[PATCH net 6/6] afs: Fix client call Rx-phase signal handling

[David Howells <dhowells@redhat.com>]

Fix the handling of signals in client rxrpc calls made by the afs
filesystem.  Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.

Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know.  It may even be worse than that
for older servers.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/rxrpc.c          |   34 ++--------------------------------
 include/net/af_rxrpc.h  |    4 +---
 net/rxrpc/af_rxrpc.c    |   33 +++------------------------------
 net/rxrpc/ar-internal.h |    1 -
 net/rxrpc/input.c       |    1 -
 5 files changed, 6 insertions(+), 67 deletions(-)

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 972e3aafa361..1ecc67da6c1a 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -604,11 +604,7 @@ static void afs_deliver_to_call(struct afs_call *call)
 long afs_wait_for_call_to_complete(struct afs_call *call,
 				   struct afs_addr_cursor *ac)
 {
-	signed long rtt2, timeout;
 	long ret;
-	bool stalled = false;
-	u64 rtt;
-	u32 life, last_life;
 	bool rxrpc_complete = false;
 
 	DECLARE_WAITQUEUE(myself, current);
@@ -619,14 +615,6 @@ long afs_wait_for_call_to_complete(struct afs_call *call,
 	if (ret < 0)
 		goto out;
 
-	rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);
-	rtt2 = nsecs_to_jiffies64(rtt) * 2;
-	if (rtt2 < 2)
-		rtt2 = 2;
-
-	timeout = rtt2;
-	rxrpc_kernel_check_life(call->net->socket, call->rxcall, &last_life);
-
 	add_wait_queue(&call->waitq, &myself);
 	for (;;) {
 		set_current_state(TASK_UNINTERRUPTIBLE);
@@ -637,37 +625,19 @@ long afs_wait_for_call_to_complete(struct afs_call *call,
 			call->need_attention = false;
 			__set_current_state(TASK_RUNNING);
 			afs_deliver_to_call(call);
-			timeout = rtt2;
 			continue;
 		}
 
 		if (afs_check_call_state(call, AFS_CALL_COMPLETE))
 			break;
 
-		if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall, &life)) {
+		if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
 			/* rxrpc terminated the call. */
 			rxrpc_complete = true;
 			break;
 		}
 
-		if (call->intr && timeout == 0 &&
-		    life == last_life && signal_pending(current)) {
-			if (stalled)
-				break;
-			__set_current_state(TASK_RUNNING);
-			rxrpc_kernel_probe_life(call->net->socket, call->rxcall);
-			timeout = rtt2;
-			stalled = true;
-			continue;
-		}
-
-		if (life != last_life) {
-			timeout = rtt2;
-			last_life = life;
-			stalled = false;
-		}
-
-		timeout = schedule_timeout(timeout);
+		schedule();
 	}
 
 	remove_wait_queue(&call->waitq, &myself);
diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index 8e547b4d88c8..04e97bab6f28 100644
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -64,9 +64,7 @@ int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
 			       rxrpc_user_attach_call_t, unsigned long, gfp_t,
 			       unsigned int);
 void rxrpc_kernel_set_tx_length(struct socket *, struct rxrpc_call *, s64);
-bool rxrpc_kernel_check_life(const struct socket *, const struct rxrpc_call *,
-			     u32 *);
-void rxrpc_kernel_probe_life(struct socket *, struct rxrpc_call *);
+bool rxrpc_kernel_check_life(const struct socket *, const struct rxrpc_call *);
 u32 rxrpc_kernel_get_epoch(struct socket *, struct rxrpc_call *);
 bool rxrpc_kernel_get_reply_time(struct socket *, struct rxrpc_call *,
 				 ktime_t *);
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 7603cf811f75..15ee92d79581 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -371,44 +371,17 @@ EXPORT_SYMBOL(rxrpc_kernel_end_call);
  * rxrpc_kernel_check_life - Check to see whether a call is still alive
  * @sock: The socket the call is on
  * @call: The call to check
- * @_life: Where to store the life value
  *
- * Allow a kernel service to find out whether a call is still alive - ie. we're
- * getting ACKs from the server.  Passes back in *_life a number representing
- * the life state which can be compared to that returned by a previous call and
- * return true if the call is still alive.
- *
- * If the life state stalls, rxrpc_kernel_probe_life() should be called and
- * then 2RTT waited.
+ * Allow a kernel service to find out whether a call is still alive -
+ * ie. whether it has completed.
  */
 bool rxrpc_kernel_check_life(const struct socket *sock,
-			     const struct rxrpc_call *call,
-			     u32 *_life)
+			     const struct rxrpc_call *call)
 {
-	*_life = call->acks_latest;
 	return call->state != RXRPC_CALL_COMPLETE;
 }
 EXPORT_SYMBOL(rxrpc_kernel_check_life);
 
-/**
- * rxrpc_kernel_probe_life - Poke the peer to see if it's still alive
- * @sock: The socket the call is on
- * @call: The call to check
- *
- * In conjunction with rxrpc_kernel_check_life(), allow a kernel service to
- * find out whether a call is still alive by pinging it.  This should cause the
- * life state to be bumped in about 2*RTT.
- *
- * The must be called in TASK_RUNNING state on pain of might_sleep() objecting.
- */
-void rxrpc_kernel_probe_life(struct socket *sock, struct rxrpc_call *call)
-{
-	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
-			  rxrpc_propose_ack_ping_for_check_life);
-	rxrpc_send_ack_packet(call, true, NULL);
-}
-EXPORT_SYMBOL(rxrpc_kernel_probe_life);
-
 /**
  * rxrpc_kernel_get_epoch - Retrieve the epoch value from a call.
  * @sock: The socket the call is on
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 1f72f43b082d..3eb1ab40ca5c 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -675,7 +675,6 @@ struct rxrpc_call {
 
 	/* transmission-phase ACK management */
 	ktime_t			acks_latest_ts;	/* Timestamp of latest ACK received */
-	rxrpc_serial_t		acks_latest;	/* serial number of latest ACK received */
 	rxrpc_seq_t		acks_lowest_nak; /* Lowest NACK in the buffer (or ==tx_hard_ack) */
 	rxrpc_seq_t		acks_lost_top;	/* tx_top at the time lost-ack ping sent */
 	rxrpc_serial_t		acks_lost_ping;	/* Serial number of probe ACK */
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index ef10fbf71b15..69e09d69c896 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -882,7 +882,6 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	    before(prev_pkt, call->ackr_prev_seq))
 		goto out;
 	call->acks_latest_ts = skb->tstamp;
-	call->acks_latest = sp->hdr.serial;
 
 	call->ackr_first_seq = first_soft_ack;
 	call->ackr_prev_seq = prev_pkt;