hpfs: Replace simple_strtoul with kstrtoint in hpfs_parse_param

kstrtoint() is better because simple_strtoul() ignores overflow and the
type of 'timeshift' is 'int' rather than 'unsigned long'. Using kstrtoint()
is more concise too.

Signed-off-by: Su Hui <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>

Author: Su Hui

fs/hpfs/super.c

@@ -404,15 +404,11 @@ static int hpfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 		break;
 	case Opt_timeshift:
 		{
-			int m = 1;
 			char *rhs = param->string;
 			int timeshift;
 
-			if (*rhs == '-') m = -1;
-			if (*rhs == '+' || *rhs == '-') rhs++;
-			timeshift = simple_strtoul(rhs, &rhs, 0) * m;
-			if (*rhs)
-					return -EINVAL;
+			if (kstrtoint(rhs, 0, &timeshift))
+				return -EINVAL;
 			ctx->timeshift = timeshift;
 			break;
 		}