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 <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Steve Hodgson
David S. Miller
Родитель
90d683afd1
Коммит
f7d6f379db
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@ -222,7 +222,6 @@ struct efx_tx_queue {
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* If both this and skb are %NULL, the buffer slot is currently free.
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* @data: Pointer to ethernet header
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* @len: Buffer length, in bytes.
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* @unmap_addr: DMA address to unmap
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*/
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struct efx_rx_buffer {
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dma_addr_t dma_addr;
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@ -230,7 +229,6 @@ struct efx_rx_buffer {
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struct page *page;
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char *data;
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unsigned int len;
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dma_addr_t unmap_addr;
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};
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/**
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@ -257,11 +255,6 @@ struct efx_rx_buffer {
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* @alloc_page_count: RX allocation strategy counter.
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* @alloc_skb_count: RX allocation strategy counter.
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* @slow_fill: Timer used to defer efx_nic_generate_fill_event().
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* @buf_page: Page for next RX buffer.
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* We can use a single page for multiple RX buffers. This tracks
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* the remaining space in the allocation.
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* @buf_dma_addr: Page's DMA address.
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* @buf_data: Page's host address.
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* @flushed: Use when handling queue flushing
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*/
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struct efx_rx_queue {
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@ -284,9 +277,6 @@ struct efx_rx_queue {
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struct timer_list slow_fill;
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unsigned int slow_fill_count;
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struct page *buf_page;
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dma_addr_t buf_dma_addr;
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char *buf_data;
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enum efx_flush_state flushed;
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};
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@ -98,155 +98,132 @@ static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
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return PAGE_SIZE << efx->rx_buffer_order;
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}
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/**
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* efx_init_rx_buffer_skb - create new RX buffer using skb-based allocation
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* efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers
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*
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* @rx_queue: Efx RX queue
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* @rx_buf: RX buffer structure to populate
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*
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* This allocates memory for a new receive buffer, maps it for DMA,
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* and populates a struct efx_rx_buffer with the relevant
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* information. Return a negative error code or 0 on success.
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* This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a
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* struct efx_rx_buffer for each one. Return a negative error code or 0
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* on success. May fail having only inserted fewer than EFX_RX_BATCH
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* buffers.
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*/
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static int efx_init_rx_buffer_skb(struct efx_rx_queue *rx_queue,
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struct efx_rx_buffer *rx_buf)
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static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
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{
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struct efx_nic *efx = rx_queue->efx;
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struct net_device *net_dev = efx->net_dev;
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struct efx_rx_buffer *rx_buf;
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int skb_len = efx->rx_buffer_len;
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unsigned index, count;
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rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
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if (unlikely(!rx_buf->skb))
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return -ENOMEM;
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for (count = 0; count < EFX_RX_BATCH; ++count) {
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index = rx_queue->added_count & EFX_RXQ_MASK;
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rx_buf = efx_rx_buffer(rx_queue, index);
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/* Adjust the SKB for padding and checksum */
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skb_reserve(rx_buf->skb, NET_IP_ALIGN);
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rx_buf->len = skb_len - NET_IP_ALIGN;
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rx_buf->data = (char *)rx_buf->skb->data;
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rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
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rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
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if (unlikely(!rx_buf->skb))
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return -ENOMEM;
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rx_buf->page = NULL;
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rx_buf->dma_addr = pci_map_single(efx->pci_dev,
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rx_buf->data, rx_buf->len,
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PCI_DMA_FROMDEVICE);
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/* Adjust the SKB for padding and checksum */
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skb_reserve(rx_buf->skb, NET_IP_ALIGN);
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rx_buf->len = skb_len - NET_IP_ALIGN;
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rx_buf->data = (char *)rx_buf->skb->data;
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rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
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if (unlikely(pci_dma_mapping_error(efx->pci_dev, rx_buf->dma_addr))) {
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dev_kfree_skb_any(rx_buf->skb);
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rx_buf->skb = NULL;
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return -EIO;
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rx_buf->dma_addr = pci_map_single(efx->pci_dev,
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rx_buf->data, rx_buf->len,
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PCI_DMA_FROMDEVICE);
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if (unlikely(pci_dma_mapping_error(efx->pci_dev,
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rx_buf->dma_addr))) {
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dev_kfree_skb_any(rx_buf->skb);
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rx_buf->skb = NULL;
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return -EIO;
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}
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++rx_queue->added_count;
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++rx_queue->alloc_skb_count;
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}
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return 0;
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}
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/**
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* efx_init_rx_buffer_page - create new RX buffer using page-based allocation
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* efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers
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*
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* @rx_queue: Efx RX queue
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* @rx_buf: RX buffer structure to populate
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*
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* This allocates memory for a new receive buffer, maps it for DMA,
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* and populates a struct efx_rx_buffer with the relevant
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* information. Return a negative error code or 0 on success.
