[PATCH net-next V3] tun/macvtap: use consume_skb() instead of kfree_skb() when needed

[PATCH net-next V3] tun/macvtap: use consume_skb() instead of kfree_skb() when needed

[Jason Wang]

To be more friendly with drop monitor, we should only call kfree_skb() when
the packets were dropped and use consume_skb() in other cases.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes from V2:
- use unlikely() when necessary
Changes from V1:
- check the return value of tun/macvtap_put_user()
---
 drivers/net/macvtap.c | 5 ++++-
 drivers/net/tun.c     | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 42a80d3..86f6bf8 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -862,7 +862,10 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q,
 		}
 		iov_iter_init(&iter, READ, iv, segs, len);
 		ret = macvtap_put_user(q, skb, &iter);
-		kfree_skb(skb);
+		if (unlikely(ret < 0))
+			kfree_skb(skb);
+		else
+			consume_skb(skb);
 		break;
 	}
 
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index ac53a73..82a9bf0 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1363,7 +1363,10 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
 
 	iov_iter_init(&iter, READ, iv, segs, len);
 	ret = tun_put_user(tun, tfile, skb, &iter);
-	kfree_skb(skb);
+	if (unlikely(ret < 0))
+		kfree_skb(skb);
+	else
+		consume_skb(skb);
 
 	return ret;
 }
-- 
1.9.1

Re: [PATCH net-next V3] tun/macvtap: use consume_skb() instead of kfree_skb() when needed

[David Miller]

From: Jason Wang <jasowang@redhat.com>
Date: Thu, 27 Nov 2014 14:36:06 +0800

> To be more friendly with drop monitor, we should only call kfree_skb() when
> the packets were dropped and use consume_skb() in other cases.
> 
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes from V2:
> - use unlikely() when necessary
> Changes from V1:
> - check the return value of tun/macvtap_put_user()

This does not apply cleanly to net-next and will thus need to
be respun, thanks.

Re: [PATCH net-next V3] tun/macvtap: use consume_skb() instead of kfree_skb() when needed

[Jason Wang]

On Sun, Nov 30, 2014 at 1:03 PM, David Miller <davem@davemloft.net> 
wrote:
> From: Jason Wang <jasowang@redhat.com>
> Date: Thu, 27 Nov 2014 14:36:06 +0800
> 
>>  To be more friendly with drop monitor, we should only call 
>> kfree_skb() when
>>  the packets were dropped and use consume_skb() in other cases.
>>  
>>  Cc: Eric Dumazet <eric.dumazet@gmail.com>
>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>  ---
>>  Changes from V2:
>>  - use unlikely() when necessary
>>  Changes from V1:
>>  - check the return value of tun/macvtap_put_user()
> 
> This does not apply cleanly to net-next and will thus need to
> be respun, thanks.

Will post V3.

Thanks