Re: [PATCH v2] xfs_bmap_util: use swap macro

From: Darrick J. Wong
Date: Wed Jul 11 2018 - 13:44:28 EST


On Mon, Jul 09, 2018 at 04:02:59PM -0500, Gustavo A. R. Silva wrote:
> Make use of the swap macro and remove some unnecessary variables.
> This makes the code easier to read and maintain. Also, reduces the
> stack usage.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

Looks ok, will test...
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

--D

> ---
> Changes in v2
> - Use swap in a couple more of places.
>
> fs/xfs/xfs_bmap_util.c | 28 +++++-----------------------
> 1 file changed, 5 insertions(+), 23 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 83b1e8c..a657d0a 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1691,7 +1691,6 @@ xfs_swap_extent_forks(
> int *src_log_flags,
> int *target_log_flags)
> {
> - struct xfs_ifork tempifp, *ifp, *tifp;
> xfs_filblks_t aforkblks = 0;
> xfs_filblks_t taforkblks = 0;
> xfs_extnum_t junk;
> @@ -1733,11 +1732,7 @@ xfs_swap_extent_forks(
> /*
> * Swap the data forks of the inodes
> */
> - ifp = &ip->i_df;
> - tifp = &tip->i_df;
> - tempifp = *ifp; /* struct copy */
> - *ifp = *tifp; /* struct copy */
> - *tifp = tempifp; /* struct copy */
> + swap(ip->i_df, tip->i_df);
>
> /*
> * Fix the on-disk inode values
> @@ -1746,13 +1741,8 @@ xfs_swap_extent_forks(
> ip->i_d.di_nblocks = tip->i_d.di_nblocks - taforkblks + aforkblks;
> tip->i_d.di_nblocks = tmp + taforkblks - aforkblks;
>
> - tmp = (uint64_t) ip->i_d.di_nextents;
> - ip->i_d.di_nextents = tip->i_d.di_nextents;
> - tip->i_d.di_nextents = tmp;
> -
> - tmp = (uint64_t) ip->i_d.di_format;
> - ip->i_d.di_format = tip->i_d.di_format;
> - tip->i_d.di_format = tmp;
> + swap(ip->i_d.di_nextents, tip->i_d.di_nextents);
> + swap(ip->i_d.di_format, tip->i_d.di_format);
>
> /*
> * The extents in the source inode could still contain speculative
> @@ -1846,7 +1836,6 @@ xfs_swap_extents(
> int src_log_flags, target_log_flags;
> int error = 0;
> int lock_flags;
> - struct xfs_ifork *cowfp;
> uint64_t f;
> int resblks = 0;
>
> @@ -1987,18 +1976,11 @@ xfs_swap_extents(
>
> /* Swap the cow forks. */
> if (xfs_sb_version_hasreflink(&mp->m_sb)) {
> - xfs_extnum_t extnum;
> -
> ASSERT(ip->i_cformat == XFS_DINODE_FMT_EXTENTS);
> ASSERT(tip->i_cformat == XFS_DINODE_FMT_EXTENTS);
>
> - extnum = ip->i_cnextents;
> - ip->i_cnextents = tip->i_cnextents;
> - tip->i_cnextents = extnum;
> -
> - cowfp = ip->i_cowfp;
> - ip->i_cowfp = tip->i_cowfp;
> - tip->i_cowfp = cowfp;
> + swap(ip->i_cnextents, tip->i_cnextents);
> + swap(ip->i_cowfp, tip->i_cowfp);
>
> if (ip->i_cowfp && ip->i_cowfp->if_bytes)
> xfs_inode_set_cowblocks_tag(ip);
> --
> 2.7.4
>
> --
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