drivers/net/sfc/rx.c

   1 /****************************************************************************
   2  * Driver for Solarflare Solarstorm network controllers and boards
   3  * Copyright 2005-2006 Fen Systems Ltd.
   4  * Copyright 2005-2009 Solarflare Communications Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation, incorporated herein by reference.
   9  */
  10
  11 #include <linux/socket.h>
  12 #include <linux/in.h>
  13 #include <linux/slab.h>
  14 #include <linux/ip.h>
  15 #include <linux/tcp.h>
  16 #include <linux/udp.h>
  17 #include <net/ip.h>
  18 #include <net/checksum.h>
  19 #include "net_driver.h"
  20 #include "efx.h"
  21 #include "nic.h"
  22 #include "selftest.h"
  23 #include "workarounds.h"
  24
  25 /* Number of RX descriptors pushed at once. */
  26 #define EFX_RX_BATCH  8
  27
  28 /* Maximum size of a buffer sharing a page */
  29 #define EFX_RX_HALF_PAGE ((PAGE_SIZE >> 1) - sizeof(struct efx_rx_page_state))
  30
  31 /* Size of buffer allocated for skb header area. */
  32 #define EFX_SKB_HEADERS  64u
  33
  34 /*
  35  * rx_alloc_method - RX buffer allocation method
  36  *
  37  * This driver supports two methods for allocating and using RX buffers:
  38  * each RX buffer may be backed by an skb or by an order-n page.
  39  *
  40  * When LRO is in use then the second method has a lower overhead,
  41  * since we don't have to allocate then free skbs on reassembled frames.
  42  *
  43  * Values:
  44  *   - RX_ALLOC_METHOD_AUTO = 0
  45  *   - RX_ALLOC_METHOD_SKB  = 1
  46  *   - RX_ALLOC_METHOD_PAGE = 2
  47  *
  48  * The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count
  49  * controlled by the parameters below.
  50  *
  51  *   - Since pushing and popping descriptors are separated by the rx_queue
  52  *     size, so the watermarks should be ~rxd_size.
  53  *   - The performance win by using page-based allocation for LRO is less
  54  *     than the performance hit of using page-based allocation of non-LRO,
  55  *     so the watermarks should reflect this.
  56  *
  57  * Per channel we maintain a single variable, updated by each channel:
  58  *
  59  *   rx_alloc_level += (lro_performed ? RX_ALLOC_FACTOR_LRO :
  60  *                      RX_ALLOC_FACTOR_SKB)
  61  * Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which
  62  * limits the hysteresis), and update the allocation strategy:
  63  *
  64  *   rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_LRO ?
  65  *                      RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB)
  66  */
  67 static int rx_alloc_method = RX_ALLOC_METHOD_AUTO;
  68
  69 #define RX_ALLOC_LEVEL_LRO 0x2000
  70 #define RX_ALLOC_LEVEL_MAX 0x3000
  71 #define RX_ALLOC_FACTOR_LRO 1
  72 #define RX_ALLOC_FACTOR_SKB (-2)
  73
  74 /* This is the percentage fill level below which new RX descriptors
  75  * will be added to the RX descriptor ring.
  76  */
  77 static unsigned int rx_refill_threshold = 90;
  78
  79 /* This is the percentage fill level to which an RX queue will be refilled
  80  * when the "RX refill threshold" is reached.
  81  */
  82 static unsigned int rx_refill_limit = 95;
  83
  84 /*
  85  * RX maximum head room required.
  86  *
  87  * This must be at least 1 to prevent overflow and at least 2 to allow
  88  * pipelined receives.
  89  */
  90 #define EFX_RXD_HEAD_ROOM 2
  91
  92 static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf)
  93 {
  94         /* Offset is always within one page, so we don't need to consider
  95          * the page order.
