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sbitmap: add helpers for add/del wait queue handling

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After commit 5d2ee7122c, 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: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2018-12-20 08:49:00 -07:00
parent 3a762de55b
commit 9f6b7ef6c3
2 changed files with 40 additions and 6 deletions
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16
include/linux/sbitmap.h
View File

@ -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 */

30
lib/sbitmap.c
View File

@ -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);