/**************************************************************************** * Driver for Solarflare Solarstorm network controllers and boards * Copyright 2005-2006 Fen Systems Ltd. * Copyright 2005-2011 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 #include "net_driver.h" #include "efx.h" #include "nic.h" #include "selftest.h" #include "workarounds.h" /* Number of RX descriptors pushed at once. */ #define EFX_RX_BATCH 8 /* Maximum size of a buffer sharing a page */ #define EFX_RX_HALF_PAGE ((PAGE_SIZE >> 1) - sizeof(struct efx_rx_page_state)) /* 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 GRO 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 GRO is less * than the performance hit of using page-based allocation of non-GRO, * so the watermarks should reflect this. * * Per channel we maintain a single variable, updated by each channel: * * rx_alloc_level += (gro_performed ? RX_ALLOC_FACTOR_GRO : * 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_GRO ? * RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB) */ static int rx_alloc_method = RX_ALLOC_METHOD_AUTO; #define RX_ALLOC_LEVEL_GRO 0x2000 #define RX_ALLOC_LEVEL_MAX 0x3000 #define RX_ALLOC_FACTOR_GRO 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 /* Offset of ethernet header within page */ static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx, 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->dma_addr & (PAGE_SIZE - 1)) + efx->type->rx_buffer_hash_size; } static inline unsigned int efx_rx_buf_size(struct efx_nic *efx) { return PAGE_SIZE << efx->rx_buffer_order; } static u8 *efx_rx_buf_eh(struct efx_nic *efx, struct efx_rx_buffer *buf) { if (buf->is_page) return page_address(buf->u.page) + efx_rx_buf_offset(efx, buf); else return (u8 *)buf->u.skb->data + efx->type->rx_buffer_hash_size; } static inline u32 efx_rx_buf_hash(const u8 *eh) { /* The ethernet header is always directly after any hash. */ #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || NET_IP_ALIGN % 4 == 0 return __le32_to_cpup((const __le32 *)(eh - 4)); #else const u8 *data = eh - 4; return (u32)data[0] | (u32)data[1] << 8 | (u32)data[2] << 16 | (u32)data[3] << 24; #endif } /** * efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers * * @rx_queue: Efx RX queue * * This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a * struct efx_rx_buffer for each one. Return a negative error code or 0 * on success. May fail having only inserted fewer than EFX_RX_BATCH * buffers. */ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue) { struct efx_nic *efx = rx_queue->efx; struct net_device *net_dev = efx->net_dev; struct efx_rx_buffer *rx_buf; struct sk_buff *skb; int skb_len = efx->rx_buffer_len; unsigned index, count; for (count = 0; count < EFX_RX_BATCH; ++count) { index = rx_queue->added_count & rx_queue->ptr_mask; rx_buf = efx_rx_buffer(rx_queue, index); rx_buf->u.skb = skb = netdev_alloc_skb(net_dev, skb_len); if (unlikely(!skb)) return -ENOMEM; /* Adjust the SKB for padding and checksum */ skb_reserve(skb, NET_IP_ALIGN); rx_buf->len = skb_len - NET_IP_ALIGN; rx_buf->is_page = false; skb->ip_summed = CHECKSUM_UNNECESSARY; rx_buf->dma_addr = pci_map_single(efx->pci_dev, skb->data, rx_buf->len, PCI_DMA_FROMDEVICE); if (unlikely(pci_dma_mapping_error(efx->pci_dev, rx_buf->dma_addr))) { dev_kfree_skb_any(skb); rx_buf->u.skb = NULL; return -EIO; } ++rx_queue->added_count; ++rx_queue->alloc_skb_count; } return 0; } /** * efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers * * @rx_queue: Efx RX queue * * This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA, * and populates struct efx_rx_buffers for each one. Return a negative error * code or 0 on success. If a single page can be split between two buffers, * then the page will either be inserted fully, or not at at all. */ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) { struct