When ibmveth_set_channels() cannot allocate a TX buffer for a new
queue, it falls back to the old queue count, and the successful
netif_set_real_num_tx_queues() call then overwrites rc. ethtool -L
reports success while the queue count is unchanged.
Return the allocation error when the fallback succeeds.
Found in review of the ibmveth multi-queue RX series and confirmed by
code inspection. Tested on a POWER10 LPAR with the TX buffer allocation
forced to fail by a test-only module parameter (not part of this patch):
ethtool -L tx 8 now fails with -ENOMEM and the device keeps its four
queues and passes traffic. No kernel selftests cover ibmveth.
Fixes: 10c2aba89cc0 ("ibmveth: Ethtool set queue support")
Signed-off-by: Mingming Cao <[email protected]>
---
drivers/net/ethernet/ibm/ibmveth.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/ibm/ibmveth.c
b/drivers/net/ethernet/ibm/ibmveth.c
index 42aa9f7bd49d..48bc4406396b 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1177,7 +1177,7 @@ static int ibmveth_set_channels(struct net_device *netdev,
struct ibmveth_adapter *adapter = netdev_priv(netdev);
unsigned int old = netdev->real_num_tx_queues,
goal = channels->tx_count;
- int rc, i;
+ int rc, i, alloc_rc = 0;
/* If the device is not open (including a failed close/open with
* IFF_UP still set) then don't allocate, just set desired
@@ -1203,6 +1203,7 @@ static int ibmveth_set_channels(struct net_device *netdev,
/* if something goes wrong, free everything we just allocated */
netdev_err(netdev, "Failed to allocate more tx queues,
returning to %d queues\n",
old);
+ alloc_rc = rc;
goal = old;
old = i;
break;
@@ -1213,6 +1214,8 @@ static int ibmveth_set_channels(struct net_device *netdev,
old);
goal = old;
old = i;
+ } else if (alloc_rc) {
+ rc = alloc_rc;
}
/* Free any that are no longer needed */
for (i = old; i > goal; i--) {
--
2.50.1 (Apple Git-155)
