linux-kernel - Re: [PATCH] AFS: Fix compilation warning

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Message-Id: <1247561931.2473.2.camel@ht.satnam>
Date:	Tue, 14 Jul 2009 14:28:51 +0530
From:	Jaswinder Singh Rajput <jaswinder@...nel.org>
To:	David Howells <dhowells@...hat.com>
Cc:	torvalds@...l.org, akpm@...ux-foundation.org,
	linux-afs@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
Subject: Re: [PATCH] AFS: Fix compilation warning

On Tue, 2009-07-14 at 14:17 +0530, Jaswinder Singh Rajput wrote:
> On Thu, 2009-07-09 at 10:44 +0100, David Howells wrote:
> > From: Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
> > 
> > Fix the following warning:
> > 
> > fs/afs/dir.c: In function 'afs_d_revalidate':
> > fs/afs/dir.c:567: warning: 'fid.vnode' may be used uninitialized in this function
> > fs/afs/dir.c:567: warning: 'fid.unique' may be used uninitialized in this function
> > 
> > by marking the 'fid' variable as an uninitialized_var.  The problem is that gcc
> > doesn't always manage to work out that fid is always set on the path through
> > the function that uses it.
> > 
> > Cc: linux-afs@...ts.infradead.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
> > Signed-off-by: David Howells <dhowells@...hat.com>
> > ---
> > 
> 
> Have you tried this approach :
> 
> diff --git a/fs/afs/dir.c b/fs/afs/dir.c
> index 9bd7577..09cb5bb 100644
> --- a/fs/afs/dir.c
> +++ b/fs/afs/dir.c
> @@ -607,53 +607,56 @@ static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
>  
>  	/* search the directory for this vnode */
>  	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
> -	switch (ret) {
> -	case 0:
> -		/* the filename maps to something */
> -		if (!dentry->d_inode)
> -			goto out_bad;
> -		if (is_bad_inode(dentry->d_inode)) {
> -			printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
> -			       parent->d_name.name, dentry->d_name.name);
> +	if (ret < 0) {
> +		switch (ret) {
> +		case -ENOENT:
> +			/* the filename is unknown */
> +			_debug("%s: dirent not found", dentry->d_name.name);
> +			if (dentry->d_inode)
> +				goto not_found;
> +			goto out_valid;
> +
> +		default:
> +			_debug("failed to iterate dir %s: %d",
> +			       parent->d_name.name, ret);
>  			goto out_bad;
>  		}
> +	}
>  
> -		/* if the vnode ID has changed, then the dirent points to a
> -		 * different file */
> -		if (fid.vnode != vnode->fid.vnode) {
> -			_debug("%s: dirent changed [%u != %u]",
> -			       dentry->d_name.name, fid.vnode,
> -			       vnode->fid.vnode);
> -			goto not_found;
> -		}
> -
> -		/* if the vnode ID uniqifier has changed, then the file has
> -		 * been deleted and replaced, and the original vnode ID has
> -		 * been reused */
> -		if (fid.unique != vnode->fid.unique) {
> -			_debug("%s: file deleted (uq %u -> %u I:%llu)",
> -			       dentry->d_name.name, fid.unique,
> -			       vnode->fid.unique,
> -			       (unsigned long long)dentry->d_inode->i_version);
> -			spin_lock(&vnode->lock);
> -			set_bit(AFS_VNODE_DELETED, &vnode->flags);
> -			spin_unlock(&vnode->lock);
> -			goto not_found;
> -		}
> -		goto out_valid;
> -
> -	case -ENOENT:
> -		/* the filename is unknown */
> -		_debug("%s: dirent not found", dentry->d_name.name);
> -		if (dentry->d_inode)
> -			goto not_found;
> -		goto out_valid;
> -
> -	default:
> -		_debug("failed to iterate dir %s: %d",
> -		       parent->d_name.name, ret);
> +	/* the filename maps to something */
> +	if (!dentry->d_inode)
>  		goto out_bad;
> +	if (is_bad_inode(dentry->d_inode)) {
> +		printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
> +		       parent->d_name.name, dentry->d_name.name);
> +		goto out_bad;
> +	}
> +
> +	/*
> +	 * if the vnode ID has changed, then the dirent points to a
> +	 * different file
> +	 */
> +	if (fid.vnode != vnode->fid.vnode) {
> +		_debug("%s: dirent changed [%u != %u]",
> +		       dentry->d_name.name, fid.vnode, vnode->fid.vnode);
> +		goto not_found;
> +	}
> +
> +	/*
> +	 * if the vnode ID uniqifier has changed, then the file has been
> +	 * deleted and replaced, and the original vnode ID has been reused
> +	 */
> +	if (fid.unique != vnode->fid.unique) {
> +		_debug("%s: file deleted (uq %u -> %u I:%llu)",
> +		       dentry->d_name.name, fid.unique,
> +		       vnode->fid.unique,
> +		       (unsigned long long)dentry->d_inode->i_version);
> +		spin_lock(&vnode->lock);
> +		set_bit(AFS_VNODE_DELETED, &vnode->flags);
> +		spin_unlock(&vnode->lock);
> +		goto not_found;
>  	}
> +	goto out_valid;

You can also remove this goto. So by this way, you can get rid of :

1. compiler warning
2. fix 80 column wrap problem
3. remove one goto

Enjoy.
--
JSR


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