Ben Hutchings | 8ceee66 | 2008-04-27 12:55:59 +0100 | [diff] [blame] | 1 | /**************************************************************************** |
| 2 | * Driver for Solarflare Solarstorm network controllers and boards |
| 3 | * Copyright 2005-2006 Fen Systems Ltd. |
| 4 | * Copyright 2005-2008 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/pci.h> |
| 12 | #include <linux/tcp.h> |
| 13 | #include <linux/ip.h> |
| 14 | #include <linux/in.h> |
| 15 | #include <linux/if_ether.h> |
| 16 | #include <linux/highmem.h> |
| 17 | #include "net_driver.h" |
| 18 | #include "tx.h" |
| 19 | #include "efx.h" |
| 20 | #include "falcon.h" |
| 21 | #include "workarounds.h" |
| 22 | |
| 23 | /* |
| 24 | * TX descriptor ring full threshold |
| 25 | * |
| 26 | * The tx_queue descriptor ring fill-level must fall below this value |
| 27 | * before we restart the netif queue |
| 28 | */ |
| 29 | #define EFX_NETDEV_TX_THRESHOLD(_tx_queue) \ |
| 30 | (_tx_queue->efx->type->txd_ring_mask / 2u) |
| 31 | |
| 32 | /* We want to be able to nest calls to netif_stop_queue(), since each |
| 33 | * channel can have an individual stop on the queue. |
| 34 | */ |
| 35 | void efx_stop_queue(struct efx_nic *efx) |
| 36 | { |
| 37 | spin_lock_bh(&efx->netif_stop_lock); |
| 38 | EFX_TRACE(efx, "stop TX queue\n"); |
| 39 | |
| 40 | atomic_inc(&efx->netif_stop_count); |
| 41 | netif_stop_queue(efx->net_dev); |
| 42 | |
| 43 | spin_unlock_bh(&efx->netif_stop_lock); |
| 44 | } |
| 45 | |
| 46 | /* Wake netif's TX queue |
| 47 | * We want to be able to nest calls to netif_stop_queue(), since each |
| 48 | * channel can have an individual stop on the queue. |
| 49 | */ |
| 50 | inline void efx_wake_queue(struct efx_nic *efx) |
| 51 | { |
| 52 | local_bh_disable(); |
| 53 | if (atomic_dec_and_lock(&efx->netif_stop_count, |
| 54 | &efx->netif_stop_lock)) { |
| 55 | EFX_TRACE(efx, "waking TX queue\n"); |
| 56 | netif_wake_queue(efx->net_dev); |
| 57 | spin_unlock(&efx->netif_stop_lock); |
| 58 | } |
| 59 | local_bh_enable(); |
| 60 | } |
| 61 | |
| 62 | static inline void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, |
| 63 | struct efx_tx_buffer *buffer) |
| 64 | { |
| 65 | if (buffer->unmap_len) { |
| 66 | struct pci_dev *pci_dev = tx_queue->efx->pci_dev; |
| 67 | if (buffer->unmap_single) |
| 68 | pci_unmap_single(pci_dev, buffer->unmap_addr, |
| 69 | buffer->unmap_len, PCI_DMA_TODEVICE); |
| 70 | else |
| 71 | pci_unmap_page(pci_dev, buffer->unmap_addr, |
| 72 | buffer->unmap_len, PCI_DMA_TODEVICE); |
| 73 | buffer->unmap_len = 0; |
| 74 | buffer->unmap_single = 0; |
| 75 | } |
| 76 | |
| 77 | if (buffer->skb) { |
| 78 | dev_kfree_skb_any((struct sk_buff *) buffer->skb); |
| 79 | buffer->skb = NULL; |
| 80 | EFX_TRACE(tx_queue->efx, "TX queue %d transmission id %x " |
| 81 | "complete\n", tx_queue->queue, read_ptr); |
| 82 | } |
| 83 | } |
| 84 | |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 85 | /** |
| 86 | * struct efx_tso_header - a DMA mapped buffer for packet headers |
| 87 | * @next: Linked list of free ones. |
| 88 | * The list is protected by the TX queue lock. |
| 89 | * @dma_unmap_len: Length to unmap for an oversize buffer, or 0. |
| 90 | * @dma_addr: The DMA address of the header below. |
| 91 | * |
| 92 | * This controls the memory used for a TSO header. Use TSOH_DATA() |
| 93 | * to find the packet header data. Use TSOH_SIZE() to calculate the |
| 94 | * total size required for a given packet header length. TSO headers |
| 95 | * in the free list are exactly %TSOH_STD_SIZE bytes in size. |
| 96 | */ |
| 97 | struct efx_tso_header { |
| 98 | union { |
| 99 | struct efx_tso_header *next; |
| 100 | size_t unmap_len; |
| 101 | }; |
| 102 | dma_addr_t dma_addr; |
| 103 | }; |
| 104 | |
| 105 | static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, |
| 106 | const struct sk_buff *skb); |
| 107 | static void efx_fini_tso(struct efx_tx_queue *tx_queue); |
| 108 | static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, |
| 109 | struct efx_tso_header *tsoh); |
| 110 | |
| 111 | static inline void efx_tsoh_free(struct efx_tx_queue *tx_queue, |
| 112 | struct efx_tx_buffer *buffer) |
| 113 | { |
| 114 | if (buffer->tsoh) { |
| 115 | if (likely(!buffer->tsoh->unmap_len)) { |
| 116 | buffer->tsoh->next = tx_queue->tso_headers_free; |
| 117 | tx_queue->tso_headers_free = buffer->tsoh; |
| 118 | } else { |
| 119 | efx_tsoh_heap_free(tx_queue, buffer->tsoh); |
| 120 | } |
| 121 | buffer->tsoh = NULL; |
| 122 | } |
| 123 | } |
| 124 | |
Ben Hutchings | 8ceee66 | 2008-04-27 12:55:59 +0100 | [diff] [blame] | 125 | |
| 126 | /* |
| 127 | * Add a socket buffer to a TX queue |
| 128 | * |
| 129 | * This maps all fragments of a socket buffer for DMA and adds them to |
| 130 | * the TX queue. The queue's insert pointer will be incremented by |
| 131 | * the number of fragments in the socket buffer. |
| 132 | * |
| 133 | * If any DMA mapping fails, any mapped fragments will be unmapped, |
| 134 | * the queue's insert pointer will be restored to its original value. |
| 135 | * |
| 136 | * Returns NETDEV_TX_OK or NETDEV_TX_BUSY |
| 137 | * You must hold netif_tx_lock() to call this function. |
