[PATCH v2 net-next] net: remove bypassed check in sch_direct_xmit()

[PATCH v2 net-next] net: remove bypassed check in sch_direct_xmit()

[Song Liu]

Checking netif_xmit_frozen_or_stopped() at the end of sch_direct_xmit()
is being bypassed. This is because "ret" from sch_direct_xmit() will be
either NETDEV_TX_OK or NETDEV_TX_BUSY, and only ret == NETDEV_TX_OK == 0
will reach the condition:

    if (ret && netif_xmit_frozen_or_stopped(txq))
        return false;

This patch cleans up the code by removing the whole condition.

For more discussion about this, please refer to
   https://marc.info/?t=152727195700008

Signed-off-by: Song Liu <songliubraving@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
---
 net/sched/sch_generic.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 760ab1b..69078c8 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -346,9 +346,6 @@ bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 		return false;
 	}
 
-	if (ret && netif_xmit_frozen_or_stopped(txq))
-		return false;
-
 	return true;
 }
 
-- 
2.9.5

Re: [PATCH v2 net-next] net: remove bypassed check in sch_direct_xmit()

[David Miller]

From: Song Liu <songliubraving@fb.com>
Date: Tue, 29 May 2018 10:03:21 -0700

> Checking netif_xmit_frozen_or_stopped() at the end of sch_direct_xmit()
> is being bypassed. This is because "ret" from sch_direct_xmit() will be
> either NETDEV_TX_OK or NETDEV_TX_BUSY, and only ret == NETDEV_TX_OK == 0
> will reach the condition:
> 
>     if (ret && netif_xmit_frozen_or_stopped(txq))
>         return false;
> 
> This patch cleans up the code by removing the whole condition.
> 
> For more discussion about this, please refer to
>    https://marc.info/?t=152727195700008
> 
> Signed-off-by: Song Liu <songliubraving@fb.com>

Applied, thanks.