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* This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA,
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* and populates struct efx_rx_buffers for each one. Return a negative error
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* code or 0 on success. If a single page can be split between two buffers,
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* then the page will either be inserted fully, or not at at all.
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*/
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static int efx_init_rx_buffer_page(struct efx_rx_queue *rx_queue,
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struct efx_rx_buffer *rx_buf)
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static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
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{
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struct efx_nic *efx = rx_queue->efx;
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int bytes, space, offset;
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struct efx_rx_buffer *rx_buf;
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struct page *page;
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char *page_addr;
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dma_addr_t dma_addr;
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unsigned index, count;
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bytes = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
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/* We can split a page between two buffers */
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BUILD_BUG_ON(EFX_RX_BATCH & 1);
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/* If there is space left in the previously allocated page,
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* then use it. Otherwise allocate a new one */
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rx_buf->page = rx_queue->buf_page;
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if (rx_buf->page == NULL) {
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dma_addr_t dma_addr;
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rx_buf->page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
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efx->rx_buffer_order);
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if (unlikely(rx_buf->page == NULL))
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for (count = 0; count < EFX_RX_BATCH; ++count) {
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page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
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efx->rx_buffer_order);
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if (unlikely(page == NULL))
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return -ENOMEM;
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dma_addr = pci_map_page(efx->pci_dev, rx_buf->page,
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0, efx_rx_buf_size(efx),
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dma_addr = pci_map_page(efx->pci_dev, page, 0,
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efx_rx_buf_size(efx),
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PCI_DMA_FROMDEVICE);
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if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
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__free_pages(rx_buf->page, efx->rx_buffer_order);
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rx_buf->page = NULL;
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__free_pages(page, efx->rx_buffer_order);
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return -EIO;
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}
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EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1));
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page_addr = page_address(page) + EFX_PAGE_IP_ALIGN;
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dma_addr += EFX_PAGE_IP_ALIGN;
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rx_queue->buf_page = rx_buf->page;
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rx_queue->buf_dma_addr = dma_addr;
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rx_queue->buf_data = (page_address(rx_buf->page) +
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EFX_PAGE_IP_ALIGN);
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}
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split:
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index = rx_queue->added_count & EFX_RXQ_MASK;
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rx_buf = efx_rx_buffer(rx_queue, index);
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rx_buf->dma_addr = dma_addr;
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rx_buf->skb = NULL;
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rx_buf->page = page;
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rx_buf->data = page_addr;
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rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
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++rx_queue->added_count;
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++rx_queue->alloc_page_count;
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rx_buf->len = bytes;
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rx_buf->data = rx_queue->buf_data;
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offset = efx_rx_buf_offset(rx_buf);
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rx_buf->dma_addr = rx_queue->buf_dma_addr + offset;
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/* Try to pack multiple buffers per page */
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if (efx->rx_buffer_order == 0) {
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/* The next buffer starts on the next 512 byte boundary */
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rx_queue->buf_data += ((bytes + 0x1ff) & ~0x1ff);
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offset += ((bytes + 0x1ff) & ~0x1ff);
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space = efx_rx_buf_size(efx) - offset;
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if (space >= bytes) {
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/* Refs dropped on kernel releasing each skb */
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get_page(rx_queue->buf_page);
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goto out;
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if ((~count & 1) && (efx->rx_buffer_len < (PAGE_SIZE >> 1))) {
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/* Use the second half of the page */
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get_page(page);
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dma_addr += (PAGE_SIZE >> 1);
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page_addr += (PAGE_SIZE >> 1);
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++count;
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goto split;
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}
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}
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/* This is the final RX buffer for this page, so mark it for
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* unmapping */
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rx_queue->buf_page = NULL;
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rx_buf->unmap_addr = rx_queue->buf_dma_addr;
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out:
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return 0;
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}
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/* This allocates memory for a new receive buffer, maps it for DMA,
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* and populates a struct efx_rx_buffer with the relevant
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* information.
