/**************************************************************************** * 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 #include "net_driver.h" #include "rx.h" #include "efx.h" #include "falcon.h" #include "selftest.h" #include "workarounds.h" /* Number of RX descriptors pushed at once. */ #define EFX_RX_BATCH 8 /* Size of buffer allocated for skb header area. */ #define EFX_SKB_HEADERS 64u /* * rx_alloc_method - RX buffer allocation method * * This driver supports two methods for allocating and using RX buffers: * each RX buffer may be backed by an skb or by an order-n page. * * When LRO is in use then the second method has a lower overhead, * since we don't have to allocate then free skbs on reassembled frames. * * Values: * - RX_ALLOC_METHOD_AUTO = 0 * - RX_ALLOC_METHOD_SKB = 1 * - RX_ALLOC_METHOD_PAGE = 2 * * The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count * controlled by the parameters below. * * - Since pushing and popping descriptors are separated by the rx_queue * size, so the watermarks should be ~rxd_size. * - The performance win by using page-based allocation for LRO is less * than the performance hit of using page-based allocation of non-LRO, * so the watermarks should reflect this. * * Per channel we maintain a single variable, updated by each channel: * * rx_alloc_level += (lro_performed ? RX_ALLOC_FACTOR_LRO : * RX_ALLOC_FACTOR_SKB) * Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which * limits the hysteresis), and update the allocation strategy: * * rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_LRO ? * RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB) */ static int rx_alloc_method = RX_ALLOC_METHOD_AUTO; #define RX_ALLOC_LEVEL_LRO 0x2000 #define RX_ALLOC_LEVEL_MAX 0x3000 #define RX_ALLOC_FACTOR_LRO 1 #define RX_ALLOC_FACTOR_SKB (-2) /* This is the percentage fill level below which new RX descriptors * will be added to the RX descriptor ring. */ static unsigned int rx_refill_threshold = 90; /* This is the percentage fill level to which an RX queue will be refilled * when the "RX refill threshold" is reached. */ static unsigned int rx_refill_limit = 95; /* * RX maximum head room required. * * This must be at least 1 to prevent overflow and at least 2 to allow * pipelined receives. */ #define EFX_RXD_HEAD_ROOM 2 static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf) { /* Offset is always within one page, so we don't need to consider * the page order. */ return (__force unsigned long) buf->data & (PAGE_SIZE - 1); } static inline unsigned int efx_rx_buf_size(struct efx_nic *efx) { return PAGE_SIZE << efx->rx_buffer_order; } /** * efx_init_rx_buffer_skb - create new RX buffer using skb-based allocation * * @rx_queue: Efx RX queue * @rx_buf: RX buffer structure to populate * * This allocates memory for a new receive buffer, maps it for DMA, * and populates a struct efx_rx_buffer with the relevant * information. Return a negative error code or 0 on success. */ static int efx_init_rx_buffer_skb(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf) { struct efx_nic *efx = rx_queue->efx; struct net_device *net_dev = efx->net_dev; int skb_len = efx->rx_buffer_len; rx_buf->skb = netdev_alloc_skb(net_dev, skb_len); if (unlikely(!rx_buf->skb)) return -ENOMEM; /* Adjust the SKB for padding and checksum */ skb_reserve(rx_buf->skb, NET_IP_ALIGN); rx_buf->len = skb_len - NET_IP_ALIGN; rx_buf->data = (char *)rx_buf->skb->data; rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY; rx_buf->dma_addr = pci_map_single(efx->pci_dev, rx_buf->data, rx_buf->len, PCI_DMA_FROMDEVICE); if (unlikely(pci_dma_mapping_error(efx->pci_dev, rx_buf->dma_addr))) { dev_kfree_skb_any(rx_buf->skb); rx_buf->skb = NULL; return -EIO; } return 0; } /** * efx_init_rx_buffer_page - create new RX buffer using page-based allocation * * @rx_queue: Efx RX queue * @rx_buf: RX buffer structure to populate * * This allocates memory for a new receive buffer, maps it for DMA, * and populates a struct efx_rx_buffer with the relevant * information. Return a negative error code or 0 on success. */ static int efx_init_rx_buffer_page(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf) { struct efx_nic *efx = rx_queue->efx; int bytes, space, offset; bytes = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN; /* If there is space left in the previously allocated page, * then use it. Otherwise allocate a new one */ rx_buf->page = rx_queue->buf_page; if (rx_buf->page == NULL) { dma_addr_t dma_addr; rx_buf->page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC, efx->rx_buffer_order); if (unlikely(rx_buf->page == NULL)) return -ENOMEM; dma_addr = pci_map_page(efx->pci_dev, rx_buf->page, 0, efx_rx_buf_size(efx), PCI_DMA_FROMDEVICE); if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) { __free_pages(rx_buf->page, efx->rx_buffer_order); rx_buf->page = NULL; return -EIO; } rx_queue->buf_page = rx_buf->page; rx_queue->buf_dma_addr = dma_addr; rx_queue->buf_data = (page_address(rx_buf->page) + EFX_PAGE_IP_ALIGN); } rx_buf->len = bytes; rx_buf->data = rx_queue->buf_data; offset = efx_rx_buf_offset(rx_buf); rx_buf->dma_addr = rx_queue->buf_dma_addr + offset; /* Try to pack multiple buffers per page */ if (efx->rx_buffer_order == 0) { /* The next buffer starts on the next 512 byte boundary */ rx_queue->buf_data += ((bytes + 0x1ff) & ~0x1ff); offset += ((bytes + 0x1ff) & ~0x1ff); space = efx_rx_buf_size(efx) - offset; if (space >= bytes) { /* Refs dropped on kernel releasing each skb */ get_page(rx_queue->buf_page); goto out; } } /* This is the final RX buffer for this page, so mark it for * unmapping */ rx_queue->buf_page = NULL; rx_buf->unmap_addr = rx_queue->buf_dma_addr; out: return 0; } /* This allocates memory for a new receive buffer, maps it for DMA, * and populates a struct efx_rx_buffer with the relevant * information. */ static int efx_init_rx_buffer(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *new_rx_buf) { int rc = 0; if (rx_queue->channel->rx_alloc_push_pages) { new_rx_buf->skb = NULL; rc = efx_init_rx_buffer_page(rx_queue, new_rx_buf); rx_queue->alloc_page_count++; } else { new_rx_buf->page = NULL; rc = efx_init_rx_buffer_skb(rx_queue, new_rx_buf); rx_queue->alloc_skb_count++; } if (unlikely(rc < 0)) EFX_LOG_RL(rx_queue->efx, "%s RXQ[%d] =%d\n", __func__, rx_queue->queue, rc); return rc; } static void efx_unmap_rx_buffer(struct efx_nic *efx, struct efx_rx_buffer *rx_buf) { if (rx_buf->page) { EFX_BUG_ON_PARANOID(rx_buf->skb); if (rx_buf->unmap_addr) { pci_unmap_page(efx->pci_dev, rx_buf->unmap_addr, efx_rx_buf_size(efx), PCI_DMA_FROMDEVICE); rx_buf->unmap_addr = 0; } } else if (likely(rx_buf->skb)) { pci_unmap_single(efx->pci_dev, rx_buf->dma_addr, rx_buf->len, PCI_DMA_FROMDEVICE); } } static void efx_free_rx_buffer(struct efx_nic *efx, struct efx_rx_buffer *rx_buf) { if (rx_buf->page) { __free_pages(rx_buf->page, efx->rx_buffer_order); rx_buf->page = NULL; } else if (likely(rx_buf->skb)) { dev_kfree_skb_any(rx_buf->skb); rx_buf->skb = NULL; } } static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf) { efx_unmap_rx_buffer(rx_queue->efx, rx_buf); efx_free_rx_buffer(rx_queue->efx, rx_buf); } /** * efx_fast_push_rx_descriptors - push new RX descriptors quickly * @rx_queue: RX descriptor queue * @retry: Recheck the fill level * This will aim to fill the RX descriptor queue up to * @rx_queue->@fast_fill_limit. If there is insufficient atomic * memory to do so, the caller should retry. */ static int __efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, int retry) { struct efx_rx_buffer *rx_buf; unsigned fill_level, index; int i, space, rc = 0; /* Calculate current fill level. Do this outside the lock, * because most of the time we'll end up not wanting to do the * fill anyway. */ fill_level = (rx_queue->added_count - rx_queue->removed_count); EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE); /* Don't fill if we don't need to */ if (fill_level >= rx_queue->fast_fill_trigger) return 0; /* Record minimum fill level */ if (unlikely(fill_level < rx_queue->min_fill)) { if (fill_level) rx_queue->min_fill = fill_level; } /* Acquire RX add lock. If this lock is contended, then a fast * fill must already be in progress (e.g. in the refill * tasklet), so we don't need to do anything */ if (!spin_trylock_bh(&rx_queue->add_lock)) return -1; retry: /* Recalculate current fill level now that we have the lock */ fill_level = (rx_queue->added_count - rx_queue->removed_count); EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE); space = rx_queue->fast_fill_limit - fill_level; if (space < EFX_RX_BATCH) goto out_unlock; EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from" " level %d to level %d using %s allocation\n", rx_queue->queue, fill_level, rx_queue->fast_fill_limit, rx_queue->channel->rx_alloc_push_pages ? "page" : "skb"); do { for (i = 0; i < EFX_RX_BATCH; ++i) { index = rx_queue->added_count & EFX_RXQ_MASK; rx_buf = efx_rx_buffer(rx_queue, index); rc = efx_init_rx_buffer(rx_queue, rx_buf); if (unlikely(rc)) goto out; ++rx_queue->added_count; } } while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH); EFX_TRACE(rx_queue->efx, "RX queue %d fast-filled descriptor ring " "to level %d\n", rx_queue->queue, rx_queue->added_count - rx_queue->removed_count); out: /* Send write pointer to card. */ falcon_notify_rx_desc(rx_queue); /* If the fast fill is running inside from the refill tasklet, then * for SMP systems it may be running on a different CPU to * RX event processing, which means that the fill level may now be * out of date. */ if (unlikely(retry && (rc == 0))) goto retry; out_unlock: spin_unlock_bh(&rx_queue->add_lock); return rc; } /** * efx_fast_push_rx_descriptors - push new RX descriptors quickly * @rx_queue: RX descriptor queue * * This will aim to fill the RX descriptor queue up to * @rx_queue->@fast_fill_limit. If there is insufficient memory to do so, * it will schedule a work item to immediately continue the fast fill */ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) { int rc; rc = __efx_fast_push_rx_descriptors(rx_queue, 0); if (unlikely(rc)) { /* Schedule the work item to run immediately. The hope is * that work is immediately pending to free some memory * (e.g. an RX event or TX completion) */ efx_schedule_slow_fill(rx_queue, 0); } } void efx_rx_work(struct work_struct *data) { struct efx_rx_queue *rx_queue; int rc; rx_queue = container_of(data, struct efx_rx_queue, work.work); if (unlikely(!rx_queue->channel->enabled)) return; EFX_TRACE(rx_queue->efx, "RX queue %d worker thread executing on CPU " "%d\n", rx_queue->queue, raw_smp_processor_id()); ++rx_queue->slow_fill_count; /* Push new RX descriptors, allowing at least 1 jiffy for * the kernel to free some more memory. */ rc = __efx_fast_push_rx_descriptors(rx_queue, 1); if (rc) efx_schedule_slow_fill(rx_queue, 1); } static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf, int len, bool *discard, bool *leak_packet) { struct efx_nic *efx = rx_queue->efx; unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding; if (likely(len <= max_len)) return; /* The packet must be discarded, but this is only a fatal error * if the caller indicated it was */ *discard = true; if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) { EFX_ERR_RL(efx, " RX queue %d seriously overlength " "RX event (0x%x > 0x%x+0x%x). Leaking\n", rx_queue->queue, len, max_len, efx->type->rx_buffer_padding); /* If this buffer was skb-allocated, then the meta * data at the end of the