TechPanelGM/kernel_xiaomi_sm8250
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Revert "block: don't release queue's sysfs lock during switching elevator"

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This reverts commit ee3d84e67d.

It breaks the abi and is not needed in Android devices.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia641807b9d11b32ce1d4d71f3f0672f116ecaa0e
This commit is contained in:
Greg Kroah-Hartman
2021-03-04 16:12:49 +01:00
parent bd792f5690
commit c44751f1ba
2 changed files with 31 additions and 3 deletions
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3
block/blk-sysfs.c
View File

@@ -933,7 +933,6 @@ int blk_register_queue(struct gendisk *disk)
blk_mq_debugfs_register(q);
}
mutex_lock(&q->sysfs_lock);
/*
* The flag of QUEUE_FLAG_REGISTERED isn't set yet, so elevator
* switch won't happen at all.
@@ -941,7 +940,6 @@ int blk_register_queue(struct gendisk *disk)
if (q->request_fn || (q->mq_ops && q->elevator)) {
ret = elv_register_queue(q, false);
if (ret) {
mutex_unlock(&q->sysfs_lock);
mutex_unlock(&q->sysfs_dir_lock);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(dev);
@@ -951,6 +949,7 @@ int blk_register_queue(struct gendisk *disk)
has_elevator = true;
}
mutex_lock(&q->sysfs_lock);
blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
wbt_enable_default(q);
blk_throtl_register_queue(q);

31
block/elevator.c
View File

@@ -856,9 +856,11 @@ int elv_register_queue(struct request_queue *q, bool uevent)
if (uevent)
kobject_uevent(&e->kobj, KOBJ_ADD);
mutex_lock(&q->sysfs_lock);
e->registered = 1;
if (!e->uses_mq && e->type->ops.sq.elevator_registered_fn)
e->type->ops.sq.elevator_registered_fn(q);
mutex_unlock(&q->sysfs_lock);
}
return error;
}
@@ -876,9 +878,11 @@ void elv_unregister_queue(struct request_queue *q)
kobject_uevent(&e->kobj, KOBJ_REMOVE);
kobject_del(&e->kobj);
mutex_lock(&q->sysfs_lock);
e->registered = 0;
/* Re-enable throttling in case elevator disabled it */
wbt_enable_default(q);
mutex_unlock(&q->sysfs_lock);
}
}
@@ -949,11 +953,32 @@ int elevator_switch_mq(struct request_queue *q,
lockdep_assert_held(&q->sysfs_lock);
if (q->elevator) {
if (q->elevator->registered)
if (q->elevator->registered) {
mutex_unlock(&q->sysfs_lock);
/*
* Concurrent elevator switch can't happen becasue
* sysfs write is always exclusively on same file.
*
* Also the elevator queue won't be freed after
* sysfs_lock is released becasue kobject_del() in
* blk_unregister_queue() waits for completion of
* .store & .show on its attributes.
*/
elv_unregister_queue(q);
mutex_lock(&q->sysfs_lock);
}
ioc_clear_queue(q);
elevator_exit(q, q->elevator);
/*
* sysfs_lock may be dropped, so re-check if queue is
* unregistered. If yes, don't switch to new elevator
* any more
*/
if (!blk_queue_registered(q))
return 0;
}
ret = blk_mq_init_sched(q, new_e);
@@ -961,7 +986,11 @@ int elevator_switch_mq(struct request_queue *q,
goto out;
if (new_e) {
mutex_unlock(&q->sysfs_lock);
ret = elv_register_queue(q, true);
mutex_lock(&q->sysfs_lock);
if (ret) {
elevator_exit(q, q->elevator);
goto out;