Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release

1 files changed, 646 insertions, 0 deletions

diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
new file mode 100644
index 000000000..52ef1fca0
--- /dev/null
+++ b/net/smc/smc_tx.c
@@ -0,0 +1,646 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * Manage send buffer.
+ * Producer:
+ * Copy user space data into send buffer, if send buffer space available.
+ * Consumer:
+ * Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available.
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#include <linux/net.h>
+#include <linux/rcupdate.h>
+#include <linux/workqueue.h>
+#include <linux/sched/signal.h>
+
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#include "smc.h"
+#include "smc_wr.h"
+#include "smc_cdc.h"
+#include "smc_close.h"
+#include "smc_ism.h"
+#include "smc_tx.h"
+
+#define SMC_TX_WORK_DELAY       0
+#define SMC_TX_CORK_DELAY       (HZ >> 2)       /* 250 ms */
+
+/***************************** sndbuf producer *******************************/
+
+/* callback implementation for sk.sk_write_space()
+ * to wakeup sndbuf producers that blocked with smc_tx_wait().
+ * called under sk_socket lock.
+ */
+static void smc_tx_write_space(struct sock *sk)
+{
+        struct socket *sock = sk->sk_socket;
+        struct smc_sock *smc = smc_sk(sk);
+        struct socket_wq *wq;
+
+        /* similar to sk_stream_write_space */
+        if (atomic_read(&smc->conn.sndbuf_space) && sock) {
+                clear_bit(SOCK_NOSPACE, &sock->flags);
+                rcu_read_lock();
+                wq = rcu_dereference(sk->sk_wq);
+                if (skwq_has_sleeper(wq))
+                        wake_up_interruptible_poll(&wq->wait,
+                                                   EPOLLOUT | EPOLLWRNORM |
+                                                   EPOLLWRBAND);
+                if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
+                        sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
+                rcu_read_unlock();
+        }
+}
+
+/* Wakeup sndbuf producers that blocked with smc_tx_wait().
+ * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
+ */
+void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
+{
+        if (smc->sk.sk_socket &&
+            test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags))
+                smc->sk.sk_write_space(&smc->sk);
+}
+
+/* blocks sndbuf producer until at least one byte of free space available
+ * or urgent Byte was consumed
+ */
+static int smc_tx_wait(struct smc_sock *smc, int flags)
+{
+        DEFINE_WAIT_FUNC(wait, woken_wake_function);
+        struct smc_connection *conn = &smc->conn;
+        struct sock *sk = &smc->sk;
+        long timeo;
+        int rc = 0;
+
+        /* similar to sk_stream_wait_memory */
+        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+        add_wait_queue(sk_sleep(sk), &wait);
+        while (1) {
+                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+                if (sk->sk_err ||
+                    (sk->sk_shutdown & SEND_SHUTDOWN) ||
+                    conn->killed ||
+                    conn->local_tx_ctrl.conn_state_flags.peer_done_writing) {
+                        rc = -EPIPE;
+                        break;
+                }
+                if (smc_cdc_rxed_any_close(conn)) {
+                        rc = -ECONNRESET;
+                        break;
+                }
+                if (!timeo) {
+                        /* ensure EPOLLOUT is subsequently generated */
+                        set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+                        rc = -EAGAIN;
+                        break;
+                }
+                if (signal_pending(current)) {
+                        rc = sock_intr_errno(timeo);
+                        break;
+                }
+                sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+                if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend)
+                        break; /* at least 1 byte of free & no urgent data */
+                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+                sk_wait_event(sk, &timeo,
+                              sk->sk_err ||
+                              (sk->sk_shutdown & SEND_SHUTDOWN) ||
+                              smc_cdc_rxed_any_close(conn) ||
+                              (atomic_read(&conn->sndbuf_space) &&
+                               !conn->urg_tx_pend),
+                              &wait);
+        }
+        remove_wait_queue(sk_sleep(sk), &wait);
+        return rc;
+}
+
+static bool smc_tx_is_corked(struct smc_sock *smc)
+{
+        struct tcp_sock *tp = tcp_sk(smc->clcsock->sk);
+
+        return (tp->nonagle & TCP_NAGLE_CORK) ? true : false;
+}
+
+/* sndbuf producer: main API called by socket layer.
