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From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, jasowang@redhat.com
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	jfreimann@redhat.com, tiwei.bie@intel.com,
	maxime.coquelin@redhat.com
Subject: [PATCH V3 07/15] vhost_net: calculate last used length once for mergeable buffer
Date: Wed, 17 Jul 2019 06:52:47 -0400
Message-ID: <20190717105255.63488-8-jasowang@redhat.com> (raw)
In-Reply-To: <20190717105255.63488-1-jasowang@redhat.com>

This patch tries to calculate last used length once instead of
twice. This can help to convert to use shadow used ring API for
RX.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index cf47e6e348f4..1a67f889cbc1 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1065,12 +1065,12 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
 		}
 		heads[headcount].id = cpu_to_vhost32(vq, d);
 		len = iov_length(vq->iov + seg, in);
-		heads[headcount].len = cpu_to_vhost32(vq, len);
 		datalen -= len;
+		heads[headcount].len = cpu_to_vhost32(vq,
+				       datalen >= 0 ? len : len + datalen);
 		++headcount;
 		seg += in;
 	}
-	heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
 	*iovcount = seg;
 	if (unlikely(log))
 		*log_num = nlogs;
-- 
2.18.1


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-17 10:52 [PATCH V3 00/15] Packed virtqueue support for vhost Jason Wang
2019-07-17 10:52 ` [PATCH V3 01/15] vhost: simplify meta data pointer accessing Jason Wang
2019-07-17 10:52 ` [PATCH V3 02/15] vhost: remove the unnecessary parameter of vhost_vq_avail_empty() Jason Wang
2019-07-17 10:52 ` [PATCH V3 03/15] vhost: remove unnecessary parameter of vhost_enable_notify()/vhost_disable_notify Jason Wang
2019-07-17 10:52 ` [PATCH V3 04/15] vhost-net: don't use vhost_add_used_n() for zerocopy Jason Wang
2019-07-17 10:52 ` [PATCH V3 05/15] vhost: introduce helpers to manipulate shadow used ring Jason Wang
2019-07-17 10:52 ` [PATCH V3 06/15] vhost_net: switch TX to use shadow used ring API Jason Wang
2019-07-17 10:52 ` Jason Wang [this message]
2019-07-17 10:52 ` [PATCH V3 08/15] vhost_net: switch to use shadow used ring API for RX Jason Wang
2019-07-17 10:52 ` [PATCH V3 09/15] vhost: do not export vhost_add_used_n() and vhost_add_used_and_signal_n() Jason Wang
2019-07-17 10:52 ` [PATCH V3 10/15] vhost: hide used ring layout from device Jason Wang
2019-07-17 10:52 ` [PATCH V3 11/15] vhost: do not use vring_used_elem Jason Wang
2019-07-17 10:52 ` [PATCH V3 12/15] vhost: vhost_put_user() can accept metadata type Jason Wang
2019-07-17 10:52 ` [PATCH V3 13/15] vhost: packed ring support Jason Wang
2019-07-17 10:52 ` [PATCH V3 14/15] vhost: event suppression for packed ring Jason Wang
2019-07-17 10:52 ` [PATCH V3 15/15] vhost: enable packed virtqueues Jason Wang
2019-07-17 11:02 ` [PATCH V3 00/15] Packed virtqueue support for vhost Michael S. Tsirkin
2019-07-17 12:27   ` Jason Wang
2019-07-17 14:28     ` Michael S. Tsirkin

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