From 3a68f19d7afb80f548d016effbc6ed52643a8085 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 20 Dec 2012 18:48:20 +0000 Subject: sfc: Properly sync RX DMA buffer when it is not the last in the page We may currently allocate two RX DMA buffers to a page, and only unmap the page when the second is completed. We do not sync the first RX buffer to be completed; this can result in packet loss or corruption if the last RX buffer completed in a NAPI poll is the first in a page and is not DMA-coherent. (In the middle of a NAPI poll, we will handle the following RX completion and unmap the page *before* looking at the content of the first buffer.) Signed-off-by: Ben Hutchings --- drivers/net/ethernet/sfc/rx.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c index d780a0d096b4..a5754916478e 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -236,7 +236,8 @@ 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) + struct efx_rx_buffer *rx_buf, + unsigned int used_len) { if ((rx_buf->flags & EFX_RX_BUF_PAGE) && rx_buf->u.page) { struct efx_rx_page_state *state; @@ -247,6 +248,10 @@ static void efx_unmap_rx_buffer(struct efx_nic *efx, state->dma_addr, efx_rx_buf_size(efx), DMA_FROM_DEVICE); + } else if (used_len) { + dma_sync_single_for_cpu(&efx->pci_dev->dev, + rx_buf->dma_addr, used_len, + DMA_FROM_DEVICE); } } else if (!(rx_buf->flags & EFX_RX_BUF_PAGE) && rx_buf->u.skb) { dma_unmap_single(&efx->pci_dev->dev, rx_buf->dma_addr, @@ -269,7 +274,7 @@ static void efx_free_rx_buffer(struct efx_nic *efx, 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_unmap_rx_buffer(rx_queue->efx, rx_buf, 0); efx_free_rx_buffer(rx_queue->efx, rx_buf); } @@ -535,10 +540,10 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, goto out; } - /* Release card resources - assumes all RX buffers consumed in-order - * per RX queue + /* Release and/or sync DMA mapping - assumes all RX buffers + * consumed in-order per RX queue */ - efx_unmap_rx_buffer(efx, rx_buf); + efx_unmap_rx_buffer(efx, rx_buf, len); /* Prefetch nice and early so data will (hopefully) be in cache by * the time we look at it. -- cgit v1.2.3 From b590ace09d51cd39744e0f7662c5e4a0d1b5d952 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 10 Jan 2013 23:51:54 +0000 Subject: sfc: Fix efx_rx_buf_offset() in the presence of swiotlb We assume that the mapping between DMA and virtual addresses is done on whole pages, so we can find the page offset of an RX buffer using the lower bits of the DMA address. However, swiotlb maps in units of 2K, breaking this assumption. Add an explicit page_offset field to struct efx_rx_buffer. Signed-off-by: Ben Hutchings --- drivers/net/ethernet/sfc/net_driver.h | 4 +++- drivers/net/ethernet/sfc/rx.c | 10 +++++----- 2 files changed, 8 insertions(+), 6 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h index 2d756c1d7142..0a90abd2421b 100644 --- a/drivers/net/ethernet/sfc/net_driver.h +++ b/drivers/net/ethernet/sfc/net_driver.h @@ -210,6 +210,7 @@ struct efx_tx_queue { * Will be %NULL if the buffer slot is currently free. * @page: The associated page buffer. Valif iff @flags & %EFX_RX_BUF_PAGE. * Will be %NULL if the buffer slot is currently free. + * @page_offset: Offset within page. Valid iff @flags & %EFX_RX_BUF_PAGE. * @len: Buffer length, in bytes. * @flags: Flags for buffer and packet state. */ @@ -219,7 +220,8 @@ struct efx_rx_buffer { struct sk_buff *skb; struct page *page; } u; - unsigned int len; + u16 page_offset; + u16 len; u16 flags; }; #define EFX_RX_BUF_PAGE 0x0001 diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c index a5754916478e..879ff5849bbd 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -90,11 +90,7 @@ static unsigned int rx_refill_threshold; 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 ((unsigned int) buf->dma_addr & (PAGE_SIZE - 1)) + - efx->type->rx_buffer_hash_size; + return buf->page_offset + efx->type->rx_buffer_hash_size; } static inline unsigned int efx_rx_buf_size(struct efx_nic *efx) { @@ -187,6 +183,7 @@ 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; + unsigned int page_offset; struct efx_rx_page_state *state; dma_addr_t dma_addr; unsigned index, count; @@ -211,12 +208,14 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) state->dma_addr = dma_addr; dma_addr += sizeof(struct efx_rx_page_state); + page_offset = 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->page_offset = page_offset; rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN; rx_buf->flags = EFX_RX_BUF_PAGE; ++rx_queue->added_count; @@ -227,6 +226,7 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) /* Use the second half of the page */ get_page(page); dma_addr += (PAGE_SIZE >> 1); + page_offset += (PAGE_SIZE >> 1); ++count; goto split; } -- cgit v1.2.3 From 29c69a4882641285a854d6d03ca5adbba68c0034 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 28 Jan 2013 19:01:06 +0000 Subject: sfc: Detach net device when stopping queues for reconfiguration We must only ever stop TX queues when they are full or the net device is not 'ready' so far as the net core, and specifically the watchdog, is concerned. Otherwise, the watchdog may fire *immediately* if no packets have been added to the queue in the last 5 seconds. The device is ready if all the following are true: (a) It has a qdisc (b) It is marked present (c) It is running (d) The link is reported up (a) and (c) are normally true, and must not be changed by a driver. (d) is under our control, but fake link changes may disturb userland. This leaves (b). We already mark the device absent during reset and self-test, but we need to do the same during MTU changes and ring reallocation. We don't need to do this when the device is brought down because then (c) is already false. Signed-off-by: Ben Hutchings --- drivers/net/ethernet/sfc/efx.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c index bf57b3cb16ab..0bc00991d310 100644 --- a/drivers/net/ethernet/sfc/efx.c +++ b/drivers/net/ethernet/sfc/efx.c @@ -779,6 +779,7 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries) tx_queue->txd.entries); } + efx_device_detach_sync(efx); efx_stop_all(efx); efx_stop_interrupts(efx, true); @@ -832,6 +833,7 @@ out: efx_start_interrupts(efx, true); efx_start_all(efx); + netif_device_attach(efx->net_dev); return rc; rollback: @@ -1641,8 +1643,12 @@ static void efx_stop_all(struct efx_nic *efx) /* Flush efx_mac_work(), refill_workqueue, monitor_work */ efx_flush_all(efx); - /* Stop the kernel transmit interface late, so the watchdog - * timer isn't ticking over the flush */ + /* Stop the kernel transmit interface. This is only valid if + * the device is stopped or detached; otherwise the watchdog + * may fire immediately. + */ + WARN_ON(netif_running(efx->net_dev) && + netif_device_present(efx->net_dev)); netif_tx_disable(efx->net_dev); efx_stop_datapath(efx); @@ -1963,16 +1969,18 @@ static int efx_change_mtu(struct net_device *net_dev, int new_mtu) if (new_mtu > EFX_MAX_MTU) return -EINVAL; - efx_stop_all(efx); - netif_dbg(efx, drv, efx->net_dev, "changing MTU to %d\n", new_mtu); + efx_device_detach_sync(efx); + efx_stop_all(efx); + mutex_lock(&efx->mac_lock); net_dev->mtu = new_mtu; efx->type->reconfigure_mac(efx); mutex_unlock(&efx->mac_lock); efx_start_all(efx); + netif_device_attach(efx->net_dev); return 0; } -- cgit v1.2.3