PM / Domains: Handle safely genpd_syscore_switch() call on non-genpd device

genpd_syscore_switch() had two problems:
 1. It silently assumed that device, it is being called for, belongs
    to generic power domain and used container_of() on its power
    domain pointer.  Such assumption might not be true always.

2. It iterated over list of generic power domains without holding
   gpd_list_lock mutex thus list could have been modified at the same
   time.

Usage of genpd_lookup_dev() solves both problems as it is safe a call
for non-generic power domains and uses mutex when iterating.

Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index bbbb1d72395b..b8d7907ee101 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1148,8 +1148,8 @@ static void genpd_syscore_switch(struct device *dev, bool suspend)
 {
         struct generic_pm_domain *genpd;
 
-        genpd = dev_to_genpd(dev);
-        if (!pm_genpd_present(genpd))
+        genpd = genpd_lookup_dev(dev);
+        if (!genpd)
                 return;
 
         if (suspend) {