linux-kernel - Re: [Cluster-devel] gfs2: gfs2_dir_get_hash_table(): avoiding deferred vfree() is easy here...

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Message-ID: <38038928.16891302.1416489183602.JavaMail.zimbra@redhat.com>
Date:	Thu, 20 Nov 2014 08:13:03 -0500 (EST)
From:	Bob Peterson <rpeterso@...hat.com>
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	linux-kernel@...r.kernel.org, cluster-devel@...hat.com
Subject: Re: [Cluster-devel] gfs2: gfs2_dir_get_hash_table(): avoiding
 deferred vfree() is easy here...

----- Original Message -----
> vfree() is allowed under spinlock these days, but it's cheaper when
> it doesn't step into deferred case and here it's very easy to avoid.
> 
> Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
> ---
>  fs/gfs2/dir.c |    7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
> index c247fed..c5a34f0 100644
> --- a/fs/gfs2/dir.c
> +++ b/fs/gfs2/dir.c
> @@ -370,11 +370,12 @@ static __be64 *gfs2_dir_get_hash_table(struct
> gfs2_inode *ip)
>  	}
>  
>  	spin_lock(&inode->i_lock);
> -	if (ip->i_hash_cache)
> -		kvfree(hc);
> -	else
> +	if (likely(!ip->i_hash_cache)) {
>  		ip->i_hash_cache = hc;
> +		hc = NULL;
> +	}
>  	spin_unlock(&inode->i_lock);
> +	kvfree(hc);
>  
>  	return ip->i_hash_cache;
>  }
> --
> 1.7.10.4
> 
> 

ACK

Bob Peterson
Red Hat File Systems
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