}
EXPORT_SYMBOL_GPL(bio_blkio_cgroup);
+static bool blkcg_policy_enabled(struct request_queue *q,
+ const struct blkio_policy_type *pol)
+{
+ return pol && test_bit(pol->plid, q->blkcg_pols);
+}
+
+static size_t blkg_pd_size(const struct blkio_policy_type *pol)
+{
+ return sizeof(struct blkg_policy_data) + pol->pdata_size;
+}
+
/**
* blkg_free - free a blkg
* @blkg: blkg to free
struct blkio_policy_type *pol = blkio_policy[i];
struct blkg_policy_data *pd;
- if (!pol)
+ if (!blkcg_policy_enabled(q, pol))
continue;
/* alloc per-policy data and attach it to blkg */
- pd = kzalloc_node(sizeof(*pd) + pol->pdata_size, GFP_ATOMIC,
- q->node);
+ pd = kzalloc_node(blkg_pd_size(pol), GFP_ATOMIC, q->node);
if (!pd) {
blkg_free(blkg);
return NULL;
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkio_policy_type *pol = blkio_policy[i];
- if (pol)
+ if (blkcg_policy_enabled(blkg->q, pol))
pol->ops.blkio_init_group_fn(blkg);
}
blkg_put(blkg);
}
-/*
- * XXX: This updates blkg policy data in-place for root blkg, which is
- * necessary across elevator switch and policy registration as root blkgs
- * aren't shot down. This broken and racy implementation is temporary.
- * Eventually, blkg shoot down will be replaced by proper in-place update.
- */
-void update_root_blkg_pd(struct request_queue *q,
- const struct blkio_policy_type *pol)
-{
- struct blkio_group *blkg = blkg_lookup(&blkio_root_cgroup, q);
- struct blkg_policy_data *pd;
-
- if (!blkg)
- return;
-
- kfree(blkg->pd[pol->plid]);
- blkg->pd[pol->plid] = NULL;
-
- if (!pol)
- return;
-
- pd = kzalloc(sizeof(*pd) + pol->pdata_size, GFP_KERNEL);
- WARN_ON_ONCE(!pd);
-
- blkg->pd[pol->plid] = pd;
- pd->blkg = blkg;
- pol->ops.blkio_init_group_fn(blkg);
-}
-EXPORT_SYMBOL_GPL(update_root_blkg_pd);
-
/**
* blkg_destroy_all - destroy all blkgs associated with a request_queue
* @q: request_queue of interest
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkio_policy_type *pol = blkio_policy[i];
- if (pol && pol->ops.blkio_reset_group_stats_fn)
+ if (blkcg_policy_enabled(blkg->q, pol) &&
+ pol->ops.blkio_reset_group_stats_fn)
pol->ops.blkio_reset_group_stats_fn(blkg);
}
}
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
- if (blkg->pd[pol->plid])
+ if (blkcg_policy_enabled(blkg->q, pol))
total += prfill(sf, blkg->pd[pol->plid]->pdata, data);
spin_unlock_irq(&blkcg->lock);
rcu_read_lock();
spin_lock_irq(disk->queue->queue_lock);
- blkg = blkg_lookup_create(blkcg, disk->queue, false);
+ if (blkcg_policy_enabled(disk->queue, pol))
+ blkg = blkg_lookup_create(blkcg, disk->queue, false);
+ else
+ blkg = ERR_PTR(-EINVAL);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
return ret;
}
-static void blkcg_bypass_start(void)
- __acquires(&all_q_mutex)
-{
- struct request_queue *q;
-
- mutex_lock(&all_q_mutex);
-
- list_for_each_entry(q, &all_q_list, all_q_node) {
- blk_queue_bypass_start(q);
- blkg_destroy_all(q, false);
- }
-}
-
-static void blkcg_bypass_end(void)
- __releases(&all_q_mutex)
-{
- struct request_queue *q;
-
- list_for_each_entry(q, &all_q_list, all_q_node)
- blk_queue_bypass_end(q);
-
- mutex_unlock(&all_q_mutex);
-}
-
struct cgroup_subsys blkio_subsys = {
.name = "blkio",
.create = blkiocg_create,
};
EXPORT_SYMBOL_GPL(blkio_subsys);
+/**
+ * blkcg_activate_policy - activate a blkcg policy on a request_queue
+ * @q: request_queue of interest
+ * @pol: blkcg policy to activate
+ *
+ * Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through
+ * bypass mode to populate its blkgs with policy_data for @pol.