+ * called under sock lock.
+ */
+int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
+{
+        size_t copylen, send_done = 0, send_remaining = len;
+        size_t chunk_len, chunk_off, chunk_len_sum;
+        struct smc_connection *conn = &smc->conn;
+        union smc_host_cursor prep;
+        struct sock *sk = &smc->sk;
+        char *sndbuf_base;
+        int tx_cnt_prep;
+        int writespace;
+        int rc, chunk;
+
+        /* This should be in poll */
+        sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
+                rc = -EPIPE;
+                goto out_err;
+        }
+
+        while (msg_data_left(msg)) {
+                if (sk->sk_state == SMC_INIT)
+                        return -ENOTCONN;
+                if (smc->sk.sk_shutdown & SEND_SHUTDOWN ||
+                    (smc->sk.sk_err == ECONNABORTED) ||
+                    conn->killed)
+                        return -EPIPE;
+                if (smc_cdc_rxed_any_close(conn))
+                        return send_done ?: -ECONNRESET;
+
+                if (msg->msg_flags & MSG_OOB)
+                        conn->local_tx_ctrl.prod_flags.urg_data_pending = 1;
+
+                if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) {
+                        if (send_done)
+                                return send_done;
+                        rc = smc_tx_wait(smc, msg->msg_flags);
+                        if (rc)
+                                goto out_err;
+                        continue;
+                }
+
+                /* initialize variables for 1st iteration of subsequent loop */
+                /* could be just 1 byte, even after smc_tx_wait above */
+                writespace = atomic_read(&conn->sndbuf_space);
+                /* not more than what user space asked for */
+                copylen = min_t(size_t, send_remaining, writespace);
+                /* determine start of sndbuf */
+                sndbuf_base = conn->sndbuf_desc->cpu_addr;
+                smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
+                tx_cnt_prep = prep.count;
+                /* determine chunks where to write into sndbuf */
+                /* either unwrapped case, or 1st chunk of wrapped case */
+                chunk_len = min_t(size_t, copylen, conn->sndbuf_desc->len -
+                                  tx_cnt_prep);
+                chunk_len_sum = chunk_len;
+                chunk_off = tx_cnt_prep;
+                smc_sndbuf_sync_sg_for_cpu(conn);
+                for (chunk = 0; chunk < 2; chunk++) {
+                        rc = memcpy_from_msg(sndbuf_base + chunk_off,
+                                             msg, chunk_len);
+                        if (rc) {
+                                smc_sndbuf_sync_sg_for_device(conn);
+                                if (send_done)
+                                        return send_done;
+                                goto out_err;
+                        }
+                        send_done += chunk_len;
+                        send_remaining -= chunk_len;
+
+                        if (chunk_len_sum == copylen)
+                                break; /* either on 1st or 2nd iteration */
+                        /* prepare next (== 2nd) iteration */
+                        chunk_len = copylen - chunk_len; /* remainder */
+                        chunk_len_sum += chunk_len;
+                        chunk_off = 0; /* modulo offset in send ring buffer */
+                }
+                smc_sndbuf_sync_sg_for_device(conn);
+                /* update cursors */
+                smc_curs_add(conn->sndbuf_desc->len, &prep, copylen);
+                smc_curs_copy(&conn->tx_curs_prep, &prep, conn);
+                /* increased in send tasklet smc_cdc_tx_handler() */
+                smp_mb__before_atomic();
+                atomic_sub(copylen, &conn->sndbuf_space);
+                /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
+                smp_mb__after_atomic();
+                /* since we just produced more new data into sndbuf,
+                 * trigger sndbuf consumer: RDMA write into peer RMBE and CDC
+                 */
+                if ((msg->msg_flags & MSG_OOB) && !send_remaining)
+                        conn->urg_tx_pend = true;
