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

From: Darrick J. Wong
Date: Thu Aug 31 2017 - 10:58:11 EST


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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