bdi: add a ->dev_name field to struct backing_dev_info (6bd87eec) · Commits · 戴 / test

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: ("memcg: fix a crash in wb_workfn when a device disappears") Reported-by:

Yufen Yu <yuyufen@huawei.com> Signed-off-by:

Christoph Hellwig <hch@lst.de> Reviewed-by:

Jan Kara <jack@suse.cz> Reviewed-by:

Bart Van Assche <bvanassche@acm.org> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

include/linux/backing-dev-defs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -219,6 +219,7 @@ 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
		@@ -938,7 +938,8 @@ 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);

		@@ -1047,7 +1048,7 @@ 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);

Admin message