efx_nic *efx = rx_queue->efx; struct efx_rx_buffer *rx_buf; struct page *page; void *page_addr; struct efx_rx_page_state *state; dma_addr_t dma_addr; unsigned index, count; /* We can split a page between two buffers */ BUILD_BUG_ON(EFX_RX_BATCH & 1); for (count = 0; count < EFX_RX_BATCH; ++count) { page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC, efx->rx_buffer_order); if (unlikely(page == NULL)) return -ENOMEM; dma_addr = pci_map_page(efx->pci_dev, page, 0, efx_rx_buf_size(efx), PCI_DMA_FROMDEVICE); if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) { __free_pages(page, efx->rx_buffer_order); return -EIO; } page_addr = page_address(page); state = page_addr; state->refcnt = 0; state->dma_addr = dma_addr; page_addr += sizeof(struct efx_rx_page_state); dma_addr += sizeof(struct efx_rx_page_state); split: index = rx_queue->added_count & rx_queue->ptr_mask; rx_buf = efx_rx_buffer(rx_queue, index); rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN; rx_buf->u.page = page; rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN; rx_buf->is_page = true; ++rx_queue->added_count; ++rx_queue->alloc_page_count; ++state->refcnt; if ((~count & 1) && (efx->rx_buffer_len <= EFX_RX_HALF_PAGE)) { /* Use the second half of the page */ get_page(page); dma_addr += (PAGE_SIZE >> 1); page_addr += (PAGE_SIZE >> 1); ++count; goto split; } } return 0; } static void efx_unmap_rx_buffer(struct efx_nic *efx, struct efx_rx_buffer *rx_buf) { if (rx_buf->is_page && rx_buf->u.page) { struct efx_rx_page_state *state; state = page_address(rx_buf->u.page); if (--state->refcnt == 0) { pci_unmap_page(efx->pci_dev, state->dma_addr, efx_rx_buf_size(efx), PCI_DMA_FROMDEVICE); } } else if (!rx_buf->is_page && rx_buf->u.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->is_page && rx_buf->u.page) { __free_pages(rx_buf->u.page, efx->rx_buffer_order); rx_buf->u.page = NULL; } else if (!rx_buf->is_page && rx_buf->u.skb) { dev_kfree_skb_any(rx_buf->u.skb); rx_buf->u.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); } /* Attempt to resurrect the other receive buffer that used to share this page, * which had previously been passed up to the kernel and freed. */ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf) { struct efx_rx_page_state *state = page_address(rx_buf->u.page); struct efx_rx_buffer *new_buf; unsigned fill_level, index; /* +1 because efx_rx_packet() incremented removed_count. +1 because * we'd like to insert an additional descriptor whilst leaving * EFX_RXD_HEAD_ROOM for the non-recycle path */ fill_level = (rx_queue->added_count - rx_queue->removed_count + 2); if (unlikely(fill_level > rx_queue->max_fill)) { /* We could place "state" on a list, and drain the list in * efx_fast_push_rx_descriptors(). For now, this will do. */ return; } ++state->refcnt; get_page(rx_buf->u.page); index = rx_queue->added_count & rx_queue->ptr_mask; new_buf = efx_rx_buffer(rx_queue, index); new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1); new_buf->u.page = rx_buf->u.page; new_buf->len = rx_buf->len; new_buf->is_page = true; ++rx_queue->added_count; } /* Recycle the given rx buffer directly back into the rx_queue. There is * always room to add this buffer, because we've just popped a buffer. */ static void efx_recycle_rx_buffer(struct efx_channel *channel, struct efx_rx_buffer *rx_buf) { struct efx_nic *efx = channel->efx; struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel); struct efx_rx_buffer *new_buf; unsigned index; if (rx_buf->is_page && efx->rx_buffer_len <= EFX_RX_HALF_PAGE && page_count(rx_buf->u.page) == 1) efx_resurrect_rx_buffer(rx_queue, rx_buf); index = rx_queue->added_count & rx_queue->ptr_mask; new_buf = efx_rx_buffer(rx_queue, index); memcpy(new_buf, rx_buf, sizeof(*new_buf)); rx_buf->u.page = NULL; ++rx_queue->added_count; } /** * 