Messages in this thread | | | Date | Mon, 11 Dec 2023 13:09:32 +0100 | From | Stefano Garzarella <> | Subject | Re: [PATCH net-next v7 2/4] virtio/vsock: send credit update during setting SO_RCVLOWAT |
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On Thu, Dec 07, 2023 at 12:18:47AM +0300, Arseniy Krasnov wrote: >Send credit update message when SO_RCVLOWAT is updated and it is bigger >than number of bytes in rx queue. It is needed, because 'poll()' will >wait until number of bytes in rx queue will be not smaller than >SO_RCVLOWAT, so kick sender to send more data. Otherwise mutual hungup >for tx/rx is possible: sender waits for free space and receiver is >waiting data in 'poll()'. > >Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com> >--- > Changelog: > v1 -> v2: > * Update commit message by removing 'This patch adds XXX' manner. > * Do not initialize 'send_update' variable - set it directly during > first usage. > v3 -> v4: > * Fit comment in 'virtio_transport_notify_set_rcvlowat()' to 80 chars. > v4 -> v5: > * Do not change callbacks order in transport structures. > v5 -> v6: > * Reorder callbacks in transport structures. > * Do to send credit update when 'fwd_cnt' == 'last_fwd_cnt'. > > drivers/vhost/vsock.c | 1 + > include/linux/virtio_vsock.h | 1 + > net/vmw_vsock/virtio_transport.c | 1 + > net/vmw_vsock/virtio_transport_common.c | 30 +++++++++++++++++++++++++ > net/vmw_vsock/vsock_loopback.c | 1 + > 5 files changed, 34 insertions(+)
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> >diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c >index f75731396b7e..ec20ecff85c7 100644 >--- a/drivers/vhost/vsock.c >+++ b/drivers/vhost/vsock.c >@@ -449,6 +449,7 @@ static struct virtio_transport vhost_transport = { > .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, > .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, > .notify_buffer_size = virtio_transport_notify_buffer_size, >+ .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat, > > .read_skb = virtio_transport_read_skb, > }, >diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h >index ebb3ce63d64d..c82089dee0c8 100644 >--- a/include/linux/virtio_vsock.h >+++ b/include/linux/virtio_vsock.h >@@ -256,4 +256,5 @@ void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit); > void virtio_transport_deliver_tap_pkt(struct sk_buff *skb); > int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list); > int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor); >+int virtio_transport_notify_set_rcvlowat(struct vsock_sock *vsk, int val); > #endif /* _LINUX_VIRTIO_VSOCK_H */ >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >index af5bab1acee1..f495b9e5186b 100644 >--- a/net/vmw_vsock/virtio_transport.c >+++ b/net/vmw_vsock/virtio_transport.c >@@ -537,6 +537,7 @@ static struct virtio_transport virtio_transport = { > .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, > .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, > .notify_buffer_size = virtio_transport_notify_buffer_size, >+ .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat, > > .read_skb = virtio_transport_read_skb, > }, >diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >index f6dc896bf44c..e137d740804e 100644 >--- a/net/vmw_vsock/virtio_transport_common.c >+++ b/net/vmw_vsock/virtio_transport_common.c >@@ -1684,6 +1684,36 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto > } > EXPORT_SYMBOL_GPL(virtio_transport_read_skb); > >+int virtio_transport_notify_set_rcvlowat(struct vsock_sock *vsk, int val) >+{ >+ struct virtio_vsock_sock *vvs = vsk->trans; >+ bool send_update; >+ >+ spin_lock_bh(&vvs->rx_lock); >+ >+ /* If number of available bytes is less than new SO_RCVLOWAT value, >+ * kick sender to send more data, because sender may sleep in its >+ * 'send()' syscall waiting for enough space at our side. Also >+ * don't send credit update when peer already knows actual value - >+ * such transmission will be useless. >+ */ >+ send_update = (vvs->rx_bytes < val) && >+ (vvs->fwd_cnt != vvs->last_fwd_cnt); >+ >+ spin_unlock_bh(&vvs->rx_lock); >+ >+ if (send_update) { >+ int err; >+ >+ err = virtio_transport_send_credit_update(vsk); >+ if (err < 0) >+ return err; >+ } >+ >+ return 0; >+} >+EXPORT_SYMBOL_GPL(virtio_transport_notify_set_rcvlowat); >+ > MODULE_LICENSE("GPL v2"); > MODULE_AUTHOR("Asias He"); > MODULE_DESCRIPTION("common code for virtio vsock"); >diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c >index 048640167411..6dea6119f5b2 100644 >--- a/net/vmw_vsock/vsock_loopback.c >+++ b/net/vmw_vsock/vsock_loopback.c >@@ -96,6 +96,7 @@ static struct virtio_transport loopback_transport = { > .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, > .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, > .notify_buffer_size = virtio_transport_notify_buffer_size, >+ .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat, > > .read_skb = virtio_transport_read_skb, > }, >-- >2.25.1 >
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