Re: [PATCH 6/6] mm: remove generic_writepages

[Jan Kara <jack@suse.cz>]

On Thu 29-12-22 06:10:31, Christoph Hellwig wrote:
> Now that all external callers are gone, just fold it into do_writepages.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me. Feel free to add:

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

								Honza


> ---
>  include/linux/writeback.h |  2 --
>  mm/page-writeback.c       | 53 +++++++++++----------------------------
>  2 files changed, 15 insertions(+), 40 deletions(-)
> 
> diff --git a/include/linux/writeback.h b/include/linux/writeback.h
> index 06f9291b6fd512..2554b71765e9d0 100644
> --- a/include/linux/writeback.h
> +++ b/include/linux/writeback.h
> @@ -369,8 +369,6 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb);
>  typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
>  				void *data);
>  
> -int generic_writepages(struct address_space *mapping,
> -		       struct writeback_control *wbc);
>  void tag_pages_for_writeback(struct address_space *mapping,
>  			     pgoff_t start, pgoff_t end);
>  int write_cache_pages(struct address_space *mapping,
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index ad608ef2a24365..dfeeceebba0ae0 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2526,12 +2526,8 @@ int write_cache_pages(struct address_space *mapping,
>  }
>  EXPORT_SYMBOL(write_cache_pages);
>  
> -/*
> - * Function used by generic_writepages to call the real writepage
> - * function and set the mapping flags on error
> - */
> -static int __writepage(struct page *page, struct writeback_control *wbc,
> -		       void *data)
> +static int writepage_cb(struct page *page, struct writeback_control *wbc,
> +		void *data)
>  {
>  	struct address_space *mapping = data;
>  	int ret = mapping->a_ops->writepage(page, wbc);
> @@ -2539,34 +2535,6 @@ static int __writepage(struct page *page, struct writeback_control *wbc,
>  	return ret;
>  }
>  
> -/**
> - * generic_writepages - walk the list of dirty pages of the given address space and writepage() all of them.
> - * @mapping: address space structure to write
> - * @wbc: subtract the number of written pages from *@wbc->nr_to_write
> - *
> - * This is a library function, which implements the writepages()
> - * address_space_operation.
> - *
> - * Return: %0 on success, negative error code otherwise
> - */
> -int generic_writepages(struct address_space *mapping,
> -		       struct writeback_control *wbc)
> -{
> -	struct blk_plug plug;
> -	int ret;
> -
> -	/* deal with chardevs and other special file */
> -	if (!mapping->a_ops->writepage)
> -		return 0;
> -
> -	blk_start_plug(&plug);
> -	ret = write_cache_pages(mapping, wbc, __writepage, mapping);
> -	blk_finish_plug(&plug);
> -	return ret;
> -}
> -
> -EXPORT_SYMBOL(generic_writepages);
> -
>  int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
>  {
>  	int ret;
> @@ -2577,11 +2545,20 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
>  	wb = inode_to_wb_wbc(mapping->host, wbc);
>  	wb_bandwidth_estimate_start(wb);
>  	while (1) {
> -		if (mapping->a_ops->writepages)
> +		if (mapping->a_ops->writepages) {
>  			ret = mapping->a_ops->writepages(mapping, wbc);
> -		else
> -			ret = generic_writepages(mapping, wbc);
> -		if ((ret != -ENOMEM) || (wbc->sync_mode != WB_SYNC_ALL))
> +		} else if (mapping->a_ops->writepage) {
> +			struct blk_plug plug;
> +
> +			blk_start_plug(&plug);
> +			ret = write_cache_pages(mapping, wbc, writepage_cb,
> +						mapping);
> +			blk_finish_plug(&plug);
> +		} else {
> +			/* deal with chardevs and other special files */
> +			ret = 0;
> +		}
> +		if (ret != -ENOMEM || wbc->sync_mode != WB_SYNC_ALL)
>  			break;
>  
>  		/*
> -- 
> 2.35.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR