h->length  = cpu_to_be32(size);
 }
 
-static void _prepare_header(struct drbd_tconn *tconn, int vnr, struct p_header *h,
-                           enum drbd_packet cmd, int size)
+static void prepare_header(struct drbd_tconn *tconn, int vnr, struct p_header *h,
+                          enum drbd_packet cmd, int size)
 {
        if (tconn->agreed_pro_version >= 95)
                prepare_header95(&h->h95, cmd, size);
                prepare_header80(&h->h80, cmd, size);
 }
 
-static void prepare_header(struct drbd_conf *mdev, struct p_header *h,
-                          enum drbd_packet cmd, int size)
-{
-       _prepare_header(mdev->tconn, mdev->vnr, h, cmd, size);
-}
-
-/* the appropriate socket mutex must be held already */
-int _conn_send_cmd(struct drbd_tconn *tconn, int vnr, struct drbd_socket *sock,
-                  enum drbd_packet cmd, struct p_header *h, size_t size,
-                  unsigned msg_flags)
-{
-       int err;
-
-       _prepare_header(tconn, vnr, h, cmd, size - sizeof(struct p_header));
-       err = drbd_send_all(tconn, sock->socket, h, size, msg_flags);
-       if (err && !signal_pending(current))
-               conn_warn(tconn, "short send %s size=%d\n",
-                         cmdname(cmd), (int)size);
-       return err;
-}
-
-/* don't pass the socket. we may only look at it
- * when we hold the appropriate socket mutex.
- */
-int conn_send_cmd(struct drbd_tconn *tconn, int vnr, struct drbd_socket *sock,
-                 enum drbd_packet cmd, struct p_header *h, size_t size)
-{
-       int err = -EIO;
-
-       mutex_lock(&sock->mutex);
-       if (sock->socket)
-               err = _conn_send_cmd(tconn, vnr, sock, cmd, h, size, 0);
-       mutex_unlock(&sock->mutex);
-       return err;
-}
-
-int conn_send_cmd2(struct drbd_tconn *tconn, enum drbd_packet cmd, char *data,
-                  size_t size)
-{
-       struct p_header80 h;
-       int err;
-
-       prepare_header80(&h, cmd, size);
-       err = drbd_get_data_sock(tconn);
-       if (!err) {
-               err = drbd_send_all(tconn, tconn->data.socket, &h, sizeof(h), 0);
-               if (!err)
-                       err = drbd_send_all(tconn, tconn->data.socket, data, size, 0);
-               drbd_put_data_sock(tconn);
-       }
-       return err;
-}
-
 void *conn_prepare_command(struct drbd_tconn *tconn, struct drbd_socket *sock)
 {
        mutex_lock(&sock->mutex);
         */
        msg_flags = data ? MSG_MORE : 0;
 
-       _prepare_header(tconn, vnr, sock->sbuf, cmd,
-                       header_size - sizeof(struct p_header) + size);
+       prepare_header(tconn, vnr, sock->sbuf, cmd,
+                      header_size - sizeof(struct p_header) + size);
        err = drbd_send_all(tconn, sock->socket, sock->sbuf, header_size,
                            msg_flags);
        if (data && !err)
 
 int drbd_send_ping(struct drbd_tconn *tconn)
 {
-       struct p_header h;
-       return conn_send_cmd(tconn, 0, &tconn->meta, P_PING, &h, sizeof(h));
+       struct drbd_socket *sock;
+
+       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);
 }
 
 int drbd_send_ping_ack(struct drbd_tconn *tconn)
 {
-       struct p_header h;
-       return conn_send_cmd(tconn, 0, &tconn->meta, P_PING_ACK, &h, sizeof(h));
+       struct drbd_socket *sock;
+
+       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);
 }
 
 int drbd_send_sync_param(struct drbd_conf *mdev)
 {
-       struct p_rs_param_95 *p;
        struct drbd_socket *sock;
-       int size, err;
+       struct p_rs_param_95 *p;
+       int size;
        const int apv = mdev->tconn->agreed_pro_version;
+       enum drbd_packet cmd;
+
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
 
        size = apv <= 87 ? sizeof(struct p_rs_param)
                : apv == 88 ? sizeof(struct p_rs_param)
                : apv <= 94 ? sizeof(struct p_rs_param_89)
                : /* apv >= 95 */ sizeof(struct p_rs_param_95);
 
