Re: [PATCH 5/4] iomap: remove unused private field from ioend

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Apr 06, 2021 at 06:27:54AM -0400, Brian Foster wrote:
> The only remaining user of ->io_private is the generic ioend merging
> infrastructure. The only user of that is XFS, which no longer sets
> ->io_private or passes an associated merge callback. Remove the
> unused parameter and the ->io_private field.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> ---
>  fs/iomap/buffered-io.c | 7 +------
>  fs/xfs/xfs_aops.c      | 2 +-
>  include/linux/iomap.h  | 5 +----

This iomap change needs to be cc'd to fsdevel just in case there's
anyone planning to use it.  To my knowledge gfs2 and zonefs don't use
io_private and don't have any plans to, but let's not yank the rug from
under them.

(Code change looks good to me, fwiw)

--D

>  3 files changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 414769a6ad11..b7753a7907e2 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -1134,9 +1134,7 @@ iomap_ioend_can_merge(struct iomap_ioend *ioend, struct iomap_ioend *next)
>  }
>  
>  void
> -iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends,
> -		void (*merge_private)(struct iomap_ioend *ioend,
> -				struct iomap_ioend *next))
> +iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends)
>  {
>  	struct iomap_ioend *next;
>  
> @@ -1148,8 +1146,6 @@ iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends,
>  			break;
>  		list_move_tail(&next->io_list, &ioend->io_list);
>  		ioend->io_size += next->io_size;
> -		if (next->io_private && merge_private)
> -			merge_private(ioend, next);
>  	}
>  }
>  EXPORT_SYMBOL_GPL(iomap_ioend_try_merge);
> @@ -1235,7 +1231,6 @@ iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc,
>  	ioend->io_inode = inode;
>  	ioend->io_size = 0;
>  	ioend->io_offset = offset;
> -	ioend->io_private = NULL;
>  	ioend->io_bio = bio;
>  	return ioend;
>  }
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 87c2912f147d..e24e0a005b48 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -146,7 +146,7 @@ xfs_end_io(
>  	while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
>  			io_list))) {
>  		list_del_init(&ioend->io_list);
> -		iomap_ioend_try_merge(ioend, &tmp, NULL);
> +		iomap_ioend_try_merge(ioend, &tmp);
>  		xfs_end_ioend(ioend);
>  	}
>  }
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index d202fd2d0f91..c87d0cb0de6d 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -198,7 +198,6 @@ struct iomap_ioend {
>  	struct inode		*io_inode;	/* file being written to */
>  	size_t			io_size;	/* size of the extent */
>  	loff_t			io_offset;	/* offset in the file */
> -	void			*io_private;	/* file system private data */
>  	struct bio		*io_bio;	/* bio being built */
>  	struct bio		io_inline_bio;	/* MUST BE LAST! */
>  };
> @@ -234,9 +233,7 @@ struct iomap_writepage_ctx {
>  
>  void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
>  void iomap_ioend_try_merge(struct iomap_ioend *ioend,
> -		struct list_head *more_ioends,
> -		void (*merge_private)(struct iomap_ioend *ioend,
> -				struct iomap_ioend *next));
> +		struct list_head *more_ioends);
>  void iomap_sort_ioends(struct list_head *ioend_list);
>  int iomap_writepage(struct page *page, struct writeback_control *wbc,
>  		struct iomap_writepage_ctx *wpc,
> -- 
> 2.26.3
>