))
 774                 return -EINVAL;
 775
 776         rtnl_lock();
 777         mutex_lock(&xs->mutex);
 778         if (xs->state != XSK_READY) {
 779                 err = -EBUSY;
 780                 goto out_release;
 781         }
 782
 783         dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
 784         if (!dev) {
 785                 err = -ENODEV;
 786                 goto out_release;
 787         }
 788
 789         if (!xs->rx && !xs->tx) {
 790                 err = -EINVAL;
 791                 goto out_unlock;
 792         }
 793
 794         qid = sxdp->sxdp_queue_id;
 795
 796         if (flags & XDP_SHARED_UMEM) {
 797                 struct xdp_sock *umem_xs;
 798                 struct socket *sock;
 799
 800                 if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) ||
 801                     (flags & XDP_USE_NEED_WAKEUP)) {
 802                         /* Cannot specify flags for shared sockets. */
 803                         err = -EINVAL;
 804                         goto out_unlock;
 805                 }
 806
 807                 if (xs->umem) {
 808                         /* We have already our own. */
 809                         err = -EINVAL;
 810                         goto out_unlock;
 811                 }
 812
 813                 sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
 814                 if (IS_ERR(sock)) {
 815                         err = PTR_ERR(sock);
 816                         goto out_unlock;
 817                 }
 818
 819                 umem_xs = xdp_sk(sock->sk);
 820                 if (!xsk_is_bound(umem_xs)) {
 821                         err = -EBADF;
 822                         sockfd_put(sock);
 823                         goto out_unlock;
 824                 }
 825
 826                 if (umem_xs->queue_id != qid || umem_xs->dev != dev) {
 827                         /* Share the umem with another socket on another qid
 828                          * and/or device.
 829                          */
 830                         xs->pool = xp_create_and_assign_umem(xs,
 831                                                              umem_xs->umem);
 832                         if (!xs->pool) {
 833                                 err = -ENOMEM;
 834                                 sockfd_put(sock);
 835                                 goto out_unlock;
 836                         }
 837
 838                         err = xp_assign_dev_shared(xs->pool, umem_xs->umem,
 839                                                    dev, qid);
 840                         if (err) {
 841                                 xp_destroy(xs->pool);
 842                                 xs->pool = NULL;
 843                                 sockfd_put(sock);
 844                                 goto out_unlock;
 845                         }
 846                 } else {
 847                         /* Share the buffer pool with the other socket. */
 848                         if (xs->fq_tmp || xs->cq_tmp) {
 849                                 /* Do not allow setting your own fq or cq. */
 850                                 err = -EINVAL;
 851                                 sockfd_put(sock);
 852                                 goto out_unlock;
 853                         }
 854
 855                         xp_get_pool(umem_xs->pool);
 856                         xs->pool = umem_xs->pool;
 857                 }
 858
 859                 xdp_get_umem(umem_xs->umem);
 860                 WRITE_ONCE(xs->umem, umem_xs->umem);
 861                 sockfd_put(sock);
 862         } else if (!xs->umem || !xsk_validate_queues(xs)) {
 863                 err = -EINVAL;
 864                 goto out_unlock;
 865         } else {
 866                 /* This xsk has its own umem. */
 867                 xs->pool = xp_create_and_assign_umem(xs, xs->umem);
 868                 if (!xs->pool) {
 869                         err = -ENOMEM;
 870                         goto out_unlock;
 871                 }
 872
 873                 err = xp_assign_dev(xs->pool, dev, qid, flags);
 874                 if (err) {
 875                         xp_destroy(xs->pool);
 876                         xs->pool = NULL;
 877                         goto out_unlock;
 878                 }
 879         }
 880
 881         xs->dev = dev;
 882         xs->zc = xs->umem->zc;
 883         xs->queue_id = qid;
 884         xp_add_xsk(xs->pool, xs);
 885
 886 out_unlock:
 887         if (err) {
 888                 dev_put(dev);
 889         } else {
 890                 /* Matches smp_rmb() in bind() for shared umem
 891                  * sockets, and xsk_is_bound().
