drbd: Replace and remove old primitives

Centralize sock->mutex locking and unlocking in [drbd|conn]_prepare_command()
and [drbd|conn]_send_comman().

Therefore all *_send_* functions are touched to use these primitives instead
of drbd_get_data_sock()/drbd_put_data_sock() and former helper functions.

That change makes the *_send_* functions more standardized.

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

4 files changed, 319 insertions, 373 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 729c96fc0c87..663f7b611756 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1060,22 +1060,6 @@ static inline struct drbd_conf *vnr_to_mdev(struct drbd_tconn *tconn, int vnr)
         return (struct drbd_conf *)idr_find(&tconn->volumes, vnr);
 }
 
-static inline int drbd_get_data_sock(struct drbd_tconn *tconn)
-{
-        mutex_lock(&tconn->data.mutex);
-        if (!tconn->data.socket) {
-                /* Disconnected.  */
-                mutex_unlock(&tconn->data.mutex);
-                return -EIO;
-        }
-        return 0;
-}
-
-static inline void drbd_put_data_sock(struct drbd_tconn *tconn)
-{
-        mutex_unlock(&tconn->data.mutex);
-}
-
 /*
  * function declarations
  *************************/
@@ -1118,13 +1102,6 @@ extern int _conn_send_state_req(struct drbd_tconn *, int vnr, enum drbd_packet c
                                 union drbd_state, union drbd_state);
 extern int _drbd_send_state(struct drbd_conf *mdev);
 extern int drbd_send_state(struct drbd_conf *mdev);
-extern 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);
-extern 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);
-extern int conn_send_cmd2(struct drbd_tconn *tconn, enum drbd_packet cmd,
-                          char *data, size_t size);
 extern int drbd_send_sync_param(struct drbd_conf *mdev);
 extern void drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr,
                             u32 set_size);
@@ -1149,7 +1126,7 @@ extern int drbd_send_ov_request(struct drbd_conf *mdev,sector_t sector,int size)
 
 extern int drbd_send_bitmap(struct drbd_conf *mdev);
 extern void drbd_send_sr_reply(struct drbd_conf *mdev, enum drbd_state_rv retcode);
-extern int conn_send_sr_reply(struct drbd_tconn *tconn, enum drbd_state_rv retcode);
+extern void conn_send_sr_reply(struct drbd_tconn *tconn, enum drbd_state_rv retcode);
 extern void drbd_free_bc(struct drbd_backing_dev *ldev);
 extern void drbd_mdev_cleanup(struct drbd_conf *mdev);
 void drbd_print_uuids(struct drbd_conf *mdev, const char *text);
@@ -1885,26 +1862,6 @@ static inline void request_ping(struct drbd_tconn *tconn)
         wake_asender(tconn);
 }
 
-static inline int _drbd_send_cmd(struct drbd_conf *mdev, struct drbd_socket *sock,
-                                  enum drbd_packet cmd, struct p_header *h, size_t size,
-                                  unsigned msg_flags)
-{
-        return _conn_send_cmd(mdev->tconn, mdev->vnr, sock, cmd, h, size, msg_flags);
-}
-
-static inline int drbd_send_cmd(struct drbd_conf *mdev, struct drbd_socket *sock,
-                                enum drbd_packet cmd, struct p_header *h, size_t size)
-{
-        return conn_send_cmd(mdev->tconn, mdev->vnr, sock, cmd, h, size);
-}
-
-static inline int drbd_send_short_cmd(struct drbd_conf *mdev,
-                                      enum drbd_packet cmd)
-{
-        struct p_header h;
-        return drbd_send_cmd(mdev, &mdev->tconn->data, cmd, &h, sizeof(h));
-}
-
 extern void *conn_prepare_command(struct drbd_tconn *, struct drbd_socket *);
 extern void *drbd_prepare_command(struct drbd_conf *, struct drbd_socket *);
 extern int conn_send_command(struct drbd_tconn *, struct drbd_socket *,
@@ -1916,19 +1873,8 @@ extern int drbd_send_command(struct drbd_conf *, struct drbd_socket *,
 
