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Revert "rxrpc: Allow failed client calls to be retried"

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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>
This commit is contained in:
David Howells
2019-01-10 16:59:13 +00:00
committed by David S. Miller
parent 70a44f9f6e
commit e122d845a0
7 changed files with 24 additions and 252 deletions
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97
net/rxrpc/call_object.c
View File

@@ -324,48 +324,6 @@ error:
return ERR_PTR(ret);
}
/*
* Retry a call to a new address. It is expected that the Tx queue of the call
* will contain data previously packaged for an old call.
*/
int rxrpc_retry_client_call(struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct rxrpc_conn_parameters *cp,
struct sockaddr_rxrpc *srx,
gfp_t gfp)
{
const void *here = __builtin_return_address(0);
int ret;
/* Set up or get a connection record and set the protocol parameters,
* including channel number and call ID.
*/
ret = rxrpc_connect_call(rx, call, cp, srx, gfp);
if (ret < 0)
goto error;
trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
here, NULL);
rxrpc_start_call_timer(call);
_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
_leave(" = 0");
return 0;
error:
rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
RX_CALL_DEAD, ret);
trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
here, ERR_PTR(ret));
_leave(" = %d", ret);
return ret;
}
/*
* Set up an incoming call. call->conn points to the connection.
* This is called in BH context and isn't allowed to fail.
@@ -533,61 +491,6 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
_leave("");
}
/*
* Prepare a kernel service call for retry.
*/
int rxrpc_prepare_call_for_retry(struct rxrpc_sock *rx, struct rxrpc_call *call)
{
const void *here = __builtin_return_address(0);
int i;
u8 last = 0;
_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
here, (const void *)call->flags);
ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
ASSERTCMP(call->completion, !=, RXRPC_CALL_REMOTELY_ABORTED);
ASSERTCMP(call->completion, !=, RXRPC_CALL_LOCALLY_ABORTED);
ASSERT(list_empty(&call->recvmsg_link));
del_timer_sync(&call->timer);
_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, call->conn);
if (call->conn)
rxrpc_disconnect_call(call);
if (rxrpc_is_service_call(call) ||
!call->tx_phase ||
call->tx_hard_ack != 0 ||
call->rx_hard_ack != 0 ||
call->rx_top != 0)
return -EINVAL;
call->state = RXRPC_CALL_UNINITIALISED;
call->completion = RXRPC_CALL_SUCCEEDED;
call->call_id = 0;
call->cid = 0;
call->cong_cwnd = 0;
call->cong_extra = 0;
call->cong_ssthresh = 0;
call->cong_mode = 0;
call->cong_dup_acks = 0;
call->cong_cumul_acks = 0;
call->acks_lowest_nak = 0;
for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
last |= call->rxtx_annotations[i];
call->rxtx_annotations[i] &= RXRPC_TX_ANNO_LAST;
call->rxtx_annotations[i] |= RXRPC_TX_ANNO_RETRANS;
}
_leave(" = 0");
return 0;
}
/*
* release all the calls associated with a socket
*/