From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: linux-xfs@vger.kernel.org, Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH] xfs: avoid -Wint-in-bool-context warning in xfs_bmap_util.c
Date: Fri, 2 Jun 2017 21:50:41 -0700 [thread overview]
Message-ID: <20170603045041.GF5636@birch.djwong.org> (raw)
In-Reply-To: <20170603042107.17469-1-ebiggers3@gmail.com>
On Fri, Jun 02, 2017 at 09:21:07PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> XFS triggers gcc 7's -Wint-in-bool-context warning (on by default with
> -Wall), which warns about arithmetic in a boolean context that has no
> effect on the result:
>
> In file included from fs/xfs/xfs_inode.h:22:0,
> from fs/xfs/xfs_bmap_util.c:29:
> fs/xfs/xfs_bmap_util.c: In function ‘xfs_swap_extents_check_format’:
> fs/xfs/libxfs/xfs_inode_fork.h:90:30: warning: ‘<<’ in boolean context, did you mean ‘<’ ? [-Wint-in-bool-context]
> #define XFS_IFORK_BOFF(ip) ((int)((ip)->i_d.di_forkoff << 3))
> ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> fs/xfs/xfs_bmap_util.c:1620:7: note: in expansion of macro ‘XFS_IFORK_BOFF’
> if (XFS_IFORK_BOFF(ip) &&
> ^~~~~~~~~~~~~~
> fs/xfs/libxfs/xfs_inode_fork.h:90:30: warning: ‘<<’ in boolean context, did you mean ‘<’ ? [-Wint-in-bool-context]
> #define XFS_IFORK_BOFF(ip) ((int)((ip)->i_d.di_forkoff << 3))
> ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> fs/xfs/xfs_bmap_util.c:1630:7: note: in expansion of macro ‘XFS_IFORK_BOFF’
> if (XFS_IFORK_BOFF(tip) &&
> ^~~~~~~~~~~~~~
>
> This is more or less a false positive, because the useless arithmetic is
> just the left shift in XFS_IFORK_BOFF(). Use XFS_IFORK_Q() instead to
> make the warnings go away, while having the same behavior and being more
> consistent with other places in XFS which also use XFS_IFORK_Q().
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Arnd Bergmann already sent the exact same patch[1] for 4.13, but, er,
thanks for spotting this! :)
--D
[1] https://marc.info/?l=linux-xfs&m=149498134833721&w=2
> ---
> fs/xfs/xfs_bmap_util.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 7ac80a1facf2..05a6fdf5976d 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1613,7 +1613,7 @@ xfs_swap_extents_check_format(
> * extent format...
> */
> if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
> - if (XFS_IFORK_BOFF(ip) &&
> + if (XFS_IFORK_Q(ip) &&
> XFS_BMAP_BMDR_SPACE(tip->i_df.if_broot) > XFS_IFORK_BOFF(ip))
> return -EINVAL;
> if (XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <=
> @@ -1623,7 +1623,7 @@ xfs_swap_extents_check_format(
>
> /* Reciprocal target->temp btree format checks */
> if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
> - if (XFS_IFORK_BOFF(tip) &&
> + if (XFS_IFORK_Q(tip) &&
> XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > XFS_IFORK_BOFF(tip))
> return -EINVAL;
> if (XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <=
> --
> 2.13.0
>
> --
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next prev parent reply other threads:[~2017-06-03 4:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-03 4:21 [PATCH] xfs: avoid -Wint-in-bool-context warning in xfs_bmap_util.c Eric Biggers
2017-06-03 4:50 ` Darrick J. Wong [this message]
2017-06-03 5:23 ` Eric Biggers
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