 extern int drbd_send_ping(struct drbd_tconn *tconn);
 extern int drbd_send_ping_ack(struct drbd_tconn *tconn);
-
-static inline int drbd_send_state_req(struct drbd_conf *mdev,
-                                      union drbd_state mask, union drbd_state val)
-{
-        return _conn_send_state_req(mdev->tconn, mdev->vnr, P_STATE_CHG_REQ, mask, val);
-}
-
-static inline int conn_send_state_req(struct drbd_tconn *tconn,
-                                      union drbd_state mask, union drbd_state val)
-{
-        enum drbd_packet cmd = tconn->agreed_pro_version < 100 ? P_STATE_CHG_REQ : P_CONN_ST_CHG_REQ;
-        return _conn_send_state_req(tconn, 0, cmd, mask, val);
-}
+extern int drbd_send_state_req(struct drbd_conf *, union drbd_state, union drbd_state);
+extern int conn_send_state_req(struct drbd_tconn *, union drbd_state, union drbd_state);
 
 static inline void drbd_thread_stop(struct drbd_thread *thi)
 {
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 606a9ecbe044..230622f1aae2 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -717,8 +717,8 @@ static void prepare_header95(struct p_header95 *h, enum drbd_packet cmd, int siz
         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);
@@ -726,59 +726,6 @@ static void _prepare_header(struct drbd_tconn *tconn, int vnr, struct p_header *
                 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);
@@ -811,8 +758,8 @@ 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);
+        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)
@@ -845,22 +792,36 @@ int drbd_send_command(struct drbd_conf *mdev, struct drbd_socket *sock,
 
 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)
@@ -868,112 +829,98 @@ int drbd_send_sync_param(struct drbd_conf *mdev)
                 : 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)
@@ -1006,7 +953,8 @@ void drbd_print_uuids(struct drbd_conf *mdev, const char *text)
 
 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);
@@ -1015,14 +963,19 @@ void drbd_gen_and_send_sync_uuid(struct drbd_conf *mdev)
         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;
 
@@ -1041,14 +994,17 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
                 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);
 }
 
 /**
@@ -1058,50 +1014,72 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
 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)
@@ -1224,21 +1202,20 @@ int fill_bitmap_rle_bits(struct drbd_conf *mdev,
 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;
 
@@ -1247,14 +1224,14 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev, struct bm_xfer_ctx *c)
         } 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;
 
@@ -1314,23 +1291,31 @@ static int _drbd_send_bitmap(struct drbd_conf *mdev)
 
 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);
 }
 
 /**
@@ -1344,16 +1329,21 @@ void drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr, u32 set_size)
 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,
@@ -1403,43 +1393,51 @@ int drbd_send_ack_ex(struct drbd_conf *mdev, enum drbd_packet cmd,
 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
@@ -1632,39 +1630,30 @@ static u32 bio_flags_to_wire(struct drbd_conf *mdev, unsigned long bi_rw)
  */
 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
@@ -1688,7 +1677,7 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
                          * 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);
@@ -1697,8 +1686,7 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
                      ... Be noisy about digest too large ...
                 } */
         }
-
-        drbd_put_data_sock(mdev->tconn);
+        mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */
 
         return err;
 }
@@ -1710,51 +1698,43 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
 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);
 }
 
 /*
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index e52a929d9ed3..40fe7199d5f7 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -729,24 +729,32 @@ out:
         return s_estab;
 }
 
-static int drbd_send_fp(struct drbd_tconn *tconn, struct drbd_socket *sock, enum drbd_packet cmd)
-{
-        struct p_header *h = tconn->data.sbuf;
+static int decode_header(struct drbd_tconn *, struct p_header *, struct packet_info *);
 
-        return !_conn_send_cmd(tconn, 0, sock, cmd, h, sizeof(*h), 0);
+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);
 }
 
