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