net/xdp/xsk_buff_pool.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <net/xsk_buff_pool.h>
   4 #include <net/xdp_sock.h>
   5 #include <net/xdp_sock_drv.h>
   6
   7 #include "xsk_queue.h"
   8 #include "xdp_umem.h"
   9 #include "xsk.h"
  10
  11 void xp_add_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
  12 {
  13         unsigned long flags;
  14
  15         if (!xs->tx)
  16                 return;
  17
  18         spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
  19         list_add_rcu(&xs->tx_list, &pool->xsk_tx_list);
  20         spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
  21 }
  22
  23 void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
  24 {
  25         unsigned long flags;
  26
  27         if (!xs->tx)
  28                 return;
  29
  30         spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
  31         list_del_rcu(&xs->tx_list);
  32         spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
  33 }
  34
  35 void xp_destroy(struct xsk_buff_pool *pool)
  36 {
  37         if (!pool)
  38                 return;
  39
  40         kvfree(pool->heads);
  41         kvfree(pool);
  42 }
  43
  44 struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
  45                                                 struct xdp_umem *umem)
  46 {
  47         struct xsk_buff_pool *pool;
  48         struct xdp_buff_xsk *xskb;
  49         u32 i;
  50
  51         pool = kvzalloc(struct_size(pool, free_heads, umem->chunks),
  52                         GFP_KERNEL);
  53         if (!pool)
  54                 goto out;
  55
  56         pool->heads = kvcalloc(umem->chunks, sizeof(*pool->heads), GFP_KERNEL);
  57         if (!pool->heads)
  58                 goto out;
  59
  60         pool->chunk_mask = ~((u64)umem->chunk_size - 1);
  61         pool->addrs_cnt = umem->size;
  62         pool->heads_cnt = umem->chunks;
  63         pool->free_heads_cnt = umem->chunks;
  64         pool->headroom = umem->headroom;
  65         pool->chunk_size = umem->chunk_size;
  66         pool->unaligned = umem->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
  67         pool->frame_len = umem->chunk_size - umem->headroom -
  68                 XDP_PACKET_HEADROOM;
  69         pool->umem = umem;
  70         pool->addrs = umem->addrs;
  71         INIT_LIST_HEAD(&pool->free_list);
  72         INIT_LIST_HEAD(&pool->xsk_tx_list);
  73         spin_lock_init(&pool->xsk_tx_list_lock);
  74         refcount_set(&pool->users, 1);
  75
  76         pool->fq = xs->fq_tmp;
  77         pool->cq = xs->cq_tmp;
  78         xs->fq_tmp = NULL;
  79         xs->cq_tmp = NULL;
  80
  81         for (i = 0; i < pool->free_heads_cnt; i++) {
  82                 xskb = &pool->heads[i];
  83                 xskb->pool = pool;
  84                 xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;
  85                 pool->free_heads[i] = xskb;
  86         }
  87
  88         return pool;
  89
  90 out:
  91         xp_destroy(pool);
  92         return NULL;
  93 }
  94
  95 void xp_set_rxq_info(struct xsk_buff_pool *pool, struct xdp_rxq_info *rxq)
  96 {
  97         u32 i;
  98
  99         for (i = 0; i < pool->heads_cnt; i++)
 100                 pool->heads[i].xdp.rxq = rxq;
 101 }
 102 EXPORT_SYMBOL(xp_set_rxq_info);
 103
 104 static void xp_disable_drv_zc(struct xsk_buff_pool *pool)
 105 {
 106         struct netdev_bpf bpf;
 107         int err;
 108
 109         ASSERT_RTNL();
 110
 111         if (pool->umem->zc) {
 112                 bpf.command = XDP_SETUP_XSK_POOL;
 113                 bpf.xsk.pool = NULL;
 114                 bpf.xsk.queue_id = pool->queue_id;
 115
 116                 err = pool->netdev->netdev_ops->ndo_bpf(pool->netdev, &bpf);
 117
 118                 if (err)
 119                         WARN(1, "Failed to disable zero-copy!\n");
 120         }
 121 }
 122
 123 static int __xp_assign_dev(struct xsk_buff_pool *pool,
 124                            struct net_device *netdev, u16 queue_id, u16 flags)
 125 {
 126         bool force_zc, force_copy;
 127         struct netdev_bpf bpf;
 128         int err = 0;
 129
 130         ASSERT_RTNL();
 131
 132         force_zc = flags & XDP_ZEROCOPY;
 133         force_copy = flags & XDP_COPY;
 134
 135         if (force_zc && force_copy)
 136                 return -EINVAL;
 137
 138         if (xsk_get_pool_from_qid(netdev, queue_id))
 139                 return -EBUSY;
 140
 141         pool->netdev = netdev;
 142         pool->queue_id = queue_id;
 143         err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
 144         if (err)
 145                 return err;
 146
 147         if (flags & XDP_USE_NEED_WAKEUP)
 148                 pool->uses_need_wakeup = true;
 149         /* Tx needs to be explicitly woken up the first time.  Also
 150          * for supporting drivers that do not implement this
 151          * feature. They will always have to call sendto() or poll().
