/**************************************************************************** * Driver for Solarflare Solarstorm network controllers and boards * Copyright 2005-2006 Fen Systems Ltd. * Copyright 2005-2010 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 #include #include #include "net_driver.h" #include "efx.h" #include "nic.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_TXQ_THRESHOLD(_efx) ((_efx)->txq_entries / 2u) static 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; dma_addr_t unmap_addr = (buffer->dma_addr + buffer->len - buffer->unmap_len); if (buffer->unmap_single) pci_unmap_single(pci_dev, unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); else pci_unmap_page(pci_dev, unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); buffer->unmap_len = 0; buffer->unmap_single = false; } if (buffer->skb) { dev_kfree_skb_any((struct sk_buff *) buffer->skb); buffer->skb = NULL; netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev, "TX queue %d transmission id %x complete\n", tx_queue->queue, tx_queue->read_count); } } /** * 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, 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 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; } } static inline unsigned efx_max_tx_len(struct efx_nic *efx, dma_addr_t dma_addr) { /* Depending on the NIC revision, we can use descriptor * lengths up to 8K or 8K-1. However, since PCI Express * devices must split read requests at 4K boundaries, there is * little benefit from using descriptors that cross those * boundaries and we keep things simple by not doing so. */ unsigned len = (~dma_addr & 0xfff) + 1; /* Work around hardware bug for unaligned buffers. */ if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf)) len = min_t(unsigned, len, 512 - (dma_addr & 0xf)); return len; } /* * 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. * * This function is split out from efx_hard_start_xmit to allow the * loopback test to direct packets via specific TX queues. * * Returns NETDEV_TX_OK or NETDEV_TX_BUSY * You must hold netif_tx_lock() to call this function. */ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, 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; unsigned int len, unmap_len = 0, fill_level, insert_ptr; dma_addr_t dma_addr, unmap_addr = 0; unsigned int dma_len; bool unmap_single; int q_space, i = 0; netdev_tx_t rc = NETDEV_TX_OK; EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count); if (skb_shinfo(skb)->gso_size) return efx_enqueue_skb_tso(tx_queue, skb); /* Get size of the initial fragment */ len = skb_headlen(skb); /* Pad if necessary */ if (EFX_WORKAROUND_15592(efx) && skb->len <= 32) { EFX_BUG_ON_PARANOID(skb->data_len); len = 32 + 1; if (skb_pad(skb, len - skb->len)) return NETDEV_TX_OK; } fill_level = tx_queue->insert_count - tx_queue->old_read_count; q_space = efx->txq_entries - 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 = true; dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE); /* Process all fragments */ while (1) { if (unlikely(pci_dma_mapping_error(pci_dev, 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. */ netif_tx_stop_queue(tx_queue->core_txq); /* This memory barrier protects the * change of queue state from the access * of read_count. */ smp_mb(); tx_queue->old_read_count = ACCESS_ONCE(tx_queue->read_count); fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = efx->txq_entries - 1 - fill_level; if (unlikely(q_space-- <= 0)) { rc = NETDEV_TX_BUSY; goto unwind; } smp_mb(); if (likely(!efx->loopback_selftest)) netif_tx_start_queue( tx_queue->core_txq); } insert_ptr = tx_queue->insert_count & tx_queue->ptr_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); EFX_BUG_ON_PARANOID(buffer->unmap_len); dma_len = efx_max_tx_len(efx, dma_addr); if (likely(dma_len >= len)) dma_len = len; /* 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_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; i++; /* Map for DMA */ unmap_single = false; dma_addr = skb_frag_dma_map(&pci_dev->dev, fragment, 0, len, DMA_TO_DEVICE); } /* Transfer ownership of the skb to the final buffer */ buffer->skb = skb; buffer->continuation = false; /* Pass off to hardware */ efx_nic_push_buffers(tx_queue); return NETDEV_TX_OK; pci_err: netif_err(efx, tx_err, efx->net_dev, " 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(skb); 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 & tx_queue->ptr_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) { if (unmap_single) pci_unmap_single(pci_dev, unmap_addr, unmap_len, PCI_DMA_TODEVICE); else 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 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; stop_index = (index + 1) & tx_queue->ptr_mask; read_ptr = tx_queue->read_count & tx_queue->ptr_mask; while (read_ptr != stop_index) { struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr]; if (unlikely(buffer->len == 0)) { netif_err(efx, tx_err, efx->net_dev, "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 = true; buffer->len = 0; ++tx_queue->read_count; read_ptr = tx_queue->read_count & tx_queue->ptr_mask; } } /* 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. */ netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev) { struct efx_nic *efx = netdev_priv(net_dev); struct efx_tx_queue *tx_queue; unsigned index, type; EFX_WARN_ON_PARANOID(!netif_device_present(net_dev)); index = skb_get_queue_mapping(skb); type = skb->ip_summed == CHECKSUM_PARTIAL ? EFX_TXQ_TYPE_OFFLOAD : 0; if (index >= efx->n_tx_channels) { index -= efx->n_tx_channels; type |= EFX_TXQ_TYPE_HIGHPRI; } tx_queue = efx_get_tx_queue(efx, index, type); return efx_enqueue_skb(tx_queue, skb); } void efx_init_tx_queue_core_txq(struct efx_tx_queue *tx_queue) { struct efx_nic *efx = tx_queue->efx; /* Must be inverse of queue lookup in efx_hard_start_xmit() */ tx_queue->core_txq = netdev_get_tx_queue(efx->net_dev, tx_queue->queue / EFX_TXQ_TYPES + ((tx_queue->queue & EFX_TXQ_TYPE_HIGHPRI) ? efx->n_tx_channels : 0)); } int efx_setup_tc(struct net_device *net_dev, u8 num_tc) { struct efx_nic *efx = netdev_priv(net_dev); struct efx_channel *channel; struct efx_tx_queue *tx_queue; unsigned tc; int rc; if (efx_nic_rev(efx) < EFX_REV_FALCON_B0 || num_tc > EFX_MAX_TX_TC) return -EINVAL; if (num_tc == net_dev->num_tc) return 0; for (tc = 0; tc < num_tc; tc++) { net_dev->tc_to_txq[tc].offset = tc * efx->n_tx_channels; net_dev->tc_to_txq[tc].count = efx->n_tx_channels; } if (num_tc > net_dev->num_tc) { /* Initialise high-priority queues as necessary */ efx_for_each_channel(channel, efx) { efx_for_each_possible_channel_tx_queue(tx_queue, channel) { if (!(tx_queue->queue & EFX_TXQ_TYPE_HIGHPRI)) continue; if (!tx_queue->buffer) { rc = efx_probe_tx_queue(tx_queue); if (rc) return rc; } if (!tx_queue->initialised) efx_init_tx_queue(tx_queue); efx_init_tx_queue_core_txq(tx_queue); } } } else { /* Reduce number of classes before number of queues */ net_dev->num_tc = num_tc; } rc = netif_set_real_num_tx_queues(net_dev, max_t(int, num_tc, 1) * efx->n_tx_channels); if (rc) return rc; /* Do not destroy high-priority queues when they become * unused. We would have to flush them first, and it is * fairly difficult to flush a subset of TX queues. Leave * it to efx_fini_channels(). */ net_dev->num_tc = num_tc; return 0; } 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 > tx_queue->ptr_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 the * queue state. */ smp_mb(); if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) && likely(efx->port_enabled) && likely(netif_device_present(efx->net_dev))) { fill_level = tx_queue->insert_count - tx_queue->read_count; if (fill_level < EFX_TXQ_THRESHOLD(efx)) { EFX_BUG_ON_PARANOID(!efx_dev_registered(efx)); netif_tx_wake_queue(tx_queue->core_txq); } } /* Check whether the hardware queue is now empty */ if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) { tx_queue->old_write_count = ACCESS_ONCE(tx_queue->write_count); if (tx_queue->read_count == tx_queue->old_write_count) { smp_mb(); tx_queue->empty_read_count = tx_queue->read_count | EFX_EMPTY_COUNT_VALID; } } } int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) { struct efx_nic *efx = tx_queue->efx; unsigned int entries; int i, rc; /* Create the smallest power-of-two aligned ring */ entries = max(roundup_pow_of_two(efx->txq_entries), EFX_MIN_DMAQ_SIZE); EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE); tx_queue->ptr_mask = entries - 1; netif_dbg(efx, probe, efx->net_dev, "creating TX queue %d size %#x mask %#x\n", tx_queue->queue, efx->txq_entries, tx_queue->ptr_mask); /* Allocate software ring */ tx_queue->buffer = kzalloc(entries * sizeof(*tx_queue->buffer), GFP_KERNEL); if (!tx_queue->buffer) return -ENOMEM; for (i = 0; i <= tx_queue->ptr_mask; ++i) tx_queue->buffer[i].continuation = true; /* Allocate hardware ring */ rc = efx_nic_probe_tx(tx_queue); if (rc) goto fail; return 0; fail: kfree(tx_queue->buffer); tx_queue->buffer = NULL; return rc; } void efx_init_tx_queue(struct efx_tx_queue *tx_queue) { netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, "initialising TX queue %d\n", tx_queue->queue); tx_queue->insert_count = 0; tx_queue->write_count = 0; tx_queue->old_write_count = 0; tx_queue->read_count = 0; tx_queue->old_read_count = 0; tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID; /* Set up TX descriptor ring */ efx_nic_init_tx(tx_queue); tx_queue->initialised = true; } 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->ptr_mask]; efx_dequeue_buffer(tx_queue, buffer); buffer->continuation = true; buffer->len = 0; ++tx_queue->read_count; } } void efx_fini_tx_queue(struct efx_tx_queue *tx_queue) { if (!tx_queue->initialised) return; netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, "shutting down TX queue %d\n", tx_queue->queue); tx_queue->initialised = false; /* Flush TX queue, remove descriptor ring */ efx_nic_fini_tx(tx_queue); efx_release_tx_buffers(tx_queue); /* Free up TSO header cache */ efx_fini_tso(tx_queue); } void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) { if (!tx_queue->buffer) return; netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, "destroying TX queue %d\n", tx_queue->queue); efx_nic_remove_tx(tx_queue); kfree(tx_queue->buffer); tx_queue->buffer = NULL; } /* 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. */ #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS #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) #define SKB_IPV6_OFF(skb) PTR_DIFF(ipv6_hdr(skb), (skb)->data) /** * struct tso_state - TSO state for an SKB * @out_len: Remaining length in current segment * @seqnum: Current sequence number * @ipv4_id: Current IPv4 ID, host endian * @packet_space: Remaining space in current packet * @dma_addr: DMA address of current position * @in_len: Remaining length in current SKB fragment * @unmap_len: Length of SKB fragment * @unmap_addr: DMA address of SKB fragment * @unmap_single: DMA single vs page mapping flag * @protocol: Network protocol (after any VLAN header) * @header_len: Number of bytes of header * @full_packet_size: Number of bytes to put in each outgoing segment * * 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 { /* Output position */ unsigned out_len; unsigned seqnum; unsigned ipv4_id; unsigned packet_space; /* Input position */ dma_addr_t dma_addr; unsigned in_len; unsigned unmap_len; dma_addr_t unmap_addr; bool unmap_single; __be16 protocol; unsigned header_len; int full_packet_size; }; /* * Verify that our various assumptions about sk_buffs and the conditions * under which TSO will be attempted hold true. Return the protocol number. */ static __be16 efx_tso_check_protocol(struct sk_buff *skb) { __be16 protocol = skb->protocol; EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto != protocol); if (protocol == htons(ETH_P_8021Q)) { /* Find the encapsulated protocol; reset network header * and transport header based on that. */ struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data; protocol = veh->h_vlan_encapsulated_proto; skb_set_network_header(skb, sizeof(*veh)); if (protocol == htons(ETH_P_IP)) skb_set_transport_header(skb, sizeof(*veh) + 4 * ip_hdr(skb)->ihl); else if (protocol == htons(ETH_P_IPV6)) skb_set_transport_header(skb, sizeof(*veh) + sizeof(struct ipv6hdr)); } if (protocol == htons(ETH_P_IP)) { EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP); } else { EFX_BUG_ON_PARANOID(protocol != htons(ETH_P_IPV6)); EFX_BUG_ON_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP); } EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data) + (tcp_hdr(skb)->doff << 2u)) > skb_headlen(skb)); return protocol; } /* * 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) { netif_err(tx_queue->efx, tx_err, tx_queue->efx->net_dev, "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(tx_queue->efx->pci_dev, 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 * @final_buffer: The final buffer inserted into the queue * * 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, struct efx_tx_buffer **final_buffer) { struct efx_tx_buffer *buffer; struct efx_nic *efx = tx_queue->efx; unsigned dma_len, fill_level, insert_ptr; 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->txq_entries - 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. */ netif_tx_stop_queue(tx_queue->core_txq); /* This memory barrier protects the change of * queue state from the access of read_count. */ smp_mb(); tx_queue->old_read_count = ACCESS_ONCE(tx_queue->read_count); fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = efx->txq_entries - 1 - fill_level; if (unlikely(q_space-- <= 0)) { *final_buffer = NULL; return 1; } smp_mb(); netif_tx_start_queue(tx_queue->core_txq); } insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask; buffer = &tx_queue->buffer[insert_ptr]; ++tx_queue->insert_count; EFX_BUG_ON_PARANOID(tx_queue->insert_count - tx_queue->read_count >= efx->txq_entries); 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); EFX_BUG_ON_PARANOID(buffer->tsoh); buffer->dma_addr = dma_addr; dma_len = efx_max_tx_len(efx, dma_addr); /* 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; *final_buffer = buffer; 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 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->ptr_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); 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; dma_addr_t unmap_addr; /* 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->ptr_mask]; efx_tsoh_free(tx_queue, buffer); EFX_BUG_ON_PARANOID(buffer->skb); if (buffer->unmap_len) { unmap_addr = (buffer->dma_addr + buffer->len - buffer->unmap_len); if (buffer->unmap_single) pci_unmap_single(tx_queue->efx->pci_dev, unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); else pci_unmap_page(tx_queue->efx->pci_dev, unmap_addr, buffer->unmap_len, PCI_DMA_TODEVICE); buffer->unmap_len = 0; } buffer->len = 0; buffer->continuation = true; } } /* Parse the SKB header and initialise state. */ static 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->header_len = ((tcp_hdr(skb)->doff << 2u) + PTR_DIFF(tcp_hdr(skb), skb->data)); st->full_packet_size = st->header_len + skb_shinfo(skb)->gso_size; if (st->protocol == htons(ETH_P_IP)) st->ipv4_id = ntohs(ip_hdr(skb)->id); else st->ipv4_id = 0; 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->full_packet_size; st->out_len = skb->len - st->header_len; st->unmap_len = 0; st->unmap_single = false; } static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx, skb_frag_t *frag) { st->unmap_addr = skb_frag_dma_map(&efx->pci_dev->dev, frag, 0, frag->size, DMA_TO_DEVICE); if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) { st->unmap_single = false; st->unmap_len = frag->size; st->in_len = frag->size; st->dma_addr = st->unmap_addr; return 0; } return -ENOMEM; } static int tso_get_head_fragment(struct tso_state *st, struct efx_nic *efx, const struct sk_buff *skb) { int hl = st->header_len; int len = skb_headlen(skb) - hl; st->unmap_addr = pci_map_single(efx->pci_dev, skb->data + hl, len, PCI_DMA_TODEVICE); if (likely(!pci_dma_mapping_error(efx->pci_dev, st->unmap_addr))) { st->unmap_single = true; st->unmap_len = len; st->in_len = len; st->dma_addr = st->unmap_addr; 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 int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue, const struct sk_buff *skb, struct tso_state *st) { struct efx_tx_buffer *buffer; int n, end_of_packet, rc; if (st->in_len == 0) return 0; if (st->packet_space == 0) return 0; EFX_BUG_ON_PARANOID(st->in_len <= 0); EFX_BUG_ON_PARANOID(st->packet_space <= 0); n = min(st->in_len, st->packet_space); st->packet_space -= n; st->out_len -= n; st->in_len -= n; rc = efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer); if (likely(rc == 0)) { if (st->out_len == 0) /* Transfer ownership of the skb */ buffer->skb = skb; end_of_packet = st->out_len == 0 || st->packet_space == 0; buffer->continuation = !end_of_packet; if (st->in_len == 0) { /* Transfer ownership of the pci mapping */ buffer->unmap_len = st->unmap_len; buffer->unmap_single = st->unmap_single; st->unmap_len = 0; } } st->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 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 tcphdr *tsoh_th; unsigned ip_length; u8 *header; /* Allocate a DMA-mapped header buffer. */ if (likely(TSOH_SIZE(st->header_len) <= 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->header_len); if (unlikely(!tsoh)) return -1; } header = TSOH_BUFFER(tsoh); tsoh_th = (struct tcphdr *)(header + SKB_TCP_OFF(skb)); /* Copy and update the headers. */ memcpy(header, skb->data, st->header_len); tsoh_th->seq = htonl(st->seqnum); st->seqnum += skb_shinfo(skb)->gso_size; if (st->out_len > skb_shinfo(skb)->gso_size) { /* This packet will not finish the TSO burst. */ ip_length = st->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->header_len - ETH_HDR_LEN(skb) + st->out_len; tsoh_th->fin = tcp_hdr(skb)->fin; tsoh_th->psh = tcp_hdr(skb)->psh; } if (st->protocol == htons(ETH_P_IP)) { struct iphdr *tsoh_iph = (struct iphdr *)(header + SKB_IPV4_OFF(skb)); 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->ipv4_id); st->ipv4_id++; } else { struct ipv6hdr *tsoh_iph = (struct ipv6hdr *)(header + SKB_IPV6_OFF(skb)); tsoh_iph->payload_len = htons(ip_length - sizeof(*tsoh_iph)); } 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->header_len); 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, struct sk_buff *skb) { struct efx_nic *efx = tx_queue->efx; int frag_i, rc, rc2 = NETDEV_TX_OK; struct tso_state state; /* Find the packet protocol and sanity-check it */ state.protocol = efx_tso_check_protocol(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.header_len) { /* Grab the first payload fragment. */ EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1); frag_i = 0; rc = tso_get_fragment(&state, efx, skb_shinfo(skb)->frags + frag_i); if (rc) goto mem_err; } else { rc = tso_get_head_fragment(&state, efx, skb); 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)) { rc2 = NETDEV_TX_BUSY; goto unwind; } /* Move onto the next fragment? */ if (state.in_len == 0) { if (++frag_i >= skb_shinfo(skb)->nr_frags) /* End of payload reached. */ break; rc = tso_get_fragment(&state, efx, skb_shinfo(skb)->frags + frag_i); 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 */ efx_nic_push_buffers(tx_queue); tx_queue->tso_bursts++; return NETDEV_TX_OK; mem_err: netif_err(efx, tx_err, efx->net_dev, "Out of memory for TSO headers, or PCI mapping error\n"); dev_kfree_skb_any(skb); unwind: /* Free the DMA mapping we were in the process of writing out */ if (state.unmap_len) { if (state.unmap_single) pci_unmap_single(efx->pci_dev, state.unmap_addr, state.unmap_len, PCI_DMA_TODEVICE); else pci_unmap_page(efx->pci_dev, state.unmap_addr, state.unmap_len, PCI_DMA_TODEVICE); } 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->ptr_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); }