forked from Minki/linux
e122d845a0
The changes introduced to allow rxrpc calls to be retried creates an issue
when it comes to refcounting afs_call structs. The problem is that when
rxrpc_send_data() queues the last packet for an asynchronous call, the
following sequence can occur:
(1) The notify_end_tx callback is invoked which causes the state in the
afs_call to be changed from AFS_CALL_CL_REQUESTING or
AFS_CALL_SV_REPLYING.
(2) afs_deliver_to_call() can then process event notifications from rxrpc
on the async_work queue.
(3) Delivery of events, such as an abort from the server, can cause the
afs_call state to be changed to AFS_CALL_COMPLETE on async_work.
(4) For an asynchronous call, afs_process_async_call() notes that the call
is complete and tried to clean up all the refs on async_work.
(5) rxrpc_send_data() might return the amount of data transferred
(success) or an error - which could in turn reflect a local error or a
received error.
Synchronising the clean up after rxrpc_kernel_send_data() returns an error
with the asynchronous cleanup is then tricky to get right.
Mostly revert commit c038a58ccf. The two API
functions the original commit added aren't currently used. This makes
rxrpc_kernel_send_data() always return successfully if it queued the data
it was given.
Note that this doesn't affect synchronous calls since their Rx notification
function merely pokes a wait queue and does not refcounting. The
asynchronous call notification function *has* to do refcounting and pass a
ref over the work item to avoid the need to sync the workqueue in call
cleanup.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
71 lines
2.5 KiB
C
71 lines
2.5 KiB
C
/* RxRPC kernel service interface definitions
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _NET_RXRPC_H
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#define _NET_RXRPC_H
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#include <linux/rxrpc.h>
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#include <linux/ktime.h>
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struct key;
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struct sock;
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struct socket;
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struct rxrpc_call;
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/*
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* Debug ID counter for tracing.
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*/
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extern atomic_t rxrpc_debug_id;
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typedef void (*rxrpc_notify_rx_t)(struct sock *, struct rxrpc_call *,
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unsigned long);
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typedef void (*rxrpc_notify_end_tx_t)(struct sock *, struct rxrpc_call *,
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unsigned long);
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typedef void (*rxrpc_notify_new_call_t)(struct sock *, struct rxrpc_call *,
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unsigned long);
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typedef void (*rxrpc_discard_new_call_t)(struct rxrpc_call *, unsigned long);
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typedef void (*rxrpc_user_attach_call_t)(struct rxrpc_call *, unsigned long);
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void rxrpc_kernel_new_call_notification(struct socket *,
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rxrpc_notify_new_call_t,
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rxrpc_discard_new_call_t);
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struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *,
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struct sockaddr_rxrpc *,
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struct key *,
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unsigned long,
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s64,
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gfp_t,
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rxrpc_notify_rx_t,
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bool,
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unsigned int);
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int rxrpc_kernel_send_data(struct socket *, struct rxrpc_call *,
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struct msghdr *, size_t,
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rxrpc_notify_end_tx_t);
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int rxrpc_kernel_recv_data(struct socket *, struct rxrpc_call *,
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struct iov_iter *, bool, u32 *, u16 *);
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bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *,
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u32, int, const char *);
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void rxrpc_kernel_end_call(struct socket *, struct rxrpc_call *);
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void rxrpc_kernel_get_peer(struct socket *, struct rxrpc_call *,
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struct sockaddr_rxrpc *);
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u64 rxrpc_kernel_get_rtt(struct socket *, struct rxrpc_call *);
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int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
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rxrpc_user_attach_call_t, unsigned long, gfp_t,
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unsigned int);
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void rxrpc_kernel_set_tx_length(struct socket *, struct rxrpc_call *, s64);
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u32 rxrpc_kernel_check_life(const struct socket *, const struct rxrpc_call *);
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void rxrpc_kernel_probe_life(struct socket *, struct rxrpc_call *);
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u32 rxrpc_kernel_get_epoch(struct socket *, struct rxrpc_call *);
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bool rxrpc_kernel_get_reply_time(struct socket *, struct rxrpc_call *,
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ktime_t *);
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#endif /* _NET_RXRPC_H */
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