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>

4 files changed, 110 insertions, 154 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index cb16783e78df..6d55bb75a081 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -307,32 +307,8 @@ struct p_header95 {
         u32       length;       /* Use only 24 bits of that. Ignore the highest 8 bit. */
 } __packed;
 
-struct p_header {
-        union {
-                struct p_header80 h80;
-                struct p_header95 h95;
-        };
-        u8        payload[0];
-};
-
 extern unsigned int drbd_header_size(struct drbd_tconn *tconn);
 
-/*
- * short commands, packets without payload, plain p_header:
- *   P_PING
- *   P_PING_ACK
- *   P_BECOME_SYNC_TARGET
- *   P_BECOME_SYNC_SOURCE
- *   P_UNPLUG_REMOTE
- */
-
-/*
- * commands with out-of-struct payload:
- *   P_BITMAP    (no additional fields)
- *   P_DATA, P_DATA_REPLY (see p_data)
- *   P_COMPRESSED_BITMAP (see receive_compressed_bitmap)
- */
-
 /* these defines must not be changed without changing the protocol version */
 #define DP_HARDBARRIER        1 /* depricated */
 #define DP_RW_SYNC            2 /* equals REQ_SYNC    */
@@ -343,7 +319,6 @@ extern unsigned int drbd_header_size(struct drbd_tconn *tconn);
 #define DP_DISCARD           64 /* equals REQ_DISCARD */
 
 struct p_data {
-        struct p_header head;
         u64         sector;    /* 64 bits sector number */
         u64         block_id;  /* to identify the request in protocol B&C */
         u32         seq_num;
@@ -359,7 +334,6 @@ struct p_data {
  *   P_DATA_REQUEST, P_RS_DATA_REQUEST
  */
 struct p_block_ack {
-        struct p_header head;
         u64         sector;
         u64         block_id;
         u32         blksize;
@@ -367,7 +341,6 @@ struct p_block_ack {
 } __packed;
 
 struct p_block_req {
-        struct p_header head;
         u64 sector;
         u64 block_id;
         u32 blksize;
@@ -384,7 +357,6 @@ struct p_block_req {
  */
 
 struct p_connection_features {
-        struct p_header head;   /* Note: vnr will be ignored */
         u32 protocol_min;
         u32 feature_flags;
         u32 protocol_max;
@@ -396,22 +368,18 @@ struct p_connection_features {
         u32 _pad;
         u64 reserverd[7];
 } __packed;
-/* 80 bytes, FIXED for the next century */
 
 struct p_barrier {
-        struct p_header head;
         u32 barrier;    /* barrier number _handle_ only */
         u32 pad;        /* to multiple of 8 Byte */
 } __packed;
 
 struct p_barrier_ack {
-        struct p_header head;
         u32 barrier;
         u32 set_size;
 } __packed;
 
 struct p_rs_param {
-        struct p_header head;
         u32 rate;
 
               /* Since protocol version 88 and higher. */
@@ -419,7 +387,6 @@ struct p_rs_param {
 } __packed;
 
 struct p_rs_param_89 {
-        struct p_header head;
         u32 rate;
         /* protocol version 89: */
         char verify_alg[SHARED_SECRET_MAX];
@@ -427,7 +394,6 @@ struct p_rs_param_89 {
 } __packed;
 
 struct p_rs_param_95 {
-        struct p_header head;
         u32 rate;
         char verify_alg[SHARED_SECRET_MAX];
         char csums_alg[SHARED_SECRET_MAX];
@@ -443,7 +409,6 @@ enum drbd_conn_flags {
 };
 
 struct p_protocol {
-        struct p_header head;
         u32 protocol;
         u32 after_sb_0p;
         u32 after_sb_1p;
@@ -457,17 +422,14 @@ struct p_protocol {
 } __packed;
 
 struct p_uuids {
-        struct p_header head;
         u64 uuid[UI_EXTENDED_SIZE];
 } __packed;
 
 struct p_rs_uuid {
-        struct p_header head;
         u64         uuid;
 } __packed;
 
 struct p_sizes {
-        struct p_header head;
         u64         d_size;  /* size of disk */
         u64         u_size;  /* user requested size */
         u64         c_size;  /* current exported size */
@@ -477,18 +439,15 @@ struct p_sizes {
 } __packed;
 
 struct p_state {
-        struct p_header head;
         u32         state;
 } __packed;
 
 struct p_req_state {
-        struct p_header head;
         u32         mask;
         u32         val;
 } __packed;
 
 struct p_req_state_reply {
-        struct p_header head;
         u32         retcode;
 } __packed;
 
@@ -503,14 +462,12 @@ struct p_drbd06_param {
 } __packed;
 
 struct p_discard {
-        struct p_header head;
         u64         block_id;
         u32         seq_num;
         u32         pad;
 } __packed;
 
 struct p_block_desc {
-        struct p_header head;
         u64 sector;
         u32 blksize;
         u32 pad;        /* to multiple of 8 Byte */
@@ -526,7 +483,6 @@ enum drbd_bitmap_code {
 };
 
 struct p_compressed_bm {
-        struct p_header head;
         /* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
          * (encoding & 0x80): polarity (set/unset) of first runlength
          * ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
@@ -538,7 +494,6 @@ struct p_compressed_bm {
 } __packed;
 
 struct p_delay_probe93 {
-        struct p_header head;
         u32     seq_num; /* sequence number to match the two probe packets */
         u32     offset;  /* usecs the probe got sent after the reference time point */
 } __packed;
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);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 74ed3ac263f3..7e0ab2246fb6 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -52,6 +52,7 @@ struct packet_info {
         enum drbd_packet cmd;
         unsigned int size;
         unsigned int vnr;
+        void *data;
 };
 
 enum finish_epoch {
@@ -729,14 +730,14 @@ out:
         return s_estab;
 }
 
-static int decode_header(struct drbd_tconn *, struct p_header *, struct packet_info *);
+static int decode_header(struct drbd_tconn *, void *, struct packet_info *);
 
 static int send_first_packet(struct drbd_tconn *tconn, struct drbd_socket *sock,
                              enum drbd_packet cmd)
 {
         if (!conn_prepare_command(tconn, sock))
                 return -EIO;
-        return conn_send_command(tconn, sock, cmd, sizeof(struct p_header), NULL, 0);
+        return conn_send_command(tconn, sock, cmd, 0, NULL, 0);
 }
 
 static int receive_first_packet(struct drbd_tconn *tconn, struct socket *sock)
@@ -978,36 +979,43 @@ out_release_sockets:
         return -1;
 }
 
-static int decode_header(struct drbd_tconn *tconn, struct p_header *h, struct packet_info *pi)
+static int decode_header(struct drbd_tconn *tconn, void *header, struct packet_info *pi)
 {
-        if (h->h80.magic == cpu_to_be32(DRBD_MAGIC)) {
-                pi->cmd = be16_to_cpu(h->h80.command);
-                pi->size = be16_to_cpu(h->h80.length);
-                pi->vnr = 0;
-        } else if (h->h95.magic == cpu_to_be16(DRBD_MAGIC_BIG)) {
-                pi->cmd = be16_to_cpu(h->h95.command);
-                pi->size = be32_to_cpu(h->h95.length) & 0x00ffffff;
+        unsigned int header_size = drbd_header_size(tconn);
+
+        if (header_size == sizeof(struct p_header95) &&
+            *(__be16 *)header == cpu_to_be16(DRBD_MAGIC_BIG)) {
+                struct p_header95 *h = header;
+
+                pi->cmd = be16_to_cpu(h->command);
+                pi->size = be32_to_cpu(h->length) & 0x00ffffff;
+                pi->vnr  = 0;
+        } else if (header_size == sizeof(struct p_header80) &&
+                   *(__be32 *)header == cpu_to_be32(DRBD_MAGIC)) {
+                struct p_header80 *h = header;
+                pi->cmd = be16_to_cpu(h->command);
+                pi->size = be16_to_cpu(h->length);
                 pi->vnr = 0;
         } else {
-                conn_err(tconn, "magic?? on data m: 0x%08x c: %d l: %d\n",
-                    be32_to_cpu(h->h80.magic),
-                    be16_to_cpu(h->h80.command),
-                    be16_to_cpu(h->h80.length));
+                conn_err(tconn, "Wrong magic value 0x%08x in protocol version %d\n",
+                         be32_to_cpu(*(__be32 *)header),
+                         tconn->agreed_pro_version);
                 return -EINVAL;
         }
+        pi->data = header + header_size;
         return 0;
 }
 
 static int drbd_recv_header(struct drbd_tconn *tconn, struct packet_info *pi)
 {
-        struct p_header *h = tconn->data.rbuf;
+        void *buffer = tconn->data.rbuf;
         int err;
 
-        err = drbd_recv_all_warn(tconn, h, drbd_header_size(tconn));
+        err = drbd_recv_all_warn(tconn, buffer, drbd_header_size(tconn));
         if (err)
                 return err;
 
-        err = decode_header(tconn, h, pi);
+        err = decode_header(tconn, buffer, pi);
         tconn->last_received = jiffies;
 
         return err;
@@ -1242,7 +1250,7 @@ static int receive_Barrier(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
         int rv;
-        struct p_barrier *p = tconn->data.rbuf;
+        struct p_barrier *p = pi->data;
         struct drbd_epoch *epoch;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
@@ -1560,7 +1568,7 @@ static int receive_DataReply(struct drbd_tconn *tconn, struct packet_info *pi)
         struct drbd_request *req;
         sector_t sector;
         int err;
-        struct p_data *p = tconn->data.rbuf;
+        struct p_data *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -1592,7 +1600,7 @@ static int receive_RSDataReply(struct drbd_tconn *tconn, struct packet_info *pi)
         struct drbd_conf *mdev;
         sector_t sector;
         int err;
-        struct p_data *p = tconn->data.rbuf;
+        struct p_data *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -1985,7 +1993,7 @@ static int receive_Data(struct drbd_tconn *tconn, struct packet_info *pi)
         struct drbd_conf *mdev;
         sector_t sector;
         struct drbd_peer_request *peer_req;
-        struct p_data *p = tconn->data.rbuf;
+        struct p_data *p = pi->data;
         u32 peer_seq = be32_to_cpu(p->seq_num);
         int rw = WRITE;
         u32 dp_flags;
@@ -2173,7 +2181,7 @@ static int receive_DataRequest(struct drbd_tconn *tconn, struct packet_info *pi)
         struct digest_info *di = NULL;
         int size, verb;
         unsigned int fault_type;
-        struct p_block_req *p = tconn->data.rbuf;
+        struct p_block_req *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -2893,7 +2901,7 @@ static int cmp_after_sb(enum drbd_after_sb_p peer, enum drbd_after_sb_p self)
 
 static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
 {
-        struct p_protocol *p = tconn->data.rbuf;
+        struct p_protocol *p = pi->data;
         int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
         int p_want_lose, p_two_primaries, cf;
         char p_integrity_alg[SHARED_SECRET_MAX] = "";
@@ -3033,7 +3041,7 @@ static int config_unknown_volume(struct drbd_tconn *tconn, struct packet_info *p
 static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_rs_param_95 *p = tconn->data.rbuf;
+        struct p_rs_param_95 *p;
         unsigned int header_size, data_size, exp_max_sz;
         struct crypto_hash *verify_tfm = NULL;
         struct crypto_hash *csums_tfm = NULL;
@@ -3059,22 +3067,23 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
         }
 
         if (apv <= 88) {
-                header_size = sizeof(struct p_rs_param) - sizeof(struct p_header);
+                header_size = sizeof(struct p_rs_param);
                 data_size = pi->size - header_size;
         } else if (apv <= 94) {
-                header_size = sizeof(struct p_rs_param_89) - sizeof(struct p_header);
+                header_size = sizeof(struct p_rs_param_89);
                 data_size = pi->size - header_size;
                 D_ASSERT(data_size == 0);
         } else {
-                header_size = sizeof(struct p_rs_param_95) - sizeof(struct p_header);
+                header_size = sizeof(struct p_rs_param_95);
                 data_size = pi->size - header_size;
                 D_ASSERT(data_size == 0);
         }
 
         /* initialize verify_alg and csums_alg */
+        p = pi->data;
         memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
 
-        err = drbd_recv_all(mdev->tconn, &p->head.payload, header_size);
+        err = drbd_recv_all(mdev->tconn, p, header_size);
         if (err)
                 return err;
 
