#define MAX_KEY_LEN 100
+/*
+ * blkcg_pol_mutex protects blkcg_policy[] and policy [de]activation.
+ * blkcg_pol_register_mutex nests outside of it and synchronizes entire
+ * policy [un]register operations including cgroup file additions /
+ * removals. Putting cgroup file registration outside blkcg_pol_mutex
+ * allows grabbing it from cgroup callbacks.
+ */
+static DEFINE_MUTEX(blkcg_pol_register_mutex);
static DEFINE_MUTEX(blkcg_pol_mutex);
struct blkcg blkcg_root;
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
+static LIST_HEAD(all_blkcgs); /* protected by blkcg_pol_mutex */
+
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
struct blkcg_gq *blkg;
int i;
- /*
- * XXX: We invoke cgroup_add/rm_cftypes() under blkcg_pol_mutex
- * which ends up putting cgroup's internal cgroup_tree_mutex under
- * it; however, cgroup_tree_mutex is nested above cgroup file
- * active protection and grabbing blkcg_pol_mutex from a cgroup
- * file operation creates a possible circular dependency. cgroup
- * internal locking is planned to go through further simplification
- * and this issue should go away soon. For now, let's trylock
- * blkcg_pol_mutex and restart the write on failure.
- *
- * http://lkml.kernel.org/g/5363C04B.4010400@oracle.com
- */
- if (!mutex_trylock(&blkcg_pol_mutex))
- return restart_syscall();
+ mutex_lock(&blkcg_pol_mutex);
spin_lock_irq(&blkcg->lock);
/*
{
struct blkcg *blkcg = css_to_blkcg(css);
- if (blkcg != &blkcg_root)
+ mutex_lock(&blkcg_pol_mutex);
+ list_del(&blkcg->all_blkcgs_node);
+ mutex_unlock(&blkcg_pol_mutex);
+
+ if (blkcg != &blkcg_root) {
+ int i;
+
+ for (i = 0; i < BLKCG_MAX_POLS; i++)
+ kfree(blkcg->pd[i]);
kfree(blkcg);
+ }
}
static struct cgroup_subsys_state *
struct cgroup_subsys_state *ret;
int i;
+ mutex_lock(&blkcg_pol_mutex);
+
if (!parent_css) {
blkcg = &blkcg_root;
goto done;
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&blkcg->cgwb_list);
#endif
+ list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
+
+ mutex_unlock(&blkcg_pol_mutex);
return &blkcg->css;
free_pd_blkcg:
for (i--; i >= 0; i--)
kfree(blkcg->pd[i]);
-
free_blkcg:
kfree(blkcg);
+ mutex_unlock(&blkcg_pol_mutex);
return ret;
}
const struct blkcg_policy *pol)
{
LIST_HEAD(pds);
- LIST_HEAD(cpds);
struct blkcg_gq *blkg;
struct blkg_policy_data *pd, *nd;
- struct blkcg_policy_data *cpd, *cnd;
int cnt = 0, ret;
if (blkcg_policy_enabled(q, pol))
cnt++;
spin_unlock_irq(q->queue_lock);
- /*
- * Allocate per-blkg and per-blkcg policy data
- * for all existing blkgs.