  96          */
  97         return (__force unsigned long) buf->data & (PAGE_SIZE - 1);
  98 }
  99 static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
 100 {
 101         return PAGE_SIZE << efx->rx_buffer_order;
 102 }
 103
 104 /**
 105  * efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers
 106  *
 107  * @rx_queue:           Efx RX queue
 108  *
 109  * This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a
 110  * struct efx_rx_buffer for each one. Return a negative error code or 0
 111  * on success. May fail having only inserted fewer than EFX_RX_BATCH
 112  * buffers.
 113  */
 114 static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
 115 {
 116         struct efx_nic *efx = rx_queue->efx;
 117         struct net_device *net_dev = efx->net_dev;
 118         struct efx_rx_buffer *rx_buf;
 119         int skb_len = efx->rx_buffer_len;
 120         unsigned index, count;
 121
 122         for (count = 0; count < EFX_RX_BATCH; ++count) {
 123                 index = rx_queue->added_count & EFX_RXQ_MASK;
 124                 rx_buf = efx_rx_buffer(rx_queue, index);
 125
 126                 rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
 127                 if (unlikely(!rx_buf->skb))
 128                         return -ENOMEM;
 129                 rx_buf->page = NULL;
 130
 131                 /* Adjust the SKB for padding and checksum */
 132                 skb_reserve(rx_buf->skb, NET_IP_ALIGN);
 133                 rx_buf->len = skb_len - NET_IP_ALIGN;
 134                 rx_buf->data = (char *)rx_buf->skb->data;
 135                 rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
 136
 137                 rx_buf->dma_addr = pci_map_single(efx->pci_dev,
 138                                                   rx_buf->data, rx_buf->len,
 139                                                   PCI_DMA_FROMDEVICE);
 140                 if (unlikely(pci_dma_mapping_error(efx->pci_dev,
 141                                                    rx_buf->dma_addr))) {
 142                         dev_kfree_skb_any(rx_buf->skb);
 143                         rx_buf->skb = NULL;
 144                         return -EIO;
 145                 }
 146
 147                 ++rx_queue->added_count;
 148                 ++rx_queue->alloc_skb_count;
 149         }
 150
 151         return 0;
 152 }
 153
 154 /**
 155  * efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers
 156  *
 157  * @rx_queue:           Efx RX queue
 158  *
 159  * This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA,
 160  * and populates struct efx_rx_buffers for each one. Return a negative error
 161  * code or 0 on success. If a single page can be split between two buffers,
 162  * then the page will either be inserted fully, or not at at all.
 163  */
 164 static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
 165 {
 166         struct efx_nic *efx = rx_queue->efx;
 167         struct efx_rx_buffer *rx_buf;
 168         struct page *page;
 169         void *page_addr;
 170         struct efx_rx_page_state *state;
 171         dma_addr_t dma_addr;
 172         unsigned index, count;
 173
 174         /* We can split a page between two buffers */
 175         BUILD_BUG_ON(EFX_RX_BATCH & 1);
 176
 177         for (count = 0; count < EFX_RX_BATCH; ++count) {
 178                 page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
 179                                    efx->rx_buffer_order);
 180                 if (unlikely(page == NULL))
 181                         return -ENOMEM;
 182                 dma_addr = pci_map_page(efx->pci_dev, page, 0,
 183                                         efx_rx_buf_size(efx),
 184                                         PCI_DMA_FROMDEVICE);
 185                 if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
 186                         __free_pages(page, efx->rx_buffer_order);
 187                         return -EIO;
 188                 }
 189                 page_addr = page_address(page);
 190                 state = page_addr;
 191                 state->refcnt = 0;
 192                 state->dma_addr = dma_addr;
 193
 194                 page_addr += sizeof(struct efx_rx_page_state);
 195                 dma_addr += sizeof(struct efx_rx_page_state);
 196
 197         split:
 198                 index = rx_queue->added_count & EFX_RXQ_MASK;
 199                 rx_buf = efx_rx_buffer(rx_queue, index);
 200                 rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
 201                 rx_buf->skb = NULL;
 202                 rx_buf->page = page;
 203                 rx_buf->data = page_addr + EFX_PAGE_IP_ALIGN;
 204                 rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
 205                 ++rx_queue->added_count;
 206                 ++rx_queue->alloc_page_count;
 207                 ++state->refcnt;
 208
