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https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
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 <raspl@linux.ibm.com> Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>< Signed-off-by: David S. Miller <davem@davemloft.net>
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2ef4f27ad0
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9014db202c
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@ -1163,10 +1163,12 @@ static int smc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
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goto out;
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}
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if (smc->use_fallback)
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if (smc->use_fallback) {
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rc = smc->clcsock->ops->recvmsg(smc->clcsock, msg, len, flags);
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else
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rc = smc_rx_recvmsg(smc, msg, len, flags);
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} else {
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msg->msg_namelen = 0;
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rc = smc_rx_recvmsg(smc, msg, NULL, len, flags);
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}
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out:
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release_sock(sk);
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@ -1447,6 +1449,12 @@ static ssize_t smc_sendpage(struct socket *sock, struct page *page,
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return rc;
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}
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/* Map the affected portions of the rmbe into an spd, note the number of bytes
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* to splice in conn->splice_pending, and press 'go'. Delays consumer cursor
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* updates till whenever a respective page has been fully processed.
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* Note that subsequent recv() calls have to wait till all splice() processing
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* completed.
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*/
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static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
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struct pipe_inode_info *pipe, size_t len,
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unsigned int flags)
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@ -1457,16 +1465,34 @@ static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
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smc = smc_sk(sk);
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lock_sock(sk);
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if ((sk->sk_state != SMC_ACTIVE) && (sk->sk_state != SMC_CLOSED))
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if (sk->sk_state == SMC_INIT ||
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sk->sk_state == SMC_LISTEN ||
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sk->sk_state == SMC_CLOSED)
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goto out;
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if (sk->sk_state == SMC_PEERFINCLOSEWAIT) {
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rc = 0;
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goto out;
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}
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if (smc->use_fallback) {
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rc = smc->clcsock->ops->splice_read(smc->clcsock, ppos,
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pipe, len, flags);
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} else {
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rc = -EOPNOTSUPP;
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if (*ppos) {
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rc = -ESPIPE;
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goto out;
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}
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if (flags & SPLICE_F_NONBLOCK)
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flags = MSG_DONTWAIT;
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else
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flags = 0;
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rc = smc_rx_recvmsg(smc, NULL, pipe, len, flags);
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}
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out:
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release_sock(sk);
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return rc;
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}
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@ -164,6 +164,9 @@ struct smc_connection {
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atomic_t bytes_to_rcv; /* arrived data,
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* not yet received
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*/
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atomic_t splice_pending; /* number of spliced bytes
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* pending processing
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*/
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#ifndef KERNEL_HAS_ATOMIC64
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spinlock_t acurs_lock; /* protect cursors */
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#endif
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161
net/smc/smc_rx.c
161
net/smc/smc_rx.c
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@ -43,6 +43,116 @@ static void smc_rx_wake_up(struct sock *sk)
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rcu_read_unlock();
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}
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/* Update consumer cursor
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* @conn connection to update
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* @cons consumer cursor
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* @len number of Bytes consumed
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*/
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static void smc_rx_update_consumer(struct smc_connection *conn,
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union smc_host_cursor cons, size_t len)
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{
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smc_curs_add(conn->rmbe_size, &cons, len);
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smc_curs_write(&conn->local_tx_ctrl.cons, 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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struct smc_spd_priv {
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struct smc_sock *smc;
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size_t len;
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};
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static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe,
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struct pipe_buffer *buf)
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{
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struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private;
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struct smc_sock *smc = priv->smc;
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struct smc_connection *conn;
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union smc_host_cursor cons;
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struct sock *sk = &smc->sk;
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if (sk->sk_state == SMC_CLOSED ||
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sk->sk_state == SMC_PEERFINCLOSEWAIT ||
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sk->sk_state == SMC_APPFINCLOSEWAIT)
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goto out;
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conn = &smc->conn;
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lock_sock(sk);
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smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn),
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conn);
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smc_rx_update_consumer(conn, cons, priv->len);
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release_sock(sk);
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if (atomic_sub_and_test(priv->len, &conn->splice_pending))
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smc_rx_wake_up(sk);
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out:
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kfree(priv);
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put_page(buf->page);
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sock_put(sk);
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}
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static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe,
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struct pipe_buffer *buf)
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{
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return 1;
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}
