Commit 9f6b7ef6 authored by Jens Axboe's avatar Jens Axboe
Browse files

sbitmap: add helpers for add/del wait queue handling 



After commit 5d2ee712, users of sbitmap that need wait queue
handling must use the provided helpers. But we only added
prepare_to_wait()/finish_wait() style helpers, add the equivalent
add_wait_queue/list_del wrappers as we..

This is needed to ensure kyber plays by the sbitmap waitqueue
rules.

Tested-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3a762de5

include/linux/sbitmap.h

+14 −2
Original line number Diff line number Diff line
@@ -560,13 +560,13 @@ void sbitmap_queue_wake_up(struct sbitmap_queue *sbq); 
void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m);



struct sbq_wait {

	int accounted;

	struct sbitmap_queue *sbq;	/* if set, sbq_wait is accounted */

	struct wait_queue_entry wait;

};



#define DEFINE_SBQ_WAIT(name)							\

	struct sbq_wait name = {						\

		.accounted = 0,							\

		.sbq = NULL,							\

		.wait = {							\

			.private	= current,				\

			.func		= autoremove_wake_function,		\
@@ -588,4 +588,16 @@ void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq, 
void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,

				struct sbq_wait *sbq_wait);



/*

 * Wrapper around add_wait_queue(), which maintains some extra internal state

 */

void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,

			    struct sbq_wait_state *ws,

			    struct sbq_wait *sbq_wait);



/*

 * Must be paired with sbitmap_add_wait_queue()

 */

void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait);



#endif /* __LINUX_SCALE_BITMAP_H */

lib/sbitmap.c

+26 −4
Original line number Diff line number Diff line
@@ -671,13 +671,35 @@ void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m) 
}

EXPORT_SYMBOL_GPL(sbitmap_queue_show);



void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,

			    struct sbq_wait_state *ws,

			    struct sbq_wait *sbq_wait)

{

	if (!sbq_wait->sbq) {

		sbq_wait->sbq = sbq;

		atomic_inc(&sbq->ws_active);

	}

	add_wait_queue(&ws->wait, &sbq_wait->wait);

}

EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);



void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)

{

	list_del_init(&sbq_wait->wait.entry);

	if (sbq_wait->sbq) {

		atomic_dec(&sbq_wait->sbq->ws_active);

		sbq_wait->sbq = NULL;

	}

}

EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);



void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,

			     struct sbq_wait_state *ws,

			     struct sbq_wait *sbq_wait, int state)

{

	if (!sbq_wait->accounted) {

	if (!sbq_wait->sbq) {

		atomic_inc(&sbq->ws_active);

		sbq_wait->accounted = 1;

		sbq_wait->sbq = sbq;

	}

	prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);

}
@@ -687,9 +709,9 @@ void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws, 
			 struct sbq_wait *sbq_wait)

{

	finish_wait(&ws->wait, &sbq_wait->wait);

	if (sbq_wait->accounted) {

	if (sbq_wait->sbq) {

		atomic_dec(&sbq->ws_active);

		sbq_wait->accounted = 0;

		sbq_wait->sbq = NULL;

	}

}

EXPORT_SYMBOL_GPL(sbitmap_finish_wait);

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