vduse: Requeue failed read to send_list head

When copy_to_iter() fails in vduse_dev_read_iter(), put the message back
at the head of send_list to preserve FIFO ordering and retry the oldest
pending request first.

Fixes: c8a6153b6c ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Suggested-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260226115550.1814-2-zhangtianci.1997@bytedance.com>
This commit is contained in:
Zhang Tianci 2026-02-26 19:55:49 +08:00 committed by Michael S. Tsirkin
parent c3c33e002b
commit 373ec43ded

View File

@ -221,6 +221,12 @@ static void vduse_enqueue_msg(struct list_head *head,
list_add_tail(&msg->list, head);
}
static void vduse_enqueue_msg_head(struct list_head *head,
struct vduse_dev_msg *msg)
{
list_add(&msg->list, head);
}
static void vduse_dev_broken(struct vduse_dev *dev)
{
struct vduse_dev_msg *msg, *tmp;
@ -387,7 +393,7 @@ static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
spin_lock(&dev->msg_lock);
if (ret != size) {
ret = -EFAULT;
vduse_enqueue_msg(&dev->send_list, msg);
vduse_enqueue_msg_head(&dev->send_list, msg);
goto unlock;
}
vduse_enqueue_msg(&dev->recv_list, msg);