virtio/vsock: rework MSG_PEEK for SOCK_STREAM

This reworks current implementation of MSG_PEEK logic:
1) Replaces 'skb_queue_walk_safe()' with 'skb_queue_walk()'. There is
   no need in the first one, as there are no removes of skb in loop.
2) Removes nested while loop - MSG_PEEK logic could be implemented
   without it: just iterate over skbs without removing it and copy
   data from each until destination buffer is not full.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Arseniy Krasnov 2023-07-25 20:29:09 +03:00 committed by Paolo Abeni
parent bc758ade61
commit 051e77e339

View file

@ -348,37 +348,34 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk,
size_t len)
{
struct virtio_vsock_sock *vvs = vsk->trans;
size_t bytes, total = 0, off;
struct sk_buff *skb, *tmp;
int err = -EFAULT;
struct sk_buff *skb;
size_t total = 0;
int err;
spin_lock_bh(&vvs->rx_lock);
skb_queue_walk_safe(&vvs->rx_queue, skb, tmp) {
off = 0;
skb_queue_walk(&vvs->rx_queue, skb) {
size_t bytes;
bytes = len - total;
if (bytes > skb->len)
bytes = skb->len;
spin_unlock_bh(&vvs->rx_lock);
/* sk_lock is held by caller so no one else can dequeue.
* Unlock rx_lock since memcpy_to_msg() may sleep.
*/
err = memcpy_to_msg(msg, skb->data, bytes);
if (err)
goto out;
total += bytes;
spin_lock_bh(&vvs->rx_lock);
if (total == len)
break;
while (total < len && off < skb->len) {
bytes = len - total;
if (bytes > skb->len - off)
bytes = skb->len - off;
/* sk_lock is held by caller so no one else can dequeue.
* Unlock rx_lock since memcpy_to_msg() may sleep.
*/
spin_unlock_bh(&vvs->rx_lock);
err = memcpy_to_msg(msg, skb->data + off, bytes);
if (err)
goto out;
spin_lock_bh(&vvs->rx_lock);
total += bytes;
off += bytes;
}
}
spin_unlock_bh(&vvs->rx_lock);