 152          */
 153         pool->cached_need_wakeup = XDP_WAKEUP_TX;
 154
 155         dev_hold(netdev);
 156
 157         if (force_copy)
 158                 /* For copy-mode, we are done. */
 159                 return 0;
 160
 161         if (!netdev->netdev_ops->ndo_bpf ||
 162             !netdev->netdev_ops->ndo_xsk_wakeup) {
 163                 err = -EOPNOTSUPP;
 164                 goto err_unreg_pool;
 165         }
 166
 167         bpf.command = XDP_SETUP_XSK_POOL;
 168         bpf.xsk.pool = pool;
 169         bpf.xsk.queue_id = queue_id;
 170
 171         err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
 172         if (err)
 173                 goto err_unreg_pool;
 174
 175         if (!pool->dma_pages) {
 176                 WARN(1, "Driver did not DMA map zero-copy buffers");
 177                 err = -EINVAL;
 178                 goto err_unreg_xsk;
 179         }
 180         pool->umem->zc = true;
 181         return 0;
 182
 183 err_unreg_xsk:
 184         xp_disable_drv_zc(pool);
 185 err_unreg_pool:
 186         if (!force_zc)
 187                 err = 0; /* fallback to copy mode */
 188         if (err) {
 189                 xsk_clear_pool_at_qid(netdev, queue_id);
 190                 dev_put(netdev);
 191         }
 192         return err;
 193 }
 194
 195 int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *dev,
 196                   u16 queue_id, u16 flags)
 197 {
 198         return __xp_assign_dev(pool, dev, queue_id, flags);
 199 }
 200
 201 int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem,
 202                          struct net_device *dev, u16 queue_id)
 203 {
 204         u16 flags;
 205
 206         /* One fill and completion ring required for each queue id. */
 207         if (!pool->fq || !pool->cq)
 208                 return -EINVAL;
 209
 210         flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
 211         if (pool->uses_need_wakeup)
 212                 flags |= XDP_USE_NEED_WAKEUP;
 213
 214         return __xp_assign_dev(pool, dev, queue_id, flags);
 215 }
 216
 217 void xp_clear_dev(struct xsk_buff_pool *pool)
 218 {
 219         if (!pool->netdev)
 220                 return;
 221
 222         xp_disable_drv_zc(pool);
 223         xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
 224         dev_put(pool->netdev);
 225         pool->netdev = NULL;
 226 }
 227
 228 static void xp_release_deferred(struct work_struct *work)
 229 {
 230         struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
 231                                                   work);
 232
 233         rtnl_lock();
 234         xp_clear_dev(pool);
 235         rtnl_unlock();
 236
 237         if (pool->fq) {
 238                 xskq_destroy(pool->fq);
 239                 pool->fq = NULL;
 240         }
 241
 242         if (pool->cq) {
 243                 xskq_destroy(pool->cq);
 244                 pool->cq = NULL;
 245         }
 246
 247         xdp_put_umem(pool->umem, false);
 248         xp_destroy(pool);
 249 }
 250
 251 void xp_get_pool(struct xsk_buff_pool *pool)
 252 {
 253         refcount_inc(&pool->users);
 254 }
 255
 256 bool xp_put_pool(struct xsk_buff_pool *pool)
 257 {
 258         if (!pool)
 259                 return false;
 260
 261         if (refcount_dec_and_test(&pool->users)) {
 262                 INIT_WORK(&pool->work, xp_release_deferred);
 263                 schedule_work(&pool->work);
 264                 return true;
 265         }
 266
 267         return false;
 268 }
 269
 270 static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
 271 {
 272         struct xsk_dma_map *dma_map;
 273
 274         list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
 275                 if (dma_map->netdev == pool->netdev)
 276                         return dma_map;
 277         }
 278
 279         return NULL;
 280 }
 281
 282 static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
 283                                              u32 nr_pages, struct xdp_umem *umem)
 284 {
 285         struct xsk_dma_map *dma_map;
 286
 287         dma_map = kzalloc(sizeof(*dma_map), GFP_KERNEL);
 288         if (!dma_map)
 289                 return NULL;
 290
 291         dma_map->dma_pages = kvcalloc(nr_pages, sizeof(*dma_map->dma_pages), GFP_KERNEL);
 292         if (!dma_map->dma_pages) {
 293                 kfree(dma_map);
 294                 return NULL;
 295         }
 296
 297         dma_map->netdev = netdev;
 298         dma_map->dev = dev;
 299         dma_map->dma_need_sync = false;
