[PATCH net-next v2 6/8] ibmveth: return the error when set_channels cannot add TX queues
WARM1d
From: Mingming Cao <hidden>
Date: 2026-10-05 06:09:36
Also in:
lkml, netdev
Subsystem:
ibm power virtual ethernet device driver, linux for powerpc (32-bit and 64-bit), networking drivers, the rest · Maintainers:
Nick Child, Madhavan Srinivasan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 by AI-assisted 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 <redacted>
---
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 a10ebaca9081..e242417ed8da 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c@@ -1169,7 +1169,7 @@ 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
@@ -1195,6 +1195,7 @@ 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;
@@ -1205,6 +1206,8 @@ 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--) {
--
2.39.3 (Apple Git-146)