| 138 | */ |
| 139 | static inline int efx_enqueue_skb(struct efx_tx_queue *tx_queue, |
| 140 | const struct sk_buff *skb) |
| 141 | { |
| 142 | struct efx_nic *efx = tx_queue->efx; |
| 143 | struct pci_dev *pci_dev = efx->pci_dev; |
| 144 | struct efx_tx_buffer *buffer; |
| 145 | skb_frag_t *fragment; |
| 146 | struct page *page; |
| 147 | int page_offset; |
| 148 | unsigned int len, unmap_len = 0, fill_level, insert_ptr, misalign; |
| 149 | dma_addr_t dma_addr, unmap_addr = 0; |
| 150 | unsigned int dma_len; |
| 151 | unsigned unmap_single; |
| 152 | int q_space, i = 0; |
| 153 | int rc = NETDEV_TX_OK; |
| 154 | |
| 155 | EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count); |
| 156 | |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 157 | if (skb_shinfo((struct sk_buff *)skb)->gso_size) |
| 158 | return efx_enqueue_skb_tso(tx_queue, skb); |
| 159 | |
Ben Hutchings | 8ceee66 | 2008-04-27 12:55:59 +0100 | [diff] [blame] | 160 | /* Get size of the initial fragment */ |
| 161 | len = skb_headlen(skb); |
| 162 | |
| 163 | fill_level = tx_queue->insert_count - tx_queue->old_read_count; |
| 164 | q_space = efx->type->txd_ring_mask - 1 - fill_level; |
| 165 | |
| 166 | /* Map for DMA. Use pci_map_single rather than pci_map_page |
| 167 | * since this is more efficient on machines with sparse |
| 168 | * memory. |
| 169 | */ |
| 170 | unmap_single = 1; |
| 171 | dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE); |
| 172 | |
| 173 | /* Process all fragments */ |
| 174 | while (1) { |
| 175 | if (unlikely(pci_dma_mapping_error(dma_addr))) |
| 176 | goto pci_err; |
| 177 | |
| 178 | /* Store fields for marking in the per-fragment final |
| 179 | * descriptor */ |
| 180 | unmap_len = len; |
| 181 | unmap_addr = dma_addr; |
| 182 | |
| 183 | /* Add to TX queue, splitting across DMA boundaries */ |
| 184 | do { |
| 185 | if (unlikely(q_space-- <= 0)) { |
| 186 | /* It might be that completions have |
| 187 | * happened since the xmit path last |
| 188 | * checked. Update the xmit path's |
| 189 | * copy of read_count. |
| 190 | */ |
| 191 | ++tx_queue->stopped; |
| 192 | /* This memory barrier protects the |
| 193 | * change of stopped from the access |
| 194 | * of read_count. */ |
| 195 | smp_mb(); |
| 196 | tx_queue->old_read_count = |
| 197 | *(volatile unsigned *) |
| 198 | &tx_queue->read_count; |
| 199 | fill_level = (tx_queue->insert_count |
| 200 | - tx_queue->old_read_count); |
| 201 | q_space = (efx->type->txd_ring_mask - 1 - |
| 202 | fill_level); |
| 203 | if (unlikely(q_space-- <= 0)) |
| 204 | goto stop; |
| 205 | smp_mb(); |
| 206 | --tx_queue->stopped; |
| 207 | } |
| 208 | |
| 209 | insert_ptr = (tx_queue->insert_count & |
| 210 | efx->type->txd_ring_mask); |
| 211 | buffer = &tx_queue->buffer[insert_ptr]; |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 212 | efx_tsoh_free(tx_queue, buffer); |
| 213 | EFX_BUG_ON_PARANOID(buffer->tsoh); |
Ben Hutchings | 8ceee66 | 2008-04-27 12:55:59 +0100 | [diff] [blame] | 214 | EFX_BUG_ON_PARANOID(buffer->skb); |
| 215 | EFX_BUG_ON_PARANOID(buffer->len); |
| 216 | EFX_BUG_ON_PARANOID(buffer->continuation != 1); |
| 217 | EFX_BUG_ON_PARANOID(buffer->unmap_len); |
| 218 | |
| 219 | dma_len = (((~dma_addr) & efx->type->tx_dma_mask) + 1); |
| 220 | if (likely(dma_len > len)) |
| 221 | dma_len = len; |
| 222 | |
| 223 | misalign = (unsigned)dma_addr & efx->type->bug5391_mask; |
| 224 | if (misalign && dma_len + misalign > 512) |
| 225 | dma_len = 512 - misalign; |
| 226 | |
| 227 | /* Fill out per descriptor fields */ |
| 228 | buffer->len = dma_len; |
| 229 | buffer->dma_addr = dma_addr; |
| 230 | len -= dma_len; |
| 231 | dma_addr += dma_len; |
| 232 | ++tx_queue->insert_count; |
| 233 | } while (len); |
| 234 | |
| 235 | /* Transfer ownership of the unmapping to the final buffer */ |
| 236 | buffer->unmap_addr = unmap_addr; |
| 237 | buffer->unmap_single = unmap_single; |
| 238 | buffer->unmap_len = unmap_len; |
| 239 | unmap_len = 0; |
| 240 | |
| 241 | /* Get address and size of next fragment */ |
| 242 | if (i >= skb_shinfo(skb)->nr_frags) |
| 243 | break; |
| 244 | fragment = &skb_shinfo(skb)->frags[i]; |
| 245 | len = fragment->size; |
| 246 | page = fragment->page; |
| 247 | page_offset = fragment->page_offset; |
| 248 | i++; |
| 249 | /* Map for DMA */ |
| 250 | unmap_single = 0; |
| 251 | dma_addr = pci_map_page(pci_dev, page, page_offset, len, |
| 252 | PCI_DMA_TODEVICE); |
| 253 | } |
| 254 | |
| 255 | /* Transfer ownership of the skb to the final buffer */ |
| 256 | buffer->skb = skb; |
| 257 | buffer->continuation = 0; |
| 258 | |
| 259 | /* Pass off to hardware */ |
| 260 | falcon_push_buffers(tx_queue); |
| 261 | |
| 262 | return NETDEV_TX_OK; |
| 263 | |
| 264 | pci_err: |
| 265 | EFX_ERR_RL(efx, " TX queue %d could not map skb with %d bytes %d " |
| 266 | "fragments for DMA\n", tx_queue->queue, skb->len, |
| 267 | skb_shinfo(skb)->nr_frags + 1); |
| 268 | |
| 269 | /* Mark the packet as transmitted, and free the SKB ourselves */ |
| 270 | dev_kfree_skb_any((struct sk_buff *)skb); |
| 271 | goto unwind; |
| 272 | |
| 273 | stop: |
| 274 | rc = NETDEV_TX_BUSY; |
| 275 | |
| 276 | if (tx_queue->stopped == 1) |
