From: Jason Wang <jasowang@redhat.com>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
mst@redhat.com, jasowang@redhat.com
Subject: [PATCH net-next V2 05/11] tuntap: tweak on the path of skb XDP case in tun_build_skb()
Date: Wed, 12 Sep 2018 11:17:03 +0800 [thread overview]
Message-ID: <20180912031709.14112-6-jasowang@redhat.com> (raw)
In-Reply-To: <20180912031709.14112-1-jasowang@redhat.com>
If we're sure not to go native XDP, there's no need for several things
like bh and rcu stuffs. So this patch introduces a helper to build skb
and hold page refcnt. When we found we will go through skb path, build
skb directly.
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/tun.c | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 257cf7342d54..946c6148ed75 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1635,6 +1635,23 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
return true;
}
+static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,
+ int buflen, int len, int pad, int delta)
+{
+ struct sk_buff *skb = build_skb(buf, buflen);
+
+ if (!skb)
+ return ERR_PTR(-ENOMEM);
+
+ skb_reserve(skb, pad - delta);
+ skb_put(skb, len);
+
+ get_page(alloc_frag->page);
+ alloc_frag->offset += buflen;
+
+ return skb;
+}
+
static struct sk_buff *tun_build_skb(struct tun_struct *tun,
struct tun_file *tfile,
struct iov_iter *from,
@@ -1642,7 +1659,6 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
int len, int *skb_xdp)
{
struct page_frag *alloc_frag = ¤t->task_frag;
- struct sk_buff *skb;
struct bpf_prog *xdp_prog;
int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
unsigned int delta = 0;
@@ -1672,10 +1688,12 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
* of xdp_prog above, this should be rare and for simplicity
* we do XDP on skb in case the headroom is not enough.
*/
- if (hdr->gso_type || !xdp_prog)
+ if (hdr->gso_type || !xdp_prog) {
*skb_xdp = 1;
- else
- *skb_xdp = 0;
+ return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);
+ }
+
+ *skb_xdp = 0;
local_bh_disable();
rcu_read_lock();
@@ -1719,22 +1737,13 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
trace_xdp_exception(tun->dev, xdp_prog, act);
/* fall through */
case XDP_DROP:
- goto err_xdp;
+ goto out;
}
}
rcu_read_unlock();
local_bh_enable();
- skb = build_skb(buf, buflen);
- if (!skb)
- return ERR_PTR(-ENOMEM);
-
- skb_reserve(skb, pad - delta);
- skb_put(skb, len);
- get_page(alloc_frag->page);
- alloc_frag->offset += buflen;
-
- return skb;
+ return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);
err_redirect:
put_page(alloc_frag->page);
--
2.17.1
next prev parent reply other threads:[~2018-09-12 3:17 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 3:16 [PATCH net-next V2 00/11] vhost_net TX batching Jason Wang
2018-09-12 3:16 ` [PATCH net-next V2 01/11] net: sock: introduce SOCK_XDP Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 02/11] tuntap: switch to use XDP_PACKET_HEADROOM Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 03/11] tuntap: enable bh early during processing XDP Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 04/11] tuntap: simplify error handling in tun_build_skb() Jason Wang
2018-09-12 3:17 ` Jason Wang [this message]
2018-09-12 3:17 ` [PATCH net-next V2 06/11] tuntap: split out XDP logic Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 07/11] tuntap: move XDP flushing out of tun_do_xdp() Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 08/11] tun: switch to new type of msg_control Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 09/11] tuntap: accept an array of XDP buffs through sendmsg() Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 10/11] tap: " Jason Wang
2018-09-12 3:17 ` [PATCH net-next V2 11/11] vhost_net: batch submitting XDP buffers to underlayer sockets Jason Wang
2018-09-13 18:04 ` Michael S. Tsirkin
2018-09-14 3:11 ` Jason Wang
2018-09-13 16:28 ` [PATCH net-next V2 00/11] vhost_net TX batching David Miller
2018-09-13 18:02 ` Michael S. Tsirkin
2018-09-13 18:05 ` David Miller
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