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// SPDX-License-Identifier: GPL-2.0
/*
* 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 to wakeup consumers blocked with smc_rx_wait().
* indirectly called by smc_cdc_msg_recv_action().
*/
static void smc_rx_wake_up(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, EPOLLIN | EPOLLPRI |
EPOLLRDNORM | EPOLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
(sk->sk_state == SMC_CLOSED))
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
rcu_read_unlock();
}
/* Update consumer cursor
* @conn connection to update
* @cons consumer cursor
* @len number of Bytes consumed
* Returns:
* 1 if we should end our receive, 0 otherwise
*/
static int smc_rx_update_consumer(struct smc_sock *smc,
union smc_host_cursor cons, size_t len)
{
struct smc_connection *conn = &smc->conn;
struct sock *sk = &smc->sk;
bool force = false;
int diff, rc = 0;
smc_curs_add(conn->rmb_desc->len, &cons, len);
/* did we process urgent data? */
if (conn->urg_state == SMC_URG_VALID || conn->urg_rx_skip_pend) {
diff = smc_curs_comp(conn->rmb_desc->len, &cons,
&conn->urg_curs);
if (sock_flag(sk, SOCK_URGINLINE)) {
if (diff == 0) {
force = true;
rc = 1;
conn->urg_state = SMC_URG_READ;
}
} else {
if (diff == 1) {
/* skip urgent byte */
force = true;
smc_curs_add(conn->rmb_desc->len, &cons, 1);
conn->urg_rx_skip_pend = false;
} else if (diff < -1)
/* we read past urgent byte */
conn->urg_state = SMC_URG_READ;
}
}
smc_curs_copy(&conn->local_tx_ctrl.cons, &cons, conn);
/* send consumer cursor update if required */
/* similar to advertising new TCP rcv_wnd if required */
smc_tx_consumer_update(conn, force);
return rc;
}
static void smc_rx_update_cons(struct smc_sock *smc, size_t len)
{
struct smc_connection *conn = &smc->conn;
union smc_host_cursor cons;
smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
smc_rx_update_consumer(smc, cons, len);
}
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;
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_rx_update_cons(smc, 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 = {
.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;
int bytes;
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 = &smc->conn.rmb_desc->pages;
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
* @fcrit add'l criterion to evaluate as function pointer
* 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).
*/
int smc_rx_wait(struct smc_sock *smc, long *timeo,
int (*fcrit)(struct smc_connection *conn))
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct smc_connection *conn = &smc->conn;
struct sock *sk = &smc->sk;
int rc;
if (fcrit(conn))
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 ||
fcrit(conn) ||
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;
}
static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len,
int flags)
{
struct smc_connection *conn = &smc->conn;
union smc_host_cursor cons;
struct sock *sk = &smc->sk;
int rc = 0;
if (sock_flag(sk, SOCK_URGINLINE) ||
!(conn->urg_state == SMC_URG_VALID) ||
conn->urg_state == SMC_URG_READ)
return -EINVAL;
if (conn->urg_state == SMC_URG_VALID) {
if (!(flags & MSG_PEEK))
smc->conn.urg_state = SMC_URG_READ;
msg->msg_flags |= MSG_OOB;
if (len > 0) {
if
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