1 files changed, 55 insertions, 39 deletions

diff --git a/drivers/acpi/acpica/evmisc.c b/drivers/acpi/acpica/evmisc.c
index fcaed9fb44f..8e31bb5a973 100644
--- a/drivers/acpi/acpica/evmisc.c
+++ b/drivers/acpi/acpica/evmisc.c
@@ -284,41 +284,41 @@ static void ACPI_SYSTEM_XFACE acpi_ev_notify_dispatch(void *context)
  * RETURN:      ACPI_INTERRUPT_HANDLED
  *
  * DESCRIPTION: Invoked directly from the SCI handler when a global lock
- *              release interrupt occurs. Attempt to acquire the global lock,
- *              if successful, signal the thread waiting for the lock.
+ *              release interrupt occurs.  If there's a thread waiting for
+ *              the global lock, signal it.
  *
  * NOTE: Assumes that the semaphore can be signaled from interrupt level. If
  * this is not possible for some reason, a separate thread will have to be
  * scheduled to do this.
  *
  ******************************************************************************/
+static u8 acpi_ev_global_lock_pending;
+static spinlock_t _acpi_ev_global_lock_pending_lock;
+#define acpi_ev_global_lock_pending_lock &_acpi_ev_global_lock_pending_lock
 
 static u32 acpi_ev_global_lock_handler(void *context)
 {
-	u8 acquired = FALSE;
+	acpi_status status;
+	acpi_cpu_flags flags;
 
-	/*
-	 * Attempt to get the lock.
-	 *
-	 * If we don't get it now, it will be marked pending and we will
-	 * take another interrupt when it becomes free.
-	 */
-	ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
-	if (acquired) {
+	flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
 
-		/* Got the lock, now wake all threads waiting for it */
+	if (!acpi_ev_global_lock_pending) {
+		goto out;
+	}
 
-		acpi_gbl_global_lock_acquired = TRUE;
-		/* Send a unit to the semaphore */
+	/* Send a unit to the semaphore */
 
-		if (ACPI_FAILURE
-		    (acpi_os_signal_semaphore
-		     (acpi_gbl_global_lock_semaphore, 1))) {
-			ACPI_ERROR((AE_INFO,
-				    "Could not signal Global Lock semaphore"));
-		}
+	status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
+	if (ACPI_FAILURE(status)) {
+		ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
 	}
 
+	acpi_ev_global_lock_pending = FALSE;
+
+ out:
+	acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
+
 	return (ACPI_INTERRUPT_HANDLED);
 }
 
@@ -415,6 +415,7 @@ static int acpi_ev_global_lock_acquired;
 
 acpi_status acpi_ev_acquire_global_lock(u16 timeout)
 {
+	acpi_cpu_flags flags;
 	acpi_status status = AE_OK;
 	u8 acquired = FALSE;
 
@@ -467,32 +468,47 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout)
 		return_ACPI_STATUS(AE_OK);
 	}
 
-	/* Attempt to acquire the actual hardware lock */
+	flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
+
+	do {
+
+		/* Attempt to acquire the actual hardware lock */
+
+		ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
+		if (acquired) {
+			acpi_gbl_global_lock_acquired = TRUE;
+
+			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+					  "Acquired hardware Global Lock\n"));
+			break;
+		}
 
-	ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
-	if (acquired) {
+		acpi_ev_global_lock_pending = TRUE;
 
-		/* We got the lock */
+		acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
 
+		/*
+		 * Did not get the lock. The pending bit was set above, and we
+		 * must wait until we get the global lock released interrupt.
+		 */
 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
-				  "Acquired hardware Global Lock\n"));
+				  "Waiting for hardware Global Lock\n"));
 
-		acpi_gbl_global_lock_acquired = TRUE;
-		return_ACPI_STATUS(AE_OK);
-	}
+		/*
+		 * Wait for handshake with the global lock interrupt handler.
+		 * This interface releases the interpreter if we must wait.
+		 */
+		status = acpi_ex_system_wait_semaphore(
+						acpi_gbl_global_lock_semaphore,
+						ACPI_WAIT_FOREVER);
 
-	/*
-	 * Did not get the lock. The pending bit was set above, and we must now
-	 * wait until we get the global lock released interrupt.
-	 */
-	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Waiting for hardware Global Lock\n"));
+		flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
 
-	/*
-	 * Wait for handshake with the global lock interrupt handler.
-	 * This interface releases the interpreter if we must wait.
-	 */
-	status = acpi_ex_system_wait_semaphore(acpi_gbl_global_lock_semaphore,
-					       ACPI_WAIT_FOREVER);
+	} while (ACPI_SUCCESS(status));
+
+	acpi_ev_global_lock_pending = FALSE;
+
+	acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
 
 	return_ACPI_STATUS(status);
 }