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                 goto err_unreg_xsk;
 178         }
 179         pool->umem->zc = true;
 180         return 0;
 181
 182 err_unreg_xsk:
 183         xp_disable_drv_zc(pool);
 184 err_unreg_pool:
 185         if (!force_zc)
 186                 err = 0; /* fallback to copy mode */
 187         if (err) {
 188                 xsk_clear_pool_at_qid(netdev, queue_id);
 189                 dev_put(netdev);
 190         }
 191         return err;
 192 }
 193
 194 int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *dev,
 195                   u16 queue_id, u16 flags)
 196 {
 197         return __xp_assign_dev(pool, dev, queue_id, flags);
 198 }
 199
 200 int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem,
 201                          struct net_device *dev, u16 queue_id)
 202 {
 203         u16 flags;
 204
 205         /* One fill and completion ring required for each queue id. */
 206         if (!pool->fq || !pool->cq)
 207                 return -EINVAL;
 208
 209         flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
 210         if (pool->uses_need_wakeup)
 211                 flags |= XDP_USE_NEED_WAKEUP;
 212
 213         return __xp_assign_dev(pool, dev, queue_id, flags);
 214 }
 215
 216 void xp_clear_dev(struct xsk_buff_pool *pool)
 217 {
 218         if (!pool->netdev)
 219                 return;
 220
 221         xp_disable_drv_zc(pool);
 222         xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
 223         dev_put(pool->netdev);
 224         pool->netdev = NULL;
 225 }
 226
 227 static void xp_release_deferred(struct work_struct *work)
 228 {
 229         struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
 230                                                   work);
 231
 232         rtnl_lock();
 233         xp_clear_dev(pool);
 234         rtnl_unlock();
 235
 236         if (pool->fq) {
 237                 xskq_destroy(pool->fq);
 238                 pool->fq = NULL;
 239         }
 240
 241         if (pool->cq) {
 242                 xskq_destroy(pool->cq);
 243                 pool->cq = NULL;
 244         }
 245
 246         xdp_put_umem(pool->umem, false);
 247         xp_destroy(pool);
 248 }
 249
 250 void xp_get_pool(struct xsk_buff_pool *pool)
 251 {
 252         refcount_inc(&pool->users);
 253 }
 254
 255 bool xp_put_pool(struct xsk_buff_pool *pool)
 256 {
 257         if (!pool)
 258                 return false;
 259
 260         if (refcount_dec_and_test(&pool->users)) {
 261                 INIT_WORK(&pool->work, xp_release_deferred);
 262                 schedule_work(&pool->work);
 263                 return true;
 264         }
 265
 266         return false;
 267 }
 268
 269 static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
 270 {
 271         struct xsk_dma_map *dma_map;
 272
 273         list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
 274                 if (dma_map->netdev == pool->netdev)
 275                         return dma_map;
 276         }
 277
 278         return NULL;
 279 }
 280
 281 static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
 282                                              u32 nr_pages, struct xdp_umem *umem)
 283 {
 284         struct xsk_dma_map *dma_map;
 285
 286         dma_map = kzalloc(sizeof(*dma_map), GFP_KERNEL);
 287         if (!dma_map)
 288                 return NULL;
 289
 290         dma_map->dma_pages = kvcalloc(nr_pages, sizeof(*dma_map->dma_pages), GFP_KERNEL);
 291         if (!dma_map->dma_pages) {
 292                 kfree(dma_map);
 293                 return NULL;
 294         }
 295
 296         dma_map->netdev = netdev;
 297         dma_map->dev = dev;
 298         dma_map->dma_need_sync = false;
 299         dma_map->dma_pages_cnt = nr_pages;
 300         refcount_set(&dma_map->users, 1);
 301         list_add(&dma_map->list, &umem->xsk_dma_list);
 302         return dma_map;
 303 }
 304
 305 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
 306 {
 307         list_del(&dma_map->list);
 308         kvfree(dma_map->dma_pages);
 309         kfree(dma_map);
 310 }
 311
 312 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
 313 {
 314         dma_addr_t *dma;
 315         u32 i;
 316
 317         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
