/**************************************************************************** * Driver for Solarflare Solarstorm network controllers and boards * Copyright 2005-2006 Fen Systems Ltd. * Copyright 2005-2008 Solarflare Communications Inc. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation, incorporated herein by reference. */ #include #include #include #include #include #include #include "net_driver.h" #include "tx.h" #include "efx.h" #include "falcon.h" #include "workarounds.h" /* * TX descriptor ring full threshold * * The tx_queue descriptor ring fill-level must fall below this value * before we restart the netif queue */ #define EFX_NETDEV_TX_THRESHOLD(_tx_queue) \ (_tx_queue->efx->type->txd_ring_mask / 2u) /* We want to be able to nest calls to netif_stop_queue(), since each * channel can have an individual stop on the queue. */ void efx_stop_queue(struct efx_nic *efx) { spin_lock_bh(&efx->netif_stop_lock); EFX_TRACE(efx, "stop TX queue\n"); atomic_inc(&efx->netif_stop_count); netif_stop_queue(efx->net_dev); spin_unlock_bh(&efx->netif_stop_lock); } /* Wake netif's TX queue * We want to be able to nest calls to netif_stop_queue(), since each * channel can have an individual stop on the queue. */ inline void efx_wake_queue(struct efx_nic *efx) { local_bh_disable(); if (atomic_dec_and_lock(&efx->netif_stop_count, &efx->netif_stop_lock)) { EFX_TRACE(efx, "waking TX queue\n"); netif_wake_queue(efx->net_dev); spin_unlock(&efx->netif_stop_lock); } local_bh_enable(); } static inline void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, struct efx_tx_buffer *buffer) { if (buffer->unmap_len) { struct pci_dev *pci_dev = tx_queue->efx->pci_dev; if (buffer->unmap_single) pci_unmap_single(pci_dev, buffer->unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); else pci_unmap_page(pci_dev, buffer->unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); buffer->unmap_len = 0; buffer->unmap_single = 0; } if (buffer->skb) { dev_kfree_skb_any((struct sk_buff *) buffer->skb); buffer->skb = NULL; EFX_TRACE(tx_queue->efx, "TX queue %d transmission id %x " "complete\n", tx_queue->queue, read_ptr); } } /** * struct efx_tso_header - a DMA mapped buffer for packet headers * @next: Linked list of free ones. * The list is protected by the TX queue lock. * @dma_unmap_len: Length to unmap for an oversize buffer, or 0. * @dma_addr: The DMA address of the header below. * * This controls the memory used for a TSO header. Use TSOH_DATA() * to find the packet header data. Use TSOH_SIZE() to calculate the * total size required for a given packet header length. TSO headers * in the free list are exactly %TSOH_STD_SIZE bytes in size. */ struct efx_tso_header { union { struct efx_tso_header *next; size_t unmap_len; }; dma_addr_t dma_addr; }; static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, const struct sk_buff *skb); static void efx_fini_tso(struct efx_tx_queue *tx_queue); static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh); static inline void efx_tsoh_free(struct efx_tx_queue *tx_queue, struct efx_tx_buffer *buffer) { if (buffer->tsoh) { if (likely(!buffer->tsoh->unmap_len)) { buffer->tsoh->next = tx_queue->tso_headers_free; tx_queue->tso_headers_free = buffer->tsoh; } else { efx_tsoh_heap_free(tx_queue, buffer->tsoh); } buffer->tsoh = NULL; } } /* * Add a socket buffer to a TX queue * * This maps all fragments of a socket buffer for DMA and adds them to * the TX queue. The queue's insert pointer will be incremented by * the number of fragments in the socket buffer. * * If any DMA mapping fails, any mapped fragments will be unmapped, * the queue's insert