diff options
authorChristoph Hellwig <hch@lst.de>2020-05-04 14:47:56 +0200
committerJens Axboe <axboe@kernel.dk>2020-05-09 16:07:57 -0600
commit6bd87eec23cbc9ed222bed0f5b5b02bf300e9a8d (patch)
parentd51cfc53ade3189455a1b88ec7a2ff0c24597cf8 (diff)
bdi: add a ->dev_name field to struct backing_dev_info
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 <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>
2 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index ee577a83cfe6..7367150f962a 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -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;
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index c2c44c89ee5d..efc5b83acd2d 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -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;