Commit ffb86425 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: don't check for required features in elevator_match 



Checking for the required features in the callers simplifies the code
quite a bit, so do that.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-7-hch@lst.de


[axboe: adjust for dropping patch 1, use __elevator_find()]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2eef17a2

block/elevator.c

+16 −35
Original line number Diff line number Diff line
@@ -83,10 +83,11 @@ bool elv_bio_merge_ok(struct request *rq, struct bio *bio) 
}

EXPORT_SYMBOL(elv_bio_merge_ok);



static inline bool elv_support_features(unsigned int elv_features,

					unsigned int required_features)

static inline bool elv_support_features(struct request_queue *q,

		const struct elevator_type *e)

{

	return (required_features & elv_features) == required_features;

	return (q->required_elevator_features & e->elevator_features) ==

		q->required_elevator_features;

}



/**
@@ -98,37 +99,19 @@ static inline bool elv_support_features(unsigned int elv_features, 
 * Return true if the elevator @e name matches @name and if @e provides all

 * the features specified by @required_features.

 */

static bool elevator_match(const struct elevator_type *e, const char *name,

			   unsigned int required_features)

static bool elevator_match(const struct elevator_type *e, const char *name)

{

	if (!elv_support_features(e->elevator_features, required_features))

		return false;

	if (!strcmp(e->elevator_name, name))

		return true;

	if (e->elevator_alias && !strcmp(e->elevator_alias, name))

		return true;



	return false;

	return !strcmp(e->elevator_name, name) ||

		(e->elevator_alias && !strcmp(e->elevator_alias, name));

}



/**

 * elevator_find - Find an elevator

 * @name: Name of the elevator to find

 * @required_features: Features that the elevator must provide

 *

 * Return the first registered scheduler with name @name and supporting the

 * features @required_features and NULL otherwise.

 */

static struct elevator_type *elevator_find(const char *name,

					   unsigned int required_features)

static struct elevator_type *__elevator_find(const char *name)

{

	struct elevator_type *e;



	list_for_each_entry(e, &elv_list, list) {

		if (elevator_match(e, name, required_features))

	list_for_each_entry(e, &elv_list, list)

		if (elevator_match(e, name))

			return e;

	}



	return NULL;

}
@@ -138,8 +121,8 @@ static struct elevator_type *elevator_find_get(struct request_queue *q, 
	struct elevator_type *e;



	spin_lock(&elv_list_lock);

	e = elevator_find(name, q->required_elevator_features);

	if (e && !elevator_tryget(e))

	e = __elevator_find(name);

	if (e && (!elv_support_features(q, e) || !elevator_tryget(e)))

		e = NULL;

	spin_unlock(&elv_list_lock);

	return e;
@@ -538,7 +521,7 @@ int elv_register(struct elevator_type *e) 


	/* register, don't allow duplicate names */

	spin_lock(&elv_list_lock);

	if (elevator_find(e->elevator_name, 0)) {

	if (__elevator_find(e->elevator_name)) {

		spin_unlock(&elv_list_lock);

		kmem_cache_destroy(e->icq_cache);

		return -EBUSY;
@@ -639,8 +622,7 @@ static struct elevator_type *elevator_get_by_features(struct request_queue *q) 
	spin_lock(&elv_list_lock);



	list_for_each_entry(e, &elv_list, list) {

		if (elv_support_features(e->elevator_features,

					 q->required_elevator_features)) {

		if (elv_support_features(q, e)) {

			found = e;

			break;

		}
@@ -745,7 +727,7 @@ static int elevator_change(struct request_queue *q, const char *elevator_name) 
		return elevator_switch(q, NULL);

	}



	if (q->elevator && elevator_match(q->elevator->type, elevator_name, 0))

	if (q->elevator && elevator_match(q->elevator->type, elevator_name))

		return 0;



	e = elevator_find_get(q, elevator_name);
@@ -796,8 +778,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name) 
			len += sprintf(name+len, "[%s] ", cur->elevator_name);

			continue;

		}

		if (elevator_match(e, e->elevator_name,

				   q->required_elevator_features))

		if (elv_support_features(q, e))

			len += sprintf(name+len, "%s ", e->elevator_name);

	}

	spin_unlock(&elv_list_lock);