mirror of
https://github.com/torvalds/linux.git
synced 2024-12-14 07:02:23 +00:00
5a2c5a5b08
rxrpc_recvmsg_data() schedules an ACK to be transmitted every time at least two packets have been consumed and any time it runs out of data and would return -EAGAIN to the caller. Both events may occur within a single loop, however, and if the I/O thread is quick enough it may send duplicate ACKs. The ACKs are sent to inform the peer that more space has been made in the local Rx window, but the I/O thread is going to send an ACK every couple of DATA packets anyway, so we end up sending a lot more ACKs than we really need to. So reduce the rate at which recvmsg() schedules ACKs, such that if the I/O thread sends ACKs at its normal faster rate, recvmsg() won't actually schedule ACKs until the Rx flow stops (call->rx_consumed is cleared any time we transmit an ACK for that call, resetting the counter used by recvmsg). Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org
542 lines
13 KiB
C
542 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* RxRPC recvmsg() implementation
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/net.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/export.h>
|
|
#include <linux/sched/signal.h>
|
|
|
|
#include <net/sock.h>
|
|
#include <net/af_rxrpc.h>
|
|
#include "ar-internal.h"
|
|
|
|
/*
|
|
* Post a call for attention by the socket or kernel service. Further
|
|
* notifications are suppressed by putting recvmsg_link on a dummy queue.
|
|
*/
|
|
void rxrpc_notify_socket(struct rxrpc_call *call)
|
|
{
|
|
struct rxrpc_sock *rx;
|
|
struct sock *sk;
|
|
|
|
_enter("%d", call->debug_id);
|
|
|
|
if (!list_empty(&call->recvmsg_link))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
|
|
rx = rcu_dereference(call->socket);
|
|
sk = &rx->sk;
|
|
if (rx && sk->sk_state < RXRPC_CLOSE) {
|
|
if (call->notify_rx) {
|
|
spin_lock(&call->notify_lock);
|
|
call->notify_rx(sk, call, call->user_call_ID);
|
|
spin_unlock(&call->notify_lock);
|
|
} else {
|
|
spin_lock(&rx->recvmsg_lock);
|
|
if (list_empty(&call->recvmsg_link)) {
|
|
rxrpc_get_call(call, rxrpc_call_get_notify_socket);
|
|
list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
|
|
}
|
|
spin_unlock(&rx->recvmsg_lock);
|
|
|
|
if (!sock_flag(sk, SOCK_DEAD)) {
|
|
_debug("call %ps", sk->sk_data_ready);
|
|
sk->sk_data_ready(sk);
|
|
}
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Pass a call terminating message to userspace.
|
|
*/
|
|
static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
|
|
{
|
|
u32 tmp = 0;
|
|
int ret;
|
|
|
|
switch (call->completion) {
|
|
case RXRPC_CALL_SUCCEEDED:
|
|
ret = 0;
|
|
if (rxrpc_is_service_call(call))
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
|
|
break;
|
|
case RXRPC_CALL_REMOTELY_ABORTED:
|
|
tmp = call->abort_code;
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
|
|
break;
|
|
case RXRPC_CALL_LOCALLY_ABORTED:
|
|
tmp = call->abort_code;
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
|
|
break;
|
|
case RXRPC_CALL_NETWORK_ERROR:
|
|
tmp = -call->error;
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
|
|
break;
|
|
case RXRPC_CALL_LOCAL_ERROR:
|
|
tmp = -call->error;
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
|
|
break;
|
|
default:
|
|
pr_err("Invalid terminal call state %u\n", call->completion);
|
|
BUG();
|
|
break;
|
|
}
|
|
|
|
trace_rxrpc_recvdata(call, rxrpc_recvmsg_terminal,
|
|
call->ackr_window - 1,
|
|
call->rx_pkt_offset, call->rx_pkt_len, ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Discard a packet we've used up and advance the Rx window by one.
|
|
*/
|
|
static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
|
|
{
|
|
struct rxrpc_skb_priv *sp;
|
|
struct sk_buff *skb;
|
|
rxrpc_serial_t serial;
|
|
rxrpc_seq_t old_consumed = call->rx_consumed, tseq;
|
|
bool last;
|
|
int acked;
|
|
|
|
_enter("%d", call->debug_id);
|
|
|
|
skb = skb_dequeue(&call->recvmsg_queue);
|
|
rxrpc_see_skb(skb, rxrpc_skb_see_rotate);
|
|
|
|
sp = rxrpc_skb(skb);
|
|
tseq = sp->hdr.seq;
|
|
serial = sp->hdr.serial;
|
|
last = sp->hdr.flags & RXRPC_LAST_PACKET;
|
|
|
|
/* Barrier against rxrpc_input_data(). */
|
|
if (after(tseq, call->rx_consumed))
|
|
smp_store_release(&call->rx_consumed, tseq);
|
|
|
|
rxrpc_free_skb(skb, rxrpc_skb_put_rotate);
|
|
|
|
trace_rxrpc_receive(call, last ? rxrpc_receive_rotate_last : rxrpc_receive_rotate,
|
|
serial, call->rx_consumed);
|
|
|
|
if (last)
|
|
set_bit(RXRPC_CALL_RECVMSG_READ_ALL, &call->flags);
|
|
|
|
/* Check to see if there's an ACK that needs sending. */
|
|
acked = atomic_add_return(call->rx_consumed - old_consumed,
|
|
&call->ackr_nr_consumed);
|
|
if (acked > 8 &&
|
|
!test_and_set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
|
|
rxrpc_poke_call(call, rxrpc_call_poke_idle);
|
|
}
|
|
|
|
/*
|
|
* Decrypt and verify a DATA packet.
|
|
*/
|
|
static int rxrpc_verify_data(struct rxrpc_call *call, struct sk_buff *skb)
|
|
{
|
|
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
|
|
|
|
if (sp->flags & RXRPC_RX_VERIFIED)
|
|
return 0;
|
|
return call->security->verify_packet(call, skb);
|
|
}
|
|
|
|
/*
|
|
* Deliver messages to a call. This keeps processing packets until the buffer
|
|
* is filled and we find either more DATA (returns 0) or the end of the DATA
|
|
* (returns 1). If more packets are required, it returns -EAGAIN and if the
|
|
* call has failed it returns -EIO.
|
|
*/
|
|
static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
|
|
struct msghdr *msg, struct iov_iter *iter,
|
|
size_t len, int flags, size_t *_offset)
|
|
{
|
|
struct rxrpc_skb_priv *sp;
|
|
struct sk_buff *skb;
|
|
rxrpc_seq_t seq = 0;
|
|
size_t remain;
|
|
unsigned int rx_pkt_offset, rx_pkt_len;
|
|
int copy, ret = -EAGAIN, ret2;
|
|
|
|
rx_pkt_offset = call->rx_pkt_offset;
|
|
rx_pkt_len = call->rx_pkt_len;
|
|
|
|
if (rxrpc_call_has_failed(call)) {
|
|
seq = call->ackr_window - 1;
|
|
ret = -EIO;
|
|
goto done;
|
|
}
|
|
|
|
if (test_bit(RXRPC_CALL_RECVMSG_READ_ALL, &call->flags)) {
|
|
seq = call->ackr_window - 1;
|
|
ret = 1;
|
|
goto done;
|
|
}
|
|
|
|
/* No one else can be removing stuff from the queue, so we shouldn't
|
|
* need the Rx lock to walk it.
