linux-kernel - Re: [PATCH 1/3] f2fs: fix missing kmem_cache

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Message-ID: <548127D9.4030007@cn.fujitsu.com>
Date:	Fri, 5 Dec 2014 11:34:49 +0800
From:	Gu Zheng <guz.fnst@...fujitsu.com>
To:	Jaegeuk Kim <jaegeuk@...nel.org>
CC:	<linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
	<linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [PATCH 1/3] f2fs: fix missing kmem_cache_free

Hi Jaegeuk, 
On 12/05/2014 08:49 AM, Jaegeuk Kim wrote:

> This patch fixes missing kmem_cache_free when handling errors.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/node.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index b1466cf..c59341d 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -158,7 +158,7 @@ retry:
>  		head->entry_cnt = 0;
>  
>  		if (radix_tree_insert(&nm_i->nat_set_root, set, head)) {
> -			cond_resched();
> +			kmem_cache_free(nat_entry_set_slab, head);

Why not reuse the allocated entry?
This routine is under nat_tree_lock, so the free_old->research->alloc_new
is needless, because no other ones can race with us.

>  			goto retry;

And radix_tree_insert can only fail -ENOMEM here, IMO, the in-time retry step
makes very little sense here. How about retaining the "cond_resched()" and retry
insert later?

If I misread something, please correct me.:)

Thanks,
Gu

>  		}
>  	}


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