Merge tag 'rxrpc-fixes-20200820' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc, afs: Fix probing issues

Here are some fixes for rxrpc and afs to fix issues in the RTT measuring in
rxrpc and thence the Volume Location server probing in afs:

 (1) Move the serial number of a received ACK into a local variable to
     simplify the next patch.

 (2) Fix the loss of RTT samples due to extra interposed ACKs causing
     baseline information to be discarded too early.  This is a particular
     problem for afs when it sends a single very short call to probe a
     server it hasn't talked to recently.

 (3) Fix rxrpc_kernel_get_srtt() to indicate whether it actually has seen
     any valid samples or not.

 (4) Remove a field that's set/woken, but never read/waited on.

 (5) Expose the RTT and other probe information through procfs to make
     debugging of this stuff easier.

 (6) Fix VL rotation in afs to only use summary information from VL probing
     and not the probe running state (which gets clobbered when next a
     probe is issued).

 (7) Fix VL rotation to actually return the error aggregated from the probe
     errors.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 23 insertions, 6 deletions

diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index 91eacbdcf33d..f6abcc0bbd6e 100644
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -59,7 +59,7 @@ bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *,
 void rxrpc_kernel_end_call(struct socket *, struct rxrpc_call *);
 void rxrpc_kernel_get_peer(struct socket *, struct rxrpc_call *,
 			   struct sockaddr_rxrpc *);
-u32 rxrpc_kernel_get_srtt(struct socket *, struct rxrpc_call *);
+bool rxrpc_kernel_get_srtt(struct socket *, struct rxrpc_call *, u32 *);
 int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
 			       rxrpc_user_attach_call_t, unsigned long, gfp_t,
 			       unsigned int);
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 059b6e45a028..c33079b986e8 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -138,11 +138,16 @@ enum rxrpc_recvmsg_trace {
 };
 
 enum rxrpc_rtt_tx_trace {
+	rxrpc_rtt_tx_cancel,
 	rxrpc_rtt_tx_data,
+	rxrpc_rtt_tx_no_slot,
 	rxrpc_rtt_tx_ping,
 };
 
 enum rxrpc_rtt_rx_trace {
+	rxrpc_rtt_rx_cancel,
+	rxrpc_rtt_rx_lost,
+	rxrpc_rtt_rx_obsolete,
 	rxrpc_rtt_rx_ping_response,
 	rxrpc_rtt_rx_requested_ack,
 };
@@ -339,10 +344,15 @@ enum rxrpc_tx_point {
 	E_(rxrpc_recvmsg_wait,			"WAIT")
 
 #define rxrpc_rtt_tx_traces \
+	EM(rxrpc_rtt_tx_cancel,			"CNCE") \
 	EM(rxrpc_rtt_tx_data,			"DATA") \
+	EM(rxrpc_rtt_tx_no_slot,		"FULL") \
 	E_(rxrpc_rtt_tx_ping,			"PING")
 
 #define rxrpc_rtt_rx_traces \
+	EM(rxrpc_rtt_rx_cancel,			"CNCL") \
+	EM(rxrpc_rtt_rx_obsolete,		"OBSL") \
+	EM(rxrpc_rtt_rx_lost,			"LOST") \
 	EM(rxrpc_rtt_rx_ping_response,		"PONG") \
 	E_(rxrpc_rtt_rx_requested_ack,		"RACK")
 
@@ -1087,38 +1097,43 @@ TRACE_EVENT(rxrpc_recvmsg,
 
 TRACE_EVENT(rxrpc_rtt_tx,
 	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_rtt_tx_trace why,
-		     rxrpc_serial_t send_serial),
+		     int slot, rxrpc_serial_t send_serial),
 
-	    TP_ARGS(call, why, send_serial),
+	    TP_ARGS(call, why, slot, send_serial),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		call		)
 		    __field(enum rxrpc_rtt_tx_trace,	why		)
+		    __field(int,			slot		)
 		    __field(rxrpc_serial_t,		send_serial	)
 			     ),
 
 	    TP_fast_assign(
 		    __entry->call = call->debug_id;
 		    __entry->why = why;
+		    __entry->slot = slot;
 		    __entry->send_serial = send_serial;
 			   ),
 
-	    TP_printk("c=%08x %s sr=%08x",
+	    TP_printk("c=%08x [%d] %s sr=%08x",
 		      __entry->call,
+		      __entry->slot,
 		      __print_symbolic(__entry->why, rxrpc_rtt_tx_traces),
 		      __entry->send_serial)
 	    );
 
 TRACE_EVENT(rxrpc_rtt_rx,
 	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
+		     int slot,
 		     rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 		     u32 rtt, u32 rto),
 
-	    TP_ARGS(call, why, send_serial, resp_serial, rtt, rto),
+	    TP_ARGS(call, why, slot, send_serial, resp_serial, rtt, rto),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		call		)
 		    __field(enum rxrpc_rtt_rx_trace,	why		)
+		    __field(int,			slot		)
 		    __field(rxrpc_serial_t,		send_serial	)
 		    __field(rxrpc_serial_t,		resp_serial	)
 		    __field(u32,			rtt		)
@@ -1128,14 +1143,16 @@ TRACE_EVENT(rxrpc_rtt_rx,
 	    TP_fast_assign(
 		    __entry->call = call->debug_id;
 		    __entry->why = why;
+		    __entry->slot = slot;
 		    __entry->send_serial = send_serial;
 		    __entry->resp_serial = resp_serial;
 		    __entry->rtt = rtt;
 		    __entry->rto = rto;
 			   ),
 
-	    TP_printk("c=%08x %s sr=%08x rr=%08x rtt=%u rto=%u",
+	    TP_printk("c=%08x [%d] %s sr=%08x rr=%08x rtt=%u rto=%u",
 		      __entry->call,
+		      __entry->slot,
 		      __print_symbolic(__entry->why, rxrpc_rtt_rx_traces),
 		      __entry->send_serial,
 		      __entry->resp_serial,