skb will be trashed. So * we have no choice but to leak the fragment. */ *leak_packet = (rx_buf->skb != NULL); efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY); } else { EFX_ERR_RL(efx, " RX queue %d overlength RX event " "(0x%x > 0x%x)\n", rx_queue->queue, len, max_len); } rx_queue->channel->n_rx_overlength++; } /* Pass a received packet up through the generic LRO stack * * Handles driverlink veto, and passes the fragment up via * the appropriate LRO method */ static void efx_rx_packet_lro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf, bool checksummed) { struct napi_struct *napi = &channel->napi_str; gro_result_t gro_result; /* Pass the skb/page into the LRO engine */ if (rx_buf->page) { struct sk_buff *skb = napi_get_frags(napi); if (!skb) { put_page(rx_buf->page); gro_result = GRO_DROP; goto out; } skb_shinfo(skb)->frags[0].page = rx_buf->page; skb_shinfo(skb)->frags[0].page_offset = efx_rx_buf_offset(rx_buf); skb_shinfo(skb)->frags[0].size = rx_buf->len; skb_shinfo(skb)->nr_frags = 1; skb->len = rx_buf->len; skb->data_len = rx_buf->len; skb->truesize += rx_buf->len; skb->ip_summed = checksummed ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE; gro_result = napi_gro_frags(napi); out: EFX_BUG_ON_PARANOID(rx_buf->skb); rx_buf->page = NULL; } else { EFX_BUG_ON_PARANOID(!rx_buf->skb); EFX_BUG_ON_PARANOID(!checksummed); gro_result = napi_gro_receive(napi, rx_buf->skb); rx_buf->skb = NULL; } if (gro_result == GRO_NORMAL) { channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB; } else if (gro_result != GRO_DROP) { channel->rx_alloc_level += RX_ALLOC_FACTOR_LRO; channel->irq_mod_score += 2; } } void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, unsigned int len, bool checksummed, bool discard) { struct efx_nic *efx = rx_queue->efx; struct efx_rx_buffer *rx_buf; bool leak_packet = false; rx_buf = efx_rx_buffer(rx_queue, index); EFX_BUG_ON_PARANOID(!rx_buf->data); EFX_BUG_ON_PARANOID(rx_buf->skb && rx_buf->page); EFX_BUG_ON_PARANOID(!(rx_buf->skb || rx_buf->page)); /* This allows the refill path to post another buffer. * EFX_RXD_HEAD_ROOM ensures that the slot we are using * isn't overwritten yet. */ rx_queue->removed_count++; /* Validate the length encoded in the event vs the descriptor pushed */ efx_rx_packet__check_len(rx_queue, rx_buf, len, &discard, &leak_packet); EFX_TRACE(efx, "RX queue %d received id %x at %llx+%x %s%s\n", rx_queue->queue, index, (unsigned long long)rx_buf->dma_addr, len, (checksummed ? " [SUMMED]" : ""), (discard ? " [DISCARD]" : "")); /* Discard packet, if instructed to do so */ if (unlikely(discard)) { if (unlikely(leak_packet)) rx_queue->channel->n_skbuff_leaks++; else /* We haven't called efx_unmap_rx_buffer yet, * so fini the entire rx_buffer here */ efx_fini_rx_buffer(rx_queue, rx_buf); return; } /* Release card resources - assumes all RX buffers consumed in-order * per RX queue */ efx_unmap_rx_buffer(efx, rx_buf); /* Prefetch nice and early so data will (hopefully) be in cache by * the time we look at it. */ prefetch(rx_buf->data); /* Pipeline receives so that we give time for packet headers to be * prefetched into cache. */ rx_buf->len = len; if (rx_queue->channel->rx_pkt) __efx_rx_packet(rx_queue->channel, rx_queue->channel->rx_pkt, rx_queue->channel->rx_pkt_csummed); rx_queue->channel->rx_pkt = rx_buf; rx_queue->channel->rx_pkt_csummed = checksummed; } /* Handle a received packet. Second half: Touches packet payload. */ void __efx_rx_packet(struct efx_channel *channel, struct efx_rx_buffer *rx_buf, bool checksummed) { struct efx_nic *efx = channel->efx; struct sk_buff *skb; /* If we're in loopback test, then pass the packet directly to the * loopback layer, and free the rx_buf here */ if (unlikely(efx->loopback_selftest)) { efx_loopback_rx_packet(efx, rx_buf->data, rx_buf->len); efx_free_rx_buffer(efx, rx_buf); return; } if (rx_buf->skb) { prefetch(skb_shinfo(rx_buf->skb)); skb_put(rx_buf->skb, rx_buf->len); /* Move past the ethernet header. rx_buf->data still points * at the ethernet header */ rx_buf->skb->protocol = eth_type_trans(rx_buf->skb, efx->net_dev); } if (likely(checksummed || rx_buf->page)) { efx_rx_packet_lro(channel, rx_buf, checksummed); return; } /* We now own the SKB */ skb = rx_buf->skb; rx_buf->skb = NULL; EFX_BUG_ON_PARANOID(rx_buf->page); EFX_BUG_ON_PARANOID(rx_buf->skb); EFX_BUG_ON_PARANOID(!skb); /* Set the SKB flags */ skb->ip_summed = CHECKSUM_NONE; skb_record_rx_queue(skb, channel->channel); /* Pass the packet up */ netif_receive_skb(skb); /* Update allocation strategy method */ channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB; } void efx_rx_strategy(struct efx_channel *channel) { enum efx_rx_alloc_method method = rx_alloc_method; /* Only makes sense to use page based allocation if LRO is enabled */ if (!(channel->efx->net_dev->features & NETIF_F_GRO)) { method = RX_ALLOC_METHOD_SKB; } else if (method == RX_ALLOC_METHOD_AUTO) { /* Constrain the rx_alloc_level */ if (channel->rx_alloc_level < 0) channel->rx_alloc_level = 0; else if (channel->rx_alloc_level > RX_ALLOC_LEVEL_MAX) channel->rx_alloc_level = RX_ALLOC_LEVEL_MAX; /* Decide on the allocation method */ method = ((channel->rx_alloc_level > RX_ALLOC_LEVEL_LRO) ? RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB); } /* Push the option */ channel->rx_alloc_push_pages = (method == RX_ALLOC_METHOD_PAGE); } int efx_probe_rx_queue(struct efx_rx_queue *rx_queue) { struct efx_nic *efx = rx_queue->efx; unsigned int rxq_size; int rc; EFX_LOG(efx, "creating RX queue %d\n", rx_queue->queue); /* Allocate RX buffers */ rxq_size = EFX_RXQ_SIZE * sizeof(*rx_queue->buffer); rx_queue->buffer = kzalloc(rxq_size, GFP_KERNEL); if (!rx_queue->buffer) return -ENOMEM; rc = falcon_probe_rx(rx_queue); if (rc) { kfree(rx_queue->buffer); rx_queue->buffer = NULL; } return rc; } void efx_init_rx_queue(struct efx_rx_queue *rx_queue) { unsigned int max_fill, trigger, limit; EFX_LOG(rx_queue->efx, "initialising RX queue %d\n", rx_queue->queue); /* Initialise ptr fields */ rx_queue->added_count = 0; rx_queue->notified_count = 0; rx_queue->removed_count = 0; rx_queue->min_fill = -1U; rx_queue->min_overfill = -1U; /* Initialise limit fields */ max_fill = EFX_RXQ_SIZE - EFX_RXD_HEAD_ROOM; trigger = max_fill * min(rx_refill_threshold, 100U) / 100U; limit = max_fill * min(rx_refill_limit, 100U) / 100U; rx_queue->max_fill = max_fill; rx_queue->fast_fill_trigger = trigger; rx_queue->fast_fill_limit = limit; /* Set up RX descriptor ring */ falcon_init_rx(rx_queue); } void efx_fini_rx_queue(struct efx_rx_queue *rx_queue) { int i; struct efx_rx_buffer *rx_buf; EFX_LOG(rx_queue->efx, "shutting down RX queue %d\n", rx_queue->queue); falcon_fini_rx(rx_queue); /* Release RX buffers NB start at index 0 not current HW ptr */ if (rx_queue->buffer) { for (i = 0; i <= EFX_RXQ_MASK; i++) { rx_buf = efx_rx_buffer(rx_queue, i); efx_fini_rx_buffer(rx_queue, rx_buf); } } /* For a page that is part-way through splitting into RX buffers */ if (rx_queue->buf_page != NULL) { pci_unmap_page(rx_queue->efx->pci_dev, rx_queue->buf_dma_addr, efx_rx_buf_size(rx_queue->efx), PCI_DMA_FROMDEVICE); __free_pages(rx_queue->buf_page, rx_queue->efx->rx_buffer_order); rx_queue->buf_page = NULL; } } void efx_remove_rx_queue(struct efx_rx_queue *rx_queue) { EFX_LOG(rx_queue->efx, "destroying RX queue %d\n", rx_queue->queue); falcon_remove_rx(rx_queue); kfree(rx_queue->buffer); rx_queue->buffer = NULL; } module_param(rx_alloc_method, int, 0644); MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers"); module_param(rx_refill_threshold, uint, 0444); MODULE_PARM_DESC(rx_refill_threshold, "RX descriptor ring fast/slow fill threshold (%)");