diff options
| author | Alok Tiwari <alok.a.tiwari@oracle.com> | 2025-07-06 12:43:21 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-09 19:12:07 -0700 |
| commit | 849704b8b2115647e12436e5076b8e7a4944f21a (patch) | |
| tree | 39fc2cf943af62ee77ec5ee35d0039726a08f978 | |
| parent | d55683866c79a3af1e334126f32841d05e7e4143 (diff) | |
net: thunderx: avoid direct MTU assignment after WRITE_ONCE()
The current logic in nicvf_change_mtu() writes the new MTU to
netdev->mtu using WRITE_ONCE() before verifying if the hardware
update succeeds. However on hardware update failure, it attempts
to revert to the original MTU using a direct assignment
(netdev->mtu = orig_mtu)
which violates the intended of WRITE_ONCE protection introduced in
commit 1eb2cded45b3 ("net: annotate writes on dev->mtu from
ndo_change_mtu()")
Additionally, WRITE_ONCE(netdev->mtu, new_mtu) is unnecessarily
performed even when the device is not running.
Fix this by:
Only writing netdev->mtu after successfully updating the hardware.
Skipping hardware update when the device is down, and setting MTU
directly. Remove unused variable orig_mtu.
This ensures that all writes to netdev->mtu are consistent with
WRITE_ONCE expectations and avoids unintended state corruption
on failure paths.
Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250706194327.1369390-1-alok.a.tiwari@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/cavium/thunder/nicvf_main.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c index aebb9fef3f6e..1be2dc40a1a6 100644 --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c @@ -1578,7 +1578,6 @@ napi_del: static int nicvf_change_mtu(struct net_device *netdev, int new_mtu) { struct nicvf *nic = netdev_priv(netdev); - int orig_mtu = netdev->mtu; /* For now just support only the usual MTU sized frames, * plus some headroom for VLAN, QinQ. @@ -1589,15 +1588,10 @@ static int nicvf_change_mtu(struct net_device *netdev, int new_mtu) return -EINVAL; } - WRITE_ONCE(netdev->mtu, new_mtu); - - if (!netif_running(netdev)) - return 0; - - if (nicvf_update_hw_max_frs(nic, new_mtu)) { - netdev->mtu = orig_mtu; + if (netif_running(netdev) && nicvf_update_hw_max_frs(nic, new_mtu)) return -EINVAL; - } + + WRITE_ONCE(netdev->mtu, new_mtu); return 0; } |