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static const struct pipe_buf_operations smc_pipe_ops = {
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.can_merge = 0,
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.confirm = generic_pipe_buf_confirm,
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.release = smc_rx_pipe_buf_release,
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.steal = smc_rx_pipe_buf_nosteal,
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.get = generic_pipe_buf_get
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};
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static void smc_rx_spd_release(struct splice_pipe_desc *spd,
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unsigned int i)
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{
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put_page(spd->pages[i]);
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}
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static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len,
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struct smc_sock *smc)
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{
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struct splice_pipe_desc spd;
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struct partial_page partial;
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struct smc_spd_priv *priv;
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struct page *page;
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int bytes;
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page = virt_to_page(smc->conn.rmb_desc->cpu_addr);
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->len = len;
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priv->smc = smc;
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partial.offset = src - (char *)smc->conn.rmb_desc->cpu_addr;
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partial.len = len;
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partial.private = (unsigned long)priv;
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spd.nr_pages_max = 1;
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spd.nr_pages = 1;
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spd.pages = &page;
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spd.partial = &partial;
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spd.ops = &smc_pipe_ops;
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spd.spd_release = smc_rx_spd_release;
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bytes = splice_to_pipe(pipe, &spd);
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if (bytes > 0) {
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sock_hold(&smc->sk);
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get_page(smc->conn.rmb_desc->pages);
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atomic_add(bytes, &smc->conn.splice_pending);
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}
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return bytes;
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}
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static int smc_rx_data_available_and_no_splice_pend(struct smc_connection *conn)
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{
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return atomic_read(&conn->bytes_to_rcv) &&
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!atomic_read(&conn->splice_pending);
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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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@ -74,19 +184,25 @@ int smc_rx_wait(struct smc_sock *smc, long *timeo,
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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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/* smc_rx_recvmsg - receive data from RMBE
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* @msg: copy data to receive buffer
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* @pipe: copy data to pipe if set - indicates splice() call
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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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int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
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struct pipe_inode_info *pipe, size_t len, 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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int (*func)(struct smc_connection *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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int splbytes;
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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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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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if (read_done >= target || (pipe && read_done))
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break;
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if (atomic_read(&conn->bytes_to_rcv))
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/* initialize variables for 1st iteration of subsequent loop */
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/* could be just 1 byte, even after waiting on data above */
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readable = atomic_read(&conn->bytes_to_rcv);
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splbytes = atomic_read(&conn->splice_pending);
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if (!readable || (msg && splbytes)) {
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if (splbytes)
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func = smc_rx_data_available_and_no_splice_pend;
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else
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func = smc_rx_data_available;
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smc_rx_wait(smc, &timeo, func);
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continue;
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}
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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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/* subsequent splice() calls pick up where previous left */
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if (splbytes)
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smc_curs_add(conn->rmbe_size, &cons, splbytes);
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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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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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if (msg) {
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rc = memcpy_to_msg(msg, rcvbuf_base +
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chunk_off,
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chunk_len);
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if (rc) {
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} else {
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rc = smc_rx_splice(pipe, rcvbuf_base +
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chunk_off, chunk_len,
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smc);
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}
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if (rc < 0) {
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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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/* 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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if (msg)
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smc_rx_update_consumer(conn, cons, copylen);
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}
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} while (read_remaining);
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out:
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@ -215,4 +345,5 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
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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_wake_up;
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atomic_set(&smc->conn.splice_pending, 0);
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}
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@ -18,8 +18,9 @@
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#include "smc.h"
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void smc_rx_init(struct smc_sock *smc);
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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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int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
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struct pipe_inode_info *pipe, size_t len, int flags);
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int smc_rx_wait(struct smc_sock *smc, long *timeo,
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int (*fcrit)(struct smc_connection *conn));
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static inline int smc_rx_data_available(struct smc_connection *conn)
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return atomic_read(&conn->bytes_to_rcv);
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}
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#endif /* SMC_RX_H */
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