linux-kernel - [PATCH RFC v5 09/13] vhost/net: avoid iov length math

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Date:   Sun, 7 Jun 2020 10:11:42 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
        netdev@...r.kernel.org, Jason Wang <jasowang@...hat.com>,
        eperezma@...hat.com
Subject: [PATCH RFC v5 09/13] vhost/net: avoid iov length math

Now that API exposes buffer length, we no longer need to
scan IOVs to figure it out.

Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---
 drivers/vhost/net.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 830fe84912a5..0b509be8d7b1 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -607,11 +607,9 @@ static bool vhost_exceeds_maxpend(struct vhost_net *net)
 }
 
 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
-			    size_t hdr_size, int out)
+			    size_t len, size_t hdr_size, int out)
 {
 	/* Skip header. TODO: support TSO. */
-	size_t len = iov_length(vq->iov, out);
-
 	iov_iter_init(iter, WRITE, vq->iov, out, len);
 	iov_iter_advance(iter, hdr_size);
 
@@ -640,7 +638,7 @@ static int get_tx_bufs(struct vhost_net *net,
 	}
 
 	/* Sanity check */
-	*len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
+	*len = init_iov_iter(vq, &msg->msg_iter, buf->out_len, nvq->vhost_hlen, *out);
 	if (*len == 0) {
 		vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
 			*len, nvq->vhost_hlen);
@@ -1080,7 +1078,7 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
 			nlogs += *log_num;
 			log += *log_num;
 		}
-		len = iov_length(vq->iov + seg, in);
+		len = bufs[bufcount].in_len;
 		datalen -= len;
 		++bufcount;
 		seg += in;
-- 
MST