[PATCH 5.8 153/186] block: ensure bdi->io_pages is always initialized

From: Greg Kroah-Hartman
Date: Tue Sep 08 2020 - 15:19:20 EST

From: Jens Axboe <axboe@xxxxxxxxx>

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: stable@xxxxxxxxxxxxxxx
Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting")
Reported-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -526,6 +526,7 @@ struct request_queue *__blk_alloc_queue(
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->node = node_id;