pointer will be restored to its original value. * * Returns NETDEV_TX_OK or NETDEV_TX_BUSY * You must hold netif_tx_lock() to call this function. */ static inline int efx_enqueue_skb(struct efx_tx_queue *tx_queue, const struct sk_buff *skb) { struct efx_nic *efx = tx_queue->efx; struct pci_dev *pci_dev = efx->pci_dev; struct efx_tx_buffer *buffer; skb_frag_t *fragment; struct page *page; int page_offset; unsigned int len, unmap_len = 0, fill_level, insert_ptr, misalign; dma_addr_t dma_addr, unmap_addr = 0; unsigned int dma_len; unsigned unmap_single; int q_space, i = 0; int rc = NETDEV_TX_OK; EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count); if (skb_shinfo((struct sk_buff *)skb)->gso_size) return efx_enqueue_skb_tso(tx_queue, skb); /* Get size of the initial fragment */ len = skb_headlen(skb); fill_level = tx_queue->insert_count - tx_queue->old_read_count; q_space = efx->type->txd_ring_mask - 1 - fill_level; /* Map for DMA. Use pci_map_single rather than pci_map_page * since this is more efficient on machines with sparse * memory. */ unmap_single = 1; dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE); /* Process all fragments */ while (1) { if (unlikely(pci_dma_mapping_error(dma_addr))) goto pci_err; /* Store fields for marking in the per-fragment final * descriptor */ unmap_len = len; unmap_addr = dma_addr; /* Add to TX queue, splitting across DMA boundaries */ do { if (unlikely(q_space-- <= 0)) { /* It might be that completions have * happened since the xmit path last * checked. Update the xmit path's * copy of read_count. */ ++tx_queue->stopped; /* This memory barrier protects the * change of stopped from the access * of read_count. */ smp_mb(); tx_queue->old_read_count = *(volatile unsigned *) &tx_queue->read_count; fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = (efx->type->txd_ring_mask - 1 - fill_level); if (unlikely(q_space-- <= 0)) goto stop; smp_mb(); --tx_queue->stopped; } insert_ptr = (tx_queue->insert_count & efx->type->txd_ring_mask); buffer = &tx_queue->buffer[insert_ptr]; efx_tsoh_free(tx_queue, buffer); EFX_BUG_ON_PARANOID(buffer->tsoh); EFX_BUG_ON_PARANOID(buffer->skb); EFX_BUG_ON_PARANOID(buffer->len); EFX_BUG_ON_PARANOID(buffer->continuation != 1); EFX_BUG_ON_PARANOID(buffer->unmap_len); dma_len = (((~dma_addr) & efx->type->tx_dma_mask) + 1); if (likely(dma_len > len)) dma_len = len; misalign = (unsigned)dma_addr & efx->type->bug5391_mask; if (misalign && dma_len + misalign > 512) dma_len = 512 - misalign; /* Fill out per descriptor fields */ buffer->len = dma_len; buffer->dma_addr = dma_addr; len -= dma_len; dma_addr += dma_len; ++tx_queue->insert_count; } while (len); /* Transfer ownership of the unmapping to the final buffer */ buffer->unmap_addr = unmap_addr; buffer->unmap_single = unmap_single; buffer->unmap_len = unmap_len; unmap_len = 0; /* Get address and size of next fragment */ if (i >= skb_shinfo(skb)->nr_frags) break; fragment = &skb_shinfo(skb)->frags[i]; len = fragment->size; page = fragment->page; page_offset = fragment->page_offset; i++; /* Map for DMA */ unmap_single = 0; dma_addr = pci_map_page(pci_dev, page, page_offset, len, PCI_DMA_TODEVICE); } /* Transfer ownership of the skb to the final buffer */ buffer->skb = skb; buffer->continuation = 0; /* Pass off to hardware */ falcon_push_buffers(tx_queue); return NETDEV_TX_OK; pci_err: EFX_ERR_RL(efx, " TX queue %d could not map skb with %d bytes %d " "fragments for DMA\n", tx_queue->queue, skb->len, skb_shinfo(skb)->nr_frags + 1); /* Mark the packet as transmitted, and free the SKB ourselves */ dev_kfree_skb_any((struct sk_buff *)skb); goto