| 277 | efx_stop_queue(efx); |
| 278 | |
| 279 | unwind: |
| 280 | /* Work backwards until we hit the original insert pointer value */ |
| 281 | while (tx_queue->insert_count != tx_queue->write_count) { |
| 282 | --tx_queue->insert_count; |
| 283 | insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask; |
| 284 | buffer = &tx_queue->buffer[insert_ptr]; |
| 285 | efx_dequeue_buffer(tx_queue, buffer); |
| 286 | buffer->len = 0; |
| 287 | } |
| 288 | |
| 289 | /* Free the fragment we were mid-way through pushing */ |
| 290 | if (unmap_len) |
| 291 | pci_unmap_page(pci_dev, unmap_addr, unmap_len, |
| 292 | PCI_DMA_TODEVICE); |
| 293 | |
| 294 | return rc; |
| 295 | } |
| 296 | |
| 297 | /* Remove packets from the TX queue |
| 298 | * |
| 299 | * This removes packets from the TX queue, up to and including the |
| 300 | * specified index. |
| 301 | */ |
| 302 | static inline void efx_dequeue_buffers(struct efx_tx_queue *tx_queue, |
| 303 | unsigned int index) |
| 304 | { |
| 305 | struct efx_nic *efx = tx_queue->efx; |
| 306 | unsigned int stop_index, read_ptr; |
| 307 | unsigned int mask = tx_queue->efx->type->txd_ring_mask; |
| 308 | |
| 309 | stop_index = (index + 1) & mask; |
| 310 | read_ptr = tx_queue->read_count & mask; |
| 311 | |
| 312 | while (read_ptr != stop_index) { |
| 313 | struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr]; |
| 314 | if (unlikely(buffer->len == 0)) { |
| 315 | EFX_ERR(tx_queue->efx, "TX queue %d spurious TX " |
| 316 | "completion id %x\n", tx_queue->queue, |
| 317 | read_ptr); |
| 318 | efx_schedule_reset(efx, RESET_TYPE_TX_SKIP); |
| 319 | return; |
| 320 | } |
| 321 | |
| 322 | efx_dequeue_buffer(tx_queue, buffer); |
| 323 | buffer->continuation = 1; |
| 324 | buffer->len = 0; |
| 325 | |
| 326 | ++tx_queue->read_count; |
| 327 | read_ptr = tx_queue->read_count & mask; |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /* Initiate a packet transmission on the specified TX queue. |
| 332 | * Note that returning anything other than NETDEV_TX_OK will cause the |
| 333 | * OS to free the skb. |
| 334 | * |
| 335 | * This function is split out from efx_hard_start_xmit to allow the |
| 336 | * loopback test to direct packets via specific TX queues. It is |
| 337 | * therefore a non-static inline, so as not to penalise performance |
| 338 | * for non-loopback transmissions. |
| 339 | * |
| 340 | * Context: netif_tx_lock held |
| 341 | */ |
| 342 | inline int efx_xmit(struct efx_nic *efx, |
| 343 | struct efx_tx_queue *tx_queue, struct sk_buff *skb) |
| 344 | { |
| 345 | int rc; |
| 346 | |
| 347 | /* Map fragments for DMA and add to TX queue */ |
| 348 | rc = efx_enqueue_skb(tx_queue, skb); |
| 349 | if (unlikely(rc != NETDEV_TX_OK)) |
| 350 | goto out; |
| 351 | |
| 352 | /* Update last TX timer */ |
| 353 | efx->net_dev->trans_start = jiffies; |
| 354 | |
| 355 | out: |
| 356 | return rc; |
| 357 | } |
| 358 | |
| 359 | /* Initiate a packet transmission. We use one channel per CPU |
| 360 | * (sharing when we have more CPUs than channels). On Falcon, the TX |
| 361 | * completion events will be directed back to the CPU that transmitted |
| 362 | * the packet, which should be cache-efficient. |
| 363 | * |
| 364 | * Context: non-blocking. |
| 365 | * Note that returning anything other than NETDEV_TX_OK will cause the |
| 366 | * OS to free the skb. |
| 367 | */ |
| 368 | int efx_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev) |
| 369 | { |
| 370 | struct efx_nic *efx = net_dev->priv; |
| 371 | return efx_xmit(efx, &efx->tx_queue[0], skb); |
| 372 | } |
| 373 | |
| 374 | void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index) |
| 375 | { |
| 376 | unsigned fill_level; |
| 377 | struct efx_nic *efx = tx_queue->efx; |
| 378 | |
| 379 | EFX_BUG_ON_PARANOID(index > efx->type->txd_ring_mask); |
| 380 | |
| 381 | efx_dequeue_buffers(tx_queue, index); |
| 382 | |
| 383 | /* See if we need to restart the netif queue. This barrier |
| 384 | * separates the update of read_count from the test of |
| 385 | * stopped. */ |
| 386 | smp_mb(); |
| 387 | if (unlikely(tx_queue->stopped)) { |
| 388 | fill_level = tx_queue->insert_count - tx_queue->read_count; |
| 389 | if (fill_level < EFX_NETDEV_TX_THRESHOLD(tx_queue)) { |
| 390 | EFX_BUG_ON_PARANOID(!NET_DEV_REGISTERED(efx)); |
| 391 | |
| 392 | /* Do this under netif_tx_lock(), to avoid racing |
| 393 | * with efx_xmit(). */ |
| 394 | netif_tx_lock(efx->net_dev); |
| 395 | if (tx_queue->stopped) { |
| 396 | tx_queue->stopped = 0; |
| 397 | efx_wake_queue(efx); |
| 398 | } |
| 399 | netif_tx_unlock(efx->net_dev); |
| 400 | } |
| 401 | } |
| 402 | } |
| 403 | |
| 404 | int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) |
| 405 | { |
| 406 | struct efx_nic *efx = tx_queue->efx; |
| 407 | unsigned int txq_size; |
| 408 | int i, rc; |
| 409 | |
| 410 | EFX_LOG(efx, "creating TX queue %d\n", tx_queue->queue); |
| 411 | |
| 412 | /* Allocate software ring */ |
| 413 | txq_size = (efx->type->txd_ring_mask + 1) * sizeof(*tx_queue->buffer); |
| 414 | tx_queue->buffer = kzalloc(txq_size, GFP_KERNEL); |
| 415 | if (!tx_queue->buffer) { |
| 416 | rc = -ENOMEM; |
| 417 | goto fail1; |
| 418 | } |
