drbd: Introduce drbd_header_size()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 632ca9aecef394a786a7ca9ca5f5b74d6d2ad35f..729c96fc0c870566e68078b46df98a9a4f7e19e1 100644 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -315,6 +315,8 @@ struct p_header {
        u8        payload[0];
 };
 
+extern unsigned int drbd_header_size(struct drbd_tconn *tconn);
+
 /*
  * short commands, packets without payload, plain p_header:
  *   P_PING

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 699ab11256beb9bb1605514bb4a3b7d5b86370a5..606a9ecbe044bf18cd63036d7109cf2b86de1cf6 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -689,6 +689,20 @@ void drbd_thread_current_set_cpu(struct drbd_thread *thi)
 }
 #endif
 
+/**
+ * drbd_header_size  -  size of a packet header
+ *
+ * The header size is a multiple of 8, so any payload following the header is
+ * word aligned on 64-bit architectures.  (The bitmap send and receive code
+ * relies on this.)
+ */
+unsigned int drbd_header_size(struct drbd_tconn *tconn)
+{
+       BUILD_BUG_ON(sizeof(struct p_header80) != sizeof(struct p_header95));
+       BUILD_BUG_ON(!IS_ALIGNED(sizeof(struct p_header80), 8));
+       return sizeof(struct p_header80);
+}
+
 static void prepare_header80(struct p_header80 *h, enum drbd_packet cmd, int size)
 {
        h->magic   = cpu_to_be32(DRBD_MAGIC);

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 61104dbb01720a1a126c34f65d94094ae53ed7ad..e52a929d9ed3e3c181a5530f8138cf024f90261b 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -995,7 +995,7 @@ static int drbd_recv_header(struct drbd_tconn *tconn, struct packet_info *pi)
        struct p_header *h = tconn->data.rbuf;
        int err;
 
-       err = drbd_recv_all_warn(tconn, h, sizeof(*h));
+       err = drbd_recv_all_warn(tconn, h, drbd_header_size(tconn));
        if (err)
                return err;
 
@@ -4842,7 +4842,8 @@ int drbd_asender(struct drbd_thread *thi)
        int rv;
        void *buf    = h;
        int received = 0;
-       int expect   = sizeof(struct p_header);
+       unsigned int header_size = drbd_header_size(tconn);
+       int expect   = header_size;
        int ping_timeout_active = 0;
 
        current->policy = SCHED_RR;  /* Make this a realtime task! */
@@ -4926,7 +4927,7 @@ int drbd_asender(struct drbd_thread *thi)
                                goto disconnect;
                        }
                        expect = cmd->pkt_size;
-                       if (pi.size != expect - sizeof(struct p_header)) {
+                       if (pi.size != expect - header_size) {
                                conn_err(tconn, "Wrong packet size on meta (c: %d, l: %d)\n",
                                        pi.cmd, pi.size);
                                goto reconnect;
@@ -4950,7 +4951,7 @@ int drbd_asender(struct drbd_thread *thi)
 
                        buf      = h;
                        received = 0;
-                       expect   = sizeof(struct p_header);
+                       expect   = header_size;
                        cmd      = NULL;
                }
        }