@@ -3209,7 +3218,7 @@ static void warn_if_differ_considerably(struct drbd_conf *mdev,
 static int receive_sizes(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_sizes *p = tconn->data.rbuf;
+        struct p_sizes *p = pi->data;
         enum determine_dev_size dd = unchanged;
         sector_t p_size, p_usize, my_usize;
         int ldsc = 0; /* local disk size changed */
@@ -3311,7 +3320,7 @@ static int receive_sizes(struct drbd_tconn *tconn, struct packet_info *pi)
 static int receive_uuids(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_uuids *p = tconn->data.rbuf;
+        struct p_uuids *p = pi->data;
         u64 *p_uuid;
         int i, updated_uuids = 0;
 
@@ -3411,7 +3420,7 @@ static union drbd_state convert_state(union drbd_state ps)
 static int receive_req_state(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_req_state *p = tconn->data.rbuf;
+        struct p_req_state *p = pi->data;
         union drbd_state mask, val;
         enum drbd_state_rv rv;
 
@@ -3441,7 +3450,7 @@ static int receive_req_state(struct drbd_tconn *tconn, struct packet_info *pi)
 
 static int receive_req_conn_state(struct drbd_tconn *tconn, struct packet_info *pi)
 {
-        struct p_req_state *p = tconn->data.rbuf;
+        struct p_req_state *p = pi->data;
         union drbd_state mask, val;
         enum drbd_state_rv rv;
 
@@ -3466,7 +3475,7 @@ static int receive_req_conn_state(struct drbd_tconn *tconn, struct packet_info *
 static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_state *p = tconn->data.rbuf;
+        struct p_state *p = pi->data;
         union drbd_state os, ns, peer_state;
         enum drbd_disk_state real_peer_disk;
         enum chg_state_flags cs_flags;
@@ -3623,7 +3632,7 @@ static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
 static int receive_sync_uuid(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_rs_uuid *p = tconn->data.rbuf;
+        struct p_rs_uuid *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -3661,14 +3670,13 @@ static int receive_sync_uuid(struct drbd_tconn *tconn, struct packet_info *pi)
  */
 static int
 receive_bitmap_plain(struct drbd_conf *mdev, unsigned int size,
-                     struct p_header *h, struct bm_xfer_ctx *c)
+                     unsigned long *p, struct bm_xfer_ctx *c)
 {
-        unsigned long *buffer = (unsigned long *)h->payload;
         unsigned int data_size = DRBD_SOCKET_BUFFER_SIZE -
                                  drbd_header_size(mdev->tconn);
-        unsigned int num_words = min_t(size_t, data_size / sizeof(unsigned long),
+        unsigned int num_words = min_t(size_t, data_size / sizeof(*p),
                                        c->bm_words - c->word_offset);
-        unsigned int want = num_words * sizeof(unsigned long);
+        unsigned int want = num_words * sizeof(*p);
         int err;
 
         if (want != size) {
@@ -3677,11 +3685,11 @@ receive_bitmap_plain(struct drbd_conf *mdev, unsigned int size,
         }
         if (want == 0)
                 return 0;
-        err = drbd_recv_all(mdev->tconn, buffer, want);
+        err = drbd_recv_all(mdev->tconn, p, want);
         if (err)
                 return err;
 
-        drbd_bm_merge_lel(mdev, c->word_offset, num_words, buffer);
+        drbd_bm_merge_lel(mdev, c->word_offset, num_words, p);
 
         c->word_offset += num_words;
         c->bit_offset = c->word_offset * BITS_PER_LONG;
@@ -3784,7 +3792,7 @@ decode_bitmap_c(struct drbd_conf *mdev,
                 unsigned int len)
 {
         if (dcbp_get_code(p) == RLE_VLI_Bits)
-                return recv_bm_rle_bits(mdev, p, c, len);
+                return recv_bm_rle_bits(mdev, p, c, len - sizeof(*p));
 
