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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.4 108/129] block: ensure bdi->io_pages is always initialized
Date:   Tue,  8 Sep 2020 17:25:49 +0200
Message-Id: <20200908152235.235494023@linuxfoundation.org>
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From: Jens Axboe <axboe@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: 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: Greg Kroah-Hartman <gregkh@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;