linux-kernel - [PATCH v2] tools/vm/slabinfo.c: fix sign-compare warning

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Message-ID: <20180826234947.GA9787@hori1.linux.bs1.fc.nec.co.jp>
Date:   Sun, 26 Aug 2018 23:49:47 +0000
From:   Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:     Matthew Wilcox <willy@...radead.org>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH v2] tools/vm/slabinfo.c: fix sign-compare warning

On Sat, Aug 25, 2018 at 07:21:14PM -0700, Matthew Wilcox wrote:
> On Fri, Aug 24, 2018 at 06:32:14PM +0900, Naoya Horiguchi wrote:
> > -	int hwcache_align, object_size, objs_per_slab;
> > -	int sanity_checks, slab_size, store_user, trace;
> > +	int hwcache_align, objs_per_slab;
> > +	int sanity_checks, store_user, trace;
> >  	int order, poison, reclaim_account, red_zone;
> > +	unsigned int object_size, slab_size;
> 
> Surely hwcache_align and objs_per_slab can't be negative either?
> Nor the other three.  So maybe convert all seven of these variables to
> unsigned int?
> 

Fair enough, I update the patch.
Thanks for the comment.

- Naoya

---
>From 25e19ce711cdb4aa5c4f1a04784017af48616e5f Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Date: Fri, 24 Aug 2018 18:22:40 +0900
Subject: [PATCH v2] tools/vm/slabinfo.c: fix sign-compare warning

Currently we get the following compiler warning:

    slabinfo.c:854:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if (s->object_size < min_objsize)
                          ^

due to the mismatch of signed/unsigned comparison. ->object_size and
->slab_size are never expected to be negative, so let's define them
as unsigned int.

Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
---
 tools/vm/slabinfo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/vm/slabinfo.c b/tools/vm/slabinfo.c
index f82c2eaa859d..334b16db0ebb 100644
--- a/tools/vm/slabinfo.c
+++ b/tools/vm/slabinfo.c
@@ -30,8 +30,8 @@ struct slabinfo {
 	int alias;
 	int refs;
 	int aliases, align, cache_dma, cpu_slabs, destroy_by_rcu;
-	int hwcache_align, object_size, objs_per_slab;
-	int sanity_checks, slab_size, store_user, trace;
+	unsigned int hwcache_align, object_size, objs_per_slab;
+	unsigned int sanity_checks, slab_size, store_user, trace;
 	int order, poison, reclaim_account, red_zone;
 	unsigned long partial, objects, slabs, objects_partial, objects_total;
 	unsigned long alloc_fastpath, alloc_slowpath;
-- 
2.7.4