s390/extmem: improve reporting of -ERANGE error

Interface segment_warning() reports maximum mappable physical
address for -ERANGE error. Currently that address is the value
of VMEM_MAX_PHYS macro, but that well might change. A better
way to obtain that address is calling arch_get_mappable_range()
callback - one that is used by vmem_add_mapping() and generates
-ERANGE error in the first place.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/mm/extmem.c

@@ -640,10 +640,13 @@ void segment_warning(int rc, char *seg_name)
 		pr_err("There is not enough memory to load or query "
 		       "DCSS %s\n", seg_name);
 		break;
-	case -ERANGE:
-		pr_err("DCSS %s exceeds the kernel mapping range (%lu) "
-		       "and cannot be loaded\n", seg_name, VMEM_MAX_PHYS);
+	case -ERANGE: {
+		struct range mhp_range = arch_get_mappable_range();
+
+		pr_err("DCSS %s exceeds the kernel mapping range (%llu) "
+		       "and cannot be loaded\n", seg_name, mhp_range.end + 1);
 		break;
+	}
 	default:
 		break;
 	}