| 419 | for (i = 0; i <= efx->type->txd_ring_mask; ++i) |
| 420 | tx_queue->buffer[i].continuation = 1; |
| 421 | |
| 422 | /* Allocate hardware ring */ |
| 423 | rc = falcon_probe_tx(tx_queue); |
| 424 | if (rc) |
| 425 | goto fail2; |
| 426 | |
| 427 | return 0; |
| 428 | |
| 429 | fail2: |
| 430 | kfree(tx_queue->buffer); |
| 431 | tx_queue->buffer = NULL; |
| 432 | fail1: |
| 433 | tx_queue->used = 0; |
| 434 | |
| 435 | return rc; |
| 436 | } |
| 437 | |
| 438 | int efx_init_tx_queue(struct efx_tx_queue *tx_queue) |
| 439 | { |
| 440 | EFX_LOG(tx_queue->efx, "initialising TX queue %d\n", tx_queue->queue); |
| 441 | |
| 442 | tx_queue->insert_count = 0; |
| 443 | tx_queue->write_count = 0; |
| 444 | tx_queue->read_count = 0; |
| 445 | tx_queue->old_read_count = 0; |
| 446 | BUG_ON(tx_queue->stopped); |
| 447 | |
| 448 | /* Set up TX descriptor ring */ |
| 449 | return falcon_init_tx(tx_queue); |
| 450 | } |
| 451 | |
| 452 | void efx_release_tx_buffers(struct efx_tx_queue *tx_queue) |
| 453 | { |
| 454 | struct efx_tx_buffer *buffer; |
| 455 | |
| 456 | if (!tx_queue->buffer) |
| 457 | return; |
| 458 | |
| 459 | /* Free any buffers left in the ring */ |
| 460 | while (tx_queue->read_count != tx_queue->write_count) { |
| 461 | buffer = &tx_queue->buffer[tx_queue->read_count & |
| 462 | tx_queue->efx->type->txd_ring_mask]; |
| 463 | efx_dequeue_buffer(tx_queue, buffer); |
| 464 | buffer->continuation = 1; |
| 465 | buffer->len = 0; |
| 466 | |
| 467 | ++tx_queue->read_count; |
| 468 | } |
| 469 | } |
| 470 | |
| 471 | void efx_fini_tx_queue(struct efx_tx_queue *tx_queue) |
| 472 | { |
| 473 | EFX_LOG(tx_queue->efx, "shutting down TX queue %d\n", tx_queue->queue); |
| 474 | |
| 475 | /* Flush TX queue, remove descriptor ring */ |
| 476 | falcon_fini_tx(tx_queue); |
| 477 | |
| 478 | efx_release_tx_buffers(tx_queue); |
| 479 | |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 480 | /* Free up TSO header cache */ |
| 481 | efx_fini_tso(tx_queue); |
| 482 | |
Ben Hutchings | 8ceee66 | 2008-04-27 12:55:59 +0100 | [diff] [blame] | 483 | /* Release queue's stop on port, if any */ |
| 484 | if (tx_queue->stopped) { |
| 485 | tx_queue->stopped = 0; |
| 486 | efx_wake_queue(tx_queue->efx); |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) |
| 491 | { |
| 492 | EFX_LOG(tx_queue->efx, "destroying TX queue %d\n", tx_queue->queue); |
| 493 | falcon_remove_tx(tx_queue); |
| 494 | |
| 495 | kfree(tx_queue->buffer); |
| 496 | tx_queue->buffer = NULL; |
| 497 | tx_queue->used = 0; |
| 498 | } |
| 499 | |
| 500 | |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 501 | /* Efx TCP segmentation acceleration. |
| 502 | * |
| 503 | * Why? Because by doing it here in the driver we can go significantly |
| 504 | * faster than the GSO. |
| 505 | * |
| 506 | * Requires TX checksum offload support. |
| 507 | */ |
| 508 | |
| 509 | /* Number of bytes inserted at the start of a TSO header buffer, |
| 510 | * similar to NET_IP_ALIGN. |
| 511 | */ |
| 512 | #if defined(__i386__) || defined(__x86_64__) |
| 513 | #define TSOH_OFFSET 0 |
| 514 | #else |
| 515 | #define TSOH_OFFSET NET_IP_ALIGN |
| 516 | #endif |
| 517 | |
| 518 | #define TSOH_BUFFER(tsoh) ((u8 *)(tsoh + 1) + TSOH_OFFSET) |
| 519 | |
| 520 | /* Total size of struct efx_tso_header, buffer and padding */ |
| 521 | #define TSOH_SIZE(hdr_len) \ |
| 522 | (sizeof(struct efx_tso_header) + TSOH_OFFSET + hdr_len) |
| 523 | |
| 524 | /* Size of blocks on free list. Larger blocks must be allocated from |
| 525 | * the heap. |
| 526 | */ |
| 527 | #define TSOH_STD_SIZE 128 |
| 528 | |
| 529 | #define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2)) |
| 530 | #define ETH_HDR_LEN(skb) (skb_network_header(skb) - (skb)->data) |
| 531 | #define SKB_TCP_OFF(skb) PTR_DIFF(tcp_hdr(skb), (skb)->data) |
| 532 | #define SKB_IPV4_OFF(skb) PTR_DIFF(ip_hdr(skb), (skb)->data) |
| 533 | |
| 534 | /** |
| 535 | * struct tso_state - TSO state for an SKB |
| 536 | * @remaining_len: Bytes of data we've yet to segment |
| 537 | * @seqnum: Current sequence number |
| 538 | * @packet_space: Remaining space in current packet |
| 539 | * @ifc: Input fragment cursor. |
| 540 | * Where we are in the current fragment of the incoming SKB. These |
| 541 | * values get updated in place when we split a fragment over |
| 542 | * multiple packets. |
| 543 | * @p: Parameters. |
| 544 | * These values are set once at the start of the TSO send and do |
| 545 | * not get changed as the routine progresses. |
| 546 | * |
| 547 | * The state used during segmentation. It is put into this data structure |
| 548 | * just to make it easy to pass into inline functions. |
| 549 | */ |
| 550 | struct tso_state { |
| 551 | unsigned remaining_len; |
| 552 | unsigned seqnum; |
| 553 | unsigned packet_space; |
| 554 | |
| 555 | struct { |
| 556 | /* DMA address of current position */ |
| 557 | dma_addr_t dma_addr; |
| 558 | /* Remaining length */ |
| 559 | unsigned int len; |
| 560 | /* DMA address and length of the whole fragment */ |
| 561 | unsigned int unmap_len; |
| 562 | dma_addr_t unmap_addr; |
| 563 | struct page *page; |
| 564 | unsigned page_off; |
| 565 | } ifc; |
| 566 | |
