Commit b960a34b authored by David Howells's avatar David Howells

rxrpc: Allow the kernel to mark a call as being non-interruptible

Allow kernel services using AF_RXRPC to indicate that a call should be
non-interruptible.  This allows kafs to make things like lock-extension and
writeback data storage calls non-interruptible.

If this is set, signals will be ignored for operations on that call where
possible - such as waiting to get a call channel on an rxrpc connection.

It doesn't prevent UDP sendmsg from being interrupted, but that will be
handled by packet retransmission.

rxrpc_kernel_recv_data() isn't affected by this since that never waits,
preferring instead to return -EAGAIN and leave the waiting to the caller.

Userspace initiated calls can't be set to be uninterruptible at this time.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 0ab4c959
......@@ -796,7 +796,9 @@ The kernel interface functions are as follows:
s64 tx_total_len,
gfp_t gfp,
rxrpc_notify_rx_t notify_rx,
bool upgrade);
bool upgrade,
bool intr,
unsigned int debug_id);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
......@@ -824,6 +826,13 @@ The kernel interface functions are as follows:
the server upgrade the service to a better one. The resultant service ID
is returned by rxrpc_kernel_recv_data().
intr should be set to true if the call should be interruptible. If this
is not set, this function may not return until a channel has been
allocated; if it is set, the function may return -ERESTARTSYS.
debug_id is the call debugging ID to be used for tracing. This can be
obtained by atomically incrementing rxrpc_debug_id.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
......
......@@ -417,6 +417,7 @@ void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
afs_wake_up_async_call :
afs_wake_up_call_waiter),
call->upgrade,
true,
call->debug_id);
if (IS_ERR(rxcall)) {
ret = PTR_ERR(rxcall);
......
......@@ -45,6 +45,7 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *,
gfp_t,
rxrpc_notify_rx_t,
bool,
bool,
unsigned int);
int rxrpc_kernel_send_data(struct socket *, struct rxrpc_call *,
struct msghdr *, size_t,
......
......@@ -270,6 +270,7 @@ static int rxrpc_listen(struct socket *sock, int backlog)
* @gfp: The allocation constraints
* @notify_rx: Where to send notifications instead of socket queue
* @upgrade: Request service upgrade for call
* @intr: The call is interruptible
* @debug_id: The debug ID for tracing to be assigned to the call
*
* Allow a kernel service to begin a call on the nominated socket. This just
......@@ -287,6 +288,7 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
gfp_t gfp,
rxrpc_notify_rx_t notify_rx,
bool upgrade,
bool intr,
unsigned int debug_id)
{
struct rxrpc_conn_parameters cp;
......@@ -311,6 +313,7 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
memset(&p, 0, sizeof(p));
p.user_call_ID = user_call_ID;
p.tx_total_len = tx_total_len;
p.intr = intr;
memset(&cp, 0, sizeof(cp));
cp.local = rx->local;
......
......@@ -482,6 +482,7 @@ enum rxrpc_call_flag {
RXRPC_CALL_BEGAN_RX_TIMER, /* We began the expect_rx_by timer */
RXRPC_CALL_RX_HEARD, /* The peer responded at least once to this call */
RXRPC_CALL_RX_UNDERRUN, /* Got data underrun */
RXRPC_CALL_IS_INTR, /* The call is interruptible */
};
/*
......@@ -711,6 +712,7 @@ struct rxrpc_call_params {
u32 normal; /* Max time since last call packet (msec) */
} timeouts;
u8 nr_timeouts; /* Number of timeouts specified */
bool intr; /* The call is interruptible */
};
struct rxrpc_send_params {
......
......@@ -241,6 +241,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
return call;
}
if (p->intr)
__set_bit(RXRPC_CALL_IS_INTR, &call->flags);
call->tx_total_len = p->tx_total_len;
trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
here, (const void *)p->user_call_ID);
......
......@@ -656,10 +656,14 @@ static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp)
add_wait_queue_exclusive(&call->waitq, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (test_bit(RXRPC_CALL_IS_INTR, &call->flags))
set_current_state(TASK_INTERRUPTIBLE);
else
set_current_state(TASK_UNINTERRUPTIBLE);
if (call->call_id)
break;
if (signal_pending(current)) {
if (test_bit(RXRPC_CALL_IS_INTR, &call->flags) &&
signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
......
......@@ -80,7 +80,8 @@ static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
if (call->state >= RXRPC_CALL_COMPLETE)
return call->error;
if (timeout == 0 &&
if (test_bit(RXRPC_CALL_IS_INTR, &call->flags) &&
timeout == 0 &&
tx_win == tx_start && signal_pending(current))
return -EINTR;
......@@ -620,6 +621,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
.call.tx_total_len = -1,
.call.user_call_ID = 0,
.call.nr_timeouts = 0,
.call.intr = true,
.abort_code = 0,
.command = RXRPC_CMD_SEND_DATA,
.exclusive = false,
......
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