add_disk() does not return an error status, but it can still fail if there are problems elsewhere.
In particular a recent problem caused bdi_register_dev() to sometimes fail because the name was already in use. In that case bdi->dev is NULL, so retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, "bdi"); triggers an oops, after having already produced warnings. This patch causes add_disk() to WARN and return if bdi_register_dev() fails, much like it already does if blk_alloc_devt() fails. This should make no difference on a correctly functioning system, but can make a developers life a bit easier. Signed-off-by: NeilBrown <ne...@suse.de> diff --git a/block/genhd.c b/block/genhd.c index 0a536dc05f3b..e351fc521053 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -612,6 +612,10 @@ void add_disk(struct gendisk *disk) /* Register BDI before referencing it from bdev */ bdi = &disk->queue->backing_dev_info; bdi_register_dev(bdi, disk_devt(disk)); + if (!bdi->dev) { + WARN_ON(1); + return; + } blk_register_region(disk_devt(disk), disk->minors, NULL, exact_match, exact_lock, disk);
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