- */
+ /* allocate per-blkg policy data for all existing blkgs */
while (cnt--) {
pd = kzalloc_node(pol->pd_size, GFP_KERNEL, q->node);
if (!pd) {
goto out_free;
}
list_add_tail(&pd->alloc_node, &pds);
-
- if (!pol->cpd_size)
- continue;
- cpd = kzalloc_node(pol->cpd_size, GFP_KERNEL, q->node);
- if (!cpd) {
- ret = -ENOMEM;
- goto out_free;
- }
- list_add_tail(&cpd->alloc_node, &cpds);
}
/*
spin_lock_irq(q->queue_lock);
list_for_each_entry(blkg, &q->blkg_list, q_node) {
- if (WARN_ON(list_empty(&pds)) ||
- WARN_ON(pol->cpd_size && list_empty(&cpds))) {
+ if (WARN_ON(list_empty(&pds))) {
/* umm... this shouldn't happen, just abort */
ret = -ENOMEM;
goto out_unlock;
}
- cpd = list_first_entry(&cpds, struct blkcg_policy_data,
- alloc_node);
- list_del_init(&cpd->alloc_node);
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);
- if (!pol->cpd_size)
- goto no_cpd;
- if (!blkg->blkcg->pd[pol->plid]) {
- /* Per-policy per-blkcg data */
- blkg->blkcg->pd[pol->plid] = cpd;
- cpd->plid = pol->plid;
- pol->cpd_init_fn(blkg->blkcg);
- } else { /* must free it as it has already been extracted */
- kfree(cpd);
- }
-no_cpd:
blkg->pd[pol->plid] = pd;
pd->blkg = blkg;
pd->plid = pol->plid;
blk_queue_bypass_end(q);
list_for_each_entry_safe(pd, nd, &pds, alloc_node)
kfree(pd);
- list_for_each_entry_safe(cpd, cnd, &cpds, alloc_node)
- kfree(cpd);
return ret;
}
EXPORT_SYMBOL_GPL(blkcg_activate_policy);
kfree(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
- kfree(blkg->blkcg->pd[pol->plid]);
- blkg->blkcg->pd[pol->plid] = NULL;
spin_unlock(&blkg->blkcg->lock);
}
*/
int blkcg_policy_register(struct blkcg_policy *pol)
{
+ struct blkcg *blkcg;
int i, ret;
if (WARN_ON(pol->pd_size < sizeof(struct blkg_policy_data)))
return -EINVAL;
+ mutex_lock(&blkcg_pol_register_mutex);
mutex_lock(&blkcg_pol_mutex);
/* find an empty slot */
if (!blkcg_policy[i])
break;
if (i >= BLKCG_MAX_POLS)
- goto out_unlock;
+ goto err_unlock;
- /* register and update blkgs */
+ /* register @pol */
pol->plid = i;
- blkcg_policy[i] = pol;
+ blkcg_policy[pol->plid] = pol;
+
+ /* allocate and install cpd's */
+ if (pol->cpd_size) {
+ list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
+ struct blkcg_policy_data *cpd;
+
+ cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
+ if (!cpd) {
+ mutex_unlock(&blkcg_pol_mutex);
+ goto err_free_cpds;
+ }
+
+ blkcg->pd[pol->plid] = cpd;
+ cpd->plid = pol->plid;
+ pol->cpd_init_fn(blkcg);
+ }
+ }
+
+ mutex_unlock(&blkcg_pol_mutex);
/* everything is in place, add intf files for the new policy */
if (pol->cftypes)
WARN_ON(cgroup_add_legacy_cftypes(&blkio_cgrp_subsys,
pol->cftypes));
- ret = 0;
-out_unlock:
+ mutex_unlock(&blkcg_pol_register_mutex);
+ return 0;
+
+err_free_cpds:
+ if (pol->cpd_size) {
+ list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
+ kfree(blkcg->pd[pol->plid]);
+ blkcg->pd[pol->plid] = NULL;
+ }
+ }
+ blkcg_policy[pol->plid] = NULL;
+err_unlock:
mutex_unlock(&blkcg_pol_mutex);
+ mutex_unlock(&blkcg_pol_register_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(blkcg_policy_register);
*/
void blkcg_policy_unregister(struct blkcg_policy *pol)
{
- mutex_lock(&blkcg_pol_mutex);
+ struct blkcg *blkcg;
+
+ mutex_lock(&blkcg_pol_register_mutex);
if (WARN_ON(blkcg_policy[pol->plid] != pol))
goto out_unlock;
if (pol->cftypes)
cgroup_rm_cftypes(pol->cftypes);
- /* unregister and update blkgs */
+ /* remove cpds and unregister */
+ mutex_lock(&blkcg_pol_mutex);
+
+ if (pol->cpd_size) {
+ list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
+ kfree(blkcg->pd[pol->plid]);
+ blkcg->pd[pol->plid] = NULL;
+ }
+ }
blkcg_policy[pol->plid] = NULL;
-out_unlock:
+
mutex_unlock(&blkcg_pol_mutex);
+out_unlock:
+ mutex_unlock(&blkcg_pol_register_mutex);
}
EXPORT_SYMBOL_GPL(blkcg_policy_unregister);
projects / linux-drm-fsl-dcu.git / blobdiff