-       mutex_lock(&mdev->tconn->data.mutex);
-       sock = &mdev->tconn->data;
-
-       if (likely(sock->socket != NULL)) {
-               enum drbd_packet cmd =
-                       apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
-
-               p = mdev->tconn->data.sbuf;
-
-               /* initialize verify_alg and csums_alg */
-               memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
-
-               if (get_ldev(mdev)) {
-                       p->rate = cpu_to_be32(mdev->ldev->dc.resync_rate);
-                       p->c_plan_ahead = cpu_to_be32(mdev->ldev->dc.c_plan_ahead);
-                       p->c_delay_target = cpu_to_be32(mdev->ldev->dc.c_delay_target);
-                       p->c_fill_target = cpu_to_be32(mdev->ldev->dc.c_fill_target);
-                       p->c_max_rate = cpu_to_be32(mdev->ldev->dc.c_max_rate);
-                       put_ldev(mdev);
-               } else {
-                       p->rate = cpu_to_be32(DRBD_RATE_DEF);
-                       p->c_plan_ahead = cpu_to_be32(DRBD_C_PLAN_AHEAD_DEF);
-                       p->c_delay_target = cpu_to_be32(DRBD_C_DELAY_TARGET_DEF);
-                       p->c_fill_target = cpu_to_be32(DRBD_C_FILL_TARGET_DEF);
-                       p->c_max_rate = cpu_to_be32(DRBD_C_MAX_RATE_DEF);
-               }
+       cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
 
-               if (apv >= 88)
-                       strcpy(p->verify_alg, mdev->tconn->net_conf->verify_alg);
-               if (apv >= 89)
-                       strcpy(p->csums_alg, mdev->tconn->net_conf->csums_alg);
+       /* initialize verify_alg and csums_alg */
+       memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
 
-               err = _drbd_send_cmd(mdev, sock, cmd, &p->head, size, 0);
-       } else
-               err = -EIO;
+       if (get_ldev(mdev)) {
+               p->rate = cpu_to_be32(mdev->ldev->dc.resync_rate);
+               p->c_plan_ahead = cpu_to_be32(mdev->ldev->dc.c_plan_ahead);
+               p->c_delay_target = cpu_to_be32(mdev->ldev->dc.c_delay_target);
+               p->c_fill_target = cpu_to_be32(mdev->ldev->dc.c_fill_target);
+               p->c_max_rate = cpu_to_be32(mdev->ldev->dc.c_max_rate);
+               put_ldev(mdev);
+       } else {
+               p->rate = cpu_to_be32(DRBD_RATE_DEF);
+               p->c_plan_ahead = cpu_to_be32(DRBD_C_PLAN_AHEAD_DEF);
+               p->c_delay_target = cpu_to_be32(DRBD_C_DELAY_TARGET_DEF);
+               p->c_fill_target = cpu_to_be32(DRBD_C_FILL_TARGET_DEF);
+               p->c_max_rate = cpu_to_be32(DRBD_C_MAX_RATE_DEF);
+       }
 
-       mutex_unlock(&mdev->tconn->data.mutex);
+       if (apv >= 88)
+               strcpy(p->verify_alg, mdev->tconn->net_conf->verify_alg);
+       if (apv >= 89)
+               strcpy(p->csums_alg, mdev->tconn->net_conf->csums_alg);
 
