From de1b0ee490eafdf65fac9eef9925391a8369f2dc Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 31 Aug 2020 11:20:02 -0600
Subject: [PATCH] block: ensure bdi->io_pages is always initialized
Git-commit: de1b0ee490eafdf65fac9eef9925391a8369f2dc
Patch-mainline: v5.9-rc4
References: bsc#1177749

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>
Acked-by: Jan Kara <jack@suse.cz>

---
 block/blk-core.c |    1 +
 1 file changed, 1 insertion(+)

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1041,6 +1041,7 @@ struct request_queue *blk_alloc_queue_no
 
 	q->backing_dev_info->ra_pages =
 			(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
+	q->backing_dev_info->io_pages = q->backing_dev_info->ra_pages;
 	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
 	q->backing_dev_info->name = "block";
 	q->node = node_id;