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blkcg: drop stuff unused after per-queue policy activation update
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* All_q_list is unused.  Drop all_q_{mutex|list}.

* @for_root of blkg_lookup_create() is always %false when called from
  outside blk-cgroup.c proper.  Factor out __blkg_lookup_create() so
  that it doesn't check whether @q is bypassing and use the
  underscored version for the @for_root callsite.

* blkg_destroy_all() is used only from blkcg proper and @destroy_root
  is always %true.  Make it static and drop @destroy_root.

Signed-off-by: Tejun Heo <[email protected]>
Cc: Vivek Goyal <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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@htejun @axboe
htejun authored and axboe committed Apr 20, 2012
1 parent a2b1693 commit 3c96cb3
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Showing 4 changed files with 23 additions and 48 deletions.
61 changes: 20 additions & 41 deletions block/blk-cgroup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,6 @@
#define MAX_KEY_LEN 100

static DEFINE_MUTEX(blkcg_pol_mutex);
static DEFINE_MUTEX(all_q_mutex);
static LIST_HEAD(all_q_list);

struct blkio_cgroup blkio_root_cgroup = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkio_root_cgroup);
Expand Down Expand Up @@ -179,23 +177,15 @@ struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
}
EXPORT_SYMBOL_GPL(blkg_lookup);

struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
struct request_queue *q,
bool for_root)
static struct blkio_group *__blkg_lookup_create(struct blkio_cgroup *blkcg,
struct request_queue *q)
__releases(q->queue_lock) __acquires(q->queue_lock)
{
struct blkio_group *blkg;

WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(q->queue_lock);

/*
* This could be the first entry point of blkcg implementation and
* we shouldn't allow anything to go through for a bypassing queue.
*/
if (unlikely(blk_queue_bypass(q)) && !for_root)
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);

blkg = __blkg_lookup(blkcg, q);
if (blkg)
return blkg;
Expand Down Expand Up @@ -223,6 +213,18 @@ struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
out:
return blkg;
}

struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
struct request_queue *q)
{
/*
* This could be the first entry point of blkcg implementation and
* we shouldn't allow anything to go through for a bypassing queue.
*/
if (unlikely(blk_queue_bypass(q)))
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
return __blkg_lookup_create(blkcg, q);
}
EXPORT_SYMBOL_GPL(blkg_lookup_create);

static void blkg_destroy(struct blkio_group *blkg)
Expand All @@ -249,12 +251,10 @@ static void blkg_destroy(struct blkio_group *blkg)
/**
* blkg_destroy_all - destroy all blkgs associated with a request_queue
* @q: request_queue of interest
* @destroy_root: whether to destroy root blkg or not
*
* Destroy blkgs associated with @q. If @destroy_root is %true, all are
* destroyed; otherwise, root blkg is left alone.
* Destroy all blkgs associated with @q.
*/
void blkg_destroy_all(struct request_queue *q, bool destroy_root)
static void blkg_destroy_all(struct request_queue *q)
{
struct blkio_group *blkg, *n;

Expand All @@ -263,18 +263,13 @@ void blkg_destroy_all(struct request_queue *q, bool destroy_root)
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
struct blkio_cgroup *blkcg = blkg->blkcg;

/* skip root? */
if (!destroy_root && blkg->blkcg == &blkio_root_cgroup)
continue;

spin_lock(&blkcg->lock);
blkg_destroy(blkg);
spin_unlock(&blkcg->lock);
}

spin_unlock_irq(q->queue_lock);
}
EXPORT_SYMBOL_GPL(blkg_destroy_all);

static void blkg_rcu_free(struct rcu_head *rcu_head)
{
Expand Down Expand Up @@ -492,7 +487,7 @@ int blkg_conf_prep(struct blkio_cgroup *blkcg,
spin_lock_irq(disk->queue->queue_lock);

if (blkcg_policy_enabled(disk->queue, pol))
blkg = blkg_lookup_create(blkcg, disk->queue, false);
blkg = blkg_lookup_create(blkcg, disk->queue);
else
blkg = ERR_PTR(-EINVAL);

Expand Down Expand Up @@ -625,20 +620,9 @@ static struct cgroup_subsys_state *blkiocg_create(struct cgroup *cgroup)
*/
int blkcg_init_queue(struct request_queue *q)
{
int ret;

might_sleep();

ret = blk_throtl_init(q);
if (ret)
return ret;

mutex_lock(&all_q_mutex);
INIT_LIST_HEAD(&q->all_q_node);
list_add_tail(&q->all_q_node, &all_q_list);
mutex_unlock(&all_q_mutex);

return 0;
return blk_throtl_init(q);
}

/**
Expand All @@ -662,12 +646,7 @@ void blkcg_drain_queue(struct request_queue *q)
*/
void blkcg_exit_queue(struct request_queue *q)
{
mutex_lock(&all_q_mutex);
list_del_init(&q->all_q_node);
mutex_unlock(&all_q_mutex);

blkg_destroy_all(q, true);

blkg_destroy_all(q);
blk_throtl_exit(q);
}

Expand Down Expand Up @@ -741,7 +720,7 @@ int blkcg_activate_policy(struct request_queue *q,
spin_lock_irq(q->queue_lock);

rcu_read_lock();
blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
blkg = __blkg_lookup_create(&blkio_root_cgroup, q);
rcu_read_unlock();

if (IS_ERR(blkg)) {
Expand Down
6 changes: 1 addition & 5 deletions block/blk-cgroup.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,6 @@ extern int blkcg_activate_policy(struct request_queue *q,
const struct blkio_policy_type *pol);
extern void blkcg_deactivate_policy(struct request_queue *q,
const struct blkio_policy_type *pol);
extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);

void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
u64 (*prfill)(struct seq_file *, void *, int),
Expand Down Expand Up @@ -334,8 +333,6 @@ static inline int blkcg_activate_policy(struct request_queue *q,
const struct blkio_policy_type *pol) { return 0; }
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkio_policy_type *pol) { }
static inline void blkg_destroy_all(struct request_queue *q,
bool destory_root) { }

static inline void *blkg_to_pdata(struct blkio_group *blkg,
struct blkio_policy_type *pol) { return NULL; }
Expand All @@ -354,8 +351,7 @@ extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
struct request_queue *q);
struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
struct request_queue *q,
bool for_root);
struct request_queue *q);
#else
struct cgroup;
static inline struct blkio_cgroup *
Expand Down
2 changes: 1 addition & 1 deletion block/blk-throttle.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -285,7 +285,7 @@ static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
} else {
struct blkio_group *blkg;

blkg = blkg_lookup_create(blkcg, q, false);
blkg = blkg_lookup_create(blkcg, q);

/* if %NULL and @q is alive, fall back to root_tg */
if (!IS_ERR(blkg))
Expand Down
2 changes: 1 addition & 1 deletion block/cfq-iosched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1348,7 +1348,7 @@ static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd,
} else {
struct blkio_group *blkg;

blkg = blkg_lookup_create(blkcg, q, false);
blkg = blkg_lookup_create(blkcg, q);
if (!IS_ERR(blkg))
cfqg = blkg_to_cfqg(blkg);
}
Expand Down

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