[PATCH 3.16 311/366] vmxnet3: avoid assumption about invalid dma_pa in vmxnet3_set_mc()

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>

commit fb5c6cfaec126d9a96b9dd471d4711bf4c737a6f upstream.

vmxnet3_set_mc() checks new_table_pa returned by dma_map_single()
with dma_mapping_error(), but even there it assumes zero is invalid pa
(it assumes dma_mapping_error(...,0) returns true if new_table is NULL).

The patch adds an explicit variable to track status of new_table_pa.

Found by Linux Driver Verification project (linuxtesting.org).

v2: use "bool" and "true"/"false" for boolean variables.
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2078,6 +2078,7 @@ vmxnet3_set_mc(struct net_device *netdev
 					&adapter->shared->devRead.rxFilterConf;
 	u8 *new_table = NULL;
 	dma_addr_t new_table_pa = 0;
+	bool new_table_pa_valid = false;
 	u32 new_mode = VMXNET3_RXM_UCAST;
 
 	if (netdev->flags & IFF_PROMISC) {
@@ -2105,13 +2106,15 @@ vmxnet3_set_mc(struct net_device *netdev
 							new_table,
 							rxConf->mfTableLen,
 							PCI_DMA_TODEVICE);
+				if (!dma_mapping_error(&adapter->pdev->dev,
+						       new_table_pa)) {
+					new_mode |= VMXNET3_RXM_MCAST;
+					new_table_pa_valid = true;
+					rxConf->mfTablePA = cpu_to_le64(
+								new_table_pa);
+				}
 			}
-
-			if (!dma_mapping_error(&adapter->pdev->dev,
-					       new_table_pa)) {
-				new_mode |= VMXNET3_RXM_MCAST;
-				rxConf->mfTablePA = cpu_to_le64(new_table_pa);
-			} else {
+			if (!new_table_pa_valid) {
 				netdev_info(netdev,
 					    "failed to copy mcast list, setting ALL_MULTI\n");
 				new_mode |= VMXNET3_RXM_ALL_MULTI;
@@ -2136,7 +2139,7 @@ vmxnet3_set_mc(struct net_device *netdev
 			       VMXNET3_CMD_UPDATE_MAC_FILTERS);
 	spin_unlock_irqrestore(&adapter->cmd_lock, flags);
 
-	if (new_table_pa)
+	if (new_table_pa_valid)
 		dma_unmap_single(&adapter->pdev->dev, new_table_pa,
 				 rxConf->mfTableLen, PCI_DMA_TODEVICE);
 	kfree(new_table);