| 567 | struct { |
| 568 | /* The number of bytes of header */ |
| 569 | unsigned int header_length; |
| 570 | |
| 571 | /* The number of bytes to put in each outgoing segment. */ |
| 572 | int full_packet_size; |
| 573 | |
| 574 | /* Current IPv4 ID, host endian. */ |
| 575 | unsigned ipv4_id; |
| 576 | } p; |
| 577 | }; |
| 578 | |
| 579 | |
| 580 | /* |
| 581 | * Verify that our various assumptions about sk_buffs and the conditions |
| 582 | * under which TSO will be attempted hold true. |
| 583 | */ |
| 584 | static inline void efx_tso_check_safe(const struct sk_buff *skb) |
| 585 | { |
| 586 | EFX_BUG_ON_PARANOID(skb->protocol != htons(ETH_P_IP)); |
| 587 | EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto != |
| 588 | skb->protocol); |
| 589 | EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP); |
| 590 | EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data) |
| 591 | + (tcp_hdr(skb)->doff << 2u)) > |
| 592 | skb_headlen(skb)); |
| 593 | } |
| 594 | |
| 595 | |
| 596 | /* |
| 597 | * Allocate a page worth of efx_tso_header structures, and string them |
| 598 | * into the tx_queue->tso_headers_free linked list. Return 0 or -ENOMEM. |
| 599 | */ |
| 600 | static int efx_tsoh_block_alloc(struct efx_tx_queue *tx_queue) |
| 601 | { |
| 602 | |
| 603 | struct pci_dev *pci_dev = tx_queue->efx->pci_dev; |
| 604 | struct efx_tso_header *tsoh; |
| 605 | dma_addr_t dma_addr; |
| 606 | u8 *base_kva, *kva; |
| 607 | |
| 608 | base_kva = pci_alloc_consistent(pci_dev, PAGE_SIZE, &dma_addr); |
| 609 | if (base_kva == NULL) { |
| 610 | EFX_ERR(tx_queue->efx, "Unable to allocate page for TSO" |
| 611 | " headers\n"); |
| 612 | return -ENOMEM; |
| 613 | } |
| 614 | |
| 615 | /* pci_alloc_consistent() allocates pages. */ |
| 616 | EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1u)); |
| 617 | |
| 618 | for (kva = base_kva; kva < base_kva + PAGE_SIZE; kva += TSOH_STD_SIZE) { |
| 619 | tsoh = (struct efx_tso_header *)kva; |
| 620 | tsoh->dma_addr = dma_addr + (TSOH_BUFFER(tsoh) - base_kva); |
| 621 | tsoh->next = tx_queue->tso_headers_free; |
| 622 | tx_queue->tso_headers_free = tsoh; |
| 623 | } |
| 624 | |
| 625 | return 0; |
| 626 | } |
| 627 | |
| 628 | |
| 629 | /* Free up a TSO header, and all others in the same page. */ |
| 630 | static void efx_tsoh_block_free(struct efx_tx_queue *tx_queue, |
| 631 | struct efx_tso_header *tsoh, |
| 632 | struct pci_dev *pci_dev) |
| 633 | { |
| 634 | struct efx_tso_header **p; |
| 635 | unsigned long base_kva; |
| 636 | dma_addr_t base_dma; |
| 637 | |
| 638 | base_kva = (unsigned long)tsoh & PAGE_MASK; |
| 639 | base_dma = tsoh->dma_addr & PAGE_MASK; |
| 640 | |
| 641 | p = &tx_queue->tso_headers_free; |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 642 | while (*p != NULL) { |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 643 | if (((unsigned long)*p & PAGE_MASK) == base_kva) |
| 644 | *p = (*p)->next; |
| 645 | else |
| 646 | p = &(*p)->next; |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 647 | } |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 648 | |
| 649 | pci_free_consistent(pci_dev, PAGE_SIZE, (void *)base_kva, base_dma); |
| 650 | } |
| 651 | |
| 652 | static struct efx_tso_header * |
| 653 | efx_tsoh_heap_alloc(struct efx_tx_queue *tx_queue, size_t header_len) |
| 654 | { |
| 655 | struct efx_tso_header *tsoh; |
| 656 | |
| 657 | tsoh = kmalloc(TSOH_SIZE(header_len), GFP_ATOMIC | GFP_DMA); |
| 658 | if (unlikely(!tsoh)) |
| 659 | return NULL; |
| 660 | |
| 661 | tsoh->dma_addr = pci_map_single(tx_queue->efx->pci_dev, |
| 662 | TSOH_BUFFER(tsoh), header_len, |
| 663 | PCI_DMA_TODEVICE); |
| 664 | if (unlikely(pci_dma_mapping_error(tsoh->dma_addr))) { |
| 665 | kfree(tsoh); |
| 666 | return NULL; |
| 667 | } |
| 668 | |
| 669 | tsoh->unmap_len = header_len; |
| 670 | return tsoh; |
| 671 | } |
| 672 | |
| 673 | static void |
| 674 | efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh) |
| 675 | { |
| 676 | pci_unmap_single(tx_queue->efx->pci_dev, |
| 677 | tsoh->dma_addr, tsoh->unmap_len, |
| 678 | PCI_DMA_TODEVICE); |
| 679 | kfree(tsoh); |
| 680 | } |
| 681 | |
| 682 | /** |
| 683 | * efx_tx_queue_insert - push descriptors onto the TX queue |
| 684 | * @tx_queue: Efx TX queue |
| 685 | * @dma_addr: DMA address of fragment |
| 686 | * @len: Length of fragment |
| 687 | * @skb: Only non-null for end of last segment |
| 688 | * @end_of_packet: True if last fragment in a packet |
| 689 | * @unmap_addr: DMA address of fragment for unmapping |
| 690 | * @unmap_len: Only set this in last segment of a fragment |
| 691 | * |
| 692 | * Push descriptors onto the TX queue. Return 0 on success or 1 if |
| 693 | * @tx_queue full. |
| 694 | */ |
| 695 | static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, |
| 696 | dma_addr_t dma_addr, unsigned len, |
| 697 | const struct sk_buff *skb, int end_of_packet, |
| 698 | dma_addr_t unmap_addr, unsigned unmap_len) |
| 699 | { |
| 700 | struct efx_tx_buffer *buffer; |
| 701 | struct efx_nic *efx = tx_queue->efx; |
| 702 | unsigned dma_len, fill_level, insert_ptr, misalign; |
| 703 | int q_space; |
| 704 | |
| 705 | EFX_BUG_ON_PARANOID(len <= 0); |