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 atomic * memory to do so, a slow fill will be scheduled. * * The caller must provide serialisation (none is used here). In practise, * this means this function must run from the NAPI handler, or be called * when NAPI is disabled. */ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) { struct efx_channel *channel = efx_rx_queue_channel(rx_queue); unsigned fill_level; int space, rc = 0; /* Calculate current fill level, and exit if we don't need to fill */ fill_level = (rx_queue->added_count - rx_queue->removed_count); EFX_BUG_ON_PARANOID(fill_level > rx_queue->efx->rxq_entries); if (fill_level >= rx_queue->fast_fill_trigger) goto out; /* Record minimum fill level */ if (unlikely(fill_level < rx_queue->min_fill)) { if (fill_level) rx_queue->min_fill = fill_level; } space = rx_queue->fast_fill_limit - fill_level; if (space < EFX_RX_BATCH) goto out; netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev, "RX queue %d fast-filling descriptor ring from" " level %d to level %d using %s allocation\n", efx_rx_queue_index(rx_queue), fill_level, rx_queue->fast_fill_limit, channel->rx_alloc_push_pages ? "page" : "skb"); do { if (channel->rx_alloc_push_pages) rc = efx_init_rx_buffers_page(rx_queue); else rc = efx_init_rx_buffers_skb(rx_queue); if (unlikely(rc)) { /* Ensure that we don't leave the rx queue empty */ if (rx_queue->added_count == rx_queue->removed_count) efx_schedule_slow_fill(rx_queue); goto out; } } while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH); netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev, "RX queue %d fast-filled descriptor ring " "to level %d\n", efx_rx_queue_index(rx_queue), rx_queue->added_count - rx_queue->removed_count); out: if (rx_queue->notified_count != rx_queue->added_count) efx_nic_notify_rx_desc(rx_queue); } void efx_rx_slow_fill(unsigned long context) { struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context; struct efx_channel *channel = efx_rx_queue_channel(rx_queue); /* Post an event to cause NAPI to run and refill the queue */ efx_nic_generate_fill_event(channel); ++rx_queue->slow_fill_count; } 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)) { if (net_ratelimit()) netif_err(efx, rx_err, efx->net_dev, " RX queue %d seriously overlength " "RX event (0x%x > 0x%x+0x%x). Leaking\n", efx_rx_queue_index(rx_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->is_page; efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY); } else { if (net_ratelimit()) netif_err(efx, rx_err, efx->net_dev, " RX queue %d overlength RX event " "(0x%x > 0x%x)\n", efx_rx_queue_index(rx_queue), len, max_len); } efx_rx_queue_channel(rx_queue)->n_rx_overlength++; } /* Pass a received packet up through the generic GRO stack * * Handles driverlink veto, and passes the fragment up via * the appropriate GRO method */ static void efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf, const u8 *eh, bool checksummed) { struct napi_struct *napi = &channel->napi_str; gro_result_t gro_result; /* Pass the skb/page into the GRO engine */ if (rx_buf->is_page) { struct efx_nic *efx = channel->efx; struct page *page = rx_buf->u.page; struct sk_buff *skb; rx_buf->u.page = NULL; skb = napi_get_frags(napi); if (!skb) { put_page(page); return; } if (efx->net_dev->features & NETIF_F_RXHASH) skb->rxhash = efx_rx_buf_hash(eh); skb_fill_page_desc(skb, 0, page, efx_rx_buf_offset(efx, rx_buf), rx_buf->len); skb->len = rx_buf->len; skb->data_len = rx_buf->len; skb->truesize += rx_buf->len; skb->ip_summed = checksummed ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE; skb_record_rx_queue(skb, channel->channel); gro_result = napi_gro_frags(napi); } else { struct sk_buff *skb = rx_buf->u.skb; EFX_BUG_ON_PARANOID(!checksummed); rx_buf->u.skb = NULL; gro_result = napi_gro_receive(napi, skb); } 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_GRO; 