s390/diag: Return errno's from diag204

Return different errno's from diag204 to allow users to handle them
accordingly. Instead of returning -1 regardless of the failing
condition, return -EINVAL on invalid memory address and -EOPNOTSUPP when
diag instruction fails.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: NickJackolson

arch/s390/kernel/diag.c

@@ -215,16 +215,16 @@ int diag204(unsigned long subcode, unsigned long size, void *addr)
 {
 	if (addr) {
 		if (WARN_ON_ONCE(!is_vmalloc_addr(addr)))
-			return -1;
+			return -EINVAL;
 		if (WARN_ON_ONCE(!IS_ALIGNED((unsigned long)addr, PAGE_SIZE)))
-			return -1;
+			return -EINVAL;
 	}
 	if ((subcode & DIAG204_SUBCODE_MASK) == DIAG204_SUBC_STIB4)
 		addr = (void *)pfn_to_phys(vmalloc_to_pfn(addr));
 	diag_stat_inc(DIAG_STAT_X204);
 	size = __diag204(&subcode, size, addr);
 	if (subcode)
-		return -1;
+		return -EOPNOTSUPP;
 	return size;
 }
 EXPORT_SYMBOL(diag204);