+                if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) &&
+                    (atomic_read(&conn->sndbuf_space) >
+                                                (conn->sndbuf_desc->len >> 1)))
+                        /* for a corked socket defer the RDMA writes if there
+                         * is still sufficient sndbuf_space available
+                         */
+                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
+                                           SMC_TX_CORK_DELAY);
+                else
+                        smc_tx_sndbuf_nonempty(conn);
+        } /* while (msg_data_left(msg)) */
+
+        return send_done;
+
+out_err:
+        rc = sk_stream_error(sk, msg->msg_flags, rc);
+        /* make sure we wake any epoll edge trigger waiter */
+        if (unlikely(rc == -EAGAIN))
+                sk->sk_write_space(sk);
+        return rc;
+}
+
+/***************************** sndbuf consumer *******************************/
+
+/* sndbuf consumer: actual data transfer of one target chunk with ISM write */
+int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len,
+                      u32 offset, int signal)
+{
+        struct smc_ism_position pos;
+        int rc;
+
+        memset(&pos, 0, sizeof(pos));
+        pos.token = conn->peer_token;
+        pos.index = conn->peer_rmbe_idx;
+        pos.offset = conn->tx_off + offset;
+        pos.signal = signal;
+        rc = smc_ism_write(conn->lgr->smcd, &pos, data, len);
+        if (rc)
+                conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
+        return rc;
+}
+
+/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
+static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
+                             int num_sges, struct ib_rdma_wr *rdma_wr)
+{
+        struct smc_link_group *lgr = conn->lgr;
+        struct smc_link *link = conn->lnk;
+        int rc;
+
+        rdma_wr->wr.wr_id = smc_wr_tx_get_next_wr_id(link);
+        rdma_wr->wr.num_sge = num_sges;
+        rdma_wr->remote_addr =
+                lgr->rtokens[conn->rtoken_idx][link->link_idx].dma_addr +
+                /* RMBE within RMB */
+                conn->tx_off +
+                /* offset within RMBE */
+                peer_rmbe_offset;
+        rdma_wr->rkey = lgr->rtokens[conn->rtoken_idx][link->link_idx].rkey;
+        rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL);
+        if (rc)
+                smcr_link_down_cond_sched(link);
+        return rc;
+}
+
+/* sndbuf consumer */
+static inline void smc_tx_advance_cursors(struct smc_connection *conn,
+                                          union smc_host_cursor *prod,
+                                          union smc_host_cursor *sent,
+                                          size_t len)
+{
+        smc_curs_add(conn->peer_rmbe_size, prod, len);
+        /* increased in recv tasklet smc_cdc_msg_rcv() */
+        smp_mb__before_atomic();
+        /* data in flight reduces usable snd_wnd */
+        atomic_sub(len, &conn->peer_rmbe_space);
+        /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
+        smp_mb__after_atomic();
+        smc_curs_add(conn->sndbuf_desc->len, sent, len);
+}
+
+/* SMC-R helper for smc_tx_rdma_writes() */
+static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len,
+                               size_t src_off, size_t src_len,
+                               size_t dst_off, size_t dst_len,
+                               struct smc_rdma_wr *wr_rdma_buf)
+{
+        struct smc_link *link = conn->lnk;
+
+        dma_addr_t dma_addr =
+                sg_dma_address(conn->sndbuf_desc->sgt[link->link_idx].sgl);
+        int src_len_sum = src_len, dst_len_sum = dst_len;
+        int sent_count = src_off;
+        int srcchunk, dstchunk;
+        int num_sges;
+        int rc;
+
+        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
+                struct ib_sge *sge =
+                        wr_rdma_buf->wr_tx_rdma[dstchunk].wr.sg_list;
+
+                num_sges = 0;
+                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
+                        sge[srcchunk].addr = dma_addr + src_off;
+                        sge[srcchunk].length = src_len;
+                        num_sges++;
+
+                        src_off += src_len;