 209                 if ((~count & 1) && (efx->rx_buffer_len <= EFX_RX_HALF_PAGE)) {
 210                         /* Use the second half of the page */
 211                         get_page(page);
 212                         dma_addr += (PAGE_SIZE >> 1);
 213                         page_addr += (PAGE_SIZE >> 1);
 214                         ++count;
 215                         goto split;
 216                 }
 217         }
 218
 219         return 0;
 220 }
 221
 222 static void efx_unmap_rx_buffer(struct efx_nic *efx,
 223                                 struct efx_rx_buffer *rx_buf)
 224 {
 225         if (rx_buf->page) {
 226                 struct efx_rx_page_state *state;
 227
 228                 EFX_BUG_ON_PARANOID(rx_buf->skb);
 229
 230                 state = page_address(rx_buf->page);
 231                 if (--state->refcnt == 0) {
 232                         pci_unmap_page(efx->pci_dev,
 233                                        state->dma_addr,
 234                                        efx_rx_buf_size(efx),
 235                                        PCI_DMA_FROMDEVICE);
 236                 }
 237         } else if (likely(rx_buf->skb)) {
 238                 pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
 239                                  rx_buf->len, PCI_DMA_FROMDEVICE);
 240         }
 241 }
 242
 243 static void efx_free_rx_buffer(struct efx_nic *efx,
 244                                struct efx_rx_buffer *rx_buf)
 245 {
 246         if (rx_buf->page) {
 247                 __free_pages(rx_buf->page, efx->rx_buffer_order);
 248                 rx_buf->page = NULL;
 249         } else if (likely(rx_buf->skb)) {
 250                 dev_kfree_skb_any(rx_buf->skb);
 251                 rx_buf->skb = NULL;
 252         }
 253 }
 254
 255 static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
 256                                struct efx_rx_buffer *rx_buf)
 257 {
 258         efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
 259         efx_free_rx_buffer(rx_queue->efx, rx_buf);
 260 }
 261
 262 /* Attempt to resurrect the other receive buffer that used to share this page,
 263  * which had previously been passed up to the kernel and freed. */
 264 static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,
 265                                     struct efx_rx_buffer *rx_buf)
 266 {
 267         struct efx_rx_page_state *state = page_address(rx_buf->page);
 268         struct efx_rx_buffer *new_buf;
 269         unsigned fill_level, index;
 270
 271         /* +1 because efx_rx_packet() incremented removed_count. +1 because
 272          * we'd like to insert an additional descriptor whilst leaving
 273          * EFX_RXD_HEAD_ROOM for the non-recycle path */
 274         fill_level = (rx_queue->added_count - rx_queue->removed_count + 2);
 275         if (unlikely(fill_level >= EFX_RXQ_SIZE - EFX_RXD_HEAD_ROOM)) {
 276                 /* We could place "state" on a list, and drain the list in
 277                  * efx_fast_push_rx_descriptors(). For now, this will do. */
 278                 return;
 279         }
 280
 281         ++state->refcnt;
 282         get_page(rx_buf->page);
 283
 284         index = rx_queue->added_count & EFX_RXQ_MASK;
 285         new_buf = efx_rx_buffer(rx_queue, index);
 286         new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1);
 287         new_buf->skb = NULL;
 288         new_buf->page = rx_buf->page;
 289         new_buf->data = (void *)
 290                 ((__force unsigned long)rx_buf->data ^ (PAGE_SIZE >> 1));
 291         new_buf->len = rx_buf->len;
 292         ++rx_queue->added_count;
 293 }
 294
 295 /* Recycle the given rx buffer directly back into the rx_queue. There is
 296  * always room to add this buffer, because we've just popped a buffer. */
 297 static void efx_recycle_rx_buffer(struct efx_channel *channel,
 298                                   struct efx_rx_buffer *rx_buf)
 299 {
 300         struct efx_nic *efx = channel->efx;
 301         struct efx_rx_queue *rx_queue = &efx->rx_queue[channel->channel];
 302         struct efx_rx_buffer *new_buf;
 303         unsigned index;
 304
 305         if (rx_buf->page != NULL && efx->rx_buffer_len <= EFX_RX_HALF_PAGE &&
 306             page_count(rx_buf->page) == 1)
 307                 efx_resurrect_rx_buffer(rx_queue, rx_buf);
 308
 309         index = rx_queue->added_count & EFX_RXQ_MASK;
 310         new_buf = efx_rx_buffer(rx_queue, index);
 311
 312         memcpy(new_buf, rx_buf, sizeof(*new_buf));
 313         rx_buf->page = NULL;
 314         rx_buf->skb = NULL;
 315         ++rx_queue->added_count;
 316 }
 317
 318 /**
 319  * efx_fast_push_rx_descriptors - push new RX descriptors quickly
 320  * @rx_queue:           RX descriptor queue
 321  * This will aim to fill the RX descriptor queue up to
 322  * @rx_queue->@fast_fill_limit. If there is insufficient atomic
 323  * memory to do so, a slow fill will be scheduled.