 892                  */
 893                 smp_wmb();
 894                 WRITE_ONCE(xs->state, XSK_BOUND);
 895         }
 896 out_release:
 897         mutex_unlock(&xs->mutex);
 898         rtnl_unlock();
 899         return err;
 900 }
 901
 902 struct xdp_umem_reg_v1 {
 903         __u64 addr; /* Start of packet data area */
 904         __u64 len; /* Length of packet data area */
 905         __u32 chunk_size;
 906         __u32 headroom;
 907 };
 908
 909 static int xsk_setsockopt(struct socket *sock, int level, int optname,
 910                           sockptr_t optval, unsigned int optlen)
 911 {
 912         struct sock *sk = sock->sk;
 913         struct xdp_sock *xs = xdp_sk(sk);
 914         int err;
 915
 916         if (level != SOL_XDP)
 917                 return -ENOPROTOOPT;
 918
 919         switch (optname) {
 920         case XDP_RX_RING:
 921         case XDP_TX_RING:
 922         {
 923                 struct xsk_queue **q;
 924                 int entries;
 925
 926                 if (optlen < sizeof(entries))
 927                         return -EINVAL;
 928                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
 929                         return -EFAULT;
 930
 931                 mutex_lock(&xs->mutex);
 932                 if (xs->state != XSK_READY) {
 933                         mutex_unlock(&xs->mutex);
 934                         return -EBUSY;
 935                 }
 936                 q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
 937                 err = xsk_init_queue(entries, q, false);
 938                 if (!err && optname == XDP_TX_RING)
 939                         /* Tx needs to be explicitly woken up the first time */
 940                         xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
 941                 mutex_unlock(&xs->mutex);
 942                 return err;
 943         }
 944         case XDP_UMEM_REG:
 945         {
 946                 size_t mr_size = sizeof(struct xdp_umem_reg);
 947                 struct xdp_umem_reg mr = {};
 948                 struct xdp_umem *umem;
 949
 950                 if (optlen < sizeof(struct xdp_umem_reg_v1))
 951                         return -EINVAL;
 952                 else if (optlen < sizeof(mr))
 953                         mr_size = sizeof(struct xdp_umem_reg_v1);
 954
 955                 if (copy_from_sockptr(&mr, optval, mr_size))
 956                         return -EFAULT;
 957
 958                 mutex_lock(&xs->mutex);
 959                 if (xs->state != XSK_READY || xs->umem) {
 960                         mutex_unlock(&xs->mutex);
 961                         return -EBUSY;
 962                 }
 963
 964                 umem = xdp_umem_create(&mr);
 965                 if (IS_ERR(umem)) {
 966                         mutex_unlock(&xs->mutex);
 967                         return PTR_ERR(umem);
 968                 }
 969
 970                 /* Make sure umem is ready before it can be seen by others */
 971                 smp_wmb();
 972                 WRITE_ONCE(xs->umem, umem);
 973                 mutex_unlock(&xs->mutex);
 974                 return 0;
 975         }
 976         case XDP_UMEM_FILL_RING:
 977         case XDP_UMEM_COMPLETION_RING:
 978         {
 979                 struct xsk_queue **q;
 980                 int entries;
 981
 982                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
 983                         return -EFAULT;
 984
 985                 mutex_lock(&xs->mutex);
 986                 if (xs->state != XSK_READY) {
 987                         mutex_unlock(&xs->mutex);
 988                         return -EBUSY;
 989                 }
 990
 991                 q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp :
 992                         &xs->cq_tmp;
 993                 err = xsk_init_queue(entries, q, true);
 994                 mutex_unlock(&xs->mutex);
 995                 return err;
 996         }
 997         default:
 998                 break;
 999         }
1000
1001         return -ENOPROTOOPT;
1002 }
1003
1004 static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring)
1005 {
1006         ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
1007         ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
1008         ring->desc = offsetof(struct xdp_rxtx_ring, desc);
1009 }
1010
1011 static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