+ *
+ * Activation happens with @q bypassed, so nobody would be accessing blkgs
+ * from IO path. Update of each blkg is protected by both queue and blkcg
+ * locks so that holding either lock and testing blkcg_policy_enabled() is
+ * always enough for dereferencing policy data.
+ *
+ * The caller is responsible for synchronizing [de]activations and policy
+ * [un]registerations. Returns 0 on success, -errno on failure.
+ */
+int blkcg_activate_policy(struct request_queue *q,
+ const struct blkio_policy_type *pol)
+{
+ LIST_HEAD(pds);
+ struct blkio_group *blkg;
+ struct blkg_policy_data *pd, *n;
+ int cnt = 0, ret;
+
+ if (blkcg_policy_enabled(q, pol))
+ return 0;
+
+ blk_queue_bypass_start(q);
+
+ /* make sure the root blkg exists and count the existing blkgs */
+ spin_lock_irq(q->queue_lock);
+
+ rcu_read_lock();
+ blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
+ rcu_read_unlock();
+
+ if (IS_ERR(blkg)) {
+ ret = PTR_ERR(blkg);
+ goto out_unlock;
+ }
+ q->root_blkg = blkg;
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node)
+ cnt++;
+
+ spin_unlock_irq(q->queue_lock);
+
+ /* allocate policy_data for all existing blkgs */
+ while (cnt--) {
+ pd = kzalloc_node(blkg_pd_size(pol), GFP_KERNEL, q->node);
+ if (!pd) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+ list_add_tail(&pd->alloc_node, &pds);
+ }
+
+ /*
+ * Install the allocated pds. With @q bypassing, no new blkg
+ * should have been created while the queue lock was dropped.
+ */
+ spin_lock_irq(q->queue_lock);
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node) {
+ if (WARN_ON(list_empty(&pds))) {
+ /* umm... this shouldn't happen, just abort */
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+ pd = list_first_entry(&pds, struct blkg_policy_data, alloc_node);
+ list_del_init(&pd->alloc_node);
+
+ /* grab blkcg lock too while installing @pd on @blkg */
+ spin_lock(&blkg->blkcg->lock);
+
+ blkg->pd[pol->plid] = pd;
+ pd->blkg = blkg;
+ pol->ops.blkio_init_group_fn(blkg);
+
+ spin_unlock(&blkg->blkcg->lock);
+ }
+
+ __set_bit(pol->plid, q->blkcg_pols);
+ ret = 0;
+out_unlock:
+ spin_unlock_irq(q->queue_lock);
+out_free:
+ blk_queue_bypass_end(q);
+ list_for_each_entry_safe(pd, n, &pds, alloc_node)
+ kfree(pd);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(blkcg_activate_policy);
+
+/**
+ * blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue
+ * @q: request_queue of interest
+ * @pol: blkcg policy to deactivate
+ *
+ * Deactivate @pol on @q. Follows the same synchronization rules as
+ * blkcg_activate_policy().
