rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals

Make AF_RXRPC accept MSG_WAITALL as a flag to sendmsg() to tell it to
ignore signals whilst loading up the message queue, provided progress is
being made in emptying the queue at the other side.

Progress is defined as the base of the transmit window having being
advanced within 2 RTT periods.  If the period is exceeded with no progress,
sendmsg() will return anyway, indicating how much data has been copied, if
any.

Once the supplied buffer is entirely decanted, the sendmsg() will return.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 26 insertions, 5 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 172a4f9747ac..bb1e2caa1720 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -407,7 +407,7 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 		      call->request_size);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
-	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
+	msg.msg_flags		= MSG_WAITALL | (call->send_pages ? MSG_MORE : 0);
 
 	/* We have to change the state *before* sending the last packet as
 	 * rxrpc might give us the reply before it returns from sending the
@@ -538,15 +538,26 @@ call_complete:
  */
 static int afs_wait_for_call_to_complete(struct afs_call *call)
 {
+	signed long rtt2, timeout;
 	int ret;
+	u64 rtt;
+	u32 life, last_life;
 
 	DECLARE_WAITQUEUE(myself, current);
 
 	_enter("");
 
+	rtt = rxrpc_kernel_get_rtt(afs_socket, call->rxcall);
+	rtt2 = nsecs_to_jiffies64(rtt) * 2;
+	if (rtt2 < 2)
+		rtt2 = 2;
+
+	timeout = rtt2;
+	last_life = rxrpc_kernel_check_life(afs_socket, call->rxcall);
+
 	add_wait_queue(&call->waitq, &myself);
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		set_current_state(TASK_UNINTERRUPTIBLE);
 
 		/* deliver any messages that are in the queue */
 		if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
@@ -556,10 +567,20 @@ static int afs_wait_for_call_to_complete(struct afs_call *call)
 			continue;
 		}
 
-		if (call->state == AFS_CALL_COMPLETE ||
-		    signal_pending(current))
+		if (call->state == AFS_CALL_COMPLETE)
 			break;
-		schedule();
+
+		life = rxrpc_kernel_check_life(afs_socket, call->rxcall);
+		if (timeout == 0 &&
+		    life == last_life && signal_pending(current))
+				break;
+
+		if (life != last_life) {
+			timeout = rtt2;
+			last_life = life;
+		}
+
+		timeout = schedule_timeout(timeout);
 	}
 
 	remove_wait_queue(&call->waitq, &myself);