         /* other variants had been implemented for evaluation,
          * but have been dropped as this one turned out to be "best"
@@ -3844,7 +3852,6 @@ static int receive_bitmap(struct drbd_tconn *tconn, struct packet_info *pi)
         struct drbd_conf *mdev;
         struct bm_xfer_ctx c;
         int err;
-        struct p_header *h = tconn->data.rbuf;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -3860,28 +3867,26 @@ static int receive_bitmap(struct drbd_tconn *tconn, struct packet_info *pi)
         };
 
         for(;;) {
-                if (pi->cmd == P_BITMAP) {
-                        err = receive_bitmap_plain(mdev, pi->size, h, &c);
-                } else if (pi->cmd == P_COMPRESSED_BITMAP) {
+                if (pi->cmd == P_BITMAP)
+                        err = receive_bitmap_plain(mdev, pi->size, pi->data, &c);
+                else if (pi->cmd == P_COMPRESSED_BITMAP) {
                         /* MAYBE: sanity check that we speak proto >= 90,
                          * and the feature is enabled! */
-                        struct p_compressed_bm *p;
+                        struct p_compressed_bm *p = pi->data;
 
                         if (pi->size > DRBD_SOCKET_BUFFER_SIZE - drbd_header_size(tconn)) {
                                 dev_err(DEV, "ReportCBitmap packet too large\n");
                                 err = -EIO;
                                 goto out;
                         }
-
-                        p = mdev->tconn->data.rbuf;
-                        err = drbd_recv_all(mdev->tconn, p->head.payload, pi->size);
-                        if (err)
-                               goto out;
-                        if (pi->size <= (sizeof(*p) - sizeof(p->head))) {
+                        if (pi->size <= sizeof(*p)) {
                                 dev_err(DEV, "ReportCBitmap packet too small (l:%u)\n", pi->size);
                                 err = -EIO;
                                 goto out;
                         }
+                        err = drbd_recv_all(mdev->tconn, p, pi->size);
+                        if (err)
+                               goto out;
                         err = decode_bitmap_c(mdev, p, &c, pi->size);
                 } else {
                         dev_warn(DEV, "receive_bitmap: cmd neither ReportBitMap nor ReportCBitMap (is 0x%x)", pi->cmd);
@@ -3948,7 +3953,7 @@ static int receive_UnplugRemote(struct drbd_tconn *tconn, struct packet_info *pi
 static int receive_out_of_sync(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_desc *p = tconn->data.rbuf;
+        struct p_block_desc *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -3980,13 +3985,13 @@ static struct data_cmd drbd_cmd_handler[] = {
         [P_DATA_REPLY]      = { 1, sizeof(struct p_data), receive_DataReply },
         [P_RS_DATA_REPLY]   = { 1, sizeof(struct p_data), receive_RSDataReply } ,
         [P_BARRIER]         = { 0, sizeof(struct p_barrier), receive_Barrier } ,
-        [P_BITMAP]          = { 1, sizeof(struct p_header), receive_bitmap } ,
-        [P_COMPRESSED_BITMAP] = { 1, sizeof(struct p_header), receive_bitmap } ,
-        [P_UNPLUG_REMOTE]   = { 0, sizeof(struct p_header), receive_UnplugRemote },
+        [P_BITMAP]          = { 1, 0, receive_bitmap } ,
+        [P_COMPRESSED_BITMAP] = { 1, 0, receive_bitmap } ,
+        [P_UNPLUG_REMOTE]   = { 0, 0, receive_UnplugRemote },
         [P_DATA_REQUEST]    = { 0, sizeof(struct p_block_req), receive_DataRequest },
         [P_RS_DATA_REQUEST] = { 0, sizeof(struct p_block_req), receive_DataRequest },
-        [P_SYNC_PARAM]      = { 1, sizeof(struct p_header), receive_SyncParam },
-        [P_SYNC_PARAM89]    = { 1, sizeof(struct p_header), receive_SyncParam },
+        [P_SYNC_PARAM]      = { 1, 0, receive_SyncParam },
+        [P_SYNC_PARAM89]    = { 1, 0, receive_SyncParam },
         [P_PROTOCOL]        = { 1, sizeof(struct p_protocol), receive_protocol },
         [P_UUIDS]           = { 0, sizeof(struct p_uuids), receive_uuids },
         [P_SIZES]           = { 0, sizeof(struct p_sizes), receive_sizes },
@@ -4003,7 +4008,6 @@ static struct data_cmd drbd_cmd_handler[] = {
 
 static void drbdd(struct drbd_tconn *tconn)
 {
-        struct p_header *header = tconn->data.rbuf;
         struct packet_info pi;
         size_t shs; /* sub header size */
         int err;
@@ -4021,14 +4025,14 @@ static void drbdd(struct drbd_tconn *tconn)
                         goto err_out;
                 }
 
