linux-kernel - [2.6 patch] mm/slub.c: remove unneeded NULL check

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Message-ID: <20080222195905.GM1409@cs181133002.pp.htv.fi>
Date:	Fri, 22 Feb 2008 21:59:05 +0200
From:	Adrian Bunk <bunk@...nel.org>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	clameter@....com, mpm@...enic.com,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [2.6 patch] mm/slub.c: remove unneeded NULL check

On Wed, Feb 20, 2008 at 03:52:44PM +0200, Pekka Enberg wrote:
> 
> Hi Adrian,
> 
> On 2/20/2008, "Adrian Bunk" <bunk@...nel.org> wrote:
> > The Coverity checker spotted the following inconsequent NULL checking
> > introduced by commit 8ff12cfc009a2a38d87fa7058226fe197bb2696f:
> > 
> > <--  snip  -->
> > 
> > ...
> > static inline int is_end(void *addr)
> > {
> >         return (unsigned long)addr & PAGE_MAPPING_ANON;
> > }
> > ...
> > static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
> > {
> > ...
> >         if (c->freelist)    <----------------------------------------
> >                 stat(c, DEACTIVATE_REMOTE_FREES);
> 
> I spotted this too.

I missed that.

> c->freelist should never be NULL so why not send a
> patch to Christoph?

Patch below.

cu
Adrian


<--  snip  -->


There's no reason for checking c->freelist for being NULL here (and we'd 
anyway Oops below if it was).

Signed-off-by: Adrian Bunk <bunk@...nel.org>

---
dae2a3c60f258f3ad2522b85d79b735a89d702f0 diff --git a/mm/slub.c b/mm/slub.c
index 74c65af..072e0a6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1404,8 +1404,7 @@ static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 	struct page *page = c->page;
 	int tail = 1;
 
-	if (c->freelist)
-		stat(c, DEACTIVATE_REMOTE_FREES);
+	stat(c, DEACTIVATE_REMOTE_FREES);
 	/*
 	 * Merge cpu freelist into freelist. Typically we get here
 	 * because both freelists are empty. So this is unlikely
--
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