linux-kernel - [PATCH 5.13 242/351] block: grab a device refcount in disk

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Date:   Mon, 19 Jul 2021 16:53:08 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.13 242/351] block: grab a device refcount in disk_uevent

From: Christoph Hellwig <hch@....de>

[ Upstream commit 498dcc13fd6463de29b94e160f40ed04d5477cd8 ]

Sending uevents requires the struct device to be alive.  To
ensure that grab the device refcount instead of just an inode
reference.

Fixes: bc359d03c7ec ("block: add a disk_uevent helper")
Signed-off-by: Christoph Hellwig <hch@....de>
Link: https://lore.kernel.org/r/20210701081638.246552-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 block/genhd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 9f8cb7beaad1..ad7436bd60c1 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -402,12 +402,12 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action)
 	xa_for_each(&disk->part_tbl, idx, part) {
 		if (bdev_is_partition(part) && !bdev_nr_sectors(part))
 			continue;
-		if (!bdgrab(part))
+		if (!kobject_get_unless_zero(&part->bd_device.kobj))
 			continue;
 
 		rcu_read_unlock();
 		kobject_uevent(bdev_kobj(part), action);
-		bdput(part);
+		put_device(&part->bd_device);
 		rcu_read_lock();
 	}
 	rcu_read_unlock();
-- 
2.30.2