ACPICA: Fix for update of the Global Lock Handle

Fixed a problem where the global lock handle was not properly
updated if a thread that acquired the global lock via
executing AML code then attempted to acquire the lock via the
AcpiAcquireGlobalLock interface.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/acpi/events/evmisc.c b/drivers/acpi/events/evmisc.c
index 2d34663dc1ed..d075062f5b89 100644
--- a/drivers/acpi/events/evmisc.c
+++ b/drivers/acpi/events/evmisc.c
@@ -461,6 +461,19 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout)
         acpi_ev_global_lock_acquired++;
 
         /*
+         * Update the global lock handle and check for wraparound. The handle is
+         * only used for the external global lock interfaces, but it is updated
+         * here to properly handle the case where a single thread may acquire the
+         * lock via both the AML and the acpi_acquire_global_lock interfaces. The
+         * handle is therefore updated on the first acquire from a given thread
+         * regardless of where the acquisition request originated.
+         */
+        acpi_gbl_global_lock_handle++;
+        if (acpi_gbl_global_lock_handle == 0) {
+                acpi_gbl_global_lock_handle = 1;
+        }
+
+        /*
          * Make sure that a global lock actually exists. If not, just treat
          * the lock as a standard mutex.
          */