From: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Date: Tue, 25 Jul 2023 20:29:09 +0300
Subject: virtio/vsock: rework MSG_PEEK for SOCK_STREAM
Patch-mainline: v6.6-rc1
Git-commit: 051e77e33946f932e6879bf4df2773e3c998c3a7
References: jsc#PED-5505
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/vmw_vsock/virtio_transport_common.c | 47 ++++++++++++++------------------
1 file changed, 22 insertions(+), 25 deletions(-)
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -348,37 +348,34 @@ virtio_transport_stream_do_peek(struct v
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);