4.4-stable review patch. If anyone has any objections, please let me know.
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From: Tyrel Datwyler tyreld@linux.vnet.ibm.com
[ Upstream commit 756af9c642329d54f048bac2a62f829b391f6944 ]
Commit 33a48ab105a7 ("ibmveth: Fix DMA unmap error") fixed an issue in the normal code path of ibmveth_xmit_start() that was originally introduced by Commit 6e8ab30ec677 ("ibmveth: Add scatter-gather support"). This original fix missed the error path where dma_unmap_page is wrongly called on the header portion in descs[0] which was mapped with dma_map_single. As a result a failure to DMA map any of the frags results in a dmesg warning when CONFIG_DMA_API_DEBUG is enabled.
------------[ cut here ]------------ DMA-API: ibmveth 30000002: device driver frees DMA memory with wrong function [device address=0x000000000a430000] [size=172 bytes] [mapped as page] [unmapped as single] WARNING: CPU: 1 PID: 8426 at kernel/dma/debug.c:1085 check_unmap+0x4fc/0xe10 ... <snip> ... DMA-API: Mapped at: ibmveth_start_xmit+0x30c/0xb60 dev_hard_start_xmit+0x100/0x450 sch_direct_xmit+0x224/0x490 __qdisc_run+0x20c/0x980 __dev_queue_xmit+0x1bc/0xf20
This fixes the API misuse by unampping descs[0] with dma_unmap_single.
Fixes: 6e8ab30ec677 ("ibmveth: Add scatter-gather support") Signed-off-by: Tyrel Datwyler tyreld@linux.vnet.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/ibm/ibmveth.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/net/ethernet/ibm/ibmveth.c +++ b/drivers/net/ethernet/ibm/ibmveth.c @@ -1163,11 +1163,15 @@ out:
map_failed_frags: last = i+1; - for (i = 0; i < last; i++) + for (i = 1; i < last; i++) dma_unmap_page(&adapter->vdev->dev, descs[i].fields.address, descs[i].fields.flags_len & IBMVETH_BUF_LEN_MASK, DMA_TO_DEVICE);
+ dma_unmap_single(&adapter->vdev->dev, + descs[0].fields.address, + descs[0].fields.flags_len & IBMVETH_BUF_LEN_MASK, + DMA_TO_DEVICE); map_failed: if (!firmware_has_feature(FW_FEATURE_CMO)) netdev_err(netdev, "tx: unable to map xmit buffer\n");