-static enum drbd_packet drbd_recv_fp(struct drbd_tconn *tconn, struct socket *sock)
+static int receive_first_packet(struct drbd_tconn *tconn, struct socket *sock)
 {
-        struct p_header80 h;
-        int rr;
-
-        rr = drbd_recv_short(sock, &h, sizeof(h), 0);
-
-        if (rr == sizeof(h) && h.magic == cpu_to_be32(DRBD_MAGIC))
-                return be16_to_cpu(h.command);
+        unsigned int header_size = drbd_header_size(tconn);
+        struct packet_info pi;
+        int err;
 
-        return 0xffff;
+        err = drbd_recv_short(sock, tconn->data.rbuf, header_size, 0);
+        if (err != header_size) {
+                if (err >= 0)
+                        err = -EIO;
+                return err;
+        }
+        err = decode_header(tconn, tconn->data.rbuf, &pi);
+        if (err)
+                return err;
+        return pi.cmd;
 }
 
 /**
@@ -834,10 +842,10 @@ static int drbd_connect(struct drbd_tconn *tconn)
                 if (s) {
                         if (!tconn->data.socket) {
                                 tconn->data.socket = s;
-                                drbd_send_fp(tconn, &tconn->data, P_INITIAL_DATA);
+                                send_first_packet(tconn, &tconn->data, P_INITIAL_DATA);
                         } else if (!tconn->meta.socket) {
                                 tconn->meta.socket = s;
-                                drbd_send_fp(tconn, &tconn->meta, P_INITIAL_META);
+                                send_first_packet(tconn, &tconn->meta, P_INITIAL_META);
                         } else {
                                 conn_err(tconn, "Logic error in drbd_connect()\n");
                                 goto out_release_sockets;
@@ -855,7 +863,7 @@ static int drbd_connect(struct drbd_tconn *tconn)
 retry:
                 s = drbd_wait_for_connect(tconn);
                 if (s) {
-                        try = drbd_recv_fp(tconn, s);
+                        try = receive_first_packet(tconn, s);
                         drbd_socket_okay(&tconn->data.socket);
                         drbd_socket_okay(&tconn->meta.socket);
                         switch (try) {
@@ -1324,6 +1332,10 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector,
                 crypto_hash_digestsize(mdev->tconn->integrity_r_tfm) : 0;
 
         if (dgs) {
+                /*
+                 * FIXME: Receive the incoming digest into the receive buffer
+                 *        here, together with its struct p_data?
+                 */
                 err = drbd_recv_all_warn(mdev->tconn, dig_in, dgs);
                 if (err)
                         return NULL;
@@ -4019,8 +4031,8 @@ static void drbdd(struct drbd_tconn *tconn)
 
                 err = cmd->fn(tconn, &pi);
                 if (err) {
-                        conn_err(tconn, "error receiving %s, l: %d!\n",
-                            cmdname(pi.cmd), pi.size);
+                        conn_err(tconn, "error receiving %s, e: %d l: %d!\n",
+                                 cmdname(pi.cmd), err, pi.size);
                         goto err_out;
                 }
         }
@@ -4179,27 +4191,17 @@ static int drbd_disconnected(int vnr, void *p, void *data)
  */
 static int drbd_send_features(struct drbd_tconn *tconn)
 {
-        /* ASSERT current == mdev->tconn->receiver ... */
-        struct p_connection_features *p = tconn->data.sbuf;
-        int err;
-
-        if (mutex_lock_interruptible(&tconn->data.mutex)) {
-                conn_err(tconn, "interrupted during initial handshake\n");
-                return -EINTR;
-        }
+        struct drbd_socket *sock;
+        struct p_connection_features *p;
 
-        if (tconn->data.socket == NULL) {
-                mutex_unlock(&tconn->data.mutex);
+        sock = &tconn->data;
+        p = conn_prepare_command(tconn, sock);
+        if (!p)
                 return -EIO;
-        }
-
         memset(p, 0, sizeof(*p));
         p->protocol_min = cpu_to_be32(PRO_VERSION_MIN);
         p->protocol_max = cpu_to_be32(PRO_VERSION_MAX);
-        err = _conn_send_cmd(tconn, 0, &tconn->data, P_CONNECTION_FEATURES,
-                             &p->head, sizeof(*p), 0);
-        mutex_unlock(&tconn->data.mutex);
-        return err;
+        return conn_send_command(tconn, sock, P_CONNECTION_FEATURES, sizeof(*p), NULL, 0);
 }
 