 324  *
 325  * The caller must provide serialisation (none is used here). In practise,
 326  * this means this function must run from the NAPI handler, or be called
 327  * when NAPI is disabled.
 328  */
 329 void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
 330 {
 331         struct efx_channel *channel = rx_queue->channel;
 332         unsigned fill_level;
 333         int space, rc = 0;
 334
 335         /* Calculate current fill level, and exit if we don't need to fill */
 336         fill_level = (rx_queue->added_count - rx_queue->removed_count);
 337         EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE);
 338         if (fill_level >= rx_queue->fast_fill_trigger)
 339                 goto out;
 340
 341         /* Record minimum fill level */
 342         if (unlikely(fill_level < rx_queue->min_fill)) {
 343                 if (fill_level)
 344                         rx_queue->min_fill = fill_level;
 345         }
 346
 347         space = rx_queue->fast_fill_limit - fill_level;
 348         if (space < EFX_RX_BATCH)
 349                 goto out;
 350
 351         EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
 352                   " level %d to level %d using %s allocation\n",
 353                   rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
 354                   channel->rx_alloc_push_pages ? "page" : "skb");
 355
 356         do {
 357                 if (channel->rx_alloc_push_pages)
 358                         rc = efx_init_rx_buffers_page(rx_queue);
 359                 else
 360                         rc = efx_init_rx_buffers_skb(rx_queue);
 361                 if (unlikely(rc)) {
 362                         /* Ensure that we don't leave the rx queue empty */
 363                         if (rx_queue->added_count == rx_queue->removed_count)
 364                                 efx_schedule_slow_fill(rx_queue);
 365                         goto out;
 366                 }
 367         } while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
 368
 369         EFX_TRACE(rx_queue->efx, "RX queue %d fast-filled descriptor ring "
 370                   "to level %d\n", rx_queue->queue,
 371                   rx_queue->added_count - rx_queue->removed_count);
 372
 373  out:
 374         if (rx_queue->notified_count != rx_queue->added_count)
 375                 efx_nic_notify_rx_desc(rx_queue);
 376 }
 377
 378 void efx_rx_slow_fill(unsigned long context)
 379 {
 380         struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context;
 381         struct efx_channel *channel = rx_queue->channel;
 382
 383         /* Post an event to cause NAPI to run and refill the queue */
 384         efx_nic_generate_fill_event(channel);
 385         ++rx_queue->slow_fill_count;
 386 }
 387
 388 static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
 389                                      struct efx_rx_buffer *rx_buf,
 390                                      int len, bool *discard,
 391                                      bool *leak_packet)
 392 {
 393         struct efx_nic *efx = rx_queue->efx;
 394         unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
 395
 396         if (likely(len <= max_len))
 397                 return;
 398
 399         /* The packet must be discarded, but this is only a fatal error
 400          * if the caller indicated it was
 401          */
 402         *discard = true;
 403
 404         if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) {
 405                 EFX_ERR_RL(efx, " RX queue %d seriously overlength "
 406                            "RX event (0x%x > 0x%x+0x%x). Leaking\n",
 407                            rx_queue->queue, len, max_len,
 408                            efx->type->rx_buffer_padding);
 409                 /* If this buffer was skb-allocated, then the meta
 410                  * data at the end of the skb will be trashed. So
 411                  * we have no choice but to leak the fragment.
