[PATCH 4.19 2/8] block: ensure bdi->io_pages is always initialized

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit de1b0ee490eafdf65fac9eef9925391a8369f2dc ]

If a driver leaves the limit settings as the defaults, then we don't
initialize bdi->io_pages. This means that file systems may need to
work around bdi->io_pages == 0, which is somewhat messy.

Initialize the default value just like we do for ->ra_pages.

Cc: stable@vger.kernel.org
Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting")
Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 block/blk-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index ea33d6abdcfc9..ce3710404544c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1036,6 +1036,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
 
 	q->backing_dev_info->ra_pages =
 			(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
+	q->backing_dev_info->io_pages =
+			(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
 	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
 	q->backing_dev_info->name = "block";
 	q->node = node_id;
-- 
2.25.1