[PATCH] lib/group_cpus: Fix unsigned expression compared with zero

[PATCH] lib/group_cpus: Fix unsigned expression compared with zero

[Jiapeng Chong]

The nr_present and nr_others is defined as unsigned int type,
if(nr_present < 0) and if(nr_others < 0 )is invalid. At the same time, the
return value of function __group_cpus_evenly also of type int. so modified
the types of nr_present and nr_others to int.

lib/group_cpus.c:380 group_cpus_evenly() warn: unsigned 'nr_present' is never less than zero.
lib/group_cpus.c:396 group_cpus_evenly() warn: unsigned 'nr_others' is never less than zero.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7890
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
 lib/group_cpus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index 3a0db0f51f09..08e31f2f053f 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -354,7 +354,8 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps)
 	cpumask_var_t *node_to_cpumask __free(free_node_to_cpumask) = alloc_node_to_cpumask();
 	struct cpumask *masks __free(kfree) = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL);
 	cpumask_var_t npresmsk __free(free_cpumask_var);
-	unsigned int curgrp, nr_present, nr_others;
+	unsigned int curgrp;
+	int nr_present, nr_others;
 
 	if (!masks || !node_to_cpumask || !alloc_cpumask_var(&npresmsk, GFP_KERNEL))
 		return NULL;
-- 
2.20.1.7.g153144c

Re: [PATCH] lib/group_cpus: Fix unsigned expression compared with zero

[Andrew Morton]

On Fri, 12 Jan 2024 10:02:50 +0800 Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:

> The nr_present and nr_others is defined as unsigned int type,
> if(nr_present < 0) and if(nr_others < 0 )is invalid. At the same time, the
> return value of function __group_cpus_evenly also of type int. so modified
> the types of nr_present and nr_others to int.
> 
> lib/group_cpus.c:380 group_cpus_evenly() warn: unsigned 'nr_present' is never less than zero.
> lib/group_cpus.c:396 group_cpus_evenly() warn: unsigned 'nr_others' is never less than zero.
> 
> ...
>
> --- a/lib/group_cpus.c
> +++ b/lib/group_cpus.c
> @@ -354,7 +354,8 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps)
>  	cpumask_var_t *node_to_cpumask __free(free_node_to_cpumask) = alloc_node_to_cpumask();
>  	struct cpumask *masks __free(kfree) = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL);
>  	cpumask_var_t npresmsk __free(free_cpumask_var);
> -	unsigned int curgrp, nr_present, nr_others;
> +	unsigned int curgrp;
> +	int nr_present, nr_others;
>  
>  	if (!masks || !node_to_cpumask || !alloc_cpumask_var(&npresmsk, GFP_KERNEL))
>  		return NULL;

Thanks.

Current mm.git (pushed 3 hours ago) has

	int curgrp, nr_present, nr_others;