Commit 051e77e3 authored by Arseniy Krasnov's avatar Arseniy Krasnov Committed by Paolo Abeni
Browse files

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: default avatarArseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: default avatarBobby Eshleman <bobby.eshleman@bytedance.com>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent bc758ade

net/vmw_vsock/virtio_transport_common.c

+19 −22
Original line number Diff line number Diff line
@@ -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;



		if (total == len)

			break;

	skb_queue_walk(&vvs->rx_queue, skb) {

		size_t bytes;



		while (total < len && off < skb->len) {

		bytes = len - total;

			if (bytes > skb->len - off)

				bytes = skb->len - off;

		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.

		 */

			spin_unlock_bh(&vvs->rx_lock);



			err = memcpy_to_msg(msg, skb->data + off, bytes);

		err = memcpy_to_msg(msg, skb->data, bytes);

		if (err)

			goto out;



		total += bytes;



		spin_lock_bh(&vvs->rx_lock);



			total += bytes;

			off += bytes;

		}

		if (total == len)

			break;

	}



	spin_unlock_bh(&vvs->rx_lock);