+                        if (src_off >= conn->sndbuf_desc->len)
+                                src_off -= conn->sndbuf_desc->len;
+                                                /* modulo in send ring */
+                        if (src_len_sum == dst_len)
+                                break; /* either on 1st or 2nd iteration */
+                        /* prepare next (== 2nd) iteration */
+                        src_len = dst_len - src_len; /* remainder */
+                        src_len_sum += src_len;
+                }
+                rc = smc_tx_rdma_write(conn, dst_off, num_sges,
+                                       &wr_rdma_buf->wr_tx_rdma[dstchunk]);
+                if (rc)
+                        return rc;
+                if (dst_len_sum == len)
+                        break; /* either on 1st or 2nd iteration */
+                /* prepare next (== 2nd) iteration */
+                dst_off = 0; /* modulo offset in RMBE ring buffer */
+                dst_len = len - dst_len; /* remainder */
+                dst_len_sum += dst_len;
+                src_len = min_t(int, dst_len, conn->sndbuf_desc->len -
+                                sent_count);
+                src_len_sum = src_len;
+        }
+        return 0;
+}
+
+/* SMC-D helper for smc_tx_rdma_writes() */
+static int smcd_tx_rdma_writes(struct smc_connection *conn, size_t len,
+                               size_t src_off, size_t src_len,
+                               size_t dst_off, size_t dst_len)
+{
+        int src_len_sum = src_len, dst_len_sum = dst_len;
+        int srcchunk, dstchunk;
+        int rc;
+
+        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
+                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
+                        void *data = conn->sndbuf_desc->cpu_addr + src_off;
+
+                        rc = smcd_tx_ism_write(conn, data, src_len, dst_off +
+                                               sizeof(struct smcd_cdc_msg), 0);
+                        if (rc)
+                                return rc;
+                        dst_off += src_len;
+                        src_off += src_len;
+                        if (src_off >= conn->sndbuf_desc->len)
+                                src_off -= conn->sndbuf_desc->len;
+                                                /* modulo in send ring */
+                        if (src_len_sum == dst_len)
+                                break; /* either on 1st or 2nd iteration */
+                        /* prepare next (== 2nd) iteration */
+                        src_len = dst_len - src_len; /* remainder */
+                        src_len_sum += src_len;
+                }
+                if (dst_len_sum == len)
+                        break; /* either on 1st or 2nd iteration */
+                /* prepare next (== 2nd) iteration */
+                dst_off = 0; /* modulo offset in RMBE ring buffer */
+                dst_len = len - dst_len; /* remainder */
+                dst_len_sum += dst_len;
+                src_len = min_t(int, dst_len, conn->sndbuf_desc->len - src_off);
+                src_len_sum = src_len;
+        }
+        return 0;
+}
+
+/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
+ * usable snd_wnd as max transmit
+ */
+static int smc_tx_rdma_writes(struct smc_connection *conn,
+                              struct smc_rdma_wr *wr_rdma_buf)
+{
+        size_t len, src_len, dst_off, dst_len; /* current chunk values */
+        union smc_host_cursor sent, prep, prod, cons;
+        struct smc_cdc_producer_flags *pflags;
+        int to_send, rmbespace;
+        int rc;
+
+        /* source: sndbuf */
+        smc_curs_copy(&sent, &conn->tx_curs_sent, conn);
+        smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
+        /* cf. wmem_alloc - (snd_max - snd_una) */
+        to_send = smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep);
+        if (to_send <= 0)
+                return 0;
+
+        /* destination: RMBE */
+        /* cf. snd_wnd */
+        rmbespace = atomic_read(&conn->peer_rmbe_space);
+        if (rmbespace <= 0)
+                return 0;
+        smc_curs_copy(&prod, &conn->local_tx_ctrl.prod, conn);
+        smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn);
+
