vdpa/snet: Don't discard the DPU error in snet_send_ctrl_msg()

snet_send_ctrl_msg() reads the error code the DPU reports when it ACKs
a control message, but then overwrites it with the return value of
snet_wait_for_dpu_completion(). As a result, a DESTROY, SUSPEND or
RESUME that the DPU rejects is reported to the caller as a success as
long as the DPU clears the opcode register in time.

For SUSPEND this means vhost-vdpa marks the device as suspended and
lets userspace reprogram the vrings while the DPU is still running
them; for DESTROY, snet_reset_dev() never even sees that the device
failed to stop.

Return the error from the saved ACK value once the completion wait
itself has succeeded.

Fixes: 3f3a1675b731 ("vdpa/snet: support getting and setting VQ state")
Cc: stable@vger.kernel.org
Signed-off-by: Yuho Choi <oss.patchbox@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20261005044915.264532-1-oss.patchbox@gmail.com>

0 files changed, 0 insertions, 0 deletions