This is a note to let you know that I've just added the patch titled
sfc: Properly sync RX DMA buffer when it is not the last in the page
to the 3.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sfc-properly-sync-rx-dma-buffer-when-it-is-not-the-last-in-the-page.patch
and it can be found in the queue-3.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0ea6a742ceb04ede6504f1428220d3348c02f60f Mon Sep 17 00:00:00 2001
From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
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
From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
[ Upstream commit 3a68f19d7afb80f548d016effbc6ed52643a8085 ]
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 <bhutchings@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/sfc/rx.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
--- 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(stru
}
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 e
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 ef
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 *
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.
Patches currently in stable-queue which might be from bhutchings@xxxxxxxxxxxxxx are
queue-3.8/sfc-properly-sync-rx-dma-buffer-when-it-is-not-the-last-in-the-page.patch
queue-3.8/sfc-only-use-tx-push-if-a-single-descriptor-is-to-be-written.patch
queue-3.8/sfc-fix-efx_rx_buf_offset-in-the-presence-of-swiotlb.patch
queue-3.8/drivers-net-ethernet-sfc-ptp.c-adjust-duplicate-test.patch
queue-3.8/sfc-disable-soft-interrupt-handling-during-efx_device_detach_sync.patch
queue-3.8/sfc-detach-net-device-when-stopping-queues-for-reconfiguration.patch
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