pciehp - add missing locking

This patch fixes the problem that system will panic if multiple power
on/off operations are issued to the same slot in parallel. This
problem can be easily reproduced by commands below.

    # while true; do echo 1 > power; echo 0 > power; done &
    # while true; do echo 1 > power; echo 0 > power; done &

The cause is lack of locking for enable/disable operations. This patch
fixes this problem.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index b71f774aca16..30f021c55fe5 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -92,6 +92,7 @@ struct php_ctlr_state_s {
 struct controller {
         struct controller *next;
         struct mutex crit_sect;         /* critical section mutex */
+        struct mutex ctrl_lock;         /* controller lock */
         struct php_ctlr_state_s *hpc_ctlr_handle; /* HPC controller handle */
         int num_slots;                  /* Number of slots on ctlr */
         int slot_num_inc;               /* 1 or -1 */