linux-kernel - Re: [PATCH 12/14] fs/buffer: remove ll_rw

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Message-ID: <20220831110644.id62rsymhziex2ch@quack3>
Date:   Wed, 31 Aug 2022 13:06:44 +0200
From:   Jan Kara <jack@...e.cz>
To:     Zhang Yi <yi.zhang@...wei.com>
Cc:     linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, cluster-devel@...hat.com,
        ntfs3@...ts.linux.dev, ocfs2-devel@....oracle.com,
        reiserfs-devel@...r.kernel.org, jack@...e.cz, tytso@....edu,
        akpm@...ux-foundation.org, axboe@...nel.dk,
        viro@...iv.linux.org.uk, rpeterso@...hat.com, agruenba@...hat.com,
        almaz.alexandrovich@...agon-software.com, mark@...heh.com,
        dushistov@...l.ru, hch@...radead.org, chengzhihao1@...wei.com,
        yukuai3@...wei.com
Subject: Re: [PATCH 12/14] fs/buffer: remove ll_rw_block() helper

On Wed 31-08-22 15:21:09, Zhang Yi wrote:
> Now that all ll_rw_block() users has been replaced to new safe helpers,
> we just remove it here.
> 
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/buffer.c                 | 63 +++----------------------------------
>  include/linux/buffer_head.h |  1 -
>  2 files changed, 4 insertions(+), 60 deletions(-)
> 
> diff --git a/fs/buffer.c b/fs/buffer.c
> index e14adc638bfe..d1d09e2dacc2 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -152,7 +152,7 @@ static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate)
>  
>  /*
>   * Default synchronous end-of-IO handler..  Just mark it up-to-date and
> - * unlock the buffer. This is what ll_rw_block uses too.
> + * unlock the buffer.
>   */
>  void end_buffer_read_sync(struct buffer_head *bh, int uptodate)
>  {
> @@ -491,8 +491,8 @@ int inode_has_buffers(struct inode *inode)
>   * all already-submitted IO to complete, but does not queue any new
>   * writes to the disk.
>   *
> - * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as
> - * you dirty the buffers, and then use osync_inode_buffers to wait for
> + * To do O_SYNC writes, just queue the buffer writes with write_dirty_buffer
> + * as you dirty the buffers, and then use osync_inode_buffers to wait for
>   * completion.  Any other dirty buffers which are not yet queued for
>   * write will not be flushed to disk by the osync.
>   */
> @@ -1807,7 +1807,7 @@ int __block_write_full_page(struct inode *inode, struct page *page,
>  		/*
>  		 * The page was marked dirty, but the buffers were
>  		 * clean.  Someone wrote them back by hand with
> -		 * ll_rw_block/submit_bh.  A rare case.
> +		 * write_dirty_buffer/submit_bh.  A rare case.
>  		 */
>  		end_page_writeback(page);
>  
> @@ -2714,61 +2714,6 @@ int submit_bh(blk_opf_t opf, struct buffer_head *bh)
>  }
>  EXPORT_SYMBOL(submit_bh);
>  
> -/**
> - * ll_rw_block: low-level access to block devices (DEPRECATED)
> - * @opf: block layer request operation and flags.
> - * @nr: number of &struct buffer_heads in the array
> - * @bhs: array of pointers to &struct buffer_head
> - *
> - * ll_rw_block() takes an array of pointers to &struct buffer_heads, and
> - * requests an I/O operation on them, either a %REQ_OP_READ or a %REQ_OP_WRITE.
> - * @opf contains flags modifying the detailed I/O behavior, most notably
> - * %REQ_RAHEAD.
> - *
> - * This function drops any buffer that it cannot get a lock on (with the
> - * BH_Lock state bit), any buffer that appears to be clean when doing a write
> - * request, and any buffer that appears to be up-to-date when doing read
> - * request.  Further it marks as clean buffers that are processed for
> - * writing (the buffer cache won't assume that they are actually clean
> - * until the buffer gets unlocked).
> - *
> - * ll_rw_block sets b_end_io to simple completion handler that marks
> - * the buffer up-to-date (if appropriate), unlocks the buffer and wakes
> - * any waiters. 
> - *
> - * All of the buffers must be for the same device, and must also be a
> - * multiple of the current approved size for the device.
> - */
> -void ll_rw_block(const blk_opf_t opf, int nr, struct buffer_head *bhs[])
> -{
> -	const enum req_op op = opf & REQ_OP_MASK;
> -	int i;
> -
> -	for (i = 0; i < nr; i++) {
> -		struct buffer_head *bh = bhs[i];
> -
> -		if (!trylock_buffer(bh))
> -			continue;
> -		if (op == REQ_OP_WRITE) {
> -			if (test_clear_buffer_dirty(bh)) {
> -				bh->b_end_io = end_buffer_write_sync;
> -				get_bh(bh);
> -				submit_bh(opf, bh);
> -				continue;
> -			}
> -		} else {
> -			if (!buffer_uptodate(bh)) {
> -				bh->b_end_io = end_buffer_read_sync;
> -				get_bh(bh);
> -				submit_bh(opf, bh);
> -				continue;
> -			}
> -		}
> -		unlock_buffer(bh);
> -	}
> -}
> -EXPORT_SYMBOL(ll_rw_block);
> -
>  void write_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
>  {
>  	lock_buffer(bh);
> diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
> index 8a01c07c0418..1c93ff8c8f51 100644
> --- a/include/linux/buffer_head.h
> +++ b/include/linux/buffer_head.h
> @@ -223,7 +223,6 @@ struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
>  void free_buffer_head(struct buffer_head * bh);
>  void unlock_buffer(struct buffer_head *bh);
>  void __lock_buffer(struct buffer_head *bh);
> -void ll_rw_block(blk_opf_t, int, struct buffer_head * bh[]);
>  int sync_dirty_buffer(struct buffer_head *bh);
>  int __sync_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags);
>  void write_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags);
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR