drbd: Remove headers from on-the-wire data structures (struct p_*)

Prepare the introduction of the protocol 100 headers. The actual protocol
header is removed for the packet declarations. I.e. allow us to use the
packets with different headers.

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

1 files changed, 22 insertions, 23 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 3ecbd4908cdc..b9dcc50135c4 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -703,27 +703,29 @@ unsigned int drbd_header_size(struct drbd_tconn *tconn)
         return sizeof(struct p_header80);
 }
 
-static void prepare_header80(struct p_header80 *h, enum drbd_packet cmd, int size)
+static unsigned int prepare_header80(struct p_header80 *h, enum drbd_packet cmd, int size)
 {
         h->magic   = cpu_to_be32(DRBD_MAGIC);
         h->command = cpu_to_be16(cmd);
         h->length  = cpu_to_be16(size);
+        return sizeof(struct p_header80);
 }
 
-static void prepare_header95(struct p_header95 *h, enum drbd_packet cmd, int size)
+static unsigned int prepare_header95(struct p_header95 *h, enum drbd_packet cmd, int size)
 {
         h->magic   = cpu_to_be16(DRBD_MAGIC_BIG);
         h->command = cpu_to_be16(cmd);
         h->length  = cpu_to_be32(size);
+        return sizeof(struct p_header95);
 }
 
-static void prepare_header(struct drbd_tconn *tconn, int vnr, struct p_header *h,
-                           enum drbd_packet cmd, int size)
+static unsigned int prepare_header(struct drbd_tconn *tconn, int vnr, void *buffer,
+                                   enum drbd_packet cmd, int size)
 {
         if (tconn->agreed_pro_version >= 95)
-                prepare_header95(&h->h95, cmd, size);
+                return prepare_header95(buffer, cmd, size);
         else
-                prepare_header80(&h->h80, cmd, size);
+                return prepare_header80(buffer, cmd, size);
 }
 
 void *conn_prepare_command(struct drbd_tconn *tconn, struct drbd_socket *sock)
@@ -733,7 +735,7 @@ void *conn_prepare_command(struct drbd_tconn *tconn, struct drbd_socket *sock)
                 mutex_unlock(&sock->mutex);
                 return NULL;
         }
-        return sock->sbuf;
+        return sock->sbuf + drbd_header_size(tconn);
 }
 
 void *drbd_prepare_command(struct drbd_conf *mdev, struct drbd_socket *sock)
@@ -758,8 +760,8 @@ static int __send_command(struct drbd_tconn *tconn, int vnr,
          */
         msg_flags = data ? MSG_MORE : 0;
 
-        prepare_header(tconn, vnr, sock->sbuf, cmd,
-                       header_size - sizeof(struct p_header) + size);
+        header_size += prepare_header(tconn, vnr, sock->sbuf, cmd,
+                                      header_size + size);
         err = drbd_send_all(tconn, sock->socket, sock->sbuf, header_size,
                             msg_flags);
         if (data && !err)
@@ -797,7 +799,7 @@ int drbd_send_ping(struct drbd_tconn *tconn)
         sock = &tconn->meta;
         if (!conn_prepare_command(tconn, sock))
                 return -EIO;
-        return conn_send_command(tconn, sock, P_PING, sizeof(struct p_header), NULL, 0);
+        return conn_send_command(tconn, sock, P_PING, 0, NULL, 0);
 }
 
 int drbd_send_ping_ack(struct drbd_tconn *tconn)
@@ -807,7 +809,7 @@ int drbd_send_ping_ack(struct drbd_tconn *tconn)
         sock = &tconn->meta;
         if (!conn_prepare_command(tconn, sock))
                 return -EIO;
-        return conn_send_command(tconn, sock, P_PING_ACK, sizeof(struct p_header), NULL, 0);
+        return conn_send_command(tconn, sock, P_PING_ACK, 0, NULL, 0);
 }
 
 int drbd_send_sync_param(struct drbd_conf *mdev)
@@ -1205,10 +1207,11 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev, struct bm_xfer_ctx *c)
 {
         struct drbd_socket *sock = &mdev->tconn->data;
         unsigned int header_size = drbd_header_size(mdev->tconn);
-        struct p_compressed_bm *p = sock->sbuf;
+        struct p_compressed_bm *p = sock->sbuf + header_size;
         int len, err;
 
-        len = fill_bitmap_rle_bits(mdev, p, DRBD_SOCKET_BUFFER_SIZE - sizeof(*p) /* FIXME */, c);
+        len = fill_bitmap_rle_bits(mdev, p,
+                        DRBD_SOCKET_BUFFER_SIZE - header_size - sizeof(*p), c);
         if (len < 0)
                 return -EIO;
 
@@ -1218,7 +1221,7 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev, struct bm_xfer_ctx *c)
                                      P_COMPRESSED_BITMAP, sizeof(*p) + len,
                                      NULL, 0);
                 c->packets[0]++;
-                c->bytes[0] += sizeof(*p) + len;
+                c->bytes[0] += header_size + sizeof(*p) + len;
 
                 if (c->bit_offset >= c->bm_bits)
                         len = 0; /* DONE */
@@ -1227,17 +1230,15 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev, struct bm_xfer_ctx *c)
                  * send a buffer full of plain text bits instead. */
                 unsigned int data_size;
                 unsigned long num_words;
-                struct p_header *h = sock->sbuf;
+                unsigned long *p = sock->sbuf + header_size;
 
                 data_size = DRBD_SOCKET_BUFFER_SIZE - header_size;
-                num_words = min_t(size_t, data_size / sizeof(unsigned long),
+                num_words = min_t(size_t, data_size / sizeof(*p),
                                   c->bm_words - c->word_offset);
-                len = num_words * sizeof(unsigned long);
+                len = num_words * sizeof(*p);
                 if (len)
-                        drbd_bm_get_lel(mdev, c->word_offset, num_words,
-                                        (unsigned long *)h->payload);
-                err = __send_command(mdev->tconn, mdev->vnr, sock, P_BITMAP,
-                                     sizeof(*h) + len, NULL, 0);
+                        drbd_bm_get_lel(mdev, c->word_offset, num_words, p);
+                err = __send_command(mdev->tconn, mdev->vnr, sock, P_BITMAP, len, NULL, 0);
                 c->word_offset += num_words;
                 c->bit_offset = c->word_offset * BITS_PER_LONG;
 
@@ -2556,8 +2557,6 @@ int __init drbd_init(void)
 {
         int err;
 
-        BUILD_BUG_ON(sizeof(struct p_connection_features) != 80);
-
         if (minor_count < DRBD_MINOR_COUNT_MIN || minor_count > DRBD_MINOR_COUNT_MAX) {
                 printk(KERN_ERR
                        "drbd: invalid minor_count (%d)\n", minor_count);