| 706 | |
| 707 | fill_level = tx_queue->insert_count - tx_queue->old_read_count; |
| 708 | /* -1 as there is no way to represent all descriptors used */ |
| 709 | q_space = efx->type->txd_ring_mask - 1 - fill_level; |
| 710 | |
| 711 | while (1) { |
| 712 | if (unlikely(q_space-- <= 0)) { |
| 713 | /* It might be that completions have happened |
| 714 | * since the xmit path last checked. Update |
| 715 | * the xmit path's copy of read_count. |
| 716 | */ |
| 717 | ++tx_queue->stopped; |
| 718 | /* This memory barrier protects the change of |
| 719 | * stopped from the access of read_count. */ |
| 720 | smp_mb(); |
| 721 | tx_queue->old_read_count = |
| 722 | *(volatile unsigned *)&tx_queue->read_count; |
| 723 | fill_level = (tx_queue->insert_count |
| 724 | - tx_queue->old_read_count); |
| 725 | q_space = efx->type->txd_ring_mask - 1 - fill_level; |
| 726 | if (unlikely(q_space-- <= 0)) |
| 727 | return 1; |
| 728 | smp_mb(); |
| 729 | --tx_queue->stopped; |
| 730 | } |
| 731 | |
| 732 | insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask; |
| 733 | buffer = &tx_queue->buffer[insert_ptr]; |
| 734 | ++tx_queue->insert_count; |
| 735 | |
| 736 | EFX_BUG_ON_PARANOID(tx_queue->insert_count - |
| 737 | tx_queue->read_count > |
| 738 | efx->type->txd_ring_mask); |
| 739 | |
| 740 | efx_tsoh_free(tx_queue, buffer); |
| 741 | EFX_BUG_ON_PARANOID(buffer->len); |
| 742 | EFX_BUG_ON_PARANOID(buffer->unmap_len); |
| 743 | EFX_BUG_ON_PARANOID(buffer->skb); |
| 744 | EFX_BUG_ON_PARANOID(buffer->continuation != 1); |
| 745 | EFX_BUG_ON_PARANOID(buffer->tsoh); |
| 746 | |
| 747 | buffer->dma_addr = dma_addr; |
| 748 | |
| 749 | /* Ensure we do not cross a boundary unsupported by H/W */ |
| 750 | dma_len = (~dma_addr & efx->type->tx_dma_mask) + 1; |
| 751 | |
| 752 | misalign = (unsigned)dma_addr & efx->type->bug5391_mask; |
| 753 | if (misalign && dma_len + misalign > 512) |
| 754 | dma_len = 512 - misalign; |
| 755 | |
| 756 | /* If there is enough space to send then do so */ |
| 757 | if (dma_len >= len) |
| 758 | break; |
| 759 | |
| 760 | buffer->len = dma_len; /* Don't set the other members */ |
| 761 | dma_addr += dma_len; |
| 762 | len -= dma_len; |
| 763 | } |
| 764 | |
| 765 | EFX_BUG_ON_PARANOID(!len); |
| 766 | buffer->len = len; |
| 767 | buffer->skb = skb; |
| 768 | buffer->continuation = !end_of_packet; |
| 769 | buffer->unmap_addr = unmap_addr; |
| 770 | buffer->unmap_len = unmap_len; |
| 771 | return 0; |
| 772 | } |
| 773 | |
| 774 | |
| 775 | /* |
| 776 | * Put a TSO header into the TX queue. |
| 777 | * |
| 778 | * This is special-cased because we know that it is small enough to fit in |
| 779 | * a single fragment, and we know it doesn't cross a page boundary. It |
| 780 | * also allows us to not worry about end-of-packet etc. |
| 781 | */ |
| 782 | static inline void efx_tso_put_header(struct efx_tx_queue *tx_queue, |
| 783 | struct efx_tso_header *tsoh, unsigned len) |
| 784 | { |
| 785 | struct efx_tx_buffer *buffer; |
| 786 | |
| 787 | buffer = &tx_queue->buffer[tx_queue->insert_count & |
| 788 | tx_queue->efx->type->txd_ring_mask]; |
| 789 | efx_tsoh_free(tx_queue, buffer); |
| 790 | EFX_BUG_ON_PARANOID(buffer->len); |
| 791 | EFX_BUG_ON_PARANOID(buffer->unmap_len); |
| 792 | EFX_BUG_ON_PARANOID(buffer->skb); |
| 793 | EFX_BUG_ON_PARANOID(buffer->continuation != 1); |
| 794 | EFX_BUG_ON_PARANOID(buffer->tsoh); |
| 795 | buffer->len = len; |
| 796 | buffer->dma_addr = tsoh->dma_addr; |
| 797 | buffer->tsoh = tsoh; |
| 798 | |
| 799 | ++tx_queue->insert_count; |
| 800 | } |
| 801 | |
| 802 | |
| 803 | /* Remove descriptors put into a tx_queue. */ |
| 804 | static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue) |
| 805 | { |
| 806 | struct efx_tx_buffer *buffer; |
| 807 | |
| 808 | /* Work backwards until we hit the original insert pointer value */ |
| 809 | while (tx_queue->insert_count != tx_queue->write_count) { |
| 810 | --tx_queue->insert_count; |
| 811 | buffer = &tx_queue->buffer[tx_queue->insert_count & |
| 812 | tx_queue->efx->type->txd_ring_mask]; |
| 813 | efx_tsoh_free(tx_queue, buffer); |
| 814 | EFX_BUG_ON_PARANOID(buffer->skb); |
| 815 | buffer->len = 0; |
| 816 | buffer->continuation = 1; |
| 817 | if (buffer->unmap_len) { |
| 818 | pci_unmap_page(tx_queue->efx->pci_dev, |
| 819 | buffer->unmap_addr, |
| 820 | buffer->unmap_len, PCI_DMA_TODEVICE); |
| 821 | buffer->unmap_len = 0; |
| 822 | } |
| 823 | } |
| 824 | } |
| 825 | |
| 826 | |
| 827 | /* Parse the SKB header and initialise state. */ |
| 828 | static inline void tso_start(struct tso_state *st, const struct sk_buff *skb) |
| 829 | { |
| 830 | /* All ethernet/IP/TCP headers combined size is TCP header size |
| 831 | * plus offset of TCP header relative to start of packet. |
| 832 | */ |
| 833 | st->p.header_length = ((tcp_hdr(skb)->doff << 2u) |
| 834 | + PTR_DIFF(tcp_hdr(skb), skb->data)); |
| 835 | st->p.full_packet_size = (st->p.header_length |
| 836 | + skb_shinfo(skb)->gso_size); |
| 837 | |
| 838 | st->p.ipv4_id = ntohs(ip_hdr(skb)->id); |
| 839 | st->seqnum = ntohl(tcp_hdr(skb)->seq); |
| 840 | |
| 841 | EFX_BUG_ON_PARANOID(tcp_hdr(skb)->urg); |
| 842 | EFX_BUG_ON_PARANOID(tcp_hdr(skb)->syn); |