unwind; stop: rc = NETDEV_TX_BUSY; if (tx_queue->stopped == 1) efx_stop_queue(efx); unwind: /* Work backwards until we hit the original insert pointer value */ while (tx_queue->insert_count != tx_queue->write_count) { --tx_queue->insert_count; insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask; buffer = &tx_queue->buffer[insert_ptr]; efx_dequeue_buffer(tx_queue, buffer); buffer->len = 0; } /* Free the fragment we were mid-way through pushing */ if (unmap_len) pci_unmap_page(pci_dev, unmap_addr, unmap_len, PCI_DMA_TODEVICE); return rc; } /* Remove packets from the TX queue * * This removes packets from the TX queue, up to and including the * specified index. */ static inline void efx_dequeue_buffers(struct efx_tx_queue *tx_queue, unsigned int index) { struct efx_nic *efx = tx_queue->efx; unsigned int stop_index, read_ptr; unsigned int mask = tx_queue->efx->type->txd_ring_mask; stop_index = (index + 1) & mask; read_ptr = tx_queue->read_count & mask; while (read_ptr != stop_index) { struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr]; if (unlikely(buffer->len == 0)) { EFX_ERR(tx_queue->efx, "TX queue %d spurious TX " "completion id %x\n", tx_queue->queue, read_ptr); efx_schedule_reset(efx, RESET_TYPE_TX_SKIP); return; } efx_dequeue_buffer(tx_queue, buffer); buffer->continuation = 1; buffer->len = 0; ++tx_queue->read_count; read_ptr = tx_queue->read_count & mask; } } /* Initiate a packet transmission on the specified TX queue. * Note that returning anything other than NETDEV_TX_OK will cause the * OS to free the skb. * * This function is split out from efx_hard_start_xmit to allow the * loopback test to direct packets via specific TX queues. It is * therefore a non-static inline, so as not to penalise performance * for non-loopback transmissions. * * Context: netif_tx_lock held */ inline int efx_xmit(struct efx_nic *efx, struct efx_tx_queue *tx_queue, struct sk_buff *skb) { int rc; /* Map fragments for DMA and add to TX queue */ rc = efx_enqueue_skb(tx_queue, skb); if (unlikely(rc != NETDEV_TX_OK)) goto out; /* Update last TX timer */ efx->net_dev->trans_start = jiffies; out: return rc; } /* Initiate a packet transmission. We use one channel per CPU * (sharing when we have more CPUs than channels). On Falcon, the TX * completion events will be directed back to the CPU that transmitted * the packet, which should be cache-efficient. * * Context: non-blocking. * Note that returning anything other than NETDEV_TX_OK will cause the * OS to free the skb. */ int efx_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev) { struct efx_nic *efx = net_dev->priv; return efx_xmit(efx, &efx->tx_queue[0], skb); } void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index) { unsigned fill_level; struct efx_nic *efx = tx_queue->efx; EFX_BUG_ON_PARANOID(index > efx->type->txd_ring_mask); efx_dequeue_buffers(tx_queue, index); /* See if we need to restart the netif queue. This barrier * separates the update of read_count from the test of * stopped. */ smp_mb(); if (unlikely(tx_queue->stopped)) { fill_level = tx_queue->insert_count - tx_queue->read_count; if (fill_level < EFX_NETDEV_TX_THRESHOLD(tx_queue)) { EFX_BUG_ON_PARANOID(!efx_dev_registered(efx)); /* Do this under netif_tx_lock(), to avoid racing * with efx_xmit(). */ netif_tx_lock(efx->net_dev); if (tx_queue->stopped) { tx_queue->stopped = 0; efx_wake_queue(efx); } netif_tx_unlock(efx->net_dev); } } } int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) { struct efx_nic *efx = tx_queue->efx; unsigned int txq_size; int i, rc; EFX_LOG(efx, "creating TX queue %d\n", tx_queue->queue); /* Allocate software