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PM / Domains: Do not take parent locks to modify subdomain counters 

After the subdomain counter in struct generic_pm_domain has been
changed into an atomic_t field, it is possible to modify
pm_genpd_poweron() and pm_genpd_poweroff() so that they don't take
the parents locks.  This requires pm_genpd_poweron() to increment
the parent's subdomain counter before calling itself recursively
for the parent and to decrement it if an error is to be returned.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-08-08 23:43:14 +02:00
parent c4bb3160c8
commit 3c07cbc488
1 changed files with 31 additions and 39 deletions
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70
drivers/base/power/domain.c
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@ -93,12 +93,7 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd)
int ret = 0; int ret = 0;
start: start:
if (parent) { mutex_lock(&genpd->lock);
genpd_acquire_lock(parent);
mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
} else {
mutex_lock(&genpd->lock);
}
if (genpd->status == GPD_STATE_ACTIVE if (genpd->status == GPD_STATE_ACTIVE
|| (genpd->prepared_count > 0 && genpd->suspend_power_off)) || (genpd->prepared_count > 0 && genpd->suspend_power_off))
@ -109,31 +104,33 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd)
goto out; goto out;
} }
if (parent && parent->status != GPD_STATE_ACTIVE) { if (parent) {
genpd_sd_counter_inc(parent);
mutex_unlock(&genpd->lock); mutex_unlock(&genpd->lock);
genpd_release_lock(parent);
ret = pm_genpd_poweron(parent); ret = pm_genpd_poweron(parent);
if (ret) if (ret) {
genpd_sd_counter_dec(parent);
return ret; return ret;
}
parent = NULL;
goto start; goto start;
} }
if (genpd->power_on) { if (genpd->power_on)
ret = genpd->power_on(genpd); ret = genpd->power_on(genpd);
if (ret)
goto out;
}
genpd_set_active(genpd); if (ret) {
if (parent) if (genpd->parent)
genpd_sd_counter_inc(parent); genpd_sd_counter_dec(genpd->parent);
} else {
genpd_set_active(genpd);
}
out: out:
mutex_unlock(&genpd->lock); mutex_unlock(&genpd->lock);
if (parent)
genpd_release_lock(parent);
return ret; return ret;
} }
@ -293,7 +290,8 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
genpd->poweroff_task = current; genpd->poweroff_task = current;
list_for_each_entry_reverse(dle, &genpd->dev_list, node) { list_for_each_entry_reverse(dle, &genpd->dev_list, node) {
ret = __pm_genpd_save_device(dle, genpd); ret = atomic_read(&genpd->sd_count) == 0 ?
__pm_genpd_save_device(dle, genpd) : -EBUSY;
if (ret) { if (ret) {
genpd_set_active(genpd); genpd_set_active(genpd);
goto out; goto out;
@ -308,38 +306,32 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
} }
} }
parent = genpd->parent; if (genpd->power_off) {
if (parent) { if (atomic_read(&genpd->sd_count) > 0) {
mutex_unlock(&genpd->lock); ret = -EBUSY;
genpd_acquire_lock(parent);
mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
if (genpd_abort_poweroff(genpd)) {
genpd_release_lock(parent);
goto out; goto out;
} }
}
if (genpd->power_off) { /*
* If sd_count > 0 at this point, one of the children hasn't
* managed to call pm_genpd_poweron() for the parent yet after
* incrementing it. In that case pm_genpd_poweron() will wait
* for us to drop the lock, so we can call .power_off() and let
* the pm_genpd_poweron() restore power for us (this shouldn't
* happen very often).
*/
ret = genpd->power_off(genpd); ret = genpd->power_off(genpd);
if (ret == -EBUSY) { if (ret == -EBUSY) {
genpd_set_active(genpd); genpd_set_active(genpd);
if (parent)
genpd_release_lock(parent);
goto out; goto out;
} }
} }
genpd->status = GPD_STATE_POWER_OFF; genpd->status = GPD_STATE_POWER_OFF;
if (parent) { parent = genpd->parent;
if (genpd_sd_counter_dec(parent)) if (parent && genpd_sd_counter_dec(parent))
genpd_queue_power_off_work(parent); genpd_queue_power_off_work(parent);
genpd_release_lock(parent);
}
out: out:
genpd->poweroff_task = NULL; genpd->poweroff_task = NULL;