PM / Hibernate: Fix blkdev refleaks

While cruising through the swsusp code I found few blkdev reference
leaks of resume_bdev.

swsusp_read: remove blkdev_put altogether. Some fail paths do
             not do that.
swsusp_check: make sure we always put a reference on fail paths
software_resume: all fail paths between swsusp_check and swsusp_read
                 omit swsusp_close. Add it in those cases. And since
                 swsusp_read doesn't drop the reference anymore, do
                 it here unconditionally.

[rjw: Fixed a small coding style issue.]

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/hibernate.c

@@ -693,21 +693,22 @@ static int software_resume(void)
 	/* The snapshot device should not be opened while we're running */
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 		error = -EBUSY;
+		swsusp_close(FMODE_READ);
 		goto Unlock;
 	}
 
 	pm_prepare_console();
 	error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 	if (error)
-		goto Finish;
+		goto close_finish;
 
 	error = usermodehelper_disable();
 	if (error)
-		goto Finish;
+		goto close_finish;
 
 	error = create_basic_memory_bitmaps();
 	if (error)
-		goto Finish;
+		goto close_finish;
 
 	pr_debug("PM: Preparing processes for restore.\n");
 	error = prepare_processes();
@@ -719,6 +720,7 @@ static int software_resume(void)
 	pr_debug("PM: Reading hibernation image.\n");
 
 	error = swsusp_read(&flags);
+	swsusp_close(FMODE_READ);
 	if (!error)
 		hibernation_restore(flags & SF_PLATFORM_MODE);
 
@@ -737,6 +739,9 @@ static int software_resume(void)
 	mutex_unlock(&pm_mutex);
 	pr_debug("PM: Resume from disk failed.\n");
 	return error;
+close_finish:
+	swsusp_close(FMODE_READ);
+	goto Finish;
 }
 
 late_initcall(software_resume);

kernel/power/swap.c

@@ -572,8 +572,6 @@ int swsusp_read(unsigned int *flags_p)
 		error = load_image(&handle, &snapshot, header->pages - 1);
 	release_swap_reader(&handle);
 
-	blkdev_put(resume_bdev, FMODE_READ);
-
 	if (!error)
 		pr_debug("PM: Image successfully loaded\n");
 	else
@@ -596,7 +594,7 @@ int swsusp_check(void)
 		error = bio_read_page(swsusp_resume_block,
 					swsusp_header, NULL);
 		if (error)
-			return error;
+			goto put;
 
 		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
@@ -604,8 +602,10 @@ int swsusp_check(void)
 			error = bio_write_page(swsusp_resume_block,
 						swsusp_header, NULL);
 		} else {
-			return -EINVAL;
+			error = -EINVAL;
 		}
+
+put:
 		if (error)
 			blkdev_put(resume_bdev, FMODE_READ);
 		else