| Message ID | b99b73b5-9525-bf50-ecd4-ccb361545b12@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
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@oracle.com> --D > > Signed-off-by: Eric Sandeen <sandeen@redhat.com> > --- > > 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); > } > > /* > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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); } /*
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. Signed-off-by: Eric Sandeen <sandeen@redhat.com> --- tested w/ ./check -g quota -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html