[PATCH 2/3] blk-throttle: move the throtl_data pointer from to struct gendisk

Christoph Hellwig
2023-02-13T10:41:33Z

Block throttling is only used for file system I/O, so move the
throtl_data pointer to the gendisk.

Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
---
block/blk-throttle.c | 39 ++++++++++++++++-----------------------
include/linux/blkdev.h | 8 +++-----
2 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 6a8b82939a38ad..8cece10c56515d 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -387,7 +387,7 @@ static void throtl_pd_init(struct blkg_policy_data *pd)
{
struct throtl_grp *tg = pd_to_tg(pd);
struct blkcg_gq *blkg = tg_to_blkg(tg);
- struct throtl_data *td = blkg->disk->queue->td;
+ struct throtl_data *td = blkg->disk->td;
struct throtl_service_queue *sq = &tg->service_queue;

/*
@@ -1685,13 +1685,6 @@ static struct cftype throtl_files[] = {
{ } /* terminate */
};

-static void throtl_shutdown_wq(struct request_queue *q)
-{
- struct throtl_data *td = q->td;
-
- cancel_work_sync(&td->dispatch_work);
-}
-
struct blkcg_policy blkcg_policy_throtl = {
.dfl_cftypes = throtl_files,
.legacy_cftypes = throtl_legacy_files,
@@ -2297,7 +2290,7 @@ static void throtl_track_latency(struct throtl_data *td, sector_t size,
void blk_throtl_stat_add(struct request *rq, u64 time_ns)
{
struct request_queue *q = rq->q;
- struct throtl_data *td = q->td;
+ struct throtl_data *td = q->disk->td;

throtl_track_latency(td, blk_rq_stats_sectors(rq), req_op(rq),
time_ns >> 10);
@@ -2383,7 +2376,7 @@ int blk_throtl_init(struct gendisk *disk)
INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn);
throtl_service_queue_init(&td->service_queue);

- disk->queue->td = td;
+ disk->td = td;
td->disk = disk;

td->limit_valid[LIMIT_MAX] = true;
@@ -2403,25 +2396,24 @@ int blk_throtl_init(struct gendisk *disk)

void blk_throtl_exit(struct gendisk *disk)
{
- struct request_queue *q = disk->queue;
+ struct throtl_data *td = disk->td;

- if (!q->td)
+ if (!td)
return;
- del_timer_sync(&q->td->service_queue.pending_timer);
- throtl_shutdown_wq(q);
+ del_timer_sync(&td->service_queue.pending_timer);
+ cancel_work_sync(&td->dispatch_work);
blkcg_deactivate_policy(disk, &blkcg_policy_throtl);
- free_percpu(q->td->latency_buckets[READ]);
- free_percpu(q->td->latency_buckets[WRITE]);
- kfree(q->td);
+ free_percpu(td->latency_buckets[READ]);
+ free_percpu(td->latency_buckets[WRITE]);
+ kfree(td);
}

void blk_throtl_register(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
- struct throtl_data *td;
+ struct throtl_data *td = disk->td;
int i;

- td = q->td;
BUG_ON(!td);

if (blk_queue_nonrot(q)) {
@@ -2448,9 +2440,10 @@ void blk_throtl_register(struct gendisk *disk)
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page)
{
- if (!q->td)
+ if (!q->disk->td)
return -EINVAL;
- return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice));
+ return sprintf(page, "%u\n",
+ jiffies_to_msecs(q->disk->td->throtl_slice));
}

ssize_t blk_throtl_sample_time_store(struct request_queue *q,
@@ -2459,14 +2452,14 @@ ssize_t blk_throtl_sample_time_store(struct request_queue *q,
unsigned long v;
unsigned long t;

- if (!q->td)
+ if (!q->disk->td)
return -EINVAL;
if (kstrtoul(page, 10, &v))
return -EINVAL;
t = msecs_to_jiffies(v);
if (t == 0 || t > MAX_THROTL_SLICE)
return -EINVAL;
- q->td->throtl_slice = t;
+ q->disk->td->throtl_slice = t;
return count;
}
#endif
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 79aec4ebadb9e0..f07bc82c87f8b3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -169,6 +169,9 @@ struct gendisk {
struct list_head blkg_list;
struct mutex blkcg_mutex;
#endif /* CONFIG_BLK_CGROUP */
+#ifdef CONFIG_BLK_DEV_THROTTLING
+ struct throtl_data *td;
+#endif
#ifdef CONFIG_BLK_DEV_INTEGRITY
struct kobject integrity_kobj;
#endif /* CONFIG_BLK_DEV_INTEGRITY */
@@ -516,11 +519,6 @@ struct request_queue {
spinlock_t unused_hctx_lock;

int mq_freeze_depth;
-
-#ifdef CONFIG_BLK_DEV_THROTTLING
- /* Throttle data */
- struct throtl_data *td;
-#endif
struct rcu_head rcu_head;
wait_queue_head_t mq_freeze_wq;
/*
--
2.39.1