Subject: Re: linux-next: build warning after merge of the xfs tree

From: "Darrick J. Wong" <[email-masked]>
Date: Thu, 31 Aug 2017 07:57:52 -0700

On Thu, Aug 31, 2017 at 06:30:41AM -0400, Brian Foster wrote:
> On Thu, Aug 31, 2017 at 10:07:03AM +1000, Stephen Rothwell wrote:
> > Hi all,
> > 
> > After merging the xfs tree, today's linux-next build (powerpc
> > ppc64_defconfig) produced this warning:
> > 
> > fs/xfs/xfs_buf_item.c: In function 'xfs_buf_item_unlock':
> > fs/xfs/xfs_buf_item.c:573:9: warning: unused variable 'ordered' [-Wunused-variable]
> >   bool   ordered = !!(bip->bli_flags & XFS_BLI_ORDERED);
> >          ^
> > 
> > Introduced by commit
> > 
> >   a097077ef708 ("xfs: remove unnecessary dirty bli format check for ordered bufs")
> > 
> 
> Ugh, this is due to the refactoring of this patch between v1 and v2. I
> specifically recall testing for this in v1 because I added the ordered
> bool purely to clean up the ASSERT(), then I apparently lost of track of
> it for v2.
> 
> Anyways.. Christoph, Darrick, preferences to clean this up..? I have no
> preference between the v1 or v2 factoring. Or if it's easier, we could
> always just drop something like the hunk below on top. Thoughts?
> 
> Brian
> 
> --- 8< ---
> 
> diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
> index ef2c137..f5d25f5 100644
> --- a/fs/xfs/xfs_buf_item.c
> +++ b/fs/xfs/xfs_buf_item.c
> @@ -567,10 +567,15 @@ xfs_buf_item_unlock(
>  {
>  	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
>  	struct xfs_buf		*bp = bip->bli_buf;
> -	bool			aborted = !!(lip->li_flags & XFS_LI_ABORTED);
> -	bool			hold = !!(bip->bli_flags & XFS_BLI_HOLD);
> -	bool			dirty = !!(bip->bli_flags & XFS_BLI_DIRTY);
> -	bool			ordered = !!(bip->bli_flags & XFS_BLI_ORDERED);
> +	bool			aborted;
> +	bool			hold;
> +	bool			dirty;
> +	bool			ordered;
> +
> +	aborted = !!(lip->li_flags & XFS_LI_ABORTED);
> +	hold = !!(bip->bli_flags & XFS_BLI_HOLD);
> +	dirty = !!(bip->bli_flags & XFS_BLI_DIRTY);
> +	ordered = !!(bip->bli_flags & XFS_BLI_ORDERED);

The trouble is, 'ordered' is still an unused variable on !DEBUG builds,
since the only user of ordered is that ASSERT.  So either we #ifdef
DEBUG the variable out of existence or employ one of those silly
'ordered = ordered' constructions to shut up gcc, if that even still
works.

--D

>  
>  	/* Clear the buffer's association with this transaction. */
>  	bp->b_transp = NULL;
> --
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