+        /* if usable snd_wnd closes ask peer to advertise once it opens again */
+        pflags = &conn->local_tx_ctrl.prod_flags;
+        pflags->write_blocked = (to_send >= rmbespace);
+        /* cf. usable snd_wnd */
+        len = min(to_send, rmbespace);
+
+        /* initialize variables for first iteration of subsequent nested loop */
+        dst_off = prod.count;
+        if (prod.wrap == cons.wrap) {
+                /* the filled destination area is unwrapped,
+                 * hence the available free destination space is wrapped
+                 * and we need 2 destination chunks of sum len; start with 1st
+                 * which is limited by what's available in sndbuf
+                 */
+                dst_len = min_t(size_t,
+                                conn->peer_rmbe_size - prod.count, len);
+        } else {
+                /* the filled destination area is wrapped,
+                 * hence the available free destination space is unwrapped
+                 * and we need a single destination chunk of entire len
+                 */
+                dst_len = len;
+        }
+        /* dst_len determines the maximum src_len */
+        if (sent.count + dst_len <= conn->sndbuf_desc->len) {
+                /* unwrapped src case: single chunk of entire dst_len */
+                src_len = dst_len;
+        } else {
+                /* wrapped src case: 2 chunks of sum dst_len; start with 1st: */
+                src_len = conn->sndbuf_desc->len - sent.count;
+        }
+
+        if (conn->lgr->is_smcd)
+                rc = smcd_tx_rdma_writes(conn, len, sent.count, src_len,
+                                         dst_off, dst_len);
+        else
+                rc = smcr_tx_rdma_writes(conn, len, sent.count, src_len,
+                                         dst_off, dst_len, wr_rdma_buf);
+        if (rc)
+                return rc;
+
+        if (conn->urg_tx_pend && len == to_send)
+                pflags->urg_data_present = 1;
+        smc_tx_advance_cursors(conn, &prod, &sent, len);
+        /* update connection's cursors with advanced local cursors */
+        smc_curs_copy(&conn->local_tx_ctrl.prod, &prod, conn);
+                                                        /* dst: peer RMBE */
+        smc_curs_copy(&conn->tx_curs_sent, &sent, conn);/* src: local sndbuf */
+
+        return 0;
+}
+
+/* Wakeup sndbuf consumers from any context (IRQ or process)
+ * since there is more data to transmit; usable snd_wnd as max transmit
+ */
+static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
+{
+        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
+        struct smc_link *link = conn->lnk;
+        struct smc_rdma_wr *wr_rdma_buf;
+        struct smc_cdc_tx_pend *pend;
+        struct smc_wr_buf *wr_buf;
+        int rc;
+
+        if (!link || !smc_wr_tx_link_hold(link))
+                return -ENOLINK;
+        rc = smc_cdc_get_free_slot(conn, link, &wr_buf, &wr_rdma_buf, &pend);
+        if (rc < 0) {
+                smc_wr_tx_link_put(link);
+                if (rc == -EBUSY) {
+                        struct smc_sock *smc =
+                                container_of(conn, struct smc_sock, conn);
+
+                        if (smc->sk.sk_err == ECONNABORTED)
+                                return sock_error(&smc->sk);
+                        if (conn->killed)
+                                return -EPIPE;
+                        rc = 0;
+                        mod_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
+                                         SMC_TX_WORK_DELAY);
+                }
+                return rc;
+        }
+
+        spin_lock_bh(&conn->send_lock);
+        if (link != conn->lnk) {
+                /* link of connection changed, tx_work will restart */
+                smc_wr_tx_put_slot(link,
+                                   (struct smc_wr_tx_pend_priv *)pend);
+                rc = -ENOLINK;
+                goto out_unlock;
+        }
+        if (!pflags->urg_data_present) {
+                rc = smc_tx_rdma_writes(conn, wr_rdma_buf);
+                if (rc) {
+                        smc_wr_tx_put_slot(link,
+                                           (struct smc_wr_tx_pend_priv *)pend);
+                        goto out_unlock;
+                }
