ibmveth: fix DMA unmap error in ibmveth_xmit_start error path

[ 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>

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index f210398200ece183c58470be65f3aa8c606aea9d..6c05819d995ea5570b1d44b1e40c2628d103851f 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1172,11 +1172,15 @@ 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");