[PATCH 5.4 108/129] block: ensure bdi->io_pages is always initialized

[Greg Kroah-Hartman]

From: Jens Axboe <ax...@kernel.dk>

commit de1b0ee490eafdf65fac9eef9925391a8369f2dc upstream.

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: sta...@vger.kernel.org
Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting")
Reported-by: OGAWA Hirofumi <hirof...@mail.parknet.co.jp>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

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

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -502,6 +502,7 @@ struct request_queue *blk_alloc_queue_no
                goto fail_stats;
 
        q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES;
+       q->backing_dev_info->io_pages = VM_READAHEAD_PAGES;
        q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
        q->backing_dev_info->name = "block";
        q->node = node_id;