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| author | Feng Tang <feng.tang@intel.com> | 2016-06-24 15:26:05 +0800 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2016-08-27 11:40:20 +0200 |
| commit | 5bccf7715a1d5c2a9f6d1b9301d6619429a34319 (patch) | |
| tree | 7a04a160eb7345889848368b3b3e2fbcc976f52d | |
| parent | 23f2a4ce4fc03e4f37f6fe341bbb1baace1b097e (diff) | |
| download | lwn-5bccf7715a1d5c2a9f6d1b9301d6619429a34319.tar.gz lwn-5bccf7715a1d5c2a9f6d1b9301d6619429a34319.zip | |
net: alx: Work around the DMA RX overflow issue
commit 881d0327db37ad917a367c77aff1afa1ee41e0a9 upstream.
Note: This is a verified backported patch for stable 4.4 kernel, and it
could also be applied to 4.3/4.2/4.1/3.18/3.16
There is a problem with alx devices, that the network link will be
lost in 1-5 minutes after the device is up.
>From debugging without datasheet, we found the error always
happen when the DMA RX address is set to 0x....fc0, which is very
likely to be a HW/silicon problem.
This patch will apply rx skb with 64 bytes longer space, and if the
allocated skb has a 0x...fc0 address, it will use skb_resever(skb, 64)
to advance the address, so that the RX overflow can be avoided.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=70761
Signed-off-by: Feng Tang <feng.tang@intel.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Tested-by: Ole Lukoie <olelukoie@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | drivers/net/ethernet/atheros/alx/main.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c index a85a9c2f1385..7357e54f1de9 100644 --- a/drivers/net/ethernet/atheros/alx/main.c +++ b/drivers/net/ethernet/atheros/alx/main.c @@ -86,9 +86,14 @@ static int alx_refill_rx_ring(struct alx_priv *alx, gfp_t gfp) while (!cur_buf->skb && next != rxq->read_idx) { struct alx_rfd *rfd = &rxq->rfd[cur]; - skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size, gfp); + skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size + 64, gfp); if (!skb) break; + + /* Workround for the HW RX DMA overflow issue */ + if (((unsigned long)skb->data & 0xfff) == 0xfc0) + skb_reserve(skb, 64); + dma = dma_map_single(&alx->hw.pdev->dev, skb->data, alx->rxbuf_size, DMA_FROM_DEVICE); |