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linux-next/net/smc/smc_rx.c
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement 
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00

222 lines
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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 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, 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();
}
/* 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 ||
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 (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 (!timeo)
return -EAGAIN;
}
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;
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 (!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)) {
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;
}
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