-       return err;
+       return drbd_send_command(mdev, sock, cmd, size, NULL, 0);
 }
 
 int drbd_send_protocol(struct drbd_tconn *tconn)
 {
+       struct drbd_socket *sock;
        struct p_protocol *p;
-       int size, cf, err;
+       int size, cf;
+
+       if (tconn->net_conf->dry_run && tconn->agreed_pro_version < 92) {
+               conn_err(tconn, "--dry-run is not supported by peer");
+               return -EOPNOTSUPP;
+       }
 
-       size = sizeof(struct p_protocol);
+       sock = &tconn->data;
+       p = conn_prepare_command(tconn, sock);
+       if (!p)
+               return -EIO;
 
+       size = sizeof(*p);
        if (tconn->agreed_pro_version >= 87)
                size += strlen(tconn->net_conf->integrity_alg) + 1;
 
-       /* we must not recurse into our own queue,
-        * as that is blocked during handshake */
-       p = kmalloc(size, GFP_NOIO);
-       if (p == NULL)
-               return -ENOMEM;
-
        p->protocol      = cpu_to_be32(tconn->net_conf->wire_protocol);
        p->after_sb_0p   = cpu_to_be32(tconn->net_conf->after_sb_0p);
        p->after_sb_1p   = cpu_to_be32(tconn->net_conf->after_sb_1p);
        p->after_sb_2p   = cpu_to_be32(tconn->net_conf->after_sb_2p);
        p->two_primaries = cpu_to_be32(tconn->net_conf->two_primaries);
-
        cf = 0;
        if (tconn->net_conf->want_lose)
                cf |= CF_WANT_LOSE;
-       if (tconn->net_conf->dry_run) {
-               if (tconn->agreed_pro_version >= 92)
-                       cf |= CF_DRY_RUN;
-               else {
-                       conn_err(tconn, "--dry-run is not supported by peer");
-                       kfree(p);
-                       return -EOPNOTSUPP;
-               }
-       }
+       if (tconn->net_conf->dry_run)
+               cf |= CF_DRY_RUN;
        p->conn_flags    = cpu_to_be32(cf);
 
        if (tconn->agreed_pro_version >= 87)
                strcpy(p->integrity_alg, tconn->net_conf->integrity_alg);
-
-       err = conn_send_cmd2(tconn, P_PROTOCOL, p->head.payload, size - sizeof(struct p_header));
-       kfree(p);
-       return err;
+       return conn_send_command(tconn, sock, P_PROTOCOL, size, NULL, 0);
 }
 
 int _drbd_send_uuids(struct drbd_conf *mdev, u64 uuid_flags)
 {
-       struct p_uuids p;
+       struct drbd_socket *sock;
+       struct p_uuids *p;
        int i;
 
        if (!get_ldev_if_state(mdev, D_NEGOTIATING))
                return 0;
 
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p) {
+               put_ldev(mdev);
+               return -EIO;
+       }
        for (i = UI_CURRENT; i < UI_SIZE; i++)
-               p.uuid[i] = mdev->ldev ? cpu_to_be64(mdev->ldev->md.uuid[i]) : 0;
+               p->uuid[i] = mdev->ldev ? cpu_to_be64(mdev->ldev->md.uuid[i]) : 0;
 
        mdev->comm_bm_set = drbd_bm_total_weight(mdev);
-       p.uuid[UI_SIZE] = cpu_to_be64(mdev->comm_bm_set);
+       p->uuid[UI_SIZE] = cpu_to_be64(mdev->comm_bm_set);
        uuid_flags |= mdev->tconn->net_conf->want_lose ? 1 : 0;
        uuid_flags |= test_bit(CRASHED_PRIMARY, &mdev->flags) ? 2 : 0;
        uuid_flags |= mdev->new_state_tmp.disk == D_INCONSISTENT ? 4 : 0;
-       p.uuid[UI_FLAGS] = cpu_to_be64(uuid_flags);
+       p->uuid[UI_FLAGS] = cpu_to_be64(uuid_flags);
 
        put_ldev(mdev);
-
-       return drbd_send_cmd(mdev, &mdev->tconn->data, P_UUIDS, &p.head, sizeof(p));
+       return drbd_send_command(mdev, sock, P_UUIDS, sizeof(*p), NULL, 0);
 }
 
 int drbd_send_uuids(struct drbd_conf *mdev)
 
 void drbd_gen_and_send_sync_uuid(struct drbd_conf *mdev)
 {
-       struct p_rs_uuid p;
+       struct drbd_socket *sock;
+       struct p_rs_uuid *p;
        u64 uuid;
 
        D_ASSERT(mdev->state.disk == D_UP_TO_DATE);
        drbd_uuid_set(mdev, UI_BITMAP, uuid);
        drbd_print_uuids(mdev, "updated sync UUID");
        drbd_md_sync(mdev);
-       p.uuid = cpu_to_be64(uuid);
 
-       drbd_send_cmd(mdev, &mdev->tconn->data, P_SYNC_UUID, &p.head, sizeof(p));
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (p) {
+               p->uuid = cpu_to_be64(uuid);
+               drbd_send_command(mdev, sock, P_SYNC_UUID, sizeof(*p), NULL, 0);
+       }
 }
 
 int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags flags)
 {
-       struct p_sizes p;
+       struct drbd_socket *sock;
+       struct p_sizes *p;
        sector_t d_size, u_size;
        int q_order_type, max_bio_size;
 
                max_bio_size = DRBD_MAX_BIO_SIZE; /* ... multiple BIOs per peer_request */
        }
 
-       p.d_size = cpu_to_be64(d_size);
-       p.u_size = cpu_to_be64(u_size);
-       p.c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(mdev->this_bdev));
-       p.max_bio_size = cpu_to_be32(max_bio_size);
-       p.queue_order_type = cpu_to_be16(q_order_type);
-       p.dds_flags = cpu_to_be16(flags);
-
-       return drbd_send_cmd(mdev, &mdev->tconn->data, P_SIZES, &p.head, sizeof(p));
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->d_size = cpu_to_be64(d_size);
+       p->u_size = cpu_to_be64(u_size);
+       p->c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(mdev->this_bdev));
+       p->max_bio_size = cpu_to_be32(max_bio_size);
+       p->queue_order_type = cpu_to_be16(q_order_type);
+       p->dds_flags = cpu_to_be16(flags);
+       return drbd_send_command(mdev, sock, P_SIZES, sizeof(*p), NULL, 0);
 }
 
 /**
 int drbd_send_state(struct drbd_conf *mdev)
 {
        struct drbd_socket *sock;
-       struct p_state p;
-       int err = -EIO;
-
-       mutex_lock(&mdev->tconn->data.mutex);
+       struct p_state *p;
 
-       p.state = cpu_to_be32(mdev->state.i); /* Within the send mutex */
        sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->state = cpu_to_be32(mdev->state.i); /* Within the send mutex */
+       return drbd_send_command(mdev, sock, P_STATE, sizeof(*p), NULL, 0);
+}
 
-       if (likely(sock->socket != NULL))
-               err = _drbd_send_cmd(mdev, sock, P_STATE, &p.head, sizeof(p), 0);
+int drbd_send_state_req(struct drbd_conf *mdev, union drbd_state mask, union drbd_state val)
+{
+       struct drbd_socket *sock;
+       struct p_req_state *p;
 
-       mutex_unlock(&mdev->tconn->data.mutex);
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->mask = cpu_to_be32(mask.i);
+       p->val = cpu_to_be32(val.i);
+       return drbd_send_command(mdev, sock, P_STATE_CHG_REQ, sizeof(*p), NULL, 0);
 
-       return err;
 }
 
-int _conn_send_state_req(struct drbd_tconn *tconn, int vnr, enum drbd_packet cmd,
-                        union drbd_state mask, union drbd_state val)
+int conn_send_state_req(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state val)
 {
-       struct p_req_state p;
-
-       p.mask    = cpu_to_be32(mask.i);
-       p.val     = cpu_to_be32(val.i);
+       enum drbd_packet cmd;
+       struct drbd_socket *sock;
+       struct p_req_state *p;
 
-       return conn_send_cmd(tconn, vnr, &tconn->data, cmd, &p.head, sizeof(p));
+       cmd = tconn->agreed_pro_version < 100 ? P_STATE_CHG_REQ : P_CONN_ST_CHG_REQ;
+       sock = &tconn->data;
+       p = conn_prepare_command(tconn, sock);
+       if (!p)
+               return -EIO;
+       p->mask = cpu_to_be32(mask.i);
+       p->val = cpu_to_be32(val.i);
+       return conn_send_command(tconn, sock, cmd, sizeof(*p), NULL, 0);
 }
 
 void drbd_send_sr_reply(struct drbd_conf *mdev, enum drbd_state_rv retcode)
 {
-       struct p_req_state_reply p;
-
-       p.retcode    = cpu_to_be32(retcode);
+       struct drbd_socket *sock;
+       struct p_req_state_reply *p;
 
-       drbd_send_cmd(mdev, &mdev->tconn->meta, P_STATE_CHG_REPLY, &p.head, sizeof(p));
+       sock = &mdev->tconn->meta;
+       p = drbd_prepare_command(mdev, sock);
+       if (p) {
+               p->retcode = cpu_to_be32(retcode);
+               drbd_send_command(mdev, sock, P_STATE_CHG_REPLY, sizeof(*p), NULL, 0);
+       }
 }
 
-int conn_send_sr_reply(struct drbd_tconn *tconn, enum drbd_state_rv retcode)
+void conn_send_sr_reply(struct drbd_tconn *tconn, enum drbd_state_rv retcode)
 {
-       struct p_req_state_reply p;
+       struct drbd_socket *sock;
+       struct p_req_state_reply *p;
        enum drbd_packet cmd = tconn->agreed_pro_version < 100 ? P_STATE_CHG_REPLY : P_CONN_ST_CHG_REPLY;
 
-       p.retcode    = cpu_to_be32(retcode);
-
-       return !conn_send_cmd(tconn, 0, &tconn->meta, cmd, &p.head, sizeof(p));
+       sock = &tconn->meta;
+       p = conn_prepare_command(tconn, sock);
+       if (p) {
+               p->retcode = cpu_to_be32(retcode);
+               conn_send_command(tconn, sock, cmd, sizeof(*p), NULL, 0);
+       }
 }
 
 static void dcbp_set_code(struct p_compressed_bm *p, enum drbd_bitmap_code code)
 static int
 send_bitmap_rle_or_plain(struct drbd_conf *mdev, struct bm_xfer_ctx *c)
 {
-       struct p_compressed_bm *p = mdev->tconn->data.sbuf;
+       struct drbd_socket *sock = &mdev->tconn->data;
+       struct p_compressed_bm *p = sock->sbuf;
        unsigned long num_words;
        int len, err;
 
        len = fill_bitmap_rle_bits(mdev, p, c);
-
        if (len < 0)
                return -EIO;
 
        if (len) {
                dcbp_set_code(p, RLE_VLI_Bits);
-               err = _drbd_send_cmd(mdev, &mdev->tconn->data,
-                                    P_COMPRESSED_BITMAP, &p->head,
-                                    sizeof(*p) + len, 0);
-
+               err = __send_command(mdev->tconn, mdev->vnr, sock,
+                                    P_COMPRESSED_BITMAP, sizeof(*p) + len,
+                                    NULL, 0);
                c->packets[0]++;
                c->bytes[0] += sizeof(*p) + len;
 
