diff options
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/block/elevator.c b/block/elevator.c index ebe2a1fcf011..3bcd37c2aa34 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -807,7 +807,16 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, elv_iosched_load_module(ctx.name); ctx.type = elevator_find_get(ctx.name); - down_read(&set->update_nr_hwq_lock); + /* + * Use trylock to avoid circular lock dependency with kernfs active + * reference during concurrent disk deletion: + * update_nr_hwq_lock -> kn->active (via del_gendisk -> kobject_del) + * kn->active -> update_nr_hwq_lock (via this sysfs write path) + */ + if (!down_read_trylock(&set->update_nr_hwq_lock)) { + ret = -EBUSY; + goto out; + } if (!blk_queue_no_elv_switch(q)) { ret = elevator_change(q, &ctx); if (!ret) @@ -817,6 +826,7 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, } up_read(&set->update_nr_hwq_lock); +out: if (ctx.type) elevator_put(ctx.type); return ret; |