PM / Domains: Ensure subdomain is not in use before removing

The function pm_genpd_remove_subdomain() removes a subdomain from a
generic PM domain, however, it does not check if the subdomain has any
slave domains or device attached before doing so. Therefore, add a test
to verify that the subdomain does not have any slave domains associated
or any device attached before removing.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 62f757250235..16550c63d611 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1473,6 +1473,13 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 
         mutex_lock(&genpd->lock);
 
+        if (!list_empty(&subdomain->slave_links) || subdomain->device_count) {
+                pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
+                        subdomain->name);
+                ret = -EBUSY;
+                goto out;
+        }
+
         list_for_each_entry(link, &genpd->master_links, master_node) {
                 if (link->slave != subdomain)
                         continue;
@@ -1491,6 +1498,7 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
                 break;
         }
 
+out:
         mutex_unlock(&genpd->lock);
 
         return ret;