1012 {
1013         ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer);
1014         ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
1015         ring->desc = offsetof(struct xdp_umem_ring, desc);
1016 }
1017
1018 struct xdp_statistics_v1 {
1019         __u64 rx_dropped;
1020         __u64 rx_invalid_descs;
1021         __u64 tx_invalid_descs;
1022 };
1023
1024 static int xsk_getsockopt(struct socket *sock, int level, int optname,
1025                           char __user *optval, int __user *optlen)
1026 {
1027         struct sock *sk = sock->sk;
1028         struct xdp_sock *xs = xdp_sk(sk);
1029         int len;
1030
1031         if (level != SOL_XDP)
1032                 return -ENOPROTOOPT;
1033
1034         if (get_user(len, optlen))
1035                 return -EFAULT;
1036         if (len < 0)
1037                 return -EINVAL;
1038
1039         switch (optname) {
1040         case XDP_STATISTICS:
1041         {
1042                 struct xdp_statistics stats = {};
1043                 bool extra_stats = true;
1044                 size_t stats_size;
1045
1046                 if (len < sizeof(struct xdp_statistics_v1)) {
1047                         return -EINVAL;
1048                 } else if (len < sizeof(stats)) {
1049                         extra_stats = false;
1050                         stats_size = sizeof(struct xdp_statistics_v1);
1051                 } else {
1052                         stats_size = sizeof(stats);
1053                 }
1054
1055                 mutex_lock(&xs->mutex);
1056                 stats.rx_dropped = xs->rx_dropped;
1057                 if (extra_stats) {
1058                         stats.rx_ring_full = xs->rx_queue_full;
1059                         stats.rx_fill_ring_empty_descs =
1060                                 xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
1061                         stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
1062                 } else {
1063                         stats.rx_dropped += xs->rx_queue_full;
1064                 }
1065                 stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
1066                 stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
1067                 mutex_unlock(&xs->mutex);
1068
1069                 if (copy_to_user(optval, &stats, stats_size))
1070                         return -EFAULT;
1071                 if (put_user(stats_size, optlen))
1072                         return -EFAULT;
1073
1074                 return 0;
1075         }
1076         case XDP_MMAP_OFFSETS:
1077         {
1078                 struct xdp_mmap_offsets off;
1079                 struct xdp_mmap_offsets_v1 off_v1;
1080                 bool flags_supported = true;
1081                 void *to_copy;
1082
1083                 if (len < sizeof(off_v1))
1084                         return -EINVAL;
1085                 else if (len < sizeof(off))
1086                         flags_supported = false;
1087
1088                 if (flags_supported) {
1089                         /* xdp_ring_offset is identical to xdp_ring_offset_v1
1090                          * except for the flags field added to the end.
1091                          */
1092                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1093                                                &off.rx);
1094                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1095                                                &off.tx);
1096                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1097                                                &off.fr);
1098                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1099                                                &off.cr);
1100                         off.rx.flags = offsetof(struct xdp_rxtx_ring,
1101                                                 ptrs.flags);
1102                         off.tx.flags = offsetof(struct xdp_rxtx_ring,
1103                                                 ptrs.flags);
1104                         off.fr.flags = offsetof(struct xdp_umem_ring,
1105                                                 ptrs.flags);
1106                         off.cr.flags = offsetof(struct xdp_umem_ring,
1107                                                 ptrs.flags);
1108
1109                         len = sizeof(off);
1110                         to_copy = &off;
1111                 } else {