+        }
+
+        rc = smc_cdc_msg_send(conn, wr_buf, pend);
+        if (!rc && pflags->urg_data_present) {
+                pflags->urg_data_pending = 0;
+                pflags->urg_data_present = 0;
+        }
+
+out_unlock:
+        spin_unlock_bh(&conn->send_lock);
+        smc_wr_tx_link_put(link);
+        return rc;
+}
+
+static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn)
+{
+        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
+        int rc = 0;
+
+        spin_lock_bh(&conn->send_lock);
+        if (!pflags->urg_data_present)
+                rc = smc_tx_rdma_writes(conn, NULL);
+        if (!rc)
+                rc = smcd_cdc_msg_send(conn);
+
+        if (!rc && pflags->urg_data_present) {
+                pflags->urg_data_pending = 0;
+                pflags->urg_data_present = 0;
+        }
+        spin_unlock_bh(&conn->send_lock);
+        return rc;
+}
+
+int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
+{
+        int rc;
+
+        if (conn->killed ||
+            conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
+                return -EPIPE;  /* connection being aborted */
+        if (conn->lgr->is_smcd)
+                rc = smcd_tx_sndbuf_nonempty(conn);
+        else
+                rc = smcr_tx_sndbuf_nonempty(conn);
+
+        if (!rc) {
+                /* trigger socket release if connection is closing */
+                struct smc_sock *smc = container_of(conn, struct smc_sock,
+                                                    conn);
+                smc_close_wake_tx_prepared(smc);
+        }
+        return rc;
+}
+
+/* Wakeup sndbuf consumers from process context
+ * since there is more data to transmit
+ */
+void smc_tx_work(struct work_struct *work)
+{
+        struct smc_connection *conn = container_of(to_delayed_work(work),
+                                                   struct smc_connection,
+                                                   tx_work);
+        struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
+        int rc;
+
+        lock_sock(&smc->sk);
+        if (smc->sk.sk_err)
+                goto out;
+
+        rc = smc_tx_sndbuf_nonempty(conn);
+        if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
+            !atomic_read(&conn->bytes_to_rcv))
+                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
+
+out:
+        release_sock(&smc->sk);
+}
+
+void smc_tx_consumer_update(struct smc_connection *conn, bool force)
+{
+        union smc_host_cursor cfed, cons, prod;
+        int sender_free = conn->rmb_desc->len;
+        int to_confirm;
+
+        smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
+        smc_curs_copy(&cfed, &conn->rx_curs_confirmed, conn);
+        to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons);
+        if (to_confirm > conn->rmbe_update_limit) {
+                smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn);
+                sender_free = conn->rmb_desc->len -
+                              smc_curs_diff_large(conn->rmb_desc->len,
+                                                  &cfed, &prod);
+        }
+
+        if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
+            force ||
+            ((to_confirm > conn->rmbe_update_limit) &&
+             ((sender_free <= (conn->rmb_desc->len / 2)) ||
+              conn->local_rx_ctrl.prod_flags.write_blocked))) {
+                if (conn->killed ||
+                    conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
+                        return;
+                if ((smc_cdc_get_slot_and_msg_send(conn) < 0) &&
+                    !conn->killed) {
+                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
+                                           SMC_TX_WORK_DELAY);
+                        return;
+                }
+        }
+        if (conn->local_rx_ctrl.prod_flags.write_blocked &&
+            !atomic_read(&conn->bytes_to_rcv))
+                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
+}
+
+/***************************** send initialize *******************************/
+
+/* Initialize send properties on connection establishment. NB: not __init! */
+void smc_tx_init(struct smc_sock *smc)
+{
+        smc->sk.sk_write_space = smc_tx_write_space;
+}