 318                 dma = &dma_map->dma_pages[i];
 319                 if (*dma) {
 320                         dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
 321                                              DMA_BIDIRECTIONAL, attrs);
 322                         *dma = 0;
 323                 }
 324         }
 325
 326         xp_destroy_dma_map(dma_map);
 327 }
 328
 329 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
 330 {
 331         struct xsk_dma_map *dma_map;
 332
 333         if (pool->dma_pages_cnt == 0)
 334                 return;
 335
 336         dma_map = xp_find_dma_map(pool);
 337         if (!dma_map) {
 338                 WARN(1, "Could not find dma_map for device");
 339                 return;
 340         }
 341
 342         if (!refcount_dec_and_test(&dma_map->users))
 343                 return;
 344
 345         __xp_dma_unmap(dma_map, attrs);
 346         kvfree(pool->dma_pages);
 347         pool->dma_pages_cnt = 0;
 348         pool->dev = NULL;
 349 }
 350 EXPORT_SYMBOL(xp_dma_unmap);
 351
 352 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
 353 {
 354         u32 i;
 355
 356         for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
 357                 if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
 358                         dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
 359                 else
 360                         dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
 361         }
 362 }
 363
 364 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
 365 {
 366         pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
 367         if (!pool->dma_pages)
 368                 return -ENOMEM;
 369
 370         pool->dev = dma_map->dev;
 371         pool->dma_pages_cnt = dma_map->dma_pages_cnt;
 372         pool->dma_need_sync = dma_map->dma_need_sync;
 373         memcpy(pool->dma_pages, dma_map->dma_pages,
 374                pool->dma_pages_cnt * sizeof(*pool->dma_pages));
 375
 376         return 0;
 377 }
 378
 379 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
 380                unsigned long attrs, struct page **pages, u32 nr_pages)
 381 {
 382         struct xsk_dma_map *dma_map;
 383         dma_addr_t dma;
 384         int err;
 385         u32 i;
 386
 387         dma_map = xp_find_dma_map(pool);
 388         if (dma_map) {
 389                 err = xp_init_dma_info(pool, dma_map);
 390                 if (err)
 391                         return err;
 392
 393                 refcount_inc(&dma_map->users);
 394                 return 0;
 395         }
 396
 397         dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
 398         if (!dma_map)
 399                 return -ENOMEM;
 400
 401         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
 402                 dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
 403                                          DMA_BIDIRECTIONAL, attrs);
 404                 if (dma_mapping_error(dev, dma)) {
 405                         __xp_dma_unmap(dma_map, attrs);
 406                         return -ENOMEM;
 407                 }
 408                 if (dma_need_sync(dev, dma))
 409                         dma_map->dma_need_sync = true;
 410                 dma_map->dma_pages[i] = dma;
 411         }
 412
 413         if (pool->unaligned)
 414                 xp_check_dma_contiguity(dma_map);
 415
 416         err = xp_init_dma_info(pool, dma_map);
 417         if (err) {
 418                 __xp_dma_unmap(dma_map, attrs);
 419                 return err;
 420         }
 421
 422         return 0;
 423 }
 424 EXPORT_SYMBOL(xp_dma_map);
 425
 426 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
 427                                           u64 addr)
 428 {
 429         return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
 430 }
 431
 432 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
 433 {
 434         *addr = xp_unaligned_extract_addr(*addr);
 435         if (*addr >= pool->addrs_cnt ||
 436             *addr + pool->chunk_size > pool->addrs_cnt ||
 437             xp_addr_crosses_non_contig_pg(pool, *addr))
 438                 return false;
 439         return true;
 440 }
 441
 442 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
 443 {
