[PATCH 5.10 465/717] dpaa2-eth: fix the size of the mapped SGT buffer

Greg Kroah-Hartman
2020-12-28T14:50:14Z

From: Ioana Ciornei <ioana.ciornei@nxp.com>

[ Upstream commit 54a57d1c449275ee727154ac106ec1accae012e3 ]

This patch fixes an error condition triggered when the code path which
transmits a S/G frame descriptor when the skb's headroom is not enough
for DPAA2's needs.

We are greated with a splat like the one below when a SGT structure is
recycled and that is because even though a dma_unmap is performed on the
Tx confirmation path, the unmap is not done with the proper size.

[ 714.464927] WARNING: CPU: 13 PID: 0 at drivers/iommu/io-pgtable-arm.c:281 __arm_lpae_map+0x2d4/0x30c
(...)
[ 714.465343] Call trace:
[ 714.465348] __arm_lpae_map+0x2d4/0x30c
[ 714.465353] __arm_lpae_map+0x114/0x30c
[ 714.465357] __arm_lpae_map+0x114/0x30c
[ 714.465362] __arm_lpae_map+0x114/0x30c
[ 714.465366] arm_lpae_map+0xf4/0x180
[ 714.465373] arm_smmu_map+0x4c/0xc0
[ 714.465379] __iommu_map+0x100/0x2bc
[ 714.465385] iommu_map_atomic+0x20/0x30
[ 714.465391] __iommu_dma_map+0xb0/0x110
[ 714.465397] iommu_dma_map_page+0xb8/0x120
[ 714.465404] dma_map_page_attrs+0x1a8/0x210
[ 714.465413] __dpaa2_eth_tx+0x384/0xbd0 [fsl_dpaa2_eth]
[ 714.465421] dpaa2_eth_tx+0x84/0x134 [fsl_dpaa2_eth]
[ 714.465427] dev_hard_start_xmit+0x10c/0x2b0
[ 714.465433] sch_direct_xmit+0x1a0/0x550
(...)

The dpaa2-eth driver uses an area of software annotations to transmit
necessary information from the Tx path to the Tx confirmation one. This
SWA structure has a different layout for each kind of frame that we are
dealing with: linear, S/G or XDP.

The commit referenced was incorrectly setting up the 'sgt_size' field
for the S/G type of SWA even though we are dealing with a linear skb
here.

Fixes: d70446ee1f40 ("dpaa2-eth: send a scatter-gather FD instead of realloc-ing")
Reported-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20201211171607.108034-1-ciorneiioana@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index cf9400a9886d7..d880ab2a7d962 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -878,7 +878,7 @@ static int dpaa2_eth_build_sg_fd_single_buf(struct dpaa2_eth_priv *priv,
swa = (struct dpaa2_eth_swa *)sgt_buf;
swa->type = DPAA2_ETH_SWA_SINGLE;
swa->single.skb = skb;
- swa->sg.sgt_size = sgt_buf_size;
+ swa->single.sgt_size = sgt_buf_size;

/* Separately map the SGT buffer */
sgt_addr = dma_map_single(dev, sgt_buf, sgt_buf_size, DMA_BIDIRECTIONAL);
--
2.27.0