Commit a4d96536 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm: use readahead_control to pass arguments 



In this patch, only between __do_page_cache_readahead() and
read_pages(), but it will be extended in upcoming patches.  The
read_pages() function becomes aops centric, as this makes the most sense
by the end of the patchset.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-7-willy@infradead.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 042124cc

mm/readahead.c

+19 −14
Original line number Diff line number Diff line
@@ -113,29 +113,32 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages, 


EXPORT_SYMBOL(read_cache_pages);



static void read_pages(struct address_space *mapping, struct file *filp,

		struct list_head *pages, unsigned int nr_pages, gfp_t gfp)

static void read_pages(struct readahead_control *rac, struct list_head *pages,

		gfp_t gfp)

{

	const struct address_space_operations *aops = rac->mapping->a_ops;

	struct blk_plug plug;

	unsigned page_idx;



	if (!nr_pages)

	if (!readahead_count(rac))

		return;



	blk_start_plug(&plug);



	if (mapping->a_ops->readpages) {

		mapping->a_ops->readpages(filp, mapping, pages, nr_pages);

	if (aops->readpages) {

		aops->readpages(rac->file, rac->mapping, pages,

				readahead_count(rac));

		/* Clean up the remaining pages */

		put_pages_list(pages);

		goto out;

	}



	for (page_idx = 0; page_idx < nr_pages; page_idx++) {

	for (page_idx = 0; page_idx < readahead_count(rac); page_idx++) {

		struct page *page = lru_to_page(pages);

		list_del(&page->lru);

		if (!add_to_page_cache_lru(page, mapping, page->index, gfp))

			mapping->a_ops->readpage(filp, page);

		if (!add_to_page_cache_lru(page, rac->mapping, page->index,

				gfp))

			aops->readpage(rac->file, page);

		put_page(page);

	}
@@ -143,6 +146,7 @@ out: 
	blk_finish_plug(&plug);



	BUG_ON(!list_empty(pages));

	rac->_nr_pages = 0;

}



/*
@@ -160,9 +164,12 @@ void __do_page_cache_readahead(struct address_space *mapping, 
	unsigned long end_index;	/* The last page we want to read */

	LIST_HEAD(page_pool);

	int page_idx;

	unsigned int nr_pages = 0;

	loff_t isize = i_size_read(inode);

	gfp_t gfp_mask = readahead_gfp_mask(mapping);

	struct readahead_control rac = {

		.mapping = mapping,

		.file = filp,

	};



	if (isize == 0)

		return;
@@ -185,9 +192,7 @@ void __do_page_cache_readahead(struct address_space *mapping, 
			 * contiguous pages before continuing with the next

			 * batch.

			 */

			read_pages(mapping, filp, &page_pool, nr_pages,

						gfp_mask);

			nr_pages = 0;

			read_pages(&rac, &page_pool, gfp_mask);

			continue;

		}
@@ -198,7 +203,7 @@ void __do_page_cache_readahead(struct address_space *mapping, 
		list_add(&page->lru, &page_pool);

		if (page_idx == nr_to_read - lookahead_size)

			SetPageReadahead(page);

		nr_pages++;

		rac._nr_pages++;

	}



	/*
@@ -206,7 +211,7 @@ void __do_page_cache_readahead(struct address_space *mapping, 
	 * uptodate then the caller will launch readpage again, and

	 * will then handle the error.

	 */

	read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);

	read_pages(&rac, &page_pool, gfp_mask);

}



/*

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