Commit f615bd5c authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by David Howells
Browse files

mm/readahead: Handle ractl nr_pages being modified 



Filesystems are not currently permitted to modify the number of pages
in the ractl.  An upcoming patch to add readahead_expand() changes that
rule, so remove the check and resync the loop counter after every call
to the filesystem.

Tested-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20210420200116.3715790-1-willy@infradead.org/
Link: https://lore.kernel.org/r/20210421170923.4005574-1-willy@infradead.org/ # v2
parent c790fbf2

mm/readahead.c

+2 −2
Original line number Diff line number Diff line
@@ -198,8 +198,6 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, 
	for (i = 0; i < nr_to_read; i++) {

		struct page *page = xa_load(&mapping->i_pages, index + i);



		BUG_ON(index + i != ractl->_index + ractl->_nr_pages);



		if (page && !xa_is_value(page)) {

			/*

			 * Page already present?  Kick off the current batch
@@ -210,6 +208,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, 
			 * not worth getting one just for that.

			 */

			read_pages(ractl, &page_pool, true);

			i = ractl->_index + ractl->_nr_pages - index - 1;

			continue;

		}
@@ -223,6 +222,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, 
					gfp_mask) < 0) {

			put_page(page);

			read_pages(ractl, &page_pool, true);

			i = ractl->_index + ractl->_nr_pages - index - 1;

			continue;

		}

		if (i == nr_to_read - lookahead_size)