linux-kernel - Re: [PATCH] net/udp_offload: Drop unnecessary continue

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Message-ID: <20140813170644.GA13556@its-macbook-pro.westell.com>
Date:	Wed, 13 Aug 2014 10:06:45 -0700
From:	Alexei Starovoitov <alexei.starovoitov@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Himangi Saraogi <himangi774@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Alexey Kuznetsov <kuznet@....inr.ac.ru>,
	James Morris <jmorris@...ei.org>,
	Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
	Patrick McHardy <kaber@...sh.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH] net/udp_offload: Drop unnecessary continue

On Wed, Aug 13, 2014 at 07:48:11AM -0700, Eric Dumazet wrote:
> On Wed, 2014-08-13 at 14:46 +0530, Himangi Saraogi wrote:
> > Continue is not needed at the bottom of a loop.
> > 
> > The Coccinelle semantic patch implementing this change is:
> > 
> > @@
> > @@
> > 
> > for (...;...;...) {
> >   ...
> >   if (...) {
> >     ...
> > -   continue;
> >   }
> > }
> > 
> > Signed-off-by: Himangi Saraogi <himangi774@...il.com>
> > Acked-by: Julia Lawall <julia.lawall@...6.fr>
> > ---
> >  net/ipv4/udp_offload.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> > index 59035bc..62d5b9b 100644
> > --- a/net/ipv4/udp_offload.c
> > +++ b/net/ipv4/udp_offload.c
> > @@ -269,10 +269,8 @@ unflush:
> >  			continue;
> >  
> >  		uh2 = (struct udphdr   *)(p->data + off);
> > -		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
> > +		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source))
> >  			NAPI_GRO_CB(p)->same_flow = 0;
> > -			continue;
> > -		}
> >  	}
> >  
> >  	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
> 
> 
> Please do not do that.
> 
> If we add another check later, we'll miss that the 'continue;' needs to
> be put back.
> 
> GRO stack is quite difficult to maintain, I prefer we keep this as is
> for consistency and code readability.

+1
this code as-is is definitely more readable

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