+ */
+void blkcg_deactivate_policy(struct request_queue *q,
+ const struct blkio_policy_type *pol)
+{
+ struct blkio_group *blkg;
+
+ if (!blkcg_policy_enabled(q, pol))
+ return;
+
+ blk_queue_bypass_start(q);
+ spin_lock_irq(q->queue_lock);
+
+ __clear_bit(pol->plid, q->blkcg_pols);
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node) {
+ /* grab blkcg lock too while removing @pd from @blkg */
+ spin_lock(&blkg->blkcg->lock);
+
+ if (pol->ops.blkio_exit_group_fn)
+ pol->ops.blkio_exit_group_fn(blkg);
+
+ kfree(blkg->pd[pol->plid]);
+ blkg->pd[pol->plid] = NULL;
+
+ spin_unlock(&blkg->blkcg->lock);
+ }
+
+ spin_unlock_irq(q->queue_lock);
+ blk_queue_bypass_end(q);
+}
+EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);
+
/**
* blkio_policy_register - register a blkcg policy
* @blkiop: blkcg policy to register
*/
int blkio_policy_register(struct blkio_policy_type *blkiop)
{
- struct request_queue *q;
int i, ret;
mutex_lock(&blkcg_pol_mutex);
blkiop->plid = i;
blkio_policy[i] = blkiop;
- blkcg_bypass_start();
- list_for_each_entry(q, &all_q_list, all_q_node)
- update_root_blkg_pd(q, blkiop);
- blkcg_bypass_end();
-
/* everything is in place, add intf files for the new policy */
if (blkiop->cftypes)
WARN_ON(cgroup_add_cftypes(&blkio_subsys, blkiop->cftypes));
*/
void blkio_policy_unregister(struct blkio_policy_type *blkiop)
{
- struct request_queue *q;
-
mutex_lock(&blkcg_pol_mutex);
if (WARN_ON(blkio_policy[blkiop->plid] != blkiop))
/* unregister and update blkgs */
blkio_policy[blkiop->plid] = NULL;
-
- blkcg_bypass_start();
- list_for_each_entry(q, &all_q_list, all_q_node)
- update_root_blkg_pd(q, blkiop);
- blkcg_bypass_end();
out_unlock:
mutex_unlock(&blkcg_pol_mutex);
}
/* the blkg this per-policy data belongs to */
struct blkio_group *blkg;
+ /* used during policy activation */
+ struct list_head alloc_node;
+
/* pol->pdata_size bytes of private data used by policy impl */
char pdata[] __aligned(__alignof__(unsigned long long));
};
/* Blkio controller policy registration */
extern int blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
+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);
-extern void update_root_blkg_pd(struct request_queue *q,
- const struct blkio_policy_type *pol);
void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
u64 (*prfill)(struct seq_file *, void *, int),
static inline void blkcg_exit_queue(struct request_queue *q) { }
static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
+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 update_root_blkg_pd(struct request_queue *q,
- const struct blkio_policy_type *pol) { }
static inline void *blkg_to_pdata(struct blkio_group *blkg,
struct blkio_policy_type *pol) { return NULL; }
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
struct blkg_conf_ctx ctx;
struct throtl_grp *tg;
+ struct throtl_data *td;
int ret;
ret = blkg_conf_prep(blkcg, &blkio_policy_throtl, buf, &ctx);
if (ret)
return ret;
- ret = -EINVAL;
tg = blkg_to_tg(ctx.blkg);
- if (tg) {
- struct throtl_data *td = ctx.blkg->q->td;
-
- if (!ctx.v)
- ctx.v = -1;
+ td = ctx.blkg->q->td;
- if (is_u64)
- *(u64 *)((void *)tg + cft->private) = ctx.v;
- else
- *(unsigned int *)((void *)tg + cft->private) = ctx.v;
+ if (!ctx.v)
+ ctx.v = -1;
- /* XXX: we don't need the following deferred processing */
- xchg(&tg->limits_changed, true);
- xchg(&td->limits_changed, true);
- throtl_schedule_delayed_work(td, 0);
+ if (is_u64)
+ *(u64 *)((void *)tg + cft->private) = ctx.v;
+ else
+ *(unsigned int *)((void *)tg + cft->private) = ctx.v;
- ret = 0;
- }
+ /* XXX: we don't need the following deferred processing */
+ xchg(&tg->limits_changed, true);
+ xchg(&td->limits_changed, true);
+ throtl_schedule_delayed_work(td, 0);
blkg_conf_finish(&ctx);
- return ret;
+ return 0;
}
static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft,
int blk_throtl_init(struct request_queue *q)
{
struct throtl_data *td;
- struct blkio_group *blkg;
+ int ret;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
if (!td)
q->td = td;
td->queue = q;
- /* alloc and init root group. */
- rcu_read_lock();
- spin_lock_irq(q->queue_lock);
-
- blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
- if (!IS_ERR(blkg))
- q->root_blkg = blkg;
-
- spin_unlock_irq(q->queue_lock);
- rcu_read_unlock();
-
- if (!q->root_blkg) {
+ /* activate policy */
+ ret = blkcg_activate_policy(q, &blkio_policy_throtl);
+ if (ret)
kfree(td);
- return -ENOMEM;
- }
- return 0;
+ return ret;
}
void blk_throtl_exit(struct request_queue *q)
{
BUG_ON(!q->td);
throtl_shutdown_wq(q);
+ blkcg_deactivate_policy(q, &blkio_policy_throtl);
kfree(q->td);
}
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff