PM / Hibernate: Use get_gendisk to verify partition if resume_file is integer format

Sometimes resume= parameter comes in integer style (e.g. major:minor)
and then name_to_dev_t can not detect partition properly. (especially
async device like usb, mmc).

This patch calls get_gendisk() if resumewait is true and resume_file
is in integer format to work around this problem.

Signed-off-by: Minho Ban <mhban@samsung.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Documentation/kernel-parameters.txt

@@ -2372,6 +2372,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	resume=		[SWSUSP]
 			Specify the partition device for software suspend
+			Format:
+			{/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
 
 	resume_offset=	[SWSUSP]
 			Specify the offset from the beginning of the partition

kernel/power/hibernate.c

@@ -25,6 +25,8 @@
 #include <linux/freezer.h>
 #include <linux/gfp.h>
 #include <linux/syscore_ops.h>
+#include <linux/ctype.h>
+#include <linux/genhd.h>
 #include <scsi/scsi_scan.h>
 
 #include "power.h"
@@ -722,6 +724,17 @@ static int software_resume(void)
 
 	/* Check if the device is there */
 	swsusp_resume_device = name_to_dev_t(resume_file);
+
+	/*
+	 * name_to_dev_t is ineffective to verify parition if resume_file is in
+	 * integer format. (e.g. major:minor)
+	 */
+	if (isdigit(resume_file[0]) && resume_wait) {
+		int partno;
+		while (!get_gendisk(swsusp_resume_device, &partno))
+			msleep(10);
+	}
+
 	if (!swsusp_resume_device) {
 		/*
 		 * Some device discovery might still be in progress; we need