On Wed, Apr 05, 2017 at 04:03:17PM -0500, Eric Sandeen wrote:
> ndquots is a 32-bit value, and we don't care
> about the remainder; there is no reason to use do_div
> here, it seems to be the result of a decade+ historical
> accident.
>
> Worse, the do_div implementation in userspace breaks
> when fed a 32-bit dividend, so we commented it out there
> in any case.
>
> Change to simple division, and then we can change
> userspace to match, and mandate a 64-bit dividend in
> the do_div() in userspace as well.
This looks fine since nbblks is (unsigned int) and BBTOB doesn't cast to
a 64-bit quantity, therefore 64-bit division isn't ncessary. This
passes compilation on i386 and armhf, so I guess I'll go test it.
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
>
> tested w/ ./check -g quota
>
> diff --git a/fs/xfs/libxfs/xfs_dquot_buf.c b/fs/xfs/libxfs/xfs_dquot_buf.c
> index ac9a003..747085b 100644
> --- a/fs/xfs/libxfs/xfs_dquot_buf.c
> +++ b/fs/xfs/libxfs/xfs_dquot_buf.c
> @@ -35,13 +35,8 @@
> xfs_calc_dquots_per_chunk(
> unsigned int nbblks) /* basic block units */
> {
> - unsigned int ndquots;
> -
> ASSERT(nbblks > 0);
> - ndquots = BBTOB(nbblks);
> - do_div(ndquots, sizeof(xfs_dqblk_t));
> -
> - return ndquots;
> + return BBTOB(nbblks) / sizeof(xfs_dqblk_t);
> }
>
> /*
>
> --
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