From 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f Mon Sep 17 00:00:00 2001 From: Stefan Raspl Date: Thu, 3 May 2018 18:12:39 +0200 Subject: smc: add support for splice() Provide an implementation for splice() when we are using SMC. See smc_splice_read() for further details. Signed-off-by: Stefan Raspl Signed-off-by: Ursula Braun < Signed-off-by: David S. Miller --- net/smc/smc_rx.c | 163 +++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 147 insertions(+), 16 deletions(-) (limited to 'net/smc/smc_rx.c') diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c index 7b64bee656e8..ed45569289f5 100644 --- a/net/smc/smc_rx.c +++ b/net/smc/smc_rx.c @@ -43,6 +43,116 @@ static void smc_rx_wake_up(struct sock *sk) rcu_read_unlock(); } +/* Update consumer cursor + * @conn connection to update + * @cons consumer cursor + * @len number of Bytes consumed + */ +static void smc_rx_update_consumer(struct smc_connection *conn, + union smc_host_cursor cons, size_t len) +{ + smc_curs_add(conn->rmbe_size, &cons, len); + 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); +} + +struct smc_spd_priv { + struct smc_sock *smc; + size_t len; +}; + +static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private; + struct smc_sock *smc = priv->smc; + struct smc_connection *conn; + union smc_host_cursor cons; + struct sock *sk = &smc->sk; + + if (sk->sk_state == SMC_CLOSED || + sk->sk_state == SMC_PEERFINCLOSEWAIT || + sk->sk_state == SMC_APPFINCLOSEWAIT) + goto out; + conn = &smc->conn; + lock_sock(sk); + smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn), + conn); + smc_rx_update_consumer(conn, cons, priv->len); + release_sock(sk); + if (atomic_sub_and_test(priv->len, &conn->splice_pending)) + smc_rx_wake_up(sk); +out: + kfree(priv); + put_page(buf->page); + sock_put(sk); +} + +static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + return 1; +} + +static const struct pipe_buf_operations smc_pipe_ops = { + .can_merge = 0, + .confirm = generic_pipe_buf_confirm, + .release = smc_rx_pipe_buf_release, + .steal = smc_rx_pipe_buf_nosteal, + .get = generic_pipe_buf_get +}; + +static void smc_rx_spd_release(struct splice_pipe_desc *spd, + unsigned int i) +{ + put_page(spd->pages[i]); +} + +static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len, + struct smc_sock *smc) +{ + struct splice_pipe_desc spd; + struct partial_page partial; + struct smc_spd_priv *priv; + struct page *page; + int bytes; + + page = virt_to_page(smc->conn.rmb_desc->cpu_addr); + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->len = len; + priv->smc = smc; + partial.offset = src - (char *)smc->conn.rmb_desc->cpu_addr; + partial.len = len; + partial.private = (unsigned long)priv; + + spd.nr_pages_max = 1; + spd.nr_pages = 1; + spd.pages = &page; + spd.partial = &partial; + spd.ops = &smc_pipe_ops; + spd.spd_release = smc_rx_spd_release; + + bytes = splice_to_pipe(pipe, &spd); + if (bytes > 0) { + sock_hold(&smc->sk); + get_page(smc->conn.rmb_desc->pages); + atomic_add(bytes, &smc->conn.splice_pending); + } + + return bytes; +} + +static int smc_rx_data_available_and_no_splice_pend(struct smc_connection *conn) +{ + return atomic_read(&conn->bytes_to_rcv) && + !atomic_read(&conn->splice_pending); +} + /* 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 @@ -74,19 +184,25 @@ int smc_rx_wait(struct smc_sock *smc, long *timeo, return rc; } -/* rcvbuf consumer: main API called by socket layer. - * called under sk lock. +/* smc_rx_recvmsg - receive data from RMBE + * @msg: copy data to receive buffer + * @pipe: copy data to pipe if set - indicates splice() call + * + * 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) +int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, + struct pipe_inode_info *pipe, 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; + int (*func)(struct smc_connection *conn); union smc_host_cursor cons; int readable, chunk; char *rcvbuf_base; struct sock *sk; + int splbytes; long timeo; int target; /* Read at least these many bytes */ int rc; @@ -102,12 +218,11 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len, 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) + if (read_done >= target || (pipe && read_done)) break; if (atomic_read(&conn->bytes_to_rcv)) @@ -156,11 +271,24 @@ copy: /* initialize variables for 1st iteration of subsequent loop */ /* could be just 1 byte, even after waiting on data above */ readable = atomic_read(&conn->bytes_to_rcv); + splbytes = atomic_read(&conn->splice_pending); + if (!readable || (msg && splbytes)) { + if (splbytes) + func = smc_rx_data_available_and_no_splice_pend; + else + func = smc_rx_data_available; + smc_rx_wait(smc, &timeo, func); + continue; + } + /* 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); + /* subsequent splice() calls pick up where previous left */ + if (splbytes) + smc_curs_add(conn->rmbe_size, &cons, splbytes); /* determine chunks where to read from rcvbuf */ /* either unwrapped case, or 1st chunk of wrapped case */ chunk_len = min_t(size_t, @@ -170,9 +298,16 @@ copy: smc_rmb_sync_sg_for_cpu(conn); for (chunk = 0; chunk < 2; chunk++) { if (!(flags & MSG_TRUNC)) { - rc = memcpy_to_msg(msg, rcvbuf_base + chunk_off, - chunk_len); - if (rc) { + if (msg) { + rc = memcpy_to_msg(msg, rcvbuf_base + + chunk_off, + chunk_len); + } else { + rc = smc_rx_splice(pipe, rcvbuf_base + + chunk_off, chunk_len, + smc); + } + if (rc < 0) { if (!read_done) read_done = -EFAULT; smc_rmb_sync_sg_for_device(conn); @@ -193,18 +328,13 @@ copy: /* 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); + if (msg) + smc_rx_update_consumer(conn, cons, copylen); } } while (read_remaining); out: @@ -215,4 +345,5 @@ out: void smc_rx_init(struct smc_sock *smc) { smc->sk.sk_data_ready = smc_rx_wake_up; + atomic_set(&smc->conn.splice_pending, 0); } -- cgit