ring */ txq_size = (efx->type->txd_ring_mask + 1) * sizeof(*tx_queue->buffer); tx_queue->buffer = kzalloc(txq_size, GFP_KERNEL); if (!tx_queue->buffer) { rc = -ENOMEM; goto fail1; } for (i = 0; i <= efx->type->txd_ring_mask; ++i) tx_queue->buffer[i].continuation = 1; /* Allocate hardware ring */ rc = falcon_probe_tx(tx_queue); if (rc) goto fail2; return 0; fail2: kfree(tx_queue->buffer); tx_queue->buffer = NULL; fail1: tx_queue->used = 0; return rc; } int efx_init_tx_queue(struct efx_tx_queue *tx_queue) { EFX_LOG(tx_queue->efx, "initialising TX queue %d\n", tx_queue->queue); tx_queue->insert_count = 0; tx_queue->write_count = 0; tx_queue->read_count = 0; tx_queue->old_read_count = 0; BUG_ON(tx_queue->stopped); /* Set up TX descriptor ring */ return falcon_init_tx(tx_queue); } void efx_release_tx_buffers(struct efx_tx_queue *tx_queue) { struct efx_tx_buffer *buffer; if (!tx_queue->buffer) return; /* Free any buffers left in the ring */ while (tx_queue->read_count != tx_queue->write_count) { buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->efx->type->txd_ring_mask]; efx_dequeue_buffer(tx_queue, buffer); buffer->continuation = 1; buffer->len = 0; ++tx_queue->read_count; } } void efx_fini_tx_queue(struct efx_tx_queue *tx_queue) { EFX_LOG(tx_queue->efx, "shutting down TX queue %d\n", tx_queue->queue); /* Flush TX queue, remove descriptor ring */ falcon_fini_tx(tx_queue); efx_release_tx_buffers(tx_queue); /* Free up TSO header cache */ efx_fini_tso(tx_queue); /* Release queue's stop on port, if any */ if (tx_queue->stopped) { tx_queue->stopped = 0; efx_wake_queue(tx_queue->efx); } } void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) { EFX_LOG(tx_queue->efx, "destroying TX queue %d\n", tx_queue->queue); falcon_remove_tx(tx_queue); kfree(tx_queue->buffer); tx_queue->buffer = NULL; tx_queue->used = 0; } /* Efx TCP segmentation acceleration. * * Why? Because by doing it here in the driver we can go significantly * faster than the GSO. * * Requires TX checksum offload support. */ /* Number of bytes inserted at the start of a TSO header buffer, * similar to NET_IP_ALIGN. */ #if defined(__i386__) || defined(__x86_64__) #define TSOH_OFFSET 0 #else #define TSOH_OFFSET NET_IP_ALIGN #endif #define TSOH_BUFFER(tsoh) ((u8 *)(tsoh + 1) + TSOH_OFFSET) /* Total size of struct efx_tso_header, buffer and padding */ #define TSOH_SIZE(hdr_len) \ (sizeof(struct efx_tso_header) + TSOH_OFFSET + hdr_len) /* Size of blocks on free list. Larger blocks must be allocated from * the heap. */ #define TSOH_STD_SIZE 128 #define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2)) #define ETH_HDR_LEN(skb) (skb_network_header(skb) - (skb)->data) #define SKB_TCP_OFF(skb) PTR_DIFF(tcp_hdr(skb), (skb)->data) #define SKB_IPV4_OFF(skb) PTR_DIFF(ip_hdr(skb), (skb)->data) /** * struct tso_state - TSO state for an SKB * @remaining_len: Bytes of data we've yet to segment * @seqnum: Current sequence number * @packet_space: Remaining space in current packet * @ifc: Input fragment cursor. * Where we are in the current fragment of the incoming SKB. These * values get updated in place when we split a fragment over * multiple packets. * @p: Parameters. * These values are set once at the start of the TSO send and do * not get changed as the routine progresses. * * The state used during segmentation. It is put into this data structure * just to make it easy to pass into inline functions. */ struct tso_state { unsigned remaining_len; unsigned seqnum; unsigned packet_space; struct { /* DMA address of current position */ dma_addr_t dma_addr; /* Remaining length */ unsigned int len; /* DMA