-                shs = cmd->pkt_size - sizeof(struct p_header);
-                if (pi.size - shs > 0 && !cmd->expect_payload) {
+                shs = cmd->pkt_size;
+                if (pi.size > shs && !cmd->expect_payload) {
                         conn_err(tconn, "No payload expected %s l:%d\n", cmdname(pi.cmd), pi.size);
                         goto err_out;
                 }
 
                 if (shs) {
-                        err = drbd_recv_all_warn(tconn, &header->payload, shs);
+                        err = drbd_recv_all_warn(tconn, pi.data, shs);
                         if (err)
                                 goto err_out;
                         pi.size -= shs;
@@ -4219,8 +4223,8 @@ static int drbd_send_features(struct drbd_tconn *tconn)
 static int drbd_do_features(struct drbd_tconn *tconn)
 {
         /* ASSERT current == tconn->receiver ... */
-        struct p_connection_features *p = tconn->data.rbuf;
-        const int expect = sizeof(struct p_connection_features) - sizeof(struct p_header80);
+        struct p_connection_features *p;
+        const int expect = sizeof(struct p_connection_features);
         struct packet_info pi;
         int err;
 
@@ -4244,7 +4248,8 @@ static int drbd_do_features(struct drbd_tconn *tconn)
                 return -1;
         }
 
-        err = drbd_recv_all_warn(tconn, &p->head.payload, expect);
+        p = pi.data;
+        err = drbd_recv_all_warn(tconn, p, expect);
         if (err)
                 return 0;
 
@@ -4322,8 +4327,7 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
                 rv = 0;
                 goto fail;
         }
-        rv = !conn_send_command(tconn, sock, P_AUTH_CHALLENGE,
-                                sizeof(struct p_header),
+        rv = !conn_send_command(tconn, sock, P_AUTH_CHALLENGE, 0,
                                 my_challenge, CHALLENGE_LEN);
         if (!rv)
                 goto fail;
@@ -4382,8 +4386,7 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
                 rv = 0;
                 goto fail;
         }
-        rv = !conn_send_command(tconn, sock, P_AUTH_RESPONSE,
-                                sizeof(struct p_header),
+        rv = !conn_send_command(tconn, sock, P_AUTH_RESPONSE, 0,
                                 response, resp_size);
         if (!rv)
                 goto fail;
@@ -4482,7 +4485,7 @@ int drbdd_init(struct drbd_thread *thi)
 
 static int got_conn_RqSReply(struct drbd_tconn *tconn, struct packet_info *pi)
 {
-        struct p_req_state_reply *p = tconn->meta.rbuf;
+        struct p_req_state_reply *p = pi->data;
         int retcode = be32_to_cpu(p->retcode);
 
         if (retcode >= SS_SUCCESS) {
@@ -4500,7 +4503,7 @@ static int got_conn_RqSReply(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_RqSReply(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_req_state_reply *p = tconn->meta.rbuf;
+        struct p_req_state_reply *p = pi->data;
         int retcode = be32_to_cpu(p->retcode);
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
@@ -4538,7 +4541,7 @@ static int got_PingAck(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_IsInSync(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
         sector_t sector = be64_to_cpu(p->sector);
         int blksize = be32_to_cpu(p->blksize);
 
@@ -4588,7 +4591,7 @@ validate_req_change_req_state(struct drbd_conf *mdev, u64 id, sector_t sector,
 static int got_BlockAck(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
         sector_t sector = be64_to_cpu(p->sector);
         int blksize = be32_to_cpu(p->blksize);
         enum drbd_req_event what;
@@ -4638,7 +4641,7 @@ static int got_BlockAck(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_NegAck(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
         sector_t sector = be64_to_cpu(p->sector);
         int size = be32_to_cpu(p->blksize);
         bool missing_ok = tconn->net_conf->wire_protocol == DRBD_PROT_A ||
@@ -4676,7 +4679,7 @@ static int got_NegAck(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_NegDReply(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
         sector_t sector = be64_to_cpu(p->sector);
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
@@ -4698,7 +4701,7 @@ static int got_NegRSDReply(struct drbd_tconn *tconn, struct packet_info *pi)
         struct drbd_conf *mdev;
         sector_t sector;
         int size;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -4732,7 +4735,7 @@ static int got_NegRSDReply(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_BarrierAck(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_barrier_ack *p = tconn->meta.rbuf;
+        struct p_barrier_ack *p = pi->data;
 