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_channel *channel = efx_rx_queue_channel(rx_queue); struct efx_rx_buffer *rx_buf; bool leak_packet = false; rx_buf = efx_rx_buffer(rx_queue, index); /* 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); netif_vdbg(efx, rx_status, efx->net_dev, "RX queue %d received id %x at %llx+%x %s%s\n", efx_rx_queue_index(rx_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)) channel->n_skbuff_leaks++; else efx_recycle_rx_buffer(channel, rx_buf); /* Don't hold off the previous receive */ rx_buf = NULL; goto out; } /* 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(efx_rx_buf_eh(efx, rx_buf)); /* Pipeline receives so that we give time for packet headers to be * prefetched into cache. */ rx_buf->len = len - efx->type->rx_buffer_hash_size; out: if (channel->rx_pkt) __efx_rx_packet(channel, channel->rx_pkt, channel->rx_pkt_csummed); channel->rx_pkt = rx_buf; 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; u8 *eh = efx_rx_buf_eh(efx, rx_buf); /* 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, eh, rx_buf->len); efx_free_rx_buffer(efx, rx_buf); return; } if (!rx_buf->is_page) { skb = rx_buf->u.skb; prefetch(skb_shinfo(skb)); skb_reserve(skb, efx->type->rx_buffer_hash_size); skb_put(skb, rx_buf->len); if (efx->net_dev->features & NETIF_F_RXHASH) skb->rxhash = efx_rx_buf_hash(eh); /* Move past the ethernet header. rx_buf->data still points * at the ethernet header */ skb->protocol = eth_type_trans(skb, efx->net_dev); skb_record_rx_queue(skb, channel->channel); } if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM))) checksummed = false; if (likely(checksummed || rx_buf->is_page)) { efx_rx_packet_gro(channel, rx_buf, eh, checksummed); return; } /* We now own the SKB */ skb = rx_buf->u.skb; rx_buf->u.skb = NULL; /* Set the SKB flags */ skb_checksum_none_assert(skb); /* 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 GRO 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_GRO) ? 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 entries; int rc; /* Create the smallest power-of-two aligned ring */ entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE); EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE); rx_queue->ptr_mask = entries - 1; netif_dbg(efx, probe, efx->net_dev, "creating RX queue %d size %#x mask %#x\n", efx_rx_queue_index(rx_queue), efx->rxq_entries, rx_queue->ptr_mask); /* Allocate RX buffers */ rx_queue->buffer = kcalloc(entries, sizeof(*rx_queue->buffer), GFP_KERNEL); if (!rx_queue->buffer) return -ENOMEM; rc = efx_nic_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) { struct efx_nic *efx = rx_queue->efx; unsigned int max_fill, trigger, limit; netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev, "initialising RX queue %d\n", efx_rx_queue_index(rx_queue)); /* Initialise ptr fields */ rx_queue->added_count = 0; rx_queue->notified_count = 0; rx_queue->removed_count = 0; rx_queue->min_fill = -1U; /* Initialise limit fields */ max_fill = efx->rxq_entries - 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 */ efx_nic_init_rx(rx_queue); } void efx_fini_rx_queue(struct efx_rx_queue *rx_queue) { int i; struct efx_rx_buffer *rx_buf; netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev, "shutting down RX queue %d\n", efx_rx_queue_index(rx_queue)); del_timer_sync(&rx_queue->slow_fill); efx_nic_fini_rx(rx_queue); /* Release RX buffers NB start at index 0 not current HW ptr */ if (rx_queue->buffer) { for (i = 0; i <= rx_queue->ptr_mask; i++) { rx_buf = efx_rx_buffer(rx_queue, i); efx_fini_rx_buffer(rx_queue, rx_buf); } } } void efx_remove_rx_queue(struct efx_rx_queue *rx_queue) { netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev, "destroying RX queue %d\n", efx_rx_queue_index(rx_queue)); efx_nic_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 (%)");