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: Yufen Yu <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
This commit is contained in:
Christoph Hellwig 2020-05-04 14:47:56 +02:00 • committed by Greg Kroah-Hartman
commit 03447528a3
2 changed files with 4 additions and 2 deletions

View file

@ -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);