From 8ba5366adacef220b6ce16dca777600433a22a42 Mon Sep 17 00:00:00 2001 From: Steve Hodgson Date: Thu, 24 Feb 2011 23:36:01 +0000 Subject: [PATCH] sfc: Reduce size of efx_rx_buffer by unionising skb and page [bwh: Forward-ported to net-next-2.6.] Signed-off-by: Ben Hutchings --- drivers/net/sfc/net_driver.h | 8 ++- drivers/net/sfc/rx.c | 96 +++++++++++++++++------------------- 2 files changed, 51 insertions(+), 53 deletions(-) diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h index 15b9068e5b87..59ff32ac7ec6 100644 --- a/drivers/net/sfc/net_driver.h +++ b/drivers/net/sfc/net_driver.h @@ -216,13 +216,17 @@ 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. + * @is_page: Indicates if @page is valid. If false, @skb is valid. */ struct efx_rx_buffer { dma_addr_t dma_addr; - struct sk_buff *skb; - struct page *page; + union { + struct sk_buff *skb; + struct page *page; + } u; char *data; unsigned int len; + bool is_page; }; /** diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c index 3925fd621177..bcbd2ec2d92a 100644 --- a/drivers/net/sfc/rx.c +++ b/drivers/net/sfc/rx.c @@ -129,6 +129,7 @@ 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; @@ -136,24 +137,24 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue) index = rx_queue->added_count & rx_queue->ptr_mask; rx_buf = efx_rx_buffer(rx_queue, index); - rx_buf->skb = netdev_alloc_skb(net_dev, skb_len); - if (unlikely(!rx_buf->skb)) + rx_buf->u.skb = skb = netdev_alloc_skb(net_dev, skb_len); + if (unlikely(!skb)) return -ENOMEM; - rx_buf->page = NULL; /* Adjust the SKB for padding and checksum */ - skb_reserve(rx_buf->skb, NET_IP_ALIGN); + skb_reserve(skb, NET_IP_ALIGN); + rx_buf->data = (char *)skb->data; 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->is_page = false; + 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; + dev_kfree_skb_any(skb); + rx_buf->u.skb = NULL; return -EIO; } @@ -211,10 +212,10 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) 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->skb = NULL; - rx_buf->page = page; + rx_buf->u.page = page; rx_buf->data = page_addr + EFX_PAGE_IP_ALIGN; 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; @@ -235,19 +236,17 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) static void efx_unmap_rx_buffer(struct efx_nic *efx, struct efx_rx_buffer *rx_buf) { - if (rx_buf->page) { + if (rx_buf->is_page && rx_buf->u.page) { struct efx_rx_page_state *state; - EFX_BUG_ON_PARANOID(rx_buf->skb); - - state = page_address(rx_buf->page); + 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 (likely(rx_buf->skb)) { + } 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); } @@ -256,12 +255,12 @@ static void efx_unmap_rx_buffer(struct efx_nic *efx, 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; + 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; } } @@ -277,7 +276,7 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue, 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->page); + struct efx_rx_page_state *state = page_address(rx_buf->u.page); struct efx_rx_buffer *new_buf; unsigned fill_level, index; @@ -292,16 +291,16 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, } ++state->refcnt; - get_page(rx_buf->page); + 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->skb = NULL; - new_buf->page = rx_buf->page; + new_buf->u.page = rx_buf->u.page; new_buf->data = (void *) ((__force unsigned long)rx_buf->data ^ (PAGE_SIZE >> 1)); new_buf->len = rx_buf->len; + new_buf->is_page = true; ++rx_queue->added_count; } @@ -315,16 +314,15 @@ static void efx_recycle_rx_buffer(struct efx_channel *channel, struct efx_rx_buffer *new_buf; unsigned index; - if (rx_buf->page != NULL && efx->rx_buffer_len <= EFX_RX_HALF_PAGE && - page_count(rx_buf->page) == 1) + 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->page = NULL; - rx_buf->skb = NULL; + rx_buf->u.page = NULL; ++rx_queue->added_count; } @@ -428,7 +426,7 @@ static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue, * 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); + *leak_packet = !rx_buf->is_page; efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY); } else { if (net_ratelimit()) @@ -454,13 +452,12 @@ static void efx_rx_packet_gro(struct efx_channel *channel, gro_result_t gro_result; /* Pass the skb/page into the GRO engine */ - if (rx_buf->page) { + if (rx_buf->is_page) { struct efx_nic *efx = channel->efx; - struct page *page = rx_buf->page; + struct page *page = rx_buf->u.page; struct sk_buff *skb; - EFX_BUG_ON_PARANOID(rx_buf->skb); - rx_buf->page = NULL; + rx_buf->u.page = NULL; skb = napi_get_frags(napi); if (!skb) { @@ -487,11 +484,10 @@ static void efx_rx_packet_gro(struct efx_channel *channel, gro_result = napi_gro_frags(napi); } else { - struct sk_buff *skb = rx_buf->skb; + struct sk_buff *skb = rx_buf->u.skb; - EFX_BUG_ON_PARANOID(!skb); EFX_BUG_ON_PARANOID(!checksummed); - rx_buf->skb = NULL; + rx_buf->u.skb = NULL; gro_result = napi_gro_receive(napi, skb); } @@ -514,8 +510,6 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, 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 @@ -587,32 +581,32 @@ void __efx_rx_packet(struct efx_channel *channel, return; } - if (rx_buf->skb) { - prefetch(skb_shinfo(rx_buf->skb)); + if (!rx_buf->is_page) { + skb = rx_buf->u.skb; + + prefetch(skb_shinfo(skb)); - skb_reserve(rx_buf->skb, efx->type->rx_buffer_hash_size); - skb_put(rx_buf->skb, rx_buf->len); + skb_reserve(skb, efx->type->rx_buffer_hash_size); + skb_put(skb, rx_buf->len); if (efx->net_dev->features & NETIF_F_RXHASH) - rx_buf->skb->rxhash = efx_rx_buf_hash(rx_buf); + skb->rxhash = efx_rx_buf_hash(rx_buf); /* 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); + skb->protocol = eth_type_trans(skb, efx->net_dev); - skb_record_rx_queue(rx_buf->skb, channel->channel); + skb_record_rx_queue(skb, channel->channel); } - if (likely(checksummed || rx_buf->page)) { + if (likely(checksummed || rx_buf->is_page)) { efx_rx_packet_gro(channel, rx_buf, checksummed); return; } /* We now own the SKB */ - skb = rx_buf->skb; - rx_buf->skb = NULL; - EFX_BUG_ON_PARANOID(!skb); + skb = rx_buf->u.skb; + rx_buf->u.skb = NULL; /* Set the SKB flags */ skb_checksum_none_assert(skb); -- 2.39.2