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Commit d6c434ae authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
Browse files

bdi: add a ->dev_name field to struct backing_dev_info 



[ Upstream commit 6bd87eec23cbc9ed222bed0f5b5b02bf300e9a8d ]

Cache a copy of the name for the life time of the backing_dev_info
structure so that we can reference it even after unregistering.

Fixes: 68f23b89067f ("memcg: fix a crash in wb_workfn when a device disappears")
Reported-by: default avatarYufen Yu <yuyufen@huawei.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 19a845e1

include/linux/backing-dev-defs.h

+1 −0
Original line number Diff line number Diff line
@@ -197,6 +197,7 @@ struct backing_dev_info { 
	wait_queue_head_t wb_waitq;



	struct device *dev;

	char dev_name[64];

	struct device *owner;



	struct timer_list laptop_mode_wb_timer;

mm/backing-dev.c

+3 −2
Original line number Diff line number Diff line
@@ -880,7 +880,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) 
	if (bdi->dev)	/* The driver needs to use separate queues per device */

		return 0;



	dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args);

	vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args);

	dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name);

	if (IS_ERR(dev))

		return PTR_ERR(dev);
@@ -980,7 +981,7 @@ const char *bdi_dev_name(struct backing_dev_info *bdi) 
{

	if (!bdi || !bdi->dev)

		return bdi_unknown_name;

	return dev_name(bdi->dev);

	return bdi->dev_name;

}

EXPORT_SYMBOL_GPL(bdi_dev_name);