address and length of the whole fragment */ unsigned int unmap_len; dma_addr_t unmap_addr; struct page *page; unsigned page_off; } ifc; struct { /* The number of bytes of header */ unsigned int header_length; /* The number of bytes to put in each outgoing segment. */ int full_packet_size; /* Current IPv4 ID, host endian. */ unsigned ipv4_id; } p; }; /* * Verify that our various assumptions about sk_buffs and the conditions * under which TSO will be attempted hold true. */ static inline void efx_tso_check_safe(const struct sk_buff *skb) { EFX_BUG_ON_PARANOID(skb->protocol != htons(ETH_P_IP)); EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto != skb->protocol); EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP); EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data) + (tcp_hdr(skb)->doff << 2u)) > skb_headlen(skb)); } /* * Allocate a page worth of efx_tso_header structures, and string them * into the tx_queue->tso_headers_free linked list. Return 0 or -ENOMEM. */ static int efx_tsoh_block_alloc(struct efx_tx_queue *tx_queue) { struct pci_dev *pci_dev = tx_queue->efx->pci_dev; struct efx_tso_header *tsoh; dma_addr_t dma_addr; u8 *base_kva, *kva; base_kva = pci_alloc_consistent(pci_dev, PAGE_SIZE, &dma_addr); if (base_kva == NULL) { EFX_ERR(tx_queue->efx, "Unable to allocate page for TSO" " headers\n"); return -ENOMEM; } /* pci_alloc_consistent() allocates pages. */ EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1u)); for (kva = base_kva; kva < base_kva + PAGE_SIZE; kva += TSOH_STD_SIZE) { tsoh = (struct efx_tso_header *)kva; tsoh->dma_addr = dma_addr + (TSOH_BUFFER(tsoh) - base_kva); tsoh->next = tx_queue->tso_headers_free; tx_queue->tso_headers_free = tsoh; } return 0; } /* Free up a TSO header, and all others in the same page. */ static void efx_tsoh_block_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh, struct pci_dev *pci_dev) { struct efx_tso_header **p; unsigned long base_kva; dma_addr_t base_dma; base_kva = (unsigned long)tsoh & PAGE_MASK; base_dma = tsoh->dma_addr & PAGE_MASK; p = &tx_queue->tso_headers_free; while (*p != NULL) { if (((unsigned long)*p & PAGE_MASK) == base_kva) *p = (*p)->next; else p = &(*p)->next; } pci_free_consistent(pci_dev, PAGE_SIZE, (void *)base_kva, base_dma); } static struct efx_tso_header * efx_tsoh_heap_alloc(struct efx_tx_queue *tx_queue, size_t header_len) { struct efx_tso_header *tsoh; tsoh = kmalloc(TSOH_SIZE(header_len), GFP_ATOMIC | GFP_DMA); if (unlikely(!tsoh)) return NULL; tsoh->dma_addr = pci_map_single(tx_queue->efx->pci_dev, TSOH_BUFFER(tsoh), header_len, PCI_DMA_TODEVICE); if (unlikely(pci_dma_mapping_error(tsoh->dma_addr))) { kfree(tsoh); return NULL; } tsoh->unmap_len = header_len; return tsoh; } static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh) { pci_unmap_single(tx_queue->efx->pci_dev, tsoh->dma_addr, tsoh->unmap_len, PCI_DMA_TODEVICE); kfree(tsoh); } /** * efx_tx_queue_insert - push descriptors onto the TX queue * @tx_queue: Efx TX queue * @dma_addr: DMA address of fragment * @len: Length of fragment * @skb: Only non-null for end of last segment * @end_of_packet: True if last fragment in a packet * @unmap_addr: DMA address of fragment for unmapping * @unmap_len: Only set this in last segment of a fragment * * Push descriptors onto the TX queue. Return 0 on success or 1 if * @tx_queue full. */ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, dma_addr_t dma_addr, unsigned len, const struct sk_buff *skb, int end_of_packet, dma_addr_t unmap_addr, unsigned unmap_len) { struct efx_tx_buffer *buffer; struct efx_nic *efx = tx_queue->efx; unsigned