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Release 4.11 net/smc/smc_rx.c

Directory: net/smc
/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 * Manage RMBE
 * copy new RMBE data into user space
 *
 * Copyright IBM Corp. 2016
 *
 * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/net.h>
#include <linux/rcupdate.h>
#include <linux/sched/signal.h>

#include <net/sock.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_cdc.h"
#include "smc_tx.h" /* smc_tx_consumer_update() */
#include "smc_rx.h"

/* callback implementation for sk.sk_data_ready()
 * to wakeup rcvbuf consumers that blocked with smc_rx_wait_data().
 * indirectly called by smc_cdc_msg_recv_action().
 */

static void smc_rx_data_ready(struct sock *sk) { struct socket_wq *wq; /* derived from sock_def_readable() */ /* called already in smc_listen_work() */ rcu_read_lock(); wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_sync_poll(&wq->wait, POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND); if ((sk->sk_shutdown == SHUTDOWN_MASK) || (sk->sk_state == SMC_CLOSED)) sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); else sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); rcu_read_unlock(); }

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Ursula Braun93100.00%1100.00%
Total93100.00%1100.00%

/* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted * @smc smc socket * @timeo pointer to max seconds to wait, pointer to value 0 for no timeout * Returns: * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown. * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted). */
static int smc_rx_wait_data(struct smc_sock *smc, long *timeo) { DEFINE_WAIT_FUNC(wait, woken_wake_function); struct smc_connection *conn = &smc->conn; struct sock *sk = &smc->sk; int rc; if (atomic_read(&conn->bytes_to_rcv)) return 1; sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); add_wait_queue(sk_sleep(sk), &wait); rc = sk_wait_event(sk, timeo, sk->sk_err || sk->sk_shutdown & RCV_SHUTDOWN || sock_flag(sk, SOCK_DONE) || atomic_read(&conn->bytes_to_rcv) || smc_cdc_rxed_any_close_or_senddone(conn), &wait); remove_wait_queue(sk_sleep(sk), &wait); sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); return rc; }

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Ursula Braun139100.00%1100.00%
Total139100.00%1100.00%

/* rcvbuf consumer: main API called by socket layer. * called under sk lock. */
int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len, int flags) { size_t copylen, read_done = 0, read_remaining = len; size_t chunk_len, chunk_off, chunk_len_sum; struct smc_connection *conn = &smc->conn; union smc_host_cursor cons; int readable, chunk; char *rcvbuf_base; struct sock *sk; long timeo; int target; /* Read at least these many bytes */ int rc; if (unlikely(flags & MSG_ERRQUEUE)) return -EINVAL; /* future work for sk.sk_family == AF_SMC */ if (flags & MSG_OOB) return -EINVAL; /* future work */ sk = &smc->sk; if (sk->sk_state == SMC_LISTEN) return -ENOTCONN; timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); msg->msg_namelen = 0; /* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */ rcvbuf_base = conn->rmb_desc->cpu_addr; do { /* while (read_remaining) */ if (read_done >= target) break; if (atomic_read(&conn->bytes_to_rcv)) goto copy; if (read_done) { if (sk->sk_err || sk->sk_state == SMC_CLOSED || (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo || signal_pending(current) || smc_cdc_rxed_any_close_or_senddone(conn) || conn->local_tx_ctrl.conn_state_flags. peer_conn_abort) break; } else { if (sock_flag(sk, SOCK_DONE)) break; if (sk->sk_err) { read_done = sock_error(sk); break; } if (sk->sk_shutdown & RCV_SHUTDOWN || smc_cdc_rxed_any_close_or_senddone(conn) || conn->local_tx_ctrl.conn_state_flags. peer_conn_abort) break; if (sk->sk_state == SMC_CLOSED) { if (!sock_flag(sk, SOCK_DONE)) { /* This occurs when user tries to read * from never connected socket. */ read_done = -ENOTCONN; break; } break; } if (signal_pending(current)) { read_done = sock_intr_errno(timeo); break; } } if (!atomic_read(&conn->bytes_to_rcv)) { smc_rx_wait_data(smc, &timeo); continue; } copy: /* initialize variables for 1st iteration of subsequent loop */ /* could be just 1 byte, even after smc_rx_wait_data above */ readable = atomic_read(&conn->bytes_to_rcv); /* not more than what user space asked for */ copylen = min_t(size_t, read_remaining, readable); smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn), conn); /* determine chunks where to read from rcvbuf */ /* either unwrapped case, or 1st chunk of wrapped case */ chunk_len = min_t(size_t, copylen, conn->rmbe_size - cons.count); chunk_len_sum = chunk_len; chunk_off = cons.count; for (chunk = 0; chunk < 2; chunk++) { if (!(flags & MSG_TRUNC)) { rc = memcpy_to_msg(msg, rcvbuf_base + chunk_off, chunk_len); if (rc) { if (!read_done) read_done = -EFAULT; goto out; } } read_remaining -= chunk_len; read_done += 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 recv ring buffer */ } /* update cursors */ if (!(flags & MSG_PEEK)) { smc_curs_add(conn->rmbe_size, &cons, copylen); /* increased in recv tasklet smc_cdc_msg_rcv() */ smp_mb__before_atomic(); atomic_sub(copylen, &conn->bytes_to_rcv); /* guarantee 0 <= bytes_to_rcv <= rmbe_size */ smp_mb__after_atomic(); smc_curs_write(&conn->local_tx_ctrl.cons, smc_curs_read(&cons, conn), conn); /* send consumer cursor update if required */ /* similar to advertising new TCP rcv_wnd if required */ smc_tx_consumer_update(conn); } } while (read_remaining); out: return read_done; }

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Ursula Braun597100.00%1100.00%
Total597100.00%1100.00%

/* Initialize receive properties on connection establishment. NB: not __init! */
void smc_rx_init(struct smc_sock *smc) { smc->sk.sk_data_ready = smc_rx_data_ready; }

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Ursula Braun18100.00%1100.00%
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Ursula Braun87799.66%150.00%
Ingo Molnar30.34%150.00%
Total880100.00%2100.00%
Directory: net/smc
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