From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>,
asias@redhat.com, mst@redhat.com,
Rusty Russell <rusty@rustcorp.com.au>,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: [PATCH 6/9] virtio-net: unmark scatterlist ending after virtqueue_add_buf
Date: Tue, 12 Feb 2013 13:23:32 +0100 [thread overview]
Message-ID: <1360671815-2135-7-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1360671815-2135-1-git-send-email-pbonzini@redhat.com>
Prepare for when virtqueue_add_buf will use sg_next instead of
ignoring ending markers.
Note that for_each_sg (and thus virtqueue_add_sg) allows you
to pass a "truncated" scatterlist that does not have a marker
on the last item. We rely on this in add_recvbuf_mergeable.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
drivers/net/virtio_net.c | 19 ++++++++++++++-----
1 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 35c00c5..78b6f51 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -440,13 +440,16 @@ static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
hdr = skb_vnet_hdr(skb);
sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
-
skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
err = virtqueue_add_buf(rq->vq, rq->sg, 0, 2, skb, gfp);
if (err < 0)
dev_kfree_skb(skb);
+ /* An optimization: clear the end bit set by skb_to_sgvec, so
+ * we can simply re-use rq->sg[] next time.
+ */
+ sg_unmark_end(rq->sg + 1);
return err;
}
@@ -505,8 +508,7 @@ static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
if (!page)
return -ENOMEM;
- sg_init_one(rq->sg, page_address(page), PAGE_SIZE);
-
+ sg_set_page(rq->sg, page, PAGE_SIZE, 0);
err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp);
if (err < 0)
give_pages(rq, page);
@@ -671,6 +673,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
struct virtnet_info *vi = sq->vq->vdev->priv;
unsigned num_sg;
+ int ret;
pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
@@ -710,8 +713,14 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr);
num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
- return virtqueue_add_buf(sq->vq, sq->sg, num_sg,
- 0, skb, GFP_ATOMIC);
+ ret = virtqueue_add_buf(sq->vq, sq->sg, num_sg,
+ 0, skb, GFP_ATOMIC);
+
+ /* An optimization: clear the end bit set by skb_to_sgvec, so
+ * we can simply re-use sq->sg[] next time.
+ */
+ sg_unmark_end(&sq->sg[num_sg-1]);
+ return ret;
}
static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
--
1.7.1
next prev parent reply other threads:[~2013-02-12 12:25 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-12 12:23 [PATCH 0/9] virtio: new API for addition of buffers, scatterlist changes Paolo Bonzini
2013-02-12 12:23 ` [PATCH 1/9] virtio: add functions for piecewise addition of buffers Paolo Bonzini
2013-02-12 14:56 ` Michael S. Tsirkin
2013-02-12 15:32 ` Paolo Bonzini
2013-02-12 15:43 ` Michael S. Tsirkin
2013-02-12 15:48 ` Paolo Bonzini
2013-02-12 16:13 ` Michael S. Tsirkin
2013-02-12 16:17 ` Paolo Bonzini
2013-02-12 16:35 ` Michael S. Tsirkin
2013-02-12 16:57 ` Paolo Bonzini
2013-02-12 17:34 ` Michael S. Tsirkin
2013-02-12 18:04 ` Paolo Bonzini
2013-02-12 18:23 ` Michael S. Tsirkin
2013-02-12 20:08 ` Paolo Bonzini
2013-02-12 20:49 ` Michael S. Tsirkin
2013-02-13 8:06 ` Paolo Bonzini
2013-02-13 10:33 ` Michael S. Tsirkin
2013-02-12 18:03 ` [PATCH v2 " Paolo Bonzini
2013-02-12 12:23 ` [PATCH 2/9] virtio-blk: reorganize virtblk_add_req Paolo Bonzini
2013-02-17 6:38 ` Asias He
2013-02-12 12:23 ` [PATCH 3/9] virtio-blk: use virtqueue_start_buf on bio path Paolo Bonzini
2013-02-17 6:39 ` Asias He
2013-02-12 12:23 ` [PATCH 4/9] virtio-blk: use virtqueue_start_buf on req path Paolo Bonzini
2013-02-17 6:37 ` Asias He
2013-02-18 9:05 ` Paolo Bonzini
2013-02-12 12:23 ` [PATCH 5/9] scatterlist: introduce sg_unmark_end Paolo Bonzini
2013-02-12 12:23 ` Paolo Bonzini [this message]
2013-02-12 12:23 ` [PATCH 7/9] virtio-scsi: use virtqueue_start_buf Paolo Bonzini
2013-02-12 12:23 ` [PATCH 8/9] virtio: introduce and use virtqueue_add_buf_single Paolo Bonzini
2013-02-12 12:23 ` [PATCH 9/9] virtio: reimplement virtqueue_add_buf using new functions Paolo Bonzini
2013-02-14 6:00 ` [PATCH 0/9] virtio: new API for addition of buffers, scatterlist changes Rusty Russell
2013-02-14 9:23 ` Paolo Bonzini
2013-02-15 18:04 ` Paolo Bonzini
2013-02-19 7:49 ` Rusty Russell
2013-02-19 9:11 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1360671815-2135-7-git-send-email-pbonzini@redhat.com \
--to=pbonzini@redhat.com \
--cc=asias@redhat.com \
--cc=gaowanlong@cn.fujitsu.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=rusty@rustcorp.com.au \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).