[PATCH] ext4: use kmem_cache_zalloc instead of kmem_cache_alloc/memset

[PATCH] ext4: use kmem_cache_zalloc instead of kmem_cache_alloc/memset

[Wei Yongjun]

From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset().

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
---
 fs/ext4/mballoc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8eae947..6bc21a2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2195,12 +2195,11 @@ int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
 		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
 	i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
 
-	meta_group_info[i] = kmem_cache_alloc(cachep, GFP_KERNEL);
+	meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_KERNEL);
 	if (meta_group_info[i] == NULL) {
 		ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
 		goto exit_group_info;
 	}
-	memset(meta_group_info[i], 0, kmem_cache_size(cachep));
 	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
 		&(meta_group_info[i]->bb_state));
 

Re: [PATCH] ext4: use kmem_cache_zalloc instead of kmem_cache_alloc/memset

[Ashish Sangwan]

you can add 1 more.
In function ext4_mb_new_blocks(), change:
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
to
ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS); and remove
memset(ac, 0, sizeof(struct ext4_allocation_context)); from
ext4_mb_initialize_context().

On Mon, Aug 27, 2012 at 10:10 AM, Wei Yongjun <weiyj.lk@gmail.com> wrote:
> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
>
> Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset().
>
> spatch with a semantic match is used to found this problem.
> (http://coccinelle.lip6.fr/)
>
> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> ---
>  fs/ext4/mballoc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 8eae947..6bc21a2 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2195,12 +2195,11 @@ int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
>                 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
>         i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
>
> -       meta_group_info[i] = kmem_cache_alloc(cachep, GFP_KERNEL);
> +       meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_KERNEL);
>         if (meta_group_info[i] == NULL) {
>                 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
>                 goto exit_group_info;
>         }
> -       memset(meta_group_info[i], 0, kmem_cache_size(cachep));
>         set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
>                 &(meta_group_info[i]->bb_state));
>
>
> --
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Re: [PATCH] ext4: use kmem_cache_zalloc instead of kmem_cache_alloc/memset

[Wei Yongjun]

On 08/28/2012 08:34 PM, Ashish Sangwan wrote:
> you can add 1 more.
> In function ext4_mb_new_blocks(), change:
> ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
> to
> ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS); and remove
> memset(ac, 0, sizeof(struct ext4_allocation_context)); from
> ext4_mb_initialize_context().

got it, thanks, will include in the update version patch.

>
> On Mon, Aug 27, 2012 at 10:10 AM, Wei Yongjun <weiyj.lk@gmail.com> wrote:
>> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
>>
>> Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset().
>>
>> spatch with a semantic match is used to found this problem.
>> (http://coccinelle.lip6.fr/)
>>
>> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
>> ---
>>  fs/ext4/mballoc.c | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>