        } else {
                /* was not compressible.
                 * send a buffer full of plain text bits instead. */
-               struct p_header *h = mdev->tconn->data.sbuf;
+               struct p_header *h = sock->sbuf;
                num_words = min_t(size_t, BM_PACKET_WORDS, c->bm_words - c->word_offset);
                len = num_words * sizeof(long);
                if (len)
                        drbd_bm_get_lel(mdev, c->word_offset, num_words,
                                        (unsigned long *)h->payload);
-               err = _drbd_send_cmd(mdev, &mdev->tconn->data, P_BITMAP,
-                                    h, sizeof(struct p_header80) + len, 0);
+               err = __send_command(mdev->tconn, mdev->vnr, sock, P_BITMAP,
+                                    sizeof(*h) + len, NULL, 0);
                c->word_offset += num_words;
                c->bit_offset = c->word_offset * BITS_PER_LONG;
 
 
 int drbd_send_bitmap(struct drbd_conf *mdev)
 {
-       int err;
+       struct drbd_socket *sock = &mdev->tconn->data;
+       int err = -1;
 
-       if (drbd_get_data_sock(mdev->tconn))
-               return -1;
-       err = !_drbd_send_bitmap(mdev);
-       drbd_put_data_sock(mdev->tconn);
+       mutex_lock(&sock->mutex);
+       if (sock->socket)
+               err = !_drbd_send_bitmap(mdev);
+       mutex_unlock(&sock->mutex);
        return err;
 }
+
 void drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr, u32 set_size)
 {
-       struct p_barrier_ack p;
+       struct drbd_socket *sock;
+       struct p_barrier_ack *p;
 
-       p.barrier  = barrier_nr;
-       p.set_size = cpu_to_be32(set_size);
+       if (mdev->state.conn < C_CONNECTED)
+               return;
 
-       if (mdev->state.conn >= C_CONNECTED)
-               drbd_send_cmd(mdev, &mdev->tconn->meta, P_BARRIER_ACK, &p.head, sizeof(p));
+       sock = &mdev->tconn->meta;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return;
+       p->barrier = barrier_nr;
+       p->set_size = cpu_to_be32(set_size);
+       drbd_send_command(mdev, sock, P_BARRIER_ACK, sizeof(*p), NULL, 0);
 }
 
 /**
 static int _drbd_send_ack(struct drbd_conf *mdev, enum drbd_packet cmd,
                          u64 sector, u32 blksize, u64 block_id)
 {
-       struct p_block_ack p;
+       struct drbd_socket *sock;
+       struct p_block_ack *p;
 
-       p.sector   = sector;
-       p.block_id = block_id;
-       p.blksize  = blksize;
-       p.seq_num  = cpu_to_be32(atomic_inc_return(&mdev->packet_seq));
+       if (mdev->state.conn < C_CONNECTED)
+               return -EIO;
 
-       if (!mdev->tconn->meta.socket || mdev->state.conn < C_CONNECTED)
+       sock = &mdev->tconn->meta;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
                return -EIO;
-       return drbd_send_cmd(mdev, &mdev->tconn->meta, cmd, &p.head, sizeof(p));
+       p->sector = sector;
+       p->block_id = block_id;
+       p->blksize = blksize;
+       p->seq_num = cpu_to_be32(atomic_inc_return(&mdev->packet_seq));
+       return drbd_send_command(mdev, sock, cmd, sizeof(*p), NULL, 0);
 }
 
 /* dp->sector and dp->block_id already/still in network byte order,
 int drbd_send_drequest(struct drbd_conf *mdev, int cmd,
                       sector_t sector, int size, u64 block_id)
 {
-       struct p_block_req p;
-
-       p.sector   = cpu_to_be64(sector);
-       p.block_id = block_id;
-       p.blksize  = cpu_to_be32(size);
+       struct drbd_socket *sock;
+       struct p_block_req *p;
 
-       return drbd_send_cmd(mdev, &mdev->tconn->data, cmd, &p.head, sizeof(p));
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(sector);
+       p->block_id = block_id;
+       p->blksize = cpu_to_be32(size);
+       return drbd_send_command(mdev, sock, cmd, sizeof(*p), NULL, 0);
 }
 
 int drbd_send_drequest_csum(struct drbd_conf *mdev, sector_t sector, int size,
                            void *digest, int digest_size, enum drbd_packet cmd)
 {
-       int err;
-       struct p_block_req p;
+       struct drbd_socket *sock;
+       struct p_block_req *p;
 
