Re: [PATCH v2] xfs_bmap_util: use swap macro

["Darrick J. Wong" <darrick.wong@oracle.com>]

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@embeddedor.com>

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

--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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