 444         *addr = xp_aligned_extract_addr(pool, *addr);
 445         return *addr < pool->addrs_cnt;
 446 }
 447
 448 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
 449 {
 450         struct xdp_buff_xsk *xskb;
 451         u64 addr;
 452         bool ok;
 453
 454         if (pool->free_heads_cnt == 0)
 455                 return NULL;
 456
 457         xskb = pool->free_heads[--pool->free_heads_cnt];
 458
 459         for (;;) {
 460                 if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
 461                         pool->fq->queue_empty_descs++;
 462                         xp_release(xskb);
 463                         return NULL;
 464                 }
 465
 466                 ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
 467                      xp_check_aligned(pool, &addr);
 468                 if (!ok) {
 469                         pool->fq->invalid_descs++;
 470                         xskq_cons_release(pool->fq);
 471                         continue;
 472                 }
 473                 break;
 474         }
 475         xskq_cons_release(pool->fq);
 476
 477         xskb->orig_addr = addr;
 478         xskb->xdp.data_hard_start = pool->addrs + addr + pool->headroom;
 479         if (pool->dma_pages_cnt) {
 480                 xskb->frame_dma = (pool->dma_pages[addr >> PAGE_SHIFT] &
 481                                    ~XSK_NEXT_PG_CONTIG_MASK) +
 482                                   (addr & ~PAGE_MASK);
 483                 xskb->dma = xskb->frame_dma + pool->headroom +
 484                             XDP_PACKET_HEADROOM;
 485         }
 486         return xskb;
 487 }
 488
 489 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
 490 {
 491         struct xdp_buff_xsk *xskb;
 492
 493         if (!pool->free_list_cnt) {
 494                 xskb = __xp_alloc(pool);
 495                 if (!xskb)
 496                         return NULL;
 497         } else {
 498                 pool->free_list_cnt--;
 499                 xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
 500                                         free_list_node);
 501                 list_del(&xskb->free_list_node);
 502         }
 503
 504         xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
 505         xskb->xdp.data_meta = xskb->xdp.data;
 506
 507         if (pool->dma_need_sync) {
 508                 dma_sync_single_range_for_device(pool->dev, xskb->dma, 0,
 509                                                  pool->frame_len,
 510                                                  DMA_BIDIRECTIONAL);
 511         }
 512         return &xskb->xdp;
 513 }
 514 EXPORT_SYMBOL(xp_alloc);
 515
 516 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
 517 {
 518         if (pool->free_list_cnt >= count)
 519                 return true;
 520         return xskq_cons_has_entries(pool->fq, count - pool->free_list_cnt);
 521 }
 522 EXPORT_SYMBOL(xp_can_alloc);
 523
 524 void xp_free(struct xdp_buff_xsk *xskb)
 525 {
 526         xskb->pool->free_list_cnt++;
 527         list_add(&xskb->free_list_node, &xskb->pool->free_list);
 528 }
 529 EXPORT_SYMBOL(xp_free);
 530
 531 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 532 {
 533         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
 534         return pool->addrs + addr;
 535 }
 536 EXPORT_SYMBOL(xp_raw_get_data);
 537
 538 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
 539 {
 540         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
 541         return (pool->dma_pages[addr >> PAGE_SHIFT] &
 542                 ~XSK_NEXT_PG_CONTIG_MASK) +
 543                 (addr & ~PAGE_MASK);
 544 }
 545 EXPORT_SYMBOL(xp_raw_get_dma);
 546
 547 void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb)
 548 {
 549         dma_sync_single_range_for_cpu(xskb->pool->dev, xskb->dma, 0,
 550                                       xskb->pool->frame_len, DMA_BIDIRECTIONAL);
 551 }
 552 EXPORT_SYMBOL(xp_dma_sync_for_cpu_slow);
 553
 554 void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
 555                                  size_t size)
 556 {
 557         dma_sync_single_range_for_device(pool->dev, dma, 0,
 558                                          size, DMA_BIDIRECTIONAL);
 559 }
 560 EXPORT_SYMBOL(xp_dma_sync_for_device_slow);