|
|
*/
|
|
skb = skb_peek(&call->recvmsg_queue);
|
|
while (skb) {
|
|
rxrpc_see_skb(skb, rxrpc_skb_see_recvmsg);
|
|
sp = rxrpc_skb(skb);
|
|
seq = sp->hdr.seq;
|
|
|
|
if (!(flags & MSG_PEEK))
|
|
trace_rxrpc_receive(call, rxrpc_receive_front,
|
|
sp->hdr.serial, seq);
|
|
|
|
if (msg)
|
|
sock_recv_timestamp(msg, sock->sk, skb);
|
|
|
|
if (rx_pkt_offset == 0) {
|
|
ret2 = rxrpc_verify_data(call, skb);
|
|
trace_rxrpc_recvdata(call, rxrpc_recvmsg_next, seq,
|
|
sp->offset, sp->len, ret2);
|
|
if (ret2 < 0) {
|
|
kdebug("verify = %d", ret2);
|
|
ret = ret2;
|
|
goto out;
|
|
}
|
|
rx_pkt_offset = sp->offset;
|
|
rx_pkt_len = sp->len;
|
|
} else {
|
|
trace_rxrpc_recvdata(call, rxrpc_recvmsg_cont, seq,
|
|
rx_pkt_offset, rx_pkt_len, 0);
|
|
}
|
|
|
|
/* We have to handle short, empty and used-up DATA packets. */
|
|
remain = len - *_offset;
|
|
copy = rx_pkt_len;
|
|
if (copy > remain)
|
|
copy = remain;
|
|
if (copy > 0) {
|
|
ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
|
|
copy);
|
|
if (ret2 < 0) {
|
|
ret = ret2;
|
|
goto out;
|
|
}
|
|
|
|
/* handle piecemeal consumption of data packets */
|
|
rx_pkt_offset += copy;
|
|
rx_pkt_len -= copy;
|
|
*_offset += copy;
|
|
}
|
|
|
|
if (rx_pkt_len > 0) {
|
|
trace_rxrpc_recvdata(call, rxrpc_recvmsg_full, seq,
|
|
rx_pkt_offset, rx_pkt_len, 0);
|
|
ASSERTCMP(*_offset, ==, len);
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
/* The whole packet has been transferred. */
|
|
if (sp->hdr.flags & RXRPC_LAST_PACKET)
|
|
ret = 1;
|
|
rx_pkt_offset = 0;
|
|
rx_pkt_len = 0;
|
|
|
|
skb = skb_peek_next(skb, &call->recvmsg_queue);
|
|
|
|
if (!(flags & MSG_PEEK))
|
|
rxrpc_rotate_rx_window(call);
|
|
}
|
|
|
|
out:
|
|
if (!(flags & MSG_PEEK)) {
|
|
call->rx_pkt_offset = rx_pkt_offset;
|
|
call->rx_pkt_len = rx_pkt_len;
|
|
}
|
|
done:
|
|
trace_rxrpc_recvdata(call, rxrpc_recvmsg_data_return, seq,
|
|
rx_pkt_offset, rx_pkt_len, ret);
|
|
if (ret == -EAGAIN)
|
|
set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Receive a message from an RxRPC socket
|
|
* - we need to be careful about two or more threads calling recvmsg
|
|
* simultaneously
|
|
*/
|
|
int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
|
|
int flags)
|
|
{
|
|
struct rxrpc_call *call;
|
|
struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
|
|
struct list_head *l;
|
|
unsigned int call_debug_id = 0;
|
|
size_t copied = 0;
|
|
long timeo;
|
|
int ret;
|
|
|
|
DEFINE_WAIT(wait);
|
|
|
|
trace_rxrpc_recvmsg(0, rxrpc_recvmsg_enter, 0);
|
|
|
|
if (flags & (MSG_OOB | MSG_TRUNC))
|
|
return -EOPNOTSUPP;
|
|
|
|
timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
|
|
|
|
try_again:
|
|
lock_sock(&rx->sk);
|
|
|
|
/* Return immediately if a client socket has no outstanding calls */
|
|
if (RB_EMPTY_ROOT(&rx->calls) &&
|
|
list_empty(&rx->recvmsg_q) &&
|
|
rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
|
|
release_sock(&rx->sk);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
if (list_empty(&rx->recvmsg_q)) {
|
|
ret = -EWOULDBLOCK;
|
|
if (timeo == 0) {
|
|
call = NULL;
|
|
goto error_no_call;
|
|
}
|
|
|
|
release_sock(&rx->sk);
|
|
|
|
/* Wait for something to happen */
|
|
prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
|
|
TASK_INTERRUPTIBLE);
|
|
ret = sock_error(&rx->sk);
|
|
if (ret)
|
|
goto wait_error;
|
|
|
|
if (list_empty(&rx->recvmsg_q)) {
|
|
if (signal_pending(current))
|
|
goto wait_interrupted;
|
|
trace_rxrpc_recvmsg(0, rxrpc_recvmsg_wait, 0);
|
|
timeo = schedule_timeout(timeo);
|
|
}
|
|
finish_wait(sk_sleep(&rx->sk), &wait);
|
|
goto try_again;
|
|
}
|
|
|
|
/* Find the next call and dequeue it if we're not just peeking. If we
|
|
* do dequeue it, that comes with a ref that we will need to release.
