dm: do not allow readahead to limit IO size

Update DM to set the bdi's io_pages. This fixes reads to be capped at the device's max request size (even if user's read IO exceeds the established readahead setting). Fixes: 9491ae4 ("mm: don't cap request size based on read-ahead setting") Cc: [email protected] Reviewed-by: Jens Axboe <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]> Signed-off-by: Mike Snitzer <[email protected]>
wafgo · Dec 18, 2018 · c6d6e9b · c6d6e9b
1 parent 74694bc
commit c6d6e9b
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
@@ -1927,6 +1927,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	 */
 	if (blk_queue_is_zoned(q))
 		blk_revalidate_disk_zones(t->md->disk);
+
+	/* Allow reads to exceed readahead limits */
+	q->backing_dev_info->io_pages = limits->max_sectors >> (PAGE_SHIFT - 9);
 }
 
 unsigned int dm_table_get_num_targets(struct dm_table *t)