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authorBart Van Assche <bart.vanassche@wdc.com>2018-01-17 11:48:09 -0800
committerJens Axboe <axboe@kernel.dk>2018-01-18 12:54:42 -0700
commit14a23498ba97683c6790b1bcd8b2cdfe9ad99797 (patch)
tree2fd6541a0cb24db6f70ca2ee5ae54675531b273a /block/elevator.c
parent83d016ac86428dbca8a62d3e4fdc29e3ea39e535 (diff)
downloadlinux-0-day-14a23498ba97683c6790b1bcd8b2cdfe9ad99797.tar.gz
block: Document scheduler modification locking requirements
This patch does not change any functionality. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/elevator.c')
-rw-r--r--block/elevator.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 4f00b53..e87e9b4 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -869,6 +869,8 @@ int elv_register_queue(struct request_queue *q)
struct elevator_queue *e = q->elevator;
int error;
+ lockdep_assert_held(&q->sysfs_lock);
+
error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
if (!error) {
struct elv_fs_entry *attr = e->type->elevator_attrs;
@@ -889,6 +891,8 @@ int elv_register_queue(struct request_queue *q)
void elv_unregister_queue(struct request_queue *q)
{
+ lockdep_assert_held(&q->sysfs_lock);
+
if (q) {
struct elevator_queue *e = q->elevator;
@@ -965,6 +969,8 @@ static int elevator_switch_mq(struct request_queue *q,
{
int ret;
+ lockdep_assert_held(&q->sysfs_lock);
+
blk_mq_freeze_queue(q);
blk_mq_quiesce_queue(q);
@@ -1010,6 +1016,8 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
bool old_registered = false;
int err;
+ lockdep_assert_held(&q->sysfs_lock);
+
if (q->mq_ops)
return elevator_switch_mq(q, new_e);