diff options
| -rw-r--r-- | block/blk-cgroup.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index b70096497d38..2d7b18eb7291 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -24,6 +24,7 @@ #include <linux/backing-dev.h> #include <linux/slab.h> #include <linux/delay.h> +#include <linux/wait_bit.h> #include <linux/atomic.h> #include <linux/ctype.h> #include <linux/resume_user_mode.h> @@ -611,6 +612,8 @@ restart: q->root_blkg = NULL; spin_unlock_irq(&q->queue_lock); + + wake_up_var(&q->root_blkg); } static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src) @@ -1498,6 +1501,18 @@ int blkcg_init_disk(struct gendisk *disk) struct blkcg_gq *new_blkg, *blkg; bool preloaded; + /* + * If the queue is shared across disk rebind (e.g., SCSI), the + * previous disk's blkcg state is cleaned up asynchronously via + * disk_release() -> blkcg_exit_disk(). Wait for that cleanup to + * finish (indicated by root_blkg becoming NULL) before setting up + * new blkcg state. Otherwise, we may overwrite q->root_blkg while + * the old one is still alive, and radix_tree_insert() in + * blkg_create() will fail with -EEXIST because the old entries + * still occupy the same queue id slot in blkcg->blkg_tree. + */ + wait_var_event(&q->root_blkg, !READ_ONCE(q->root_blkg)); + new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); if (!new_blkg) return -ENOMEM; |