1112                         xsk_enter_rxtx_offsets(&off_v1.rx);
1113                         xsk_enter_rxtx_offsets(&off_v1.tx);
1114                         xsk_enter_umem_offsets(&off_v1.fr);
1115                         xsk_enter_umem_offsets(&off_v1.cr);
1116
1117                         len = sizeof(off_v1);
1118                         to_copy = &off_v1;
1119                 }
1120
1121                 if (copy_to_user(optval, to_copy, len))
1122                         return -EFAULT;
1123                 if (put_user(len, optlen))
1124                         return -EFAULT;
1125
1126                 return 0;
1127         }
1128         case XDP_OPTIONS:
1129         {
1130                 struct xdp_options opts = {};
1131
1132                 if (len < sizeof(opts))
1133                         return -EINVAL;
1134
1135                 mutex_lock(&xs->mutex);
1136                 if (xs->zc)
1137                         opts.flags |= XDP_OPTIONS_ZEROCOPY;
1138                 mutex_unlock(&xs->mutex);
1139
1140                 len = sizeof(opts);
1141                 if (copy_to_user(optval, &opts, len))
1142                         return -EFAULT;
1143                 if (put_user(len, optlen))
1144                         return -EFAULT;
1145
1146                 return 0;
1147         }
1148         default:
1149                 break;
1150         }
1151
1152         return -EOPNOTSUPP;
1153 }
1154
1155 static int xsk_mmap(struct file *file, struct socket *sock,
1156                     struct vm_area_struct *vma)
1157 {
1158         loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
1159         unsigned long size = vma->vm_end - vma->vm_start;
1160         struct xdp_sock *xs = xdp_sk(sock->sk);
1161         struct xsk_queue *q = NULL;
1162         unsigned long pfn;
1163         struct page *qpg;
1164
1165         if (READ_ONCE(xs->state) != XSK_READY)
1166                 return -EBUSY;
1167
1168         if (offset == XDP_PGOFF_RX_RING) {
1169                 q = READ_ONCE(xs->rx);
1170         } else if (offset == XDP_PGOFF_TX_RING) {
1171                 q = READ_ONCE(xs->tx);
1172         } else {
1173                 /* Matches the smp_wmb() in XDP_UMEM_REG */
1174                 smp_rmb();
1175                 if (offset == XDP_UMEM_PGOFF_FILL_RING)
1176                         q = READ_ONCE(xs->fq_tmp);
1177                 else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
1178                         q = READ_ONCE(xs->cq_tmp);
1179         }
1180
1181         if (!q)
1182                 return -EINVAL;
1183
1184         /* Matches the smp_wmb() in xsk_init_queue */
1185         smp_rmb();
1186         qpg = virt_to_head_page(q->ring);
1187         if (size > page_size(qpg))
1188                 return -EINVAL;
1189
1190         pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
1191         return remap_pfn_range(vma, vma->vm_start, pfn,
1192                                size, vma->vm_page_prot);
1193 }
1194
1195 static int xsk_notifier(struct notifier_block *this,
1196                         unsigned long msg, void *ptr)
1197 {
1198         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1199         struct net *net = dev_net(dev);
1200         struct sock *sk;
1201
1202         switch (msg) {
1203         case NETDEV_UNREGISTER:
1204                 mutex_lock(&net->xdp.lock);
1205                 sk_for_each(sk, &net->xdp.list) {
1206                         struct xdp_sock *xs = xdp_sk(sk);
1207
1208                         mutex_lock(&xs->mutex);
1209                         if (xs->dev == dev) {
1210                                 sk->sk_err = ENETDOWN;
1211                                 if (!sock_flag(sk, SOCK_DEAD))
1212                                         sk->sk_error_report(sk);
1213
1214                                 xsk_unbind_dev(xs);
1215
1216                                 /* Clear device references. */
1217                                 xp_clear_dev(xs->pool);
1218                         }
1219                         mutex_unlock(&xs->mutex);
1220                 }
1221                 mutex_unlock(&net->xdp.lock);
1222                 break;
1223         }
1224         return NOTIFY_DONE;
1225 }
1226
1227 static struct proto xsk_proto = {
1228         .name =         "XDP",
1229         .owner =        THIS_MODULE,
1230         .obj_size =     sizeof(struct xdp_sock),
1231 };
1232
