From:   Andrey Ryabinin <arbn@yandex-team.com>
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Jason Wang <jasowang@redhat.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        Andrey Ryabinin <arbn@yandex-team.com>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] vhost_net: get rid of vhost_net_flush_vq() and extra flush calls
Date:   Mon, 15 Nov 2021 18:29:59 +0300
Message-Id: <20211115153003.9140-2-arbn@yandex-team.com>
In-Reply-To: <20211115153003.9140-1-arbn@yandex-team.com>
References: <20211115153003.9140-1-arbn@yandex-team.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

vhost_net_flush_vq() calls vhost_work_dev_flush() twice passing
vhost_dev pointer obtained via 'n->poll[index].dev' and
'n->vqs[index].vq.poll.dev'. This is actually the same pointer,
initialized in vhost_net_open()/vhost_dev_init()/vhost_poll_init()

Remove vhost_net_flush_vq() and call vhost_work_dev_flush() directly.
Do the flushes only once instead of several flush calls in a row
which seems rather useless.

Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com>
---
 drivers/vhost/net.c   | 11 ++---------
 drivers/vhost/vhost.h |  1 +
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 11221f6d11b8..b1feb5e0571e 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1373,16 +1373,9 @@ static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
 	*rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
 }
 
-static void vhost_net_flush_vq(struct vhost_net *n, int index)
-{
-	vhost_work_dev_flush(n->poll[index].dev);
-	vhost_work_dev_flush(n->vqs[index].vq.poll.dev);
-}
-
 static void vhost_net_flush(struct vhost_net *n)
 {
-	vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
-	vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
+	vhost_work_dev_flush(&n->dev);
 	if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
 		mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
 		n->tx_flush = true;
@@ -1572,7 +1565,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 	}
 
 	if (oldsock) {
-		vhost_net_flush_vq(n, index);
+		vhost_work_dev_flush(&n->dev);
 		sockfd_put(oldsock);
 	}
 
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 638bb640d6b4..ecbaa5c6005f 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -15,6 +15,7 @@
 #include <linux/vhost_iotlb.h>
 #include <linux/irqbypass.h>
 
+struct vhost_dev;
 struct vhost_work;
 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
 
-- 
2.32.0