diff options
Diffstat (limited to 'net/smc/smc_rx.c')
| -rw-r--r-- | net/smc/smc_rx.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c new file mode 100644 index 000000000000..c4ef9a4ec569 --- /dev/null +++ b/net/smc/smc_rx.c @@ -0,0 +1,219 @@ +/* + * 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(); +} + +/* 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; +} + +/* 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; +} + +/* 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; +} |