| 843 | EFX_BUG_ON_PARANOID(tcp_hdr(skb)->rst); |
| 844 | |
| 845 | st->packet_space = st->p.full_packet_size; |
| 846 | st->remaining_len = skb->len - st->p.header_length; |
| 847 | } |
| 848 | |
| 849 | |
| 850 | /** |
| 851 | * tso_get_fragment - record fragment details and map for DMA |
| 852 | * @st: TSO state |
| 853 | * @efx: Efx NIC |
| 854 | * @data: Pointer to fragment data |
| 855 | * @len: Length of fragment |
| 856 | * |
| 857 | * Record fragment details and map for DMA. Return 0 on success, or |
| 858 | * -%ENOMEM if DMA mapping fails. |
| 859 | */ |
| 860 | static inline int tso_get_fragment(struct tso_state *st, struct efx_nic *efx, |
| 861 | int len, struct page *page, int page_off) |
| 862 | { |
| 863 | |
| 864 | st->ifc.unmap_addr = pci_map_page(efx->pci_dev, page, page_off, |
| 865 | len, PCI_DMA_TODEVICE); |
| 866 | if (likely(!pci_dma_mapping_error(st->ifc.unmap_addr))) { |
| 867 | st->ifc.unmap_len = len; |
| 868 | st->ifc.len = len; |
| 869 | st->ifc.dma_addr = st->ifc.unmap_addr; |
| 870 | st->ifc.page = page; |
| 871 | st->ifc.page_off = page_off; |
| 872 | return 0; |
| 873 | } |
| 874 | return -ENOMEM; |
| 875 | } |
| 876 | |
| 877 | |
| 878 | /** |
| 879 | * tso_fill_packet_with_fragment - form descriptors for the current fragment |
| 880 | * @tx_queue: Efx TX queue |
| 881 | * @skb: Socket buffer |
| 882 | * @st: TSO state |
| 883 | * |
| 884 | * Form descriptors for the current fragment, until we reach the end |
| 885 | * of fragment or end-of-packet. Return 0 on success, 1 if not enough |
| 886 | * space in @tx_queue. |
| 887 | */ |
| 888 | static inline int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue, |
| 889 | const struct sk_buff *skb, |
| 890 | struct tso_state *st) |
| 891 | { |
| 892 | |
| 893 | int n, end_of_packet, rc; |
| 894 | |
| 895 | if (st->ifc.len == 0) |
| 896 | return 0; |
| 897 | if (st->packet_space == 0) |
| 898 | return 0; |
| 899 | |
| 900 | EFX_BUG_ON_PARANOID(st->ifc.len <= 0); |
| 901 | EFX_BUG_ON_PARANOID(st->packet_space <= 0); |
| 902 | |
| 903 | n = min(st->ifc.len, st->packet_space); |
| 904 | |
| 905 | st->packet_space -= n; |
| 906 | st->remaining_len -= n; |
| 907 | st->ifc.len -= n; |
| 908 | st->ifc.page_off += n; |
| 909 | end_of_packet = st->remaining_len == 0 || st->packet_space == 0; |
| 910 | |
| 911 | rc = efx_tx_queue_insert(tx_queue, st->ifc.dma_addr, n, |
| 912 | st->remaining_len ? NULL : skb, |
| 913 | end_of_packet, st->ifc.unmap_addr, |
| 914 | st->ifc.len ? 0 : st->ifc.unmap_len); |
| 915 | |
| 916 | st->ifc.dma_addr += n; |
| 917 | |
| 918 | return rc; |
| 919 | } |
| 920 | |
| 921 | |
| 922 | /** |
| 923 | * tso_start_new_packet - generate a new header and prepare for the new packet |
| 924 | * @tx_queue: Efx TX queue |
| 925 | * @skb: Socket buffer |
| 926 | * @st: TSO state |
| 927 | * |
| 928 | * Generate a new header and prepare for the new packet. Return 0 on |
| 929 | * success, or -1 if failed to alloc header. |
| 930 | */ |
| 931 | static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue, |
| 932 | const struct sk_buff *skb, |
| 933 | struct tso_state *st) |
| 934 | { |
| 935 | struct efx_tso_header *tsoh; |
| 936 | struct iphdr *tsoh_iph; |
| 937 | struct tcphdr *tsoh_th; |
| 938 | unsigned ip_length; |
| 939 | u8 *header; |
| 940 | |
| 941 | /* Allocate a DMA-mapped header buffer. */ |
| 942 | if (likely(TSOH_SIZE(st->p.header_length) <= TSOH_STD_SIZE)) { |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 943 | if (tx_queue->tso_headers_free == NULL) { |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 944 | if (efx_tsoh_block_alloc(tx_queue)) |
| 945 | return -1; |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 946 | } |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 947 | EFX_BUG_ON_PARANOID(!tx_queue->tso_headers_free); |
| 948 | tsoh = tx_queue->tso_headers_free; |
| 949 | tx_queue->tso_headers_free = tsoh->next; |
| 950 | tsoh->unmap_len = 0; |
| 951 | } else { |
| 952 | tx_queue->tso_long_headers++; |
| 953 | tsoh = efx_tsoh_heap_alloc(tx_queue, st->p.header_length); |
| 954 | if (unlikely(!tsoh)) |
| 955 | return -1; |
| 956 | } |
| 957 | |
| 958 | header = TSOH_BUFFER(tsoh); |
| 959 | tsoh_th = (struct tcphdr *)(header + SKB_TCP_OFF(skb)); |
| 960 | tsoh_iph = (struct iphdr *)(header + SKB_IPV4_OFF(skb)); |
| 961 | |
| 962 | /* Copy and update the headers. */ |
| 963 | memcpy(header, skb->data, st->p.header_length); |
| 964 | |
| 965 | tsoh_th->seq = htonl(st->seqnum); |
| 966 | st->seqnum += skb_shinfo(skb)->gso_size; |
| 967 | if (st->remaining_len > skb_shinfo(skb)->gso_size) { |
| 968 | /* This packet will not finish the TSO burst. */ |
| 969 | ip_length = st->p.full_packet_size - ETH_HDR_LEN(skb); |
| 970 | tsoh_th->fin = 0; |
| 971 | tsoh_th->psh = 0; |
| 972 | } else { |
| 973 | /* This packet will be the last in the TSO burst. */ |
| 974 | ip_length = (st->p.header_length - ETH_HDR_LEN(skb) |
| 975 | + st->remaining_len); |
| 976 | tsoh_th->fin = tcp_hdr(skb)->fin; |
| 977 | tsoh_th->psh = tcp_hdr(skb)->psh; |
| 978 | } |
| 979 | tsoh_iph->tot_len = htons(ip_length); |
| 980 | |
| 981 | /* Linux leaves suitable gaps in the IP ID space for us to fill. */ |