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*/
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static int efx_init_rx_buffer(struct efx_rx_queue *rx_queue,
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struct efx_rx_buffer *new_rx_buf)
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{
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int rc = 0;
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if (rx_queue->channel->rx_alloc_push_pages) {
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new_rx_buf->skb = NULL;
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rc = efx_init_rx_buffer_page(rx_queue, new_rx_buf);
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rx_queue->alloc_page_count++;
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} else {
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new_rx_buf->page = NULL;
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rc = efx_init_rx_buffer_skb(rx_queue, new_rx_buf);
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rx_queue->alloc_skb_count++;
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}
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if (unlikely(rc < 0))
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EFX_LOG_RL(rx_queue->efx, "%s RXQ[%d] =%d\n", __func__,
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rx_queue->queue, rc);
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return rc;
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}
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static void efx_unmap_rx_buffer(struct efx_nic *efx,
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struct efx_rx_buffer *rx_buf)
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{
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if (rx_buf->page) {
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EFX_BUG_ON_PARANOID(rx_buf->skb);
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if (rx_buf->unmap_addr) {
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pci_unmap_page(efx->pci_dev, rx_buf->unmap_addr,
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/* Unmap the buffer if there's only one buffer per page(s),
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* or this is the second half of a two buffer page. */
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if (efx->rx_buffer_order != 0 ||
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(efx_rx_buf_offset(rx_buf) & (PAGE_SIZE >> 1)) != 0) {
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pci_unmap_page(efx->pci_dev,
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rx_buf->dma_addr & ~(PAGE_SIZE - 1),
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efx_rx_buf_size(efx),
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PCI_DMA_FROMDEVICE);
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rx_buf->unmap_addr = 0;
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}
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} else if (likely(rx_buf->skb)) {
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pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
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@ -286,9 +263,9 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
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*/
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void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
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{
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struct efx_rx_buffer *rx_buf;
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unsigned fill_level, index;
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int i, space, rc = 0;
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struct efx_channel *channel = rx_queue->channel;
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unsigned fill_level;
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int space, rc = 0;
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/* Calculate current fill level, and exit if we don't need to fill */
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fill_level = (rx_queue->added_count - rx_queue->removed_count);
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@ -309,21 +286,18 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
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EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
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" level %d to level %d using %s allocation\n",
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rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
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rx_queue->channel->rx_alloc_push_pages ? "page" : "skb");
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channel->rx_alloc_push_pages ? "page" : "skb");
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do {
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for (i = 0; i < EFX_RX_BATCH; ++i) {
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index = rx_queue->added_count & EFX_RXQ_MASK;
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rx_buf = efx_rx_buffer(rx_queue, index);
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rc = efx_init_rx_buffer(rx_queue, rx_buf);
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if (unlikely(rc)) {
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/* Ensure that we don't leave the rx queue
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* empty */
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if (rx_queue->added_count == rx_queue->removed_count)
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efx_schedule_slow_fill(rx_queue);
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goto out;
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}
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++rx_queue->added_count;
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if (channel->rx_alloc_push_pages)
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rc = efx_init_rx_buffers_page(rx_queue);
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else
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rc = efx_init_rx_buffers_skb(rx_queue);
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if (unlikely(rc)) {
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/* Ensure that we don't leave the rx queue empty */
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if (rx_queue->added_count == rx_queue->removed_count)
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efx_schedule_slow_fill(rx_queue);
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goto out;
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}
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} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
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@ -638,16 +612,6 @@ void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
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efx_fini_rx_buffer(rx_queue, rx_buf);
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}
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}
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/* For a page that is part-way through splitting into RX buffers */
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if (rx_queue->buf_page != NULL) {
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pci_unmap_page(rx_queue->efx->pci_dev, rx_queue->buf_dma_addr,
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efx_rx_buf_size(rx_queue->efx),
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PCI_DMA_FROMDEVICE);
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__free_pages(rx_queue->buf_page,
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rx_queue->efx->rx_buffer_order);
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rx_queue->buf_page = NULL;
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}
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}
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void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
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