dma_len, fill_level, insert_ptr, misalign; int q_space; EFX_BUG_ON_PARANOID(len <= 0); fill_level = tx_queue->insert_count - tx_queue->old_read_count; /* -1 as there is no way to represent all descriptors used */ q_space = efx->type->txd_ring_mask - 1 - fill_level; while (1) { if (unlikely(q_space-- <= 0)) { /* It might be that completions have happened * since the xmit path last checked. Update * the xmit path's copy of read_count. */ ++tx_queue->stopped; /* This memory barrier protects the change of * stopped from the access of read_count. */ smp_mb(); tx_queue->old_read_count = *(volatile unsigned *)&tx_queue->read_count; fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = efx->type->txd_ring_mask - 1 - fill_level; if (unlikely(q_space-- <= 0)) return 1; smp_mb(); --tx_queue->stopped; } insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask; buffer = &tx_queue->buffer[insert_ptr]; ++tx_queue->insert_count; EFX_BUG_ON_PARANOID(tx_queue->insert_count - tx_queue->read_count > efx->type->txd_ring_mask); efx_tsoh_free(tx_queue, buffer); EFX_BUG_ON_PARANOID(buffer->len); EFX_BUG_ON_PARANOID(buffer->unmap_len); EFX_BUG_ON_PARANOID(buffer->skb); EFX_BUG_ON_PARANOID(buffer->continuation != 1); EFX_BUG_ON_PARANOID(buffer->tsoh); buffer->dma_addr = dma_addr; /* Ensure we do not cross a boundary unsupported by H/W */ dma_len = (~dma_addr & efx->type->tx_dma_mask) + 1; misalign = (unsigned)dma_addr & efx->type->bug5391_mask; if (misalign && dma_len + misalign > 512) dma_len = 512 - misalign; /* If there is enough space to send then do so */ if (dma_len >= len) break; buffer->len = dma_len; /* Don't set the other members */ dma_addr += dma_len; len -= dma_len; } EFX_BUG_ON_PARANOID(!len); buffer->len = len; buffer->skb = skb; buffer->continuation = !end_of_packet; buffer->unmap_addr = unmap_addr; buffer->unmap_len = unmap_len; return 0; } /* * Put a TSO header into the TX queue. * * This is special-cased because we know that it is small enough to fit in * a single fragment, and we know it doesn't cross a page boundary. It * also allows us to not worry about end-of-packet etc. */ static inline void efx_tso_put_header(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh, unsigned len) { struct efx_tx_buffer *buffer; buffer = &tx_queue->buffer[tx_queue->insert_count & tx_queue->efx->type->txd_ring_mask]; efx_tsoh_free(tx_queue, buffer); EFX_BUG_ON_PARANOID(buffer->len); EFX_BUG_ON_PARANOID(buffer->unmap_len); EFX_BUG_ON_PARANOID(buffer->skb); EFX_BUG_ON_PARANOID(buffer->continuation != 1); EFX_BUG_ON_PARANOID(buffer->tsoh); buffer->len = len; buffer->dma_addr = tsoh->dma_addr; buffer->tsoh = tsoh; ++tx_queue->insert_count; } /* Remove descriptors put into a tx_queue. */ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue) { struct efx_tx_buffer *buffer; /* Work backwards until we hit the original insert pointer value */ while (tx_queue->insert_count != tx_queue->write_count) { --tx_queue->insert_count; buffer = &tx_queue->buffer[tx_queue->insert_count & tx_queue->efx->type->txd_ring_mask]; efx_tsoh_free(tx_queue, buffer); EFX_BUG_ON_PARANOID(buffer->skb); buffer->len = 0; buffer->continuation = 1; if (buffer->unmap_len) { pci_unmap_page(tx_queue->efx->pci_dev, buffer->unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); buffer->unmap_len = 0; } } } /* Parse the SKB header and initialise state. */ static inline void tso_start(struct tso_state *st, const struct sk_buff *skb) { /* All ethernet/IP/TCP headers combined size is TCP header size * plus offset of TCP header relative to start of packet. */ st->p.header_length = ((tcp_hdr(skb)->doff << 