1233 static const struct proto_ops xsk_proto_ops = {
1234         .family         = PF_XDP,
1235         .owner          = THIS_MODULE,
1236         .release        = xsk_release,
1237         .bind           = xsk_bind,
1238         .connect        = sock_no_connect,
1239         .socketpair     = sock_no_socketpair,
1240         .accept         = sock_no_accept,
1241         .getname        = sock_no_getname,
1242         .poll           = xsk_poll,
1243         .ioctl          = sock_no_ioctl,
1244         .listen         = sock_no_listen,
1245         .shutdown       = sock_no_shutdown,
1246         .setsockopt     = xsk_setsockopt,
1247         .getsockopt     = xsk_getsockopt,
1248         .sendmsg        = xsk_sendmsg,
1249         .recvmsg        = xsk_recvmsg,
1250         .mmap           = xsk_mmap,
1251         .sendpage       = sock_no_sendpage,
1252 };
1253
1254 static void xsk_destruct(struct sock *sk)
1255 {
1256         struct xdp_sock *xs = xdp_sk(sk);
1257
1258         if (!sock_flag(sk, SOCK_DEAD))
1259                 return;
1260
1261         if (!xp_put_pool(xs->pool))
1262                 xdp_put_umem(xs->umem, !xs->pool);
1263
1264         sk_refcnt_debug_dec(sk);
1265 }
1266
1267 static int xsk_create(struct net *net, struct socket *sock, int protocol,
1268                       int kern)
1269 {
1270         struct xdp_sock *xs;
1271         struct sock *sk;
1272
1273         if (!ns_capable(net->user_ns, CAP_NET_RAW))
1274                 return -EPERM;
1275         if (sock->type != SOCK_RAW)
1276                 return -ESOCKTNOSUPPORT;
1277
1278         if (protocol)
1279                 return -EPROTONOSUPPORT;
1280
1281         sock->state = SS_UNCONNECTED;
1282
1283         sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
1284         if (!sk)
1285                 return -ENOBUFS;
1286
1287         sock->ops = &xsk_proto_ops;
1288
1289         sock_init_data(sock, sk);
1290
1291         sk->sk_family = PF_XDP;
1292
1293         sk->sk_destruct = xsk_destruct;
1294         sk_refcnt_debug_inc(sk);
1295
1296         sock_set_flag(sk, SOCK_RCU_FREE);
1297
1298         xs = xdp_sk(sk);
1299         xs->state = XSK_READY;
1300         mutex_init(&xs->mutex);
1301         spin_lock_init(&xs->rx_lock);
1302         spin_lock_init(&xs->tx_completion_lock);
1303
1304         INIT_LIST_HEAD(&xs->map_list);
1305         spin_lock_init(&xs->map_list_lock);
1306
1307         mutex_lock(&net->xdp.lock);
1308         sk_add_node_rcu(sk, &net->xdp.list);
1309         mutex_unlock(&net->xdp.lock);
1310
1311         local_bh_disable();
1312         sock_prot_inuse_add(net, &xsk_proto, 1);
1313         local_bh_enable();
1314
1315         return 0;
1316 }
1317
1318 static const struct net_proto_family xsk_family_ops = {
1319         .family = PF_XDP,
1320         .create = xsk_create,
1321         .owner  = THIS_MODULE,
1322 };
1323
1324 static struct notifier_block xsk_netdev_notifier = {
1325         .notifier_call  = xsk_notifier,
1326 };
1327
1328 static int __net_init xsk_net_init(struct net *net)
1329 {
1330         mutex_init(&net->xdp.lock);
1331         INIT_HLIST_HEAD(&net->xdp.list);
1332         return 0;
1333 }
1334
1335 static void __net_exit xsk_net_exit(struct net *net)
1336 {
1337         WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
1338 }
1339
1340 static struct pernet_operations xsk_net_ops = {
1341         .init = xsk_net_init,
1342         .exit = xsk_net_exit,
1343 };
1344
1345 static int __init xsk_init(void)
1346 {
1347         int err, cpu;
1348
1349         err = proto_register(&xsk_proto, 0 /* no slab */);
1350         if (err)
1351                 goto out;
1352
1353         err = sock_register(&xsk_family_ops);
1354         if (err)
1355                 goto out_proto;
1356
1357         err = register_pernet_subsys(&xsk_net_ops);
1358         if (err)
1359                 goto out_sk;
1360
1361         err = register_netdevice_notifier(&xsk_netdev_notifier);
1362         if (err)
1363                 goto out_pernet;
1364
1365         for_each_possible_cpu(cpu)
1366                 INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
1367         return 0;
1368
1369 out_pernet:
1370         unregister_pernet_subsys(&xsk_net_ops);
1371 out_sk:
1372         sock_unregister(PF_XDP);
1373 out_proto:
1374         proto_unregister(&xsk_proto);
1375 out:
1376         return err;
1377 }
1378
1379 fs_initcall(xsk_init);