[PATCH v1] tools/vm/slabinfo.c: fix sign-compare warning

[PATCH v1] tools/vm/slabinfo.c: fix sign-compare warning

[Naoya Horiguchi]

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@ah.jp.nec.com>
---
 tools/vm/slabinfo.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git v4.18-mmotm-2018-08-17-15-48/tools/vm/slabinfo.c v4.18-mmotm-2018-08-17-15-48_patched/tools/vm/slabinfo.c
index f82c2ea..eebeeb1 100644
--- v4.18-mmotm-2018-08-17-15-48/tools/vm/slabinfo.c
+++ v4.18-mmotm-2018-08-17-15-48_patched/tools/vm/slabinfo.c
@@ -30,9 +30,10 @@ 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;
+	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;
 	unsigned long partial, objects, slabs, objects_partial, objects_total;
 	unsigned long alloc_fastpath, alloc_slowpath;
 	unsigned long free_fastpath, free_slowpath;
-- 
2.7.0

Re: [PATCH v1] tools/vm/slabinfo.c: fix sign-compare warning

[Matthew Wilcox]

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?

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

[Naoya Horiguchi]

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@ah.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@ah.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