UPSTREAM: PM / Domains: Fix potential deadlock while adding/removing subdomains

[firefly-linux-kernel-4.4.55.git] / drivers / base / power / domain.c

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 787793d3574440f4158e890400c1751551df77d7..5decc295def447b15bb7e8e5aa146d731dfbe9c0 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1338,8 +1338,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
        if (!link)
                return -ENOMEM;
 
-       mutex_lock(&genpd->lock);
-       mutex_lock_nested(&subdomain->lock, SINGLE_DEPTH_NESTING);
+       mutex_lock(&subdomain->lock);
+       mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
 
        if (genpd->status == GPD_STATE_POWER_OFF
            &&  subdomain->status != GPD_STATE_POWER_OFF) {
@@ -1362,8 +1362,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
                genpd_sd_counter_inc(genpd);
 
  out:
-       mutex_unlock(&subdomain->lock);
        mutex_unlock(&genpd->lock);
+       mutex_unlock(&subdomain->lock);
        if (ret)
                kfree(link);
        return ret;
@@ -1384,7 +1384,8 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
        if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain))
                return -EINVAL;
 
-       mutex_lock(&genpd->lock);
+       mutex_lock(&subdomain->lock);
+       mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
 
        if (!list_empty(&subdomain->master_links) || subdomain->device_count) {
                pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
@@ -1397,22 +1398,19 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
                if (link->slave != subdomain)
                        continue;
 
-               mutex_lock_nested(&subdomain->lock, SINGLE_DEPTH_NESTING);
-
                list_del(&link->master_node);
                list_del(&link->slave_node);
                kfree(link);
                if (subdomain->status != GPD_STATE_POWER_OFF)
                        genpd_sd_counter_dec(genpd);
 
-               mutex_unlock(&subdomain->lock);
-
                ret = 0;
                break;
        }
 
 out:
        mutex_unlock(&genpd->lock);
+       mutex_unlock(&subdomain->lock);
 
        return ret;
 }