 300         dma_map->dma_pages_cnt = nr_pages;
 301         refcount_set(&dma_map->users, 1);
 302         list_add(&dma_map->list, &umem->xsk_dma_list);
 303         return dma_map;
 304 }
 305
 306 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
 307 {
 308         list_del(&dma_map->list);
 309         kvfree(dma_map->dma_pages);
 310         kfree(dma_map);
 311 }
 312
 313 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
 314 {
 315         dma_addr_t *dma;
 316         u32 i;
 317
 318         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
 319                 dma = &dma_map->dma_pages[i];
 320                 if (*dma) {
 321                         dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
 322                                              DMA_BIDIRECTIONAL, attrs);
 323                         *dma = 0;
 324                 }
 325         }
 326
 327         xp_destroy_dma_map(dma_map);
 328 }
 329
 330 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
 331 {
 332         struct xsk_dma_map *dma_map;
 333
 334         if (pool->dma_pages_cnt == 0)
 335                 return;
 336
 337         dma_map = xp_find_dma_map(pool);
 338         if (!dma_map) {
 339                 WARN(1, "Could not find dma_map for device");
 340                 return;
 341         }
 342
 343         if (!refcount_dec_and_test(&dma_map->users))
 344                 return;
 345
 346         __xp_dma_unmap(dma_map, attrs);
 347         kvfree(pool->dma_pages);
 348         pool->dma_pages_cnt = 0;
 349         pool->dev = NULL;
 350 }
 351 EXPORT_SYMBOL(xp_dma_unmap);
 352
 353 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
 354 {
 355         u32 i;
 356
 357         for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
 358                 if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
 359                         dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
 360                 else
 361                         dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
 362         }
 363 }
 364
 365 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
 366 {
 367         pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
 368         if (!pool->dma_pages)
 369                 return -ENOMEM;
 370
 371         pool->dev = dma_map->dev;
 372         pool->dma_pages_cnt = dma_map->dma_pages_cnt;
 373         pool->dma_need_sync = dma_map->dma_need_sync;
 374         memcpy(pool->dma_pages, dma_map->dma_pages,
 375                pool->dma_pages_cnt * sizeof(*pool->dma_pages));
 376
 377         return 0;
 378 }
 379
 380 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
 381                unsigned long attrs, struct page **pages, u32 nr_pages)
 382 {
 383         struct xsk_dma_map *dma_map;
 384         dma_addr_t dma;
 385         int err;
 386         u32 i;
 387
 388         dma_map = xp_find_dma_map(pool);
 389         if (dma_map) {
 390                 err = xp_init_dma_info(pool, dma_map);
 391                 if (err)
 392                         return err;
 393
 394                 refcount_inc(&dma_map->users);
 395                 return 0;
 396         }
 397
 398         dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
 399         if (!dma_map)
 400                 return -ENOMEM;
 401
 402         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
 403                 dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
 404                                          DMA_BIDIRECTIONAL, attrs);
 405                 if (dma_mapping_error(dev, dma)) {
 406                         __xp_dma_unmap(dma_map, attrs);
 407                         return -ENOMEM;
 408                 }
 409                 if (dma_need_sync(dev, dma))
 410                         dma_map->dma_need_sync = true;
 411                 dma_map->dma_pages[i] = dma;
 412         }
 413
 414         if (pool->unaligned)
 415                 xp_check_dma_contiguity(dma_map);
 416
 417         err = xp_init_dma_info(pool, dma_map);
 418         if (err) {
 419                 __xp_dma_unmap(dma_map, attrs);
 420                 return err;
 421         }
 422
 423         return 0;
 424 }
 425 EXPORT_SYMBOL(xp_dma_map);
 426
 427 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
 428                                           u64 addr)
 429 {
 430         return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
 431 }
 432
 433 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
 434 {
 435         *addr = xp_unaligned_extract_addr(*addr);
 436         if (*addr >= pool->addrs_cnt ||
