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
Subject: [RFC PATCH net-next 07/12] tuntap: simplify error handling in tun_build_skb()
Date: Mon, 21 May 2018 17:04:28 +0800 [thread overview]
Message-ID: <1526893473-20128-8-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1526893473-20128-1-git-send-email-jasowang@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/tun.c | 36 ++++++++++++++----------------------
1 file changed, 14 insertions(+), 22 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 24ecd82..f6e0f96 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1612,7 +1612,7 @@ 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 sk_buff *skb = NULL;
struct bpf_prog *xdp_prog;
int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
unsigned int delta = 0;
@@ -1638,6 +1638,9 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
if (copied != len)
return ERR_PTR(-EFAULT);
+ get_page(alloc_frag->page);
+ alloc_frag->offset += buflen;
+
/* There's a small window that XDP may be set after the check
* of xdp_prog above, this should be rare and for simplicity
* we do XDP on skb in case the headroom is not enough.
@@ -1665,24 +1668,16 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
switch (act) {
case XDP_REDIRECT:
- get_page(alloc_frag->page);
- alloc_frag->offset += buflen;
err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
xdp_do_flush_map();
if (err)
- goto err_redirect;
- rcu_read_unlock();
- preempt_enable();
- return NULL;
+ goto err_xdp;
+ goto out;
case XDP_TX:
- get_page(alloc_frag->page);
- alloc_frag->offset += buflen;
if (tun_xdp_tx(tun->dev, &xdp))
- goto err_redirect;
+ goto err_xdp;
tun_xdp_flush(tun->dev);
- rcu_read_unlock();
- preempt_enable();
- return NULL;
+ goto out;
case XDP_PASS:
delta = orig_data - xdp.data;
len = xdp.data_end - xdp.data;
@@ -1702,25 +1697,22 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
skb = build_skb(buf, buflen);
if (!skb) {
- rcu_read_unlock();
- preempt_enable();
- return ERR_PTR(-ENOMEM);
+ skb = ERR_PTR(-ENOMEM);
+ goto out;
}
skb_reserve(skb, pad - delta);
skb_put(skb, len);
- get_page(alloc_frag->page);
- alloc_frag->offset += buflen;
return skb;
-err_redirect:
- put_page(alloc_frag->page);
err_xdp:
+ alloc_frag->offset -= buflen;
+ put_page(alloc_frag->page);
+out:
rcu_read_unlock();
preempt_enable();
- this_cpu_inc(tun->pcpu_stats->rx_dropped);
- return NULL;
+ return skb;
}
/* Get packet from user space buffer */
--
2.7.4
next prev parent reply other threads:[~2018-05-21 9:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-21 9:04 [RFC PATCH net-next 00/12] XDP batching for TUN/vhost_net Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 01/12] vhost_net: introduce helper to initialize tx iov iter Jason Wang
2018-05-21 16:24 ` Jesse Brandeburg
2018-05-22 12:26 ` Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 02/12] vhost_net: introduce vhost_exceeds_weight() Jason Wang
2018-05-21 16:29 ` Jesse Brandeburg
2018-05-22 12:27 ` Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 03/12] vhost_net: introduce vhost_has_more_pkts() Jason Wang
2018-05-21 16:39 ` Jesse Brandeburg
2018-05-22 12:31 ` Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 04/12] vhost_net: split out datacopy logic Jason Wang
2018-05-21 16:46 ` Jesse Brandeburg
2018-05-22 12:39 ` Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 05/12] vhost_net: batch update used ring for datacopy TX Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 06/12] tuntap: enable premmption early Jason Wang
2018-05-21 14:32 ` Michael S. Tsirkin
2018-05-21 9:04 ` Jason Wang [this message]
2018-05-21 9:04 ` [RFC PATCH net-next 08/12] tuntap: tweak on the path of non-xdp case in tun_build_skb() Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 09/12] tuntap: split out XDP logic Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 10/12] vhost_net: build xdp buff Jason Wang
2018-05-21 16:56 ` Jesse Brandeburg
2018-05-21 22:21 ` Michael S. Tsirkin
2018-05-22 12:41 ` Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 11/12] vhost_net: passing raw xdp buff to tun Jason Wang
2018-05-21 9:04 ` [RFC PATCH net-next 12/12] vhost_net: batch submitting XDP buffers to underlayer sockets Jason Wang
2018-05-21 14:33 ` Michael S. Tsirkin
2018-05-25 17:53 ` [RFC PATCH net-next 00/12] XDP batching for TUN/vhost_net Michael S. Tsirkin
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