 412                  */
 413                 *leak_packet = (rx_buf->skb != NULL);
 414                 efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);
 415         } else {
 416                 EFX_ERR_RL(efx, " RX queue %d overlength RX event "
 417                            "(0x%x > 0x%x)\n", rx_queue->queue, len, max_len);
 418         }
 419
 420         rx_queue->channel->n_rx_overlength++;
 421 }
 422
 423 /* Pass a received packet up through the generic LRO stack
 424  *
 425  * Handles driverlink veto, and passes the fragment up via
 426  * the appropriate LRO method
 427  */
 428 static void efx_rx_packet_lro(struct efx_channel *channel,
 429                               struct efx_rx_buffer *rx_buf,
 430                               bool checksummed)
 431 {
 432         struct napi_struct *napi = &channel->napi_str;
 433         gro_result_t gro_result;
 434
 435         /* Pass the skb/page into the LRO engine */
 436         if (rx_buf->page) {
 437                 struct page *page = rx_buf->page;
 438                 struct sk_buff *skb;
 439
 440                 EFX_BUG_ON_PARANOID(rx_buf->skb);
 441                 rx_buf->page = NULL;
 442
 443                 skb = napi_get_frags(napi);
 444                 if (!skb) {
 445                         put_page(page);
 446                         return;
 447                 }
 448
 449                 skb_shinfo(skb)->frags[0].page = page;
 450                 skb_shinfo(skb)->frags[0].page_offset =
 451                         efx_rx_buf_offset(rx_buf);
 452                 skb_shinfo(skb)->frags[0].size = rx_buf->len;
 453                 skb_shinfo(skb)->nr_frags = 1;
 454
 455                 skb->len = rx_buf->len;
 456                 skb->data_len = rx_buf->len;
 457                 skb->truesize += rx_buf->len;
 458                 skb->ip_summed =
 459                         checksummed ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
 460
 461                 skb_record_rx_queue(skb, channel->channel);
 462
 463                 gro_result = napi_gro_frags(napi);
 464         } else {
 465                 struct sk_buff *skb = rx_buf->skb;
 466
 467                 EFX_BUG_ON_PARANOID(!skb);
 468                 EFX_BUG_ON_PARANOID(!checksummed);
 469                 rx_buf->skb = NULL;
 470
 471                 gro_result = napi_gro_receive(napi, skb);
 472         }
 473
 474         if (gro_result == GRO_NORMAL) {
 475                 channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
 476         } else if (gro_result != GRO_DROP) {
 477                 channel->rx_alloc_level += RX_ALLOC_FACTOR_LRO;
 478                 channel->irq_mod_score += 2;
 479         }
 480 }
 481
 482 void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
 483                    unsigned int len, bool checksummed, bool discard)
 484 {
 485         struct efx_nic *efx = rx_queue->efx;
 486         struct efx_channel *channel = rx_queue->channel;
 487         struct efx_rx_buffer *rx_buf;
 488         bool leak_packet = false;
 489
 490         rx_buf = efx_rx_buffer(rx_queue, index);
 491         EFX_BUG_ON_PARANOID(!rx_buf->data);
 492         EFX_BUG_ON_PARANOID(rx_buf->skb && rx_buf->page);
 493         EFX_BUG_ON_PARANOID(!(rx_buf->skb || rx_buf->page));
 494
 495         /* This allows the refill path to post another buffer.
 496          * EFX_RXD_HEAD_ROOM ensures that the slot we are using
 497          * isn't overwritten yet.
