Commit dd6f7f17 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add proper helpers for elevator_type module refcount management 



Make sure we have helpers for all relevant module refcount operations on
the elevator_type in elevator.h, and use them.  Move the call to the get
helper in blk_mq_elv_switch_none a bit so that it is obvious with a less
verbose comment.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-2-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 671fae5e

block/blk-mq.c

+2 −9
Original line number Diff line number Diff line
@@ -4554,17 +4554,10 @@ static bool blk_mq_elv_switch_none(struct list_head *head, 


	INIT_LIST_HEAD(&qe->node);

	qe->q = q;

	/* keep a reference to the elevator module as we'll switch back */

	__elevator_get(qe->type);

	qe->type = q->elevator->type;

	list_add(&qe->node, head);



	/*

	 * After elevator_switch, the previous elevator_queue will be

	 * released by elevator_release. The reference of the io scheduler

	 * module get by elevator_get will also be put. So we need to get

	 * a reference of the io scheduler module here to prevent it to be

	 * removed.

	 */

	__module_get(qe->type->elevator_owner);

	elevator_switch(q, NULL);

	mutex_unlock(&q->sysfs_lock);

block/elevator.c

+2 −7
Original line number Diff line number Diff line
@@ -132,11 +132,6 @@ static struct elevator_type *elevator_find(const char *name, 
	return NULL;

}



static void elevator_put(struct elevator_type *e)

{

	module_put(e->elevator_owner);

}



static struct elevator_type *elevator_get(struct request_queue *q,

					  const char *name, bool try_loading)

{
@@ -152,7 +147,7 @@ static struct elevator_type *elevator_get(struct request_queue *q, 
		e = elevator_find(name, q->required_elevator_features);

	}



	if (e && !try_module_get(e->elevator_owner))

	if (e && !elevator_tryget(e))

		e = NULL;



	spin_unlock(&elv_list_lock);
@@ -659,7 +654,7 @@ static struct elevator_type *elevator_get_by_features(struct request_queue *q) 
		}

	}



	if (found && !try_module_get(found->elevator_owner))

	if (found && !elevator_tryget(found))

		found = NULL;



	spin_unlock(&elv_list_lock);

block/elevator.h

+15 −0
Original line number Diff line number Diff line
@@ -84,6 +84,21 @@ struct elevator_type 
	struct list_head list;

};



static inline bool elevator_tryget(struct elevator_type *e)

{

	return try_module_get(e->elevator_owner);

}



static inline void __elevator_get(struct elevator_type *e)

{

	__module_get(e->elevator_owner);

}



static inline void elevator_put(struct elevator_type *e)

{

	module_put(e->elevator_owner);

}



#define ELV_HASH_BITS 6



void elv_rqhash_del(struct request_queue *q, struct request *rq);