[PATCH 4.4 35/58] s390/vmlogrdr: fix IUCV buffer allocation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>

commit 5457e03de918f7a3e294eb9d26a608ab8a579976 upstream.

The buffer for iucv_message_receive() needs to be below 2 GB. In
__iucv_message_receive(), the buffer address is casted to an u32, which
would result in either memory corruption or an addressing exception when
using addresses >= 2 GB.

Fix this by using GFP_DMA for the buffer allocation.

Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/s390/char/vmlogrdr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/s390/char/vmlogrdr.c
+++ b/drivers/s390/char/vmlogrdr.c
@@ -872,7 +872,7 @@ static int __init vmlogrdr_init(void)
 		goto cleanup;
 
 	for (i=0; i < MAXMINOR; ++i ) {
-		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
+		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 		if (!sys_ser[i].buffer) {
 			rc = -ENOMEM;
 			break;