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

Jan Kara
2023-01-02T12:16:27Z

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