 437             *addr + pool->chunk_size > pool->addrs_cnt ||
 438             xp_addr_crosses_non_contig_pg(pool, *addr))
 439                 return false;
 440         return true;
 441 }
 442
 443 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
 444 {
 445         *addr = xp_aligned_extract_addr(pool, *addr);
 446         return *addr < pool->addrs_cnt;
 447 }
 448
 449 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
 450 {
 451         struct xdp_buff_xsk *xskb;
 452         u64 addr;
 453         bool ok;
 454
 455         if (pool->free_heads_cnt == 0)
 456                 return NULL;
 457
 458         xskb = pool->free_heads[--pool->free_heads_cnt];
 459
 460         for (;;) {
 461                 if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
 462                         pool->fq->queue_empty_descs++;
 463                         xp_release(xskb);
 464                         return NULL;
 465                 }
 466
 467                 ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
 468                      xp_check_aligned(pool, &addr);
 469                 if (!ok) {
 470                         pool->fq->invalid_descs++;
 471                         xskq_cons_release(pool->fq);
 472                         continue;
 473                 }
 474                 break;
 475         }
 476         xskq_cons_release(pool->fq);
 477
 478         xskb->orig_addr = addr;
 479         xskb->xdp.data_hard_start = pool->addrs + addr + pool->headroom;
 480         if (pool->dma_pages_cnt) {
 481                 xskb->frame_dma = (pool->dma_pages[addr >> PAGE_SHIFT] &
 482                                    ~XSK_NEXT_PG_CONTIG_MASK) +
 483                                   (addr & ~PAGE_MASK);
 484                 xskb->dma = xskb->frame_dma + pool->headroom +
 485                             XDP_PACKET_HEADROOM;
 486         }
 487         return xskb;
 488 }
 489
 490 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
 491 {
 492         struct xdp_buff_xsk *xskb;
 493
 494         if (!pool->free_list_cnt) {
 495                 xskb = __xp_alloc(pool);
 496                 if (!xskb)
 497                         return NULL;
 498         } else {
 499                 pool->free_list_cnt--;
 500                 xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
 501                                         free_list_node);
 502                 list_del(&xskb->free_list_node);
 503         }
 504
 505         xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
 506         xskb->xdp.data_meta = xskb->xdp.data;
 507
 508         if (pool->dma_need_sync) {
 509                 dma_sync_single_range_for_device(pool->dev, xskb->dma, 0,
 510                                                  pool->frame_len,
 511                                                  DMA_BIDIRECTIONAL);
 512         }
 513         return &xskb->xdp;
 514 }
 515 EXPORT_SYMBOL(xp_alloc);
 516
 517 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
 518 {
 519         if (pool->free_list_cnt >= count)
 520                 return true;
 521         return xskq_cons_has_entries(pool->fq, count - pool->free_list_cnt);
 522 }
 523 EXPORT_SYMBOL(xp_can_alloc);
 524
 525 void xp_free(struct xdp_buff_xsk *xskb)
 526 {
 527         xskb->pool->free_list_cnt++;
 528         list_add(&xskb->free_list_node, &xskb->pool->free_list);
 529 }
 530 EXPORT_SYMBOL(xp_free);
 531
 532 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 533 {
 534         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
 535         return pool->addrs + addr;
 536 }
 537 EXPORT_SYMBOL(xp_raw_get_data);
 538
 539 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
 540 {
 541         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
 542         return (pool->dma_pages[addr >> PAGE_SHIFT] &
 543                 ~XSK_NEXT_PG_CONTIG_MASK) +
 544                 (addr & ~PAGE_MASK);
 545 }
 546 EXPORT_SYMBOL(xp_raw_get_dma);
 547
 548 void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb)
 549 {
 550         dma_sync_single_range_for_cpu(xskb->pool->dev, xskb->dma, 0,
 551                                       xskb->pool->frame_len, DMA_BIDIRECTIONAL);
 552 }
 553 EXPORT_SYMBOL(xp_dma_sync_for_cpu_slow);
 554
 555 void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
 556                                  size_t size)
 557 {
 558         dma_sync_single_range_for_device(pool->dev, dma, 0,
 559                                          size, DMA_BIDIRECTIONAL);
 560 }
 561 EXPORT_SYMBOL(xp_dma_sync_for_device_slow);