 498          */
 499         rx_queue->removed_count++;
 500
 501         /* Validate the length encoded in the event vs the descriptor pushed */
 502         efx_rx_packet__check_len(rx_queue, rx_buf, len,
 503                                  &discard, &leak_packet);
 504
 505         EFX_TRACE(efx, "RX queue %d received id %x at %llx+%x %s%s\n",
 506                   rx_queue->queue, index,
 507                   (unsigned long long)rx_buf->dma_addr, len,
 508                   (checksummed ? " [SUMMED]" : ""),
 509                   (discard ? " [DISCARD]" : ""));
 510
 511         /* Discard packet, if instructed to do so */
 512         if (unlikely(discard)) {
 513                 if (unlikely(leak_packet))
 514                         channel->n_skbuff_leaks++;
 515                 else
 516                         efx_recycle_rx_buffer(channel, rx_buf);
 517
 518                 /* Don't hold off the previous receive */
 519                 rx_buf = NULL;
 520                 goto out;
 521         }
 522
 523         /* Release card resources - assumes all RX buffers consumed in-order
 524          * per RX queue
 525          */
 526         efx_unmap_rx_buffer(efx, rx_buf);
 527
 528         /* Prefetch nice and early so data will (hopefully) be in cache by
 529          * the time we look at it.
 530          */
 531         prefetch(rx_buf->data);
 532
 533         /* Pipeline receives so that we give time for packet headers to be
 534          * prefetched into cache.
 535          */
 536         rx_buf->len = len;
 537 out:
 538         if (rx_queue->channel->rx_pkt)
 539                 __efx_rx_packet(rx_queue->channel,
 540                                 rx_queue->channel->rx_pkt,
 541                                 rx_queue->channel->rx_pkt_csummed);
 542         rx_queue->channel->rx_pkt = rx_buf;
 543         rx_queue->channel->rx_pkt_csummed = checksummed;
 544 }
 545
 546 /* Handle a received packet.  Second half: Touches packet payload. */
 547 void __efx_rx_packet(struct efx_channel *channel,
 548                      struct efx_rx_buffer *rx_buf, bool checksummed)
 549 {
 550         struct efx_nic *efx = channel->efx;
 551         struct sk_buff *skb;
 552
 553         /* If we're in loopback test, then pass the packet directly to the
 554          * loopback layer, and free the rx_buf here
 555          */
 556         if (unlikely(efx->loopback_selftest)) {
 557                 efx_loopback_rx_packet(efx, rx_buf->data, rx_buf->len);
 558                 efx_free_rx_buffer(efx, rx_buf);
 559                 return;
 560         }
 561
 562         if (rx_buf->skb) {
 563                 prefetch(skb_shinfo(rx_buf->skb));
 564
 565                 skb_put(rx_buf->skb, rx_buf->len);
 566
 567                 /* Move past the ethernet header. rx_buf->data still points
 568                  * at the ethernet header */
 569                 rx_buf->skb->protocol = eth_type_trans(rx_buf->skb,
 570                                                        efx->net_dev);
 571
 572                 skb_record_rx_queue(rx_buf->skb, channel->channel);
 573         }
 574
 575         if (likely(checksummed || rx_buf->page)) {
 576                 efx_rx_packet_lro(channel, rx_buf, checksummed);
 577                 return;
 578         }
 579
 580         /* We now own the SKB */
 581         skb = rx_buf->skb;
 582         rx_buf->skb = NULL;
 583         EFX_BUG_ON_PARANOID(!skb);
 584
 585         /* Set the SKB flags */
 586         skb->ip_summed = CHECKSUM_NONE;
 587
 588         /* Pass the packet up */
 589         netif_receive_skb(skb);
 590
 591         /* Update allocation strategy method */
 592         channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
 593 }
 594
 595 void efx_rx_strategy(struct efx_channel *channel)
 596 {
 597         enum efx_rx_alloc_method method = rx_alloc_method;
 598
 599         /* Only makes sense to use page based allocation if LRO is enabled */
 600         if (!(channel->efx->net_dev->features & NETIF_F_GRO)) {
 601                 method = RX_ALLOC_METHOD_SKB;
 602         } else if (method == RX_ALLOC_METHOD_AUTO) {
 603                 /* Constrain the rx_alloc_level */
 604                 if (channel->rx_alloc_level < 0)
 605                         channel->rx_alloc_level = 0;
 606                 else if (channel->rx_alloc_level > RX_ALLOC_LEVEL_MAX)
 607                         channel->rx_alloc_level = RX_ALLOC_LEVEL_MAX;
 608
 609                 /* Decide on the allocation method */
 610                 method = ((channel->rx_alloc_level > RX_ALLOC_LEVEL_LRO) ?