|
|
*/
|
|
spin_lock(&rx->recvmsg_lock);
|
|
l = rx->recvmsg_q.next;
|
|
call = list_entry(l, struct rxrpc_call, recvmsg_link);
|
|
if (!(flags & MSG_PEEK))
|
|
list_del_init(&call->recvmsg_link);
|
|
else
|
|
rxrpc_get_call(call, rxrpc_call_get_recvmsg);
|
|
spin_unlock(&rx->recvmsg_lock);
|
|
|
|
call_debug_id = call->debug_id;
|
|
trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_dequeue, 0);
|
|
|
|
/* We're going to drop the socket lock, so we need to lock the call
|
|
* against interference by sendmsg.
|
|
*/
|
|
if (!mutex_trylock(&call->user_mutex)) {
|
|
ret = -EWOULDBLOCK;
|
|
if (flags & MSG_DONTWAIT)
|
|
goto error_requeue_call;
|
|
ret = -ERESTARTSYS;
|
|
if (mutex_lock_interruptible(&call->user_mutex) < 0)
|
|
goto error_requeue_call;
|
|
}
|
|
|
|
release_sock(&rx->sk);
|
|
|
|
if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
|
|
BUG();
|
|
|
|
if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
|
|
if (flags & MSG_CMSG_COMPAT) {
|
|
unsigned int id32 = call->user_call_ID;
|
|
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
|
|
sizeof(unsigned int), &id32);
|
|
} else {
|
|
unsigned long idl = call->user_call_ID;
|
|
|
|
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
|
|
sizeof(unsigned long), &idl);
|
|
}
|
|
if (ret < 0)
|
|
goto error_unlock_call;
|
|
}
|
|
|
|
if (msg->msg_name && call->peer) {
|
|
size_t len = sizeof(call->dest_srx);
|
|
|
|
memcpy(msg->msg_name, &call->dest_srx, len);
|
|
msg->msg_namelen = len;
|
|
}
|
|
|
|
ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
|
|
flags, &copied);
|
|
if (ret == -EAGAIN)
|
|
ret = 0;
|
|
if (ret == -EIO)
|
|
goto call_failed;
|
|
if (ret < 0)
|
|
goto error_unlock_call;
|
|
|
|
if (rxrpc_call_is_complete(call) &&
|
|
skb_queue_empty(&call->recvmsg_queue))
|
|
goto call_complete;
|
|
if (rxrpc_call_has_failed(call))
|
|
goto call_failed;
|
|
|
|
rxrpc_notify_socket(call);
|
|
goto not_yet_complete;
|
|
|
|
call_failed:
|
|
rxrpc_purge_queue(&call->recvmsg_queue);
|
|
call_complete:
|
|
ret = rxrpc_recvmsg_term(call, msg);
|
|
if (ret < 0)
|
|
goto error_unlock_call;
|
|
if (!(flags & MSG_PEEK))
|
|
rxrpc_release_call(rx, call);
|
|
msg->msg_flags |= MSG_EOR;
|
|
ret = 1;
|
|
|
|
not_yet_complete:
|
|
if (ret == 0)
|
|
msg->msg_flags |= MSG_MORE;
|
|
else
|
|
msg->msg_flags &= ~MSG_MORE;
|
|
ret = copied;
|
|
|
|
error_unlock_call:
|
|
mutex_unlock(&call->user_mutex);
|
|
rxrpc_put_call(call, rxrpc_call_put_recvmsg);
|
|
trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
|
|
return ret;
|
|
|
|
error_requeue_call:
|
|
if (!(flags & MSG_PEEK)) {
|
|
spin_lock(&rx->recvmsg_lock);
|
|
list_add(&call->recvmsg_link, &rx->recvmsg_q);
|
|
spin_unlock(&rx->recvmsg_lock);
|
|
trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_requeue, 0);
|
|
} else {
|
|
rxrpc_put_call(call, rxrpc_call_put_recvmsg);
|
|
}
|
|
error_no_call:
|
|
release_sock(&rx->sk);
|
|
error_trace:
|
|
trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
