2023-04-09 19:48:37

by Arseniy Krasnov

Subject: [RFC PATCH v1] vsock/loopback: don't disable irqs for queue access

This replaces 'skb_queue_tail()' with 'virtio_vsock_skb_queue_tail()'.
The first one uses 'spin_lock_irqsave()', second uses 'spin_lock_bh()'.
There is no need to disable interrupts in the loopback transport as
there is no access to the queue with skbs from interrupt context. Both
virtio and vhost transports work in the same way.

Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/vsock_loopback.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index e3afc0c866f5..5c6360df1f31 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -31,8 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
struct vsock_loopback *vsock = &the_vsock_loopback;
int len = skb->len;

- skb_queue_tail(&vsock->pkt_queue, skb);
-
+ virtio_vsock_skb_queue_tail(&vsock->pkt_queue, skb);
queue_work(vsock->workqueue, &vsock->pkt_work);

return len;
--
2.25.1

2023-04-13 09:17:13

by Stefano Garzarella

Subject: Re: [RFC PATCH v1] vsock/loopback: don't disable irqs for queue access

On Sun, Apr 09, 2023 at 10:17:51PM +0300, Arseniy Krasnov wrote:
>This replaces 'skb_queue_tail()' with 'virtio_vsock_skb_queue_tail()'.
>The first one uses 'spin_lock_irqsave()', second uses 'spin_lock_bh()'.
>There is no need to disable interrupts in the loopback transport as
>there is no access to the queue with skbs from interrupt context. Both
>virtio and vhost transports work in the same way.

Yep, this is a good point!

>
>Signed-off-by: Arseniy Krasnov <[email protected]>
>---
> net/vmw_vsock/vsock_loopback.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

LGTM! (net-next material)

Reviewed-by: Stefano Garzarella <[email protected]>

Thanks,
Stefano

>
>diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
>index e3afc0c866f5..5c6360df1f31 100644
>--- a/net/vmw_vsock/vsock_loopback.c
>+++ b/net/vmw_vsock/vsock_loopback.c
>@@ -31,8 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
> struct vsock_loopback *vsock = &the_vsock_loopback;
> int len = skb->len;
>
>- skb_queue_tail(&vsock->pkt_queue, skb);
>-
>+ virtio_vsock_skb_queue_tail(&vsock->pkt_queue, skb);
> queue_work(vsock->workqueue, &vsock->pkt_work);
>
> return len;
>--
>2.25.1
>