         mdev = vnr_to_mdev(tconn, pi->vnr);
         if (!mdev)
@@ -4753,7 +4756,7 @@ static int got_BarrierAck(struct drbd_tconn *tconn, struct packet_info *pi)
 static int got_OVResult(struct drbd_tconn *tconn, struct packet_info *pi)
 {
         struct drbd_conf *mdev;
-        struct p_block_ack *p = tconn->meta.rbuf;
+        struct p_block_ack *p = pi->data;
         struct drbd_work *w;
         sector_t sector;
         int size;
@@ -4837,8 +4840,8 @@ struct asender_cmd {
 };
 
 static struct asender_cmd asender_tbl[] = {
-        [P_PING]            = { sizeof(struct p_header), got_Ping },
-        [P_PING_ACK]        = { sizeof(struct p_header), got_PingAck },
+        [P_PING]            = { 0, got_Ping },
+        [P_PING_ACK]        = { 0, got_PingAck },
         [P_RECV_ACK]        = { sizeof(struct p_block_ack), got_BlockAck },
         [P_WRITE_ACK]       = { sizeof(struct p_block_ack), got_BlockAck },
         [P_RS_WRITE_ACK]    = { sizeof(struct p_block_ack), got_BlockAck },
@@ -4859,11 +4862,10 @@ static struct asender_cmd asender_tbl[] = {
 int drbd_asender(struct drbd_thread *thi)
 {
         struct drbd_tconn *tconn = thi->tconn;
-        struct p_header *h = tconn->meta.rbuf;
         struct asender_cmd *cmd = NULL;
         struct packet_info pi;
         int rv;
-        void *buf    = h;
+        void *buf    = tconn->meta.rbuf;
         int received = 0;
         unsigned int header_size = drbd_header_size(tconn);
         int expect   = header_size;
@@ -4941,7 +4943,7 @@ int drbd_asender(struct drbd_thread *thi)
                 }
 
                 if (received == expect && cmd == NULL) {
-                        if (decode_header(tconn, h, &pi))
+                        if (decode_header(tconn, tconn->meta.rbuf, &pi))
                                 goto reconnect;
                         cmd = &asender_tbl[pi.cmd];
                         if (pi.cmd >= ARRAY_SIZE(asender_tbl) || !cmd->fn) {
@@ -4949,7 +4951,7 @@ int drbd_asender(struct drbd_thread *thi)
                                         pi.cmd, pi.size);
                                 goto disconnect;
                         }
-                        expect = cmd->pkt_size;
+                        expect = header_size + cmd->pkt_size;
                         if (pi.size != expect - header_size) {
                                 conn_err(tconn, "Wrong packet size on meta (c: %d, l: %d)\n",
                                         pi.cmd, pi.size);
@@ -4972,7 +4974,7 @@ int drbd_asender(struct drbd_thread *thi)
                         if (cmd == &asender_tbl[P_PING_ACK])
                                 ping_timeout_active = 0;
 
-                        buf      = h;
+                        buf      = tconn->meta.rbuf;
                         received = 0;
                         expect   = header_size;
                         cmd      = NULL;
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 78b95e902aae..086a4b6439a7 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1229,7 +1229,7 @@ int w_send_write_hint(struct drbd_work *w, int cancel)
         sock = &mdev->tconn->data;
         if (!drbd_prepare_command(mdev, sock))
                 return -EIO;
-        return drbd_send_command(mdev, sock, P_UNPLUG_REMOTE, sizeof(struct p_header), NULL, 0);
+        return drbd_send_command(mdev, sock, P_UNPLUG_REMOTE, 0, NULL, 0);
 }
 
 int w_send_out_of_sync(struct drbd_work *w, int cancel)