On 30.11.2023 11:38, Stefano Garzarella wrote: > On Thu, Nov 30, 2023 at 12:25:18AM +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@xxxxxxxxxxxxxxxxx> >> --- >> 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. >> >> drivers/vhost/vsock.c | 3 ++- >> include/linux/virtio_vsock.h | 1 + >> net/vmw_vsock/virtio_transport.c | 3 ++- >> net/vmw_vsock/virtio_transport_common.c | 27 +++++++++++++++++++++++++ >> net/vmw_vsock/vsock_loopback.c | 3 ++- >> 5 files changed, 34 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c >> index f75731396b7e..c5e58a60a546 100644 >> --- a/drivers/vhost/vsock.c >> +++ b/drivers/vhost/vsock.c >> @@ -449,8 +449,9 @@ 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, >> + .read_skb = virtio_transport_read_skb > > I think it is better to avoid this change, so when we will need to add > new callbacks, we don't need to edit this line again. > > Please avoid it also in the other place in this patch. > > The rest LGTM. Yes, I see, I thought about that, but chose beauty instead of pragmatism :) Ok, I'll fix it:) Thanks, Arseniy > > Thanks, > Stefano > >> }, >> >> .send_pkt = vhost_transport_send_pkt, >> 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..8b7bb7ca8ea5 100644 >> --- a/net/vmw_vsock/virtio_transport.c >> +++ b/net/vmw_vsock/virtio_transport.c >> @@ -537,8 +537,9 @@ 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, >> + .read_skb = virtio_transport_read_skb >> }, >> >> .send_pkt = virtio_transport_send_pkt, >> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >> index f6dc896bf44c..1cb556ad4597 100644 >> --- a/net/vmw_vsock/virtio_transport_common.c >> +++ b/net/vmw_vsock/virtio_transport_common.c >> @@ -1684,6 +1684,33 @@ 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. >> + */ >> + send_update = vvs->rx_bytes < val; >> + >> + 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..454f69838c2a 100644 >> --- a/net/vmw_vsock/vsock_loopback.c >> +++ b/net/vmw_vsock/vsock_loopback.c >> @@ -96,8 +96,9 @@ 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, >> + .read_skb = virtio_transport_read_skb >> }, >> >> .send_pkt = vsock_loopback_send_pkt, >> -- >> 2.25.1 >> >