s390/3270: Fix buffer assignment

Since commit 1b2ac5a6d61f ("s390/3270: use new address translation
helpers") rq->buffer is passed unconditionally to virt_to_dma32().
The 3270 driver allocates requests without buffer, so the value passed
to virt_to_dma32 might be NULL. Check for NULL before assigning.

Fixes: 1b2ac5a6d61f ("s390/3270: use new address translation helpers")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index 37173cb0f5f5a222b936029b8ff8e7997c401d4d..c57694be9bd32ef8cb9dc8ad794379ef2da44640 100644 (file)
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -162,7 +162,8 @@ struct raw3270_request *raw3270_request_alloc(size_t size)
        /*
         * Setup ccw.
         */
-       rq->ccw.cda = virt_to_dma32(rq->buffer);
+       if (rq->buffer)
+               rq->ccw.cda = virt_to_dma32(rq->buffer);
        rq->ccw.flags = CCW_FLAG_SLI;
 
        return rq;
@@ -188,7 +189,8 @@ int raw3270_request_reset(struct raw3270_request *rq)
                return -EBUSY;
        rq->ccw.cmd_code = 0;
        rq->ccw.count = 0;
-       rq->ccw.cda = virt_to_dma32(rq->buffer);
+       if (rq->buffer)
+               rq->ccw.cda = virt_to_dma32(rq->buffer);
        rq->ccw.flags = CCW_FLAG_SLI;
        rq->rescnt = 0;
        rq->rc = 0;