 611                           RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB);
 612         }
 613
 614         /* Push the option */
 615         channel->rx_alloc_push_pages = (method == RX_ALLOC_METHOD_PAGE);
 616 }
 617
 618 int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
 619 {
 620         struct efx_nic *efx = rx_queue->efx;
 621         unsigned int rxq_size;
 622         int rc;
 623
 624         EFX_LOG(efx, "creating RX queue %d\n", rx_queue->queue);
 625
 626         /* Allocate RX buffers */
 627         rxq_size = EFX_RXQ_SIZE * sizeof(*rx_queue->buffer);
 628         rx_queue->buffer = kzalloc(rxq_size, GFP_KERNEL);
 629         if (!rx_queue->buffer)
 630                 return -ENOMEM;
 631
 632         rc = efx_nic_probe_rx(rx_queue);
 633         if (rc) {
 634                 kfree(rx_queue->buffer);
 635                 rx_queue->buffer = NULL;
 636         }
 637         return rc;
 638 }
 639
 640 void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
 641 {
 642         unsigned int max_fill, trigger, limit;
 643
 644         EFX_LOG(rx_queue->efx, "initialising RX queue %d\n", rx_queue->queue);
 645
 646         /* Initialise ptr fields */
 647         rx_queue->added_count = 0;
 648         rx_queue->notified_count = 0;
 649         rx_queue->removed_count = 0;
 650         rx_queue->min_fill = -1U;
 651         rx_queue->min_overfill = -1U;
 652
 653         /* Initialise limit fields */
 654         max_fill = EFX_RXQ_SIZE - EFX_RXD_HEAD_ROOM;
 655         trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
 656         limit = max_fill * min(rx_refill_limit, 100U) / 100U;
 657
 658         rx_queue->max_fill = max_fill;
 659         rx_queue->fast_fill_trigger = trigger;
 660         rx_queue->fast_fill_limit = limit;
 661
 662         /* Set up RX descriptor ring */
 663         efx_nic_init_rx(rx_queue);
 664 }
 665
 666 void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
 667 {
 668         int i;
 669         struct efx_rx_buffer *rx_buf;
 670
 671         EFX_LOG(rx_queue->efx, "shutting down RX queue %d\n", rx_queue->queue);
 672
 673         del_timer_sync(&rx_queue->slow_fill);
 674         efx_nic_fini_rx(rx_queue);
 675
 676         /* Release RX buffers NB start at index 0 not current HW ptr */
 677         if (rx_queue->buffer) {
 678                 for (i = 0; i <= EFX_RXQ_MASK; i++) {
 679                         rx_buf = efx_rx_buffer(rx_queue, i);
 680                         efx_fini_rx_buffer(rx_queue, rx_buf);
 681                 }
 682         }
 683 }
 684
 685 void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
 686 {
 687         EFX_LOG(rx_queue->efx, "destroying RX queue %d\n", rx_queue->queue);
 688
 689         efx_nic_remove_rx(rx_queue);
 690
 691         kfree(rx_queue->buffer);
 692         rx_queue->buffer = NULL;
 693 }
 694
 695
 696 module_param(rx_alloc_method, int, 0644);
 697 MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers");
 698
 699 module_param(rx_refill_threshold, uint, 0444);
 700 MODULE_PARM_DESC(rx_refill_threshold,
 701                  "RX descriptor ring fast/slow fill threshold (%)");
 702