-       prepare_header(mdev, &p.head, cmd, sizeof(p) - sizeof(struct p_header) + digest_size);
-       p.sector   = cpu_to_be64(sector);
-       p.block_id = ID_SYNCER /* unused */;
-       p.blksize  = cpu_to_be32(size);
+       /* FIXME: Put the digest into the preallocated socket buffer.  */
 
-       mutex_lock(&mdev->tconn->data.mutex);
-       err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, &p, sizeof(p), 0);
-       if (!err)
-               err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, digest, digest_size, 0);
-       mutex_unlock(&mdev->tconn->data.mutex);
-       return err;
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(sector);
+       p->block_id = ID_SYNCER /* unused */;
+       p->blksize = cpu_to_be32(size);
+       return drbd_send_command(mdev, sock, cmd, sizeof(*p),
+                                digest, digest_size);
 }
 
 int drbd_send_ov_request(struct drbd_conf *mdev, sector_t sector, int size)
 {
-       struct p_block_req p;
-
-       p.sector   = cpu_to_be64(sector);
-       p.block_id = ID_SYNCER /* unused */;
-       p.blksize  = cpu_to_be32(size);
+       struct drbd_socket *sock;
+       struct p_block_req *p;
 
-       return drbd_send_cmd(mdev, &mdev->tconn->data, P_OV_REQUEST, &p.head, sizeof(p));
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(sector);
+       p->block_id = ID_SYNCER /* unused */;
+       p->blksize = cpu_to_be32(size);
+       return drbd_send_command(mdev, sock, P_OV_REQUEST, sizeof(*p), NULL, 0);
 }
 
 /* called on sndtimeo
  */
 int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
 {
-       int err;
-       struct p_data p;
+       struct drbd_socket *sock;
+       struct p_data *p;
        unsigned int dp_flags = 0;
-       void *dgb;
        int dgs;
-
-       err = drbd_get_data_sock(mdev->tconn);
-       if (err)
-               return err;
+       int err;
 
        dgs = (mdev->tconn->agreed_pro_version >= 87 && mdev->tconn->integrity_w_tfm) ?
                crypto_hash_digestsize(mdev->tconn->integrity_w_tfm) : 0;
 
-       prepare_header(mdev, &p.head, P_DATA, sizeof(p) - sizeof(struct p_header) + dgs + req->i.size);
-       p.sector   = cpu_to_be64(req->i.sector);
-       p.block_id = (unsigned long)req;
-       p.seq_num  = cpu_to_be32(req->seq_num = atomic_inc_return(&mdev->packet_seq));
-
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(req->i.sector);
+       p->block_id = (unsigned long)req;
+       p->seq_num = cpu_to_be32(req->seq_num = atomic_inc_return(&mdev->packet_seq));
        dp_flags = bio_flags_to_wire(mdev, req->master_bio->bi_rw);
-
        if (mdev->state.conn >= C_SYNC_SOURCE &&
            mdev->state.conn <= C_PAUSED_SYNC_T)
                dp_flags |= DP_MAY_SET_IN_SYNC;
-
-       p.dp_flags = cpu_to_be32(dp_flags);
-       set_bit(UNPLUG_REMOTE, &mdev->flags);
-       err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, &p,
-                           sizeof(p), dgs ? MSG_MORE : 0);
-       if (!err && dgs) {
-               dgb = mdev->tconn->int_dig_out;
-               drbd_csum_bio(mdev, mdev->tconn->integrity_w_tfm, req->master_bio, dgb);
-               err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, dgb, dgs, 0);
-       }
+       p->dp_flags = cpu_to_be32(dp_flags);
+       if (dgs)
+               drbd_csum_bio(mdev, mdev->tconn->integrity_w_tfm, req->master_bio, p + 1);
+       err = __send_command(mdev->tconn, mdev->vnr, sock, P_DATA, sizeof(*p) + dgs, NULL, req->i.size);
        if (!err) {
                /* For protocol A, we have to memcpy the payload into
                 * socket buffers, as we may complete right away
                         * currently supported in kernel crypto. */
                        unsigned char digest[64];
                        drbd_csum_bio(mdev, mdev->tconn->integrity_w_tfm, req->master_bio, digest);
-                       if (memcmp(mdev->tconn->int_dig_out, digest, dgs)) {
+                       if (memcmp(p + 1, digest, dgs)) {
                                dev_warn(DEV,
                                        "Digest mismatch, buffer modified by upper layers during write: %llus +%u\n",
                                        (unsigned long long)req->i.sector, req->i.size);
                     ... Be noisy about digest too large ...
                } */
        }
-
-       drbd_put_data_sock(mdev->tconn);
+       mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */
 
