PM / Hibernate: Thaw kernel threads in hibernation_snapshot() in error/test path

In the hibernation call path, the kernel threads are frozen inside
hibernation_snapshot(). If we happen to encounter an error further down
the road or if we are exiting early due to a successful freezer test,
then thaw kernel threads before returning to the caller.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/hibernate.c

@@ -343,13 +343,13 @@ int hibernation_snapshot(int platform_mode)
 		 * successful freezer test.
 		 */
 		freezer_test_done = true;
-		goto Cleanup;
+		goto Thaw;
 	}
 
 	error = dpm_prepare(PMSG_FREEZE);
 	if (error) {
 		dpm_complete(PMSG_RECOVER);
-		goto Cleanup;
+		goto Thaw;
 	}
 
 	suspend_console();
@@ -385,6 +385,8 @@ int hibernation_snapshot(int platform_mode)
 	platform_end(platform_mode);
 	return error;
 
+ Thaw:
+	thaw_kernel_threads();
  Cleanup:
 	swsusp_free();
 	goto Close;

kernel/power/user.c

@@ -249,16 +249,12 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		}
 		pm_restore_gfp_mask();
 		error = hibernation_snapshot(data->platform_support);
-		if (error) {
-			thaw_kernel_threads();
-		} else {
+		if (!error) {
 			error = put_user(in_suspend, (int __user *)arg);
 			if (!error && !freezer_test_done)
 				data->ready = 1;
-			if (freezer_test_done) {
+			if (freezer_test_done)
 				freezer_test_done = false;
-				thaw_kernel_threads();
-			}
 		}
 		break;