libceph: set page info with byte length

When setting page array information for message data, provide the
byte length rather than the page count ceph_msg_data_set_pages().

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index aa463b9..e6d20e8 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -220,7 +220,7 @@
 extern void ceph_con_keepalive(struct ceph_connection *con);
 
 extern void ceph_msg_data_set_pages(struct ceph_msg *msg, struct page **pages,
-				unsigned int page_count, size_t alignment);
+				size_t length, size_t alignment);
 
 extern struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
 				     bool can_fail);