swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: fe07bfda2fb9cdef8a4d4008a409bb02f35f1bd8 authored by Linus Torvalds on 01 March 2021, 00:05:19 UTC
Linux 5.12-rc1
Linux 5.12-rc1
Tip revision: fe07bfd
smc_rx.c
// 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 const struct pipe_buf_operations smc_pipe_ops = {
.release = smc_rx_pipe_buf_release,
.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 smc_cdc_conn_state_flags *cflags =
&conn->local_tx_ctrl.conn_state_flags;
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 ||
cflags->peer_conn_abort ||
sk->sk_shutdown & RCV_SHUTDOWN ||
conn->killed ||
fcrit(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 (!(flags & MSG_TRUNC))
rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1);
len = 1;
smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
if (smc_curs_diff(conn->rmb_desc->len, &cons,
&conn->urg_curs) > 1)
conn->urg_rx_skip_pend = true;
/* Urgent Byte was already accounted for, but trigger
* skipping the urgent byte in non-inline case
*/
if (!(flags & MSG_PEEK))
smc_rx_update_consumer(smc, cons, 0);
} else {
msg->msg_flags |= MSG_TRUNC;
}
return rc ? -EFAULT : len;
}
if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN)
return 0;
return -EAGAIN;
}
static bool smc_rx_recvmsg_data_available(struct smc_sock *smc)
{
struct smc_connection *conn = &smc->conn;
if (smc_rx_data_available(conn))
return true;
else if (conn->urg_state == SMC_URG_VALID)
/* we received a single urgent Byte - skip */
smc_rx_update_cons(smc, 0);
return false;
}
/* 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,
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;
if (unlikely(flags & MSG_ERRQUEUE))
return -EINVAL; /* future work for sk.sk_family == AF_SMC */
sk = &smc->sk;
if (sk->sk_state == SMC_LISTEN)
return -ENOTCONN;
if (flags & MSG_OOB)
return smc_rx_recv_urg(smc, msg, len, flags);
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
/* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */
rcvbuf_base = conn->rx_off + conn->rmb_desc->cpu_addr;
do { /* while (read_remaining) */
if (read_done >= target || (pipe && read_done))
break;
if (conn->killed)
break;
if (smc_rx_recvmsg_data_available(smc))
goto copy;
if (sk->sk_shutdown & RCV_SHUTDOWN) {
/* smc_cdc_msg_recv_action() could have run after
* above smc_rx_recvmsg_data_available()
*/
if (smc_rx_recvmsg_data_available(smc))
goto copy;
break;
}
if (read_done) {
if (sk->sk_err ||
sk->sk_state == SMC_CLOSED ||
!timeo ||
signal_pending(current))
break;
} else {
if (sk->sk_err) {
read_done = sock_error(sk);
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 (!timeo)
return -EAGAIN;
}
if (!smc_rx_data_available(conn)) {
smc_rx_wait(smc, &timeo, smc_rx_data_available);
continue;
}
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;
}
smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
/* subsequent splice() calls pick up where previous left */
if (splbytes)
smc_curs_add(conn->rmb_desc->len, &cons, splbytes);
if (conn->urg_state == SMC_URG_VALID &&
sock_flag(&smc->sk, SOCK_URGINLINE) &&
readable > 1)
readable--; /* always stop at urgent Byte */
/* not more than what user space asked for */
copylen = min_t(size_t, read_remaining, readable);
/* determine chunks where to read from rcvbuf */
/* either unwrapped case, or 1st chunk of wrapped case */
chunk_len = min_t(size_t, copylen, conn->rmb_desc->len -
cons.count);
chunk_len_sum = chunk_len;
chunk_off = cons.count;
smc_rmb_sync_sg_for_cpu(conn);
for (chunk = 0; chunk < 2; chunk++) {
if (!(flags & MSG_TRUNC)) {
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);
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 */
}
smc_rmb_sync_sg_for_device(conn);
/* update cursors */
if (!(flags & MSG_PEEK)) {
/* increased in recv tasklet smc_cdc_msg_rcv() */
smp_mb__before_atomic();
atomic_sub(copylen, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
smp_mb__after_atomic();
if (msg && smc_rx_update_consumer(smc, cons, copylen))
goto out;
}
} 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_wake_up;
atomic_set(&smc->conn.splice_pending, 0);
smc->conn.urg_state = SMC_URG_READ;
}