2u) + PTR_DIFF(tcp_hdr(skb), skb->data)); st->p.full_packet_size = (st->p.header_length + skb_shinfo(skb)->gso_size); st->p.ipv4_id = ntohs(ip_hdr(skb)->id); st->seqnum = ntohl(tcp_hdr(skb)->seq); EFX_BUG_ON_PARANOID(tcp_hdr(skb)->urg); EFX_BUG_ON_PARANOID(tcp_hdr(skb)->syn); EFX_BUG_ON_PARANOID(tcp_hdr(skb)->rst); st->packet_space = st->p.full_packet_size; st->remaining_len = skb->len - st->p.header_length; } /** * tso_get_fragment - record fragment details and map for DMA * @st: TSO state * @efx: Efx NIC * @data: Pointer to fragment data * @len: Length of fragment * * Record fragment details and map for DMA. Return 0 on success, or * -%ENOMEM if DMA mapping fails. */ static inline int tso_get_fragment(struct tso_state *st, struct efx_nic *efx, int len, struct page *page, int page_off) { st->ifc.unmap_addr = pci_map_page(efx->pci_dev, page, page_off, len, PCI_DMA_TODEVICE); if (likely(!pci_dma_mapping_error(st->ifc.unmap_addr))) { st->ifc.unmap_len = len; st->ifc.len = len; st->ifc.dma_addr = st->ifc.unmap_addr; st->ifc.page = page; st->ifc.page_off = page_off; return 0; } return -ENOMEM; } /** * tso_fill_packet_with_fragment - form descriptors for the current fragment * @tx_queue: Efx TX queue * @skb: Socket buffer * @st: TSO state * * Form descriptors for the current fragment, until we reach the end * of fragment or end-of-packet. Return 0 on success, 1 if not enough * space in @tx_queue. */ static inline int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue, const struct sk_buff *skb, struct tso_state *st) { int n, end_of_packet, rc; if (st->ifc.len == 0) return 0; if (st->packet_space == 0) return 0; EFX_BUG_ON_PARANOID(st->ifc.len <= 0); EFX_BUG_ON_PARANOID(st->packet_space <= 0); n = min(st->ifc.len, st->packet_space); st->packet_space -= n; st->remaining_len -= n; st->ifc.len -= n; st->ifc.page_off += n; end_of_packet = st->remaining_len == 0 || st->packet_space == 0; rc = efx_tx_queue_insert(tx_queue, st->ifc.dma_addr, n, st->remaining_len ? NULL : skb, end_of_packet, st->ifc.unmap_addr, st->ifc.len ? 0 : st->ifc.unmap_len); st->ifc.dma_addr += n; return rc; } /** * tso_start_new_packet - generate a new header and prepare for the new packet * @tx_queue: Efx TX queue * @skb: Socket buffer * @st: TSO state * * Generate a new header and prepare for the new packet. Return 0 on * success, or -1 if failed to alloc header. */ static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue, const struct sk_buff *skb, struct tso_state *st) { struct efx_tso_header *tsoh; struct iphdr *tsoh_iph; struct tcphdr *tsoh_th; unsigned ip_length; u8 *header; /* Allocate a DMA-mapped header buffer. */ if (likely(TSOH_SIZE(st->p.header_length) <= TSOH_STD_SIZE)) { if (tx_queue->tso_headers_free == NULL) { if (efx_tsoh_block_alloc(tx_queue)) return -1; } EFX_BUG_ON_PARANOID(!tx_queue->tso_headers_free); tsoh = tx_queue->tso_headers_free; tx_queue->tso_headers_free = tsoh->next; tsoh->unmap_len = 0; } else { tx_queue->tso_long_headers++; tsoh = efx_tsoh_heap_alloc(tx_queue, st->p.header_length); if (unlikely(!tsoh)) return -1; } header = TSOH_BUFFER(tsoh); tsoh_th = (struct tcphdr *)(header + SKB_TCP_OFF(skb)); tsoh_iph = (struct iphdr *)(header + SKB_IPV4_OFF(skb)); /* Copy and update the headers. */ memcpy(header, skb->data, st->p.header_length); tsoh_th->seq = htonl(st->seqnum); st->seqnum += skb_shinfo(skb)->gso_size; if (st->remaining_len > skb_shinfo(skb)->gso_size) { /* This packet will not finish the TSO burst. */ ip_length = st->p.full_packet_size - ETH_HDR_LEN(skb); tsoh_th->fin = 0; tsoh_th->psh = 0; } else { /* This packet will be the last in the TSO burst. */ ip_length = (st->p.header_length - ETH_HDR_LEN(skb) + st->remaining_len); tsoh_th->fin = tcp_hdr(skb)->fin; tsoh_th->psh = tcp_hdr(skb)->psh; } tsoh_iph->tot_len = htons(ip_length); /* Linux leaves suitable gaps in the IP ID space for us to fill. */ tsoh_iph->id = htons(st->p.ipv4_id); st->p.ipv4_id++; st->packet_space = skb_shinfo(skb)->gso_size; ++tx_queue->tso_packets; /* Form a descriptor for this header. */ efx_tso_put_header(tx_queue, tsoh, st->p.header_length); return 0; } /** * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer * @tx_queue: Efx TX queue * @skb: Socket buffer * * Context: You must hold netif_tx_lock() to call this function. * * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if * @skb was not enqueued. In all cases @skb is consumed. Return * %NETDEV_TX_OK or %NETDEV_TX_BUSY. */ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, const struct sk_buff *skb) { int frag_i, rc, rc2 = NETDEV_TX_OK; struct tso_state state; skb_frag_t *f; /* Verify TSO is safe - these checks should never fail. */ efx_tso_check_safe(skb); EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count); tso_start(&state, skb); /* Assume that skb header area contains exactly the headers, and * all payload is in the frag list. */ if (skb_headlen(skb) == state.p.header_length) { /* Grab the first payload fragment. */ EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1); frag_i = 0; f = &skb_shinfo(skb)->frags[frag_i]; rc = tso_get_fragment(&state, tx_queue->efx, f->size, f->page, f->page_offset); if (rc) goto mem_err; } else { /* It may look like this code fragment assumes that the * skb->data portion does not cross a page boundary, but * that is not the case. It is guaranteed to be direct * mapped memory, and therefore is physically contiguous, * and so DMA will work fine. kmap_atomic() on this region * will just return the direct mapping, so that will work * too. */ int page_off = (unsigned long)skb->data & (PAGE_SIZE - 1); int hl = state.p.header_length; rc = tso_get_fragment(&state, tx_queue->efx, skb_headlen(skb) - hl, virt_to_page(skb->data), page_off + hl); if (rc) goto mem_err; frag_i = -1; } if (tso_start_new_packet(tx_queue, skb, &state) < 0) goto mem_err; while (1) { rc = tso_fill_packet_with_fragment(tx_queue, skb, &state); if (unlikely(rc)) goto stop; /* Move onto the next fragment? */ if (state.ifc.len == 0) { if (++frag_i >= skb_shinfo(skb)->nr_frags) /* End of payload reached. */ break; f = &skb_shinfo(skb)->frags[frag_i]; rc = tso_get_fragment(&state, tx_queue->efx, f->size, f->page, f->page_offset); if (rc) goto mem_err; } /* Start at new packet? */ if (state.packet_space == 0 && tso_start_new_packet(tx_queue, skb, &state) < 0) goto mem_err; } /* Pass off to hardware */ falcon_push_buffers(tx_queue); tx_queue->tso_bursts++; return NETDEV_TX_OK; mem_err: EFX_ERR(tx_queue->efx, "Out of memory for TSO headers, or PCI mapping" " error\n"); dev_kfree_skb_any((struct sk_buff *)skb); goto unwind; stop: rc2 = NETDEV_TX_BUSY; /* Stop the queue if it wasn't stopped before. */ if (tx_queue->stopped == 1) efx_stop_queue(tx_queue->efx); unwind: efx_enqueue_unwind(tx_queue); return rc2; } /* * Free up all TSO datastructures associated with tx_queue. This * routine should be called only once the tx_queue is both empty and * will no longer be used. */ static void efx_fini_tso(struct efx_tx_queue *tx_queue) { unsigned i; if (tx_queue->buffer) { for (i = 0; i <= tx_queue->efx->type->txd_ring_mask; ++i) efx_tsoh_free(tx_queue, &tx_queue->buffer[i]); } while (tx_queue->tso_headers_free != NULL) efx_tsoh_block_free(tx_queue, tx_queue->tso_headers_free, tx_queue->efx->pci_dev); }