[PATCH 1/2] readahead: Don't shorted readahead window in read_pages()

[Jan Kara <jack@suse.cz>]

When ->readahead callback doesn't read all requested pages, read_pages()
shortens the readahead window (ra->size). However we don't know why
pages were not read and what appropriate window size is. So don't try to
secondguess the filesystem. If it needs different readahead window, it
should set it manually similary as during expansion the filesystem can
use readahead_expand().

Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/readahead.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/mm/readahead.c b/mm/readahead.c
index ea650b8b02fb..78d7f4db9966 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -158,20 +158,10 @@ static void read_pages(struct readahead_control *rac)
 
 	if (aops->readahead) {
 		aops->readahead(rac);
-		/*
-		 * Clean up the remaining folios.  The sizes in ->ra
-		 * may be used to size the next readahead, so make sure
-		 * they accurately reflect what happened.
-		 */
+		/* Clean up the remaining folios. */
 		while ((folio = readahead_folio(rac)) != NULL) {
-			unsigned long nr = folio_nr_pages(folio);
-
 			folio_get(folio);
-			rac->ra->size -= nr;
-			if (rac->ra->async_size >= nr) {
-				rac->ra->async_size -= nr;
-				filemap_remove_folio(folio);
-			}
+			filemap_remove_folio(folio);
 			folio_unlock(folio);
 			folio_put(folio);
 		}
-- 
2.35.3