drbd: silence underflow warning in read_in_block()

My static checker warns that "data_size" could be negative and underflow
the limit check.  The code looks suspicious but I don't know if it is a
real bug.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_receiver.c

@@ -1592,7 +1592,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 	struct drbd_peer_request *peer_req;
 	struct page *page;
 	int dgs, ds, err;
-	int data_size = pi->size;
+	unsigned int data_size = pi->size;
 	void *dig_in = peer_device->connection->int_dig_in;
 	void *dig_vv = peer_device->connection->int_dig_vv;
 	unsigned long *data;

include/linux/drbd.h

@@ -52,7 +52,7 @@
 #endif
 
 extern const char *drbd_buildtag(void);
-#define REL_VERSION "8.4.3"
+#define REL_VERSION "8.4.5"
 #define API_VERSION 1
 #define PRO_VERSION_MIN 86
 #define PRO_VERSION_MAX 101