From f7d6f379db61233a1740cb2c6818b9c97531771f Mon Sep 17 00:00:00 2001 From: Steve Hodgson Date: Tue, 1 Jun 2010 11:33:17 +0000 Subject: [PATCH] sfc: Support only two rx buffers per page - Pull the loop handling into efx_init_rx_buffers_(skb|page) - Remove rx_queue->buf_page, and associated clean up code - Remove unmap_addr, since unmap_addr is trivially calculable This will allow us to recycle discarded buffers directly from efx_rx_packet(), since will never be in the middle of splitting a page. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/sfc/net_driver.h | 10 -- drivers/net/sfc/rx.c | 228 +++++++++++++++-------------------- 2 files changed, 96 insertions(+), 142 deletions(-) diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h index 45398039dee..59c8ecc39ae 100644 --- a/drivers/net/sfc/net_driver.h +++ b/drivers/net/sfc/net_driver.h @@ -222,7 +222,6 @@ struct efx_tx_queue { * If both this and skb are %NULL, the buffer slot is currently free. * @data: Pointer to ethernet header * @len: Buffer length, in bytes. - * @unmap_addr: DMA address to unmap */ struct efx_rx_buffer { dma_addr_t dma_addr; @@ -230,7 +229,6 @@ struct efx_rx_buffer { struct page *page; char *data; unsigned int len; - dma_addr_t unmap_addr; }; /** @@ -257,11 +255,6 @@ struct efx_rx_buffer { * @alloc_page_count: RX allocation strategy counter. * @alloc_skb_count: RX allocation strategy counter. * @slow_fill: Timer used to defer efx_nic_generate_fill_event(). - * @buf_page: Page for next RX buffer. - * We can use a single page for multiple RX buffers. This tracks - * the remaining space in the allocation. - * @buf_dma_addr: Page's DMA address. - * @buf_data: Page's host address. * @flushed: Use when handling queue flushing */ struct efx_rx_queue { @@ -284,9 +277,6 @@ struct efx_rx_queue { struct timer_list slow_fill; unsigned int slow_fill_count; - struct page *buf_page; - dma_addr_t buf_dma_addr; - char *buf_data; enum efx_flush_state flushed; }; diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c index bf1e55e7869..615a1fcd664 100644 --- a/drivers/net/sfc/rx.c +++ b/drivers/net/sfc/rx.c @@ -98,155 +98,132 @@ 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 + * efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers * * @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. + * 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_buffer_skb(struct efx_rx_queue *rx_queue, - struct efx_rx_buffer *rx_buf) +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; int skb_len = efx->rx_buffer_len; + unsigned index, count; - rx_buf->skb = netdev_alloc_skb(net_dev, skb_len); - if (unlikely(!rx_buf->skb)) - return -ENOMEM; + for (count = 0; count < EFX_RX_BATCH; ++count) { + index = rx_queue->added_count & EFX_RXQ_MASK; + rx_buf = efx_rx_buffer(rx_queue, index); - /* 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->skb = netdev_alloc_skb(net_dev, skb_len); + if (unlikely(!rx_buf->skb)) + return -ENOMEM; + rx_buf->page = NULL; - rx_buf->dma_addr = pci_map_single(efx->pci_dev, - rx_buf->data, rx_buf->len, - PCI_DMA_FROMDEVICE); + /* 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; + } - 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; + ++rx_queue->added_count; + ++rx_queue->alloc_skb_count; } return 0; } /** - * efx_init_rx_buffer_page - create new RX buffer using page-based allocation + * efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers * * @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. + * 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_buffer_page(struct efx_rx_queue *rx_queue, - struct efx_rx_buffer *rx_buf) +static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) { 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)) + struct efx_rx_buffer *rx_buf; + struct page *page; + char *page_addr; + 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, rx_buf->page, - 0, efx_rx_buf_size(efx), + 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(rx_buf->page, efx->rx_buffer_order); - rx_buf->page = NULL; + __free_pages(page, efx->rx_buffer_order); 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; + EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1)); + page_addr = page_address(page) + EFX_PAGE_IP_ALIGN; + dma_addr += EFX_PAGE_IP_ALIGN; + + split: + index = rx_queue->added_count & EFX_RXQ_MASK; + rx_buf = efx_rx_buffer(rx_queue, index); + rx_buf->dma_addr = dma_addr; + rx_buf->skb = NULL; + rx_buf->page = page; + rx_buf->data = page_addr; + rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN; + ++rx_queue->added_count; + ++rx_queue->alloc_page_count; + + if ((~count & 1) && (efx->rx_buffer_len < (PAGE_SIZE >> 1))) { + /* Use the second half of the page */ + get_page(page); + dma_addr += (PAGE_SIZE >> 1); + page_addr += (PAGE_SIZE >> 1); + ++count; + goto split; } } - /* 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, + + /* Unmap the buffer if there's only one buffer per page(s), + * or this is the second half of a two buffer page. */ + if (efx->rx_buffer_order != 0 || + (efx_rx_buf_offset(rx_buf) & (PAGE_SIZE >> 1)) != 0) { + pci_unmap_page(efx->pci_dev, + rx_buf->dma_addr & ~(PAGE_SIZE - 1), 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, @@ -286,9 +263,9 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue, */ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) { - struct efx_rx_buffer *rx_buf; - unsigned fill_level, index; - int i, space, rc = 0; + struct efx_channel *channel = rx_queue->channel; + 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); @@ -309,21 +286,18 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) 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"); + 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)) { - /* 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; - } - ++rx_queue->added_count; + 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); @@ -638,16 +612,6 @@ void efx_fini_rx_queue(struct efx_rx_queue *rx_queue) 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) -- 2.39.5