        return err;
 }
 int drbd_send_block(struct drbd_conf *mdev, enum drbd_packet cmd,
                    struct drbd_peer_request *peer_req)
 {
+       struct drbd_socket *sock;
+       struct p_data *p;
        int err;
-       struct p_data p;
-       void *dgb;
        int dgs;
 
        dgs = (mdev->tconn->agreed_pro_version >= 87 && mdev->tconn->integrity_w_tfm) ?
                crypto_hash_digestsize(mdev->tconn->integrity_w_tfm) : 0;
 
-       prepare_header(mdev, &p.head, cmd, sizeof(p) -
-                                          sizeof(struct p_header80) +
-                                          dgs + peer_req->i.size);
-       p.sector   = cpu_to_be64(peer_req->i.sector);
-       p.block_id = peer_req->block_id;
-       p.seq_num = 0;  /* unused */
-
-       /* Only called by our kernel thread.
-        * This one may be interrupted by DRBD_SIG and/or DRBD_SIGKILL
-        * in response to admin command or module unload.
-        */
-       err = drbd_get_data_sock(mdev->tconn);
-       if (err)
-               return err;
-       err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, &p,
-                           sizeof(p), dgs ? MSG_MORE : 0);
-       if (!err && dgs) {
-               dgb = mdev->tconn->int_dig_out;
-               drbd_csum_ee(mdev, mdev->tconn->integrity_w_tfm, peer_req, dgb);
-               err = drbd_send_all(mdev->tconn, mdev->tconn->data.socket, dgb,
-                                   dgs, 0);
-       }
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(peer_req->i.sector);
+       p->block_id = peer_req->block_id;
+       p->seq_num = 0;  /* unused */
+       if (dgs)
+               drbd_csum_ee(mdev, mdev->tconn->integrity_w_tfm, peer_req, p + 1);
+       err = __send_command(mdev->tconn, mdev->vnr, sock, cmd, sizeof(*p) + dgs, NULL, peer_req->i.size);
        if (!err)
                err = _drbd_send_zc_ee(mdev, peer_req);
-       drbd_put_data_sock(mdev->tconn);
+       mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */
 
        return err;
 }
 
 int drbd_send_out_of_sync(struct drbd_conf *mdev, struct drbd_request *req)
 {
-       struct p_block_desc p;
-
-       p.sector  = cpu_to_be64(req->i.sector);
-       p.blksize = cpu_to_be32(req->i.size);
+       struct drbd_socket *sock;
+       struct p_block_desc *p;
 
-       return drbd_send_cmd(mdev, &mdev->tconn->data, P_OUT_OF_SYNC, &p.head, sizeof(p));
+       sock = &mdev->tconn->data;
+       p = drbd_prepare_command(mdev, sock);
+       if (!p)
+               return -EIO;
+       p->sector = cpu_to_be64(req->i.sector);
+       p->blksize = cpu_to_be32(req->i.size);
+       return drbd_send_command(mdev, sock, P_OUT_OF_SYNC, sizeof(*p), NULL, 0);
 }
 
 /*