 /*
@@ -4283,6 +4285,7 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
 
 static int drbd_do_auth(struct drbd_tconn *tconn)
 {
+        struct drbd_socket *sock;
         char my_challenge[CHALLENGE_LEN];  /* 64 Bytes... */
         struct scatterlist sg;
         char *response = NULL;
@@ -4294,6 +4297,8 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
         struct packet_info pi;
         int err, rv;
 
+        /* FIXME: Put the challenge/response into the preallocated socket buffer.  */
+
         desc.tfm = tconn->cram_hmac_tfm;
         desc.flags = 0;
 
@@ -4307,7 +4312,14 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
 
         get_random_bytes(my_challenge, CHALLENGE_LEN);
 
-        rv = !conn_send_cmd2(tconn, P_AUTH_CHALLENGE, my_challenge, CHALLENGE_LEN);
+        sock = &tconn->data;
+        if (!conn_prepare_command(tconn, sock)) {
+                rv = 0;
+                goto fail;
+        }
+        rv = !conn_send_command(tconn, sock, P_AUTH_CHALLENGE,
+                                sizeof(struct p_header),
+                                my_challenge, CHALLENGE_LEN);
         if (!rv)
                 goto fail;
 
@@ -4361,7 +4373,13 @@ static int drbd_do_auth(struct drbd_tconn *tconn)
                 goto fail;
         }
 
-        rv = !conn_send_cmd2(tconn, P_AUTH_RESPONSE, response, resp_size);
+        if (!conn_prepare_command(tconn, sock)) {
+                rv = 0;
+                goto fail;
+        }
+        rv = !conn_send_command(tconn, sock, P_AUTH_RESPONSE,
+                                sizeof(struct p_header),
+                                response, resp_size);
         if (!rv)
                 goto fail;
 
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 7350466ff30c..78b95e902aae 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1191,10 +1191,10 @@ int w_prev_work_done(struct drbd_work *w, int cancel)
 
 int w_send_barrier(struct drbd_work *w, int cancel)
 {
+        struct drbd_socket *sock;
         struct drbd_tl_epoch *b = container_of(w, struct drbd_tl_epoch, w);
         struct drbd_conf *mdev = w->mdev;
-        struct p_barrier *p = mdev->tconn->data.sbuf;
-        int err = 0;
+        struct p_barrier *p;
 
         /* really avoid racing with tl_clear.  w.cb may have been referenced
          * just before it was reassigned and re-queued, so double check that.
@@ -1208,26 +1208,28 @@ int w_send_barrier(struct drbd_work *w, int cancel)
         if (cancel)
                 return 0;
 
-        err = drbd_get_data_sock(mdev->tconn);
-        if (err)
-                return err;
+        sock = &mdev->tconn->data;
+        p = drbd_prepare_command(mdev, sock);
+        if (!p)
+                return -EIO;
         p->barrier = b->br_number;
         /* inc_ap_pending was done where this was queued.
          * dec_ap_pending will be done in got_BarrierAck
          * or (on connection loss) in w_clear_epoch.  */
-        err = _drbd_send_cmd(mdev, &mdev->tconn->data, P_BARRIER,
-                             &p->head, sizeof(*p), 0);
-        drbd_put_data_sock(mdev->tconn);
-
-        return err;
+        return drbd_send_command(mdev, sock, P_BARRIER, sizeof(*p), NULL, 0);
 }
 
 int w_send_write_hint(struct drbd_work *w, int cancel)
 {
         struct drbd_conf *mdev = w->mdev;
+        struct drbd_socket *sock;
+
         if (cancel)
                 return 0;
-        return drbd_send_short_cmd(mdev, P_UNPLUG_REMOTE);
+        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);
 }
 
 int w_send_out_of_sync(struct drbd_work *w, int cancel)