| 982 | tsoh_iph->id = htons(st->p.ipv4_id); |
| 983 | st->p.ipv4_id++; |
| 984 | |
| 985 | st->packet_space = skb_shinfo(skb)->gso_size; |
| 986 | ++tx_queue->tso_packets; |
| 987 | |
| 988 | /* Form a descriptor for this header. */ |
| 989 | efx_tso_put_header(tx_queue, tsoh, st->p.header_length); |
| 990 | |
| 991 | return 0; |
| 992 | } |
| 993 | |
| 994 | |
| 995 | /** |
| 996 | * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer |
| 997 | * @tx_queue: Efx TX queue |
| 998 | * @skb: Socket buffer |
| 999 | * |
| 1000 | * Context: You must hold netif_tx_lock() to call this function. |
| 1001 | * |
| 1002 | * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if |
| 1003 | * @skb was not enqueued. In all cases @skb is consumed. Return |
| 1004 | * %NETDEV_TX_OK or %NETDEV_TX_BUSY. |
| 1005 | */ |
| 1006 | static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, |
| 1007 | const struct sk_buff *skb) |
| 1008 | { |
| 1009 | int frag_i, rc, rc2 = NETDEV_TX_OK; |
| 1010 | struct tso_state state; |
| 1011 | skb_frag_t *f; |
| 1012 | |
| 1013 | /* Verify TSO is safe - these checks should never fail. */ |
| 1014 | efx_tso_check_safe(skb); |
| 1015 | |
| 1016 | EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count); |
| 1017 | |
| 1018 | tso_start(&state, skb); |
| 1019 | |
| 1020 | /* Assume that skb header area contains exactly the headers, and |
| 1021 | * all payload is in the frag list. |
| 1022 | */ |
| 1023 | if (skb_headlen(skb) == state.p.header_length) { |
| 1024 | /* Grab the first payload fragment. */ |
| 1025 | EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1); |
| 1026 | frag_i = 0; |
| 1027 | f = &skb_shinfo(skb)->frags[frag_i]; |
| 1028 | rc = tso_get_fragment(&state, tx_queue->efx, |
| 1029 | f->size, f->page, f->page_offset); |
| 1030 | if (rc) |
| 1031 | goto mem_err; |
| 1032 | } else { |
| 1033 | /* It may look like this code fragment assumes that the |
| 1034 | * skb->data portion does not cross a page boundary, but |
| 1035 | * that is not the case. It is guaranteed to be direct |
| 1036 | * mapped memory, and therefore is physically contiguous, |
| 1037 | * and so DMA will work fine. kmap_atomic() on this region |
| 1038 | * will just return the direct mapping, so that will work |
| 1039 | * too. |
| 1040 | */ |
| 1041 | int page_off = (unsigned long)skb->data & (PAGE_SIZE - 1); |
| 1042 | int hl = state.p.header_length; |
| 1043 | rc = tso_get_fragment(&state, tx_queue->efx, |
| 1044 | skb_headlen(skb) - hl, |
| 1045 | virt_to_page(skb->data), page_off + hl); |
| 1046 | if (rc) |
| 1047 | goto mem_err; |
| 1048 | frag_i = -1; |
| 1049 | } |
| 1050 | |
| 1051 | if (tso_start_new_packet(tx_queue, skb, &state) < 0) |
| 1052 | goto mem_err; |
| 1053 | |
| 1054 | while (1) { |
| 1055 | rc = tso_fill_packet_with_fragment(tx_queue, skb, &state); |
| 1056 | if (unlikely(rc)) |
| 1057 | goto stop; |
| 1058 | |
| 1059 | /* Move onto the next fragment? */ |
| 1060 | if (state.ifc.len == 0) { |
| 1061 | if (++frag_i >= skb_shinfo(skb)->nr_frags) |
| 1062 | /* End of payload reached. */ |
| 1063 | break; |
| 1064 | f = &skb_shinfo(skb)->frags[frag_i]; |
| 1065 | rc = tso_get_fragment(&state, tx_queue->efx, |
| 1066 | f->size, f->page, f->page_offset); |
| 1067 | if (rc) |
| 1068 | goto mem_err; |
| 1069 | } |
| 1070 | |
| 1071 | /* Start at new packet? */ |
| 1072 | if (state.packet_space == 0 && |
| 1073 | tso_start_new_packet(tx_queue, skb, &state) < 0) |
| 1074 | goto mem_err; |
| 1075 | } |
| 1076 | |
| 1077 | /* Pass off to hardware */ |
| 1078 | falcon_push_buffers(tx_queue); |
| 1079 | |
| 1080 | tx_queue->tso_bursts++; |
| 1081 | return NETDEV_TX_OK; |
| 1082 | |
| 1083 | mem_err: |
| 1084 | EFX_ERR(tx_queue->efx, "Out of memory for TSO headers, or PCI mapping" |
| 1085 | " error\n"); |
| 1086 | dev_kfree_skb_any((struct sk_buff *)skb); |
| 1087 | goto unwind; |
| 1088 | |
| 1089 | stop: |
| 1090 | rc2 = NETDEV_TX_BUSY; |
| 1091 | |
| 1092 | /* Stop the queue if it wasn't stopped before. */ |
| 1093 | if (tx_queue->stopped == 1) |
| 1094 | efx_stop_queue(tx_queue->efx); |
| 1095 | |
| 1096 | unwind: |
| 1097 | efx_enqueue_unwind(tx_queue); |
| 1098 | return rc2; |
| 1099 | } |
| 1100 | |
| 1101 | |
| 1102 | /* |
| 1103 | * Free up all TSO datastructures associated with tx_queue. This |
| 1104 | * routine should be called only once the tx_queue is both empty and |
| 1105 | * will no longer be used. |
| 1106 | */ |
| 1107 | static void efx_fini_tso(struct efx_tx_queue *tx_queue) |
| 1108 | { |
| 1109 | unsigned i; |
| 1110 | |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 1111 | if (tx_queue->buffer) { |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 1112 | for (i = 0; i <= tx_queue->efx->type->txd_ring_mask; ++i) |
| 1113 | efx_tsoh_free(tx_queue, &tx_queue->buffer[i]); |
Ben Hutchings | b347564 | 2008-05-16 21:15:49 +0100 | [diff] [blame^] | 1114 | } |
Ben Hutchings | b9b39b6 | 2008-05-07 12:51:12 +0100 | [diff] [blame] | 1115 | |
| 1116 | while (tx_queue->tso_headers_free != NULL) |
| 1117 | efx_tsoh_block_free(tx_queue, tx_queue->tso_headers_free, |
| 1118 | tx_queue->efx->pci_dev); |
| 1119 | } |