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authorBart Van Assche <bart.vanassche@wdc.com>2018-01-17 14:48:09 -0500
committerJens Axboe <axboe@kernel.dk>2018-01-18 14:54:42 -0500
commit14a23498ba97683c6790b1bcd8b2cdfe9ad99797 (patch)
tree2fd6541a0cb24db6f70ca2ee5ae54675531b273a
parent83d016ac86428dbca8a62d3e4fdc29e3ea39e535 (diff)
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>
-rw-r--r--block/elevator.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 4f00b53cd5fd..e87e9b43aba0 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -869,6 +869,8 @@ int elv_register_queue(struct request_queue *q)
869 struct elevator_queue *e = q->elevator; 869 struct elevator_queue *e = q->elevator;
870 int error; 870 int error;
871 871
872 lockdep_assert_held(&q->sysfs_lock);
873
872 error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); 874 error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
873 if (!error) { 875 if (!error) {
874 struct elv_fs_entry *attr = e->type->elevator_attrs; 876 struct elv_fs_entry *attr = e->type->elevator_attrs;
@@ -889,6 +891,8 @@ int elv_register_queue(struct request_queue *q)
889 891
890void elv_unregister_queue(struct request_queue *q) 892void elv_unregister_queue(struct request_queue *q)
891{ 893{
894 lockdep_assert_held(&q->sysfs_lock);
895
892 if (q) { 896 if (q) {
893 struct elevator_queue *e = q->elevator; 897 struct elevator_queue *e = q->elevator;
894 898
@@ -965,6 +969,8 @@ static int elevator_switch_mq(struct request_queue *q,
965{ 969{
966 int ret; 970 int ret;
967 971
972 lockdep_assert_held(&q->sysfs_lock);
973
968 blk_mq_freeze_queue(q); 974 blk_mq_freeze_queue(q);
969 blk_mq_quiesce_queue(q); 975 blk_mq_quiesce_queue(q);
970 976
@@ -1010,6 +1016,8 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
1010 bool old_registered = false; 1016 bool old_registered = false;
1011 int err; 1017 int err;
1012 1018
1019 lockdep_assert_held(&q->sysfs_lock);
1020
1013 if (q->mq_ops) 1021 if (q->mq_ops)
1014 return elevator_switch_mq(q, new_e); 1022 return elevator_switch_mq(q, new_e);
1015 1023