From 403c37ff75a34b50ffbaa097b532c0cdcc283c5c Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Tue, 18 Dec 2018 05:43:41 -0800 Subject: [PATCH] UPSTREAM: 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: 9491ae4a ("mm: don't cap request size based on read-ahead setting") Cc: stable@vger.kernel.org Reviewed-by: Jens Axboe Signed-off-by: Jaegeuk Kim Signed-off-by: Mike Snitzer (cherry picked from commit c6d6e9b0f6b4201c77f2cea3964dd122697e3543) Bug: 120757803 Link: https://patchwork.kernel.org/patch/10746255/ Change-Id: I876f4c5425253c2a0876d5ef7fefe36c4edcb46c --- drivers/md/dm-table.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 3d0e2c198f06..47a54deb8cb1 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1937,6 +1937,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, */ if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random)) blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q); + + /* io_pages is used for readahead */ + q->backing_dev_info->io_pages = limits->max_sectors >> (PAGE_SHIFT - 9); } unsigned int dm_table_get_num_targets(struct dm_table *t)