222 lines
6.1 KiB
C
222 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Shared Memory Communications over RDMA (SMC-R) and RoCE
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*
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* Manage RMBE
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* copy new RMBE data into user space
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*
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* Copyright IBM Corp. 2016
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*
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* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
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*/
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#include <linux/net.h>
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#include <linux/rcupdate.h>
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#include <linux/sched/signal.h>
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#include <net/sock.h>
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#include "smc.h"
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#include "smc_core.h"
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#include "smc_cdc.h"
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#include "smc_tx.h" /* smc_tx_consumer_update() */
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#include "smc_rx.h"
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/* callback implementation for sk.sk_data_ready()
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* to wakeup rcvbuf consumers that blocked with smc_rx_wait_data().
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* indirectly called by smc_cdc_msg_recv_action().
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*/
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static void smc_rx_data_ready(struct sock *sk)
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{
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struct socket_wq *wq;
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/* derived from sock_def_readable() */
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/* called already in smc_listen_work() */
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rcu_read_lock();
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wq = rcu_dereference(sk->sk_wq);
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if (skwq_has_sleeper(wq))
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wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI |
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EPOLLRDNORM | EPOLLRDBAND);
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sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
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if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
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(sk->sk_state == SMC_CLOSED))
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sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
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rcu_read_unlock();
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}
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/* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted
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* @smc smc socket
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* @timeo pointer to max seconds to wait, pointer to value 0 for no timeout
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* Returns:
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* 1 if at least 1 byte available in rcvbuf or if socket error/shutdown.
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* 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted).
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*/
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static int smc_rx_wait_data(struct smc_sock *smc, long *timeo)
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{
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DEFINE_WAIT_FUNC(wait, woken_wake_function);
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struct smc_connection *conn = &smc->conn;
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struct sock *sk = &smc->sk;
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int rc;
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if (atomic_read(&conn->bytes_to_rcv))
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return 1;
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sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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add_wait_queue(sk_sleep(sk), &wait);
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rc = sk_wait_event(sk, timeo,
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sk->sk_err ||
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sk->sk_shutdown & RCV_SHUTDOWN ||
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atomic_read(&conn->bytes_to_rcv) ||
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smc_cdc_rxed_any_close_or_senddone(conn),
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&wait);
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remove_wait_queue(sk_sleep(sk), &wait);
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sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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return rc;
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}
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/* rcvbuf consumer: main API called by socket layer.
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* called under sk lock.
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*/
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int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
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int flags)
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{
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size_t copylen, read_done = 0, read_remaining = len;
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size_t chunk_len, chunk_off, chunk_len_sum;
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struct smc_connection *conn = &smc->conn;
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union smc_host_cursor cons;
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int readable, chunk;
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char *rcvbuf_base;
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struct sock *sk;
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long timeo;
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int target; /* Read at least these many bytes */
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int rc;
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if (unlikely(flags & MSG_ERRQUEUE))
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return -EINVAL; /* future work for sk.sk_family == AF_SMC */
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if (flags & MSG_OOB)
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return -EINVAL; /* future work */
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sk = &smc->sk;
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if (sk->sk_state == SMC_LISTEN)
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return -ENOTCONN;
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timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
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target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
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msg->msg_namelen = 0;
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/* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */
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rcvbuf_base = conn->rmb_desc->cpu_addr;
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do { /* while (read_remaining) */
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if (read_done >= target)
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break;
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if (atomic_read(&conn->bytes_to_rcv))
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goto copy;
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if (read_done) {
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if (sk->sk_err ||
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sk->sk_state == SMC_CLOSED ||
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sk->sk_shutdown & RCV_SHUTDOWN ||
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!timeo ||
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signal_pending(current) ||
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smc_cdc_rxed_any_close_or_senddone(conn) ||
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conn->local_tx_ctrl.conn_state_flags.
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peer_conn_abort)
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break;
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} else {
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if (sk->sk_err) {
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read_done = sock_error(sk);
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break;
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}
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if (sk->sk_shutdown & RCV_SHUTDOWN ||
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smc_cdc_rxed_any_close_or_senddone(conn) ||
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conn->local_tx_ctrl.conn_state_flags.
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peer_conn_abort)
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break;
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if (sk->sk_state == SMC_CLOSED) {
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if (!sock_flag(sk, SOCK_DONE)) {
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/* This occurs when user tries to read
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* from never connected socket.
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*/
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read_done = -ENOTCONN;
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break;
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}
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break;
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}
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if (signal_pending(current)) {
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read_done = sock_intr_errno(timeo);
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break;
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}
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if (!timeo)
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return -EAGAIN;
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}
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if (!atomic_read(&conn->bytes_to_rcv)) {
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smc_rx_wait_data(smc, &timeo);
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continue;
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}
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copy:
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/* initialize variables for 1st iteration of subsequent loop */
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/* could be just 1 byte, even after smc_rx_wait_data above */
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readable = atomic_read(&conn->bytes_to_rcv);
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/* not more than what user space asked for */
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copylen = min_t(size_t, read_remaining, readable);
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smc_curs_write(&cons,
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smc_curs_read(&conn->local_tx_ctrl.cons, conn),
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conn);
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/* determine chunks where to read from rcvbuf */
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/* either unwrapped case, or 1st chunk of wrapped case */
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chunk_len = min_t(size_t,
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copylen, conn->rmbe_size - cons.count);
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chunk_len_sum = chunk_len;
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chunk_off = cons.count;
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smc_rmb_sync_sg_for_cpu(conn);
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for (chunk = 0; chunk < 2; chunk++) {
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if (!(flags & MSG_TRUNC)) {
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rc = memcpy_to_msg(msg, rcvbuf_base + chunk_off,
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chunk_len);
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if (rc) {
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if (!read_done)
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read_done = -EFAULT;
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smc_rmb_sync_sg_for_device(conn);
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goto out;
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}
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}
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read_remaining -= chunk_len;
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read_done += chunk_len;
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if (chunk_len_sum == copylen)
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break; /* either on 1st or 2nd iteration */
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/* prepare next (== 2nd) iteration */
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chunk_len = copylen - chunk_len; /* remainder */
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chunk_len_sum += chunk_len;
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chunk_off = 0; /* modulo offset in recv ring buffer */
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}
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smc_rmb_sync_sg_for_device(conn);
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/* update cursors */
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if (!(flags & MSG_PEEK)) {
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smc_curs_add(conn->rmbe_size, &cons, copylen);
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/* increased in recv tasklet smc_cdc_msg_rcv() */
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smp_mb__before_atomic();
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atomic_sub(copylen, &conn->bytes_to_rcv);
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/* guarantee 0 <= bytes_to_rcv <= rmbe_size */
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smp_mb__after_atomic();
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smc_curs_write(&conn->local_tx_ctrl.cons,
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smc_curs_read(&cons, conn),
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conn);
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/* send consumer cursor update if required */
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/* similar to advertising new TCP rcv_wnd if required */
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smc_tx_consumer_update(conn);
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}
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} while (read_remaining);
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out:
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return read_done;
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}
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/* Initialize receive properties on connection establishment. NB: not __init! */
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void smc_rx_init(struct smc_sock *smc)
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{
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smc->sk.sk_data_ready = smc_rx_data_ready;
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}
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