|
|
return ret;
|
|
|
|
wait_interrupted:
|
|
ret = sock_intr_errno(timeo);
|
|
wait_error:
|
|
finish_wait(sk_sleep(&rx->sk), &wait);
|
|
call = NULL;
|
|
goto error_trace;
|
|
}
|
|
|
|
/**
|
|
* rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
|
|
* @sock: The socket that the call exists on
|
|
* @call: The call to send data through
|
|
* @iter: The buffer to receive into
|
|
* @_len: The amount of data we want to receive (decreased on return)
|
|
* @want_more: True if more data is expected to be read
|
|
* @_abort: Where the abort code is stored if -ECONNABORTED is returned
|
|
* @_service: Where to store the actual service ID (may be upgraded)
|
|
*
|
|
* Allow a kernel service to receive data and pick up information about the
|
|
* state of a call. Returns 0 if got what was asked for and there's more
|
|
* available, 1 if we got what was asked for and we're at the end of the data
|
|
* and -EAGAIN if we need more data.
|
|
*
|
|
* Note that we may return -EAGAIN to drain empty packets at the end of the
|
|
* data, even if we've already copied over the requested data.
|
|
*
|
|
* *_abort should also be initialised to 0.
|
|
*/
|
|
int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
|
|
struct iov_iter *iter, size_t *_len,
|
|
bool want_more, u32 *_abort, u16 *_service)
|
|
{
|
|
size_t offset = 0;
|
|
int ret;
|
|
|
|
_enter("{%d},%zu,%d", call->debug_id, *_len, want_more);
|
|
|
|
mutex_lock(&call->user_mutex);
|
|
|
|
ret = rxrpc_recvmsg_data(sock, call, NULL, iter, *_len, 0, &offset);
|
|
*_len -= offset;
|
|
if (ret == -EIO)
|
|
goto call_failed;
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
/* We can only reach here with a partially full buffer if we have
|
|
* reached the end of the data. We must otherwise have a full buffer
|
|
* or have been given -EAGAIN.
|
|
*/
|
|
if (ret == 1) {
|
|
if (iov_iter_count(iter) > 0)
|
|
goto short_data;
|
|
if (!want_more)
|
|
goto read_phase_complete;
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
|
|
if (!want_more)
|
|
goto excess_data;
|
|
goto out;
|
|
|
|
read_phase_complete:
|
|
ret = 1;
|
|
out:
|
|
if (_service)
|
|
*_service = call->dest_srx.srx_service;
|
|
mutex_unlock(&call->user_mutex);
|
|
_leave(" = %d [%zu,%d]", ret, iov_iter_count(iter), *_abort);
|
|
return ret;
|
|
|
|
short_data:
|
|
trace_rxrpc_abort(call->debug_id, rxrpc_recvmsg_short_data,
|
|
call->cid, call->call_id, call->rx_consumed,
|
|
0, -EBADMSG);
|
|
ret = -EBADMSG;
|
|
goto out;
|
|
excess_data:
|
|
trace_rxrpc_abort(call->debug_id, rxrpc_recvmsg_excess_data,
|
|
call->cid, call->call_id, call->rx_consumed,
|
|
0, -EMSGSIZE);
|
|
ret = -EMSGSIZE;
|
|
goto out;
|
|
call_failed:
|
|
*_abort = call->abort_code;
|
|
ret = call->error;
|
|
if (call->completion == RXRPC_CALL_SUCCEEDED) {
|
|
ret = 1;
|
|
if (iov_iter_count(iter) > 0)
|
|
ret = -ECONNRESET;
|
|
}
|
|
goto out;
|
|
}
|
|
EXPORT_SYMBOL(rxrpc_kernel_recv_data);
|