rxrpc: Add tracepoint for ACK proposal

Add a tracepoint to log proposed ACKs, including whether the proposal is
used to update a pending ACK or is discarded in favour of an easlier,
higher priority ACK.

Whilst we're at it, get rid of the rxrpc_acks() function and access the
name array directly.  We do, however, need to validate the ACK reason
number given to trace_rxrpc_rx_ack() to make sure we don't overrun the
array.

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

diff --git a/include/rxrpc/packet.h b/include/rxrpc/packet.h
index fd6eb3a..703a64b 100644 (file)
--- a/include/rxrpc/packet.h
+++ b/include/rxrpc/packet.h
@@ -123,6 +123,7 @@ struct rxrpc_ackpacket {
 #define RXRPC_ACK_PING_RESPONSE                7       /* response to RXRPC_ACK_PING */
 #define RXRPC_ACK_DELAY                        8       /* nothing happened since received packet */
 #define RXRPC_ACK_IDLE                 9       /* ACK due to fully received ACK window */
+#define RXRPC_ACK__INVALID             10      /* Representation of invalid ACK reason */
 
        uint8_t         nAcks;          /* number of ACKs */
 #define RXRPC_MAXACKS  255

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 9413b17..d67a8c6 100644 (file)
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -251,7 +251,7 @@ TRACE_EVENT(rxrpc_rx_ack,
 
            TP_printk("c=%p %s f=%08x n=%u",
                      __entry->call,
-                     rxrpc_acks(__entry->reason),
+                     rxrpc_ack_names[__entry->reason],
                      __entry->first,
                      __entry->n_acks)
            );
@@ -314,7 +314,7 @@ TRACE_EVENT(rxrpc_tx_ack,
            TP_printk(" c=%p ACK  %08x %s f=%08x r=%08x n=%u",
                      __entry->call,
                      __entry->serial,
-                     rxrpc_acks(__entry->reason),
+                     rxrpc_ack_names[__entry->reason],
                      __entry->ack_first,
                      __entry->ack_serial,
                      __entry->n_acks)
@@ -505,6 +505,44 @@ TRACE_EVENT(rxrpc_rx_lose,
                      __entry->hdr.type <= 15 ? rxrpc_pkts[__entry->hdr.type] : "?UNK")
            );
 
+TRACE_EVENT(rxrpc_propose_ack,
+           TP_PROTO(struct rxrpc_call *call, enum rxrpc_propose_ack_trace why,
+                    u8 ack_reason, rxrpc_serial_t serial, bool immediate,
+                    bool background, enum rxrpc_propose_ack_outcome outcome),
+
+           TP_ARGS(call, why, ack_reason, serial, immediate, background,
+                   outcome),
+
+           TP_STRUCT__entry(
+                   __field(struct rxrpc_call *,                call            )
+                   __field(enum rxrpc_propose_ack_trace,       why             )
+                   __field(rxrpc_serial_t,                     serial          )
+                   __field(u8,                                 ack_reason      )
+                   __field(bool,                               immediate       )
+                   __field(bool,                               background      )
+                   __field(enum rxrpc_propose_ack_outcome,     outcome         )
+                            ),
+
+           TP_fast_assign(
+                   __entry->call       = call;
+                   __entry->why        = why;
+                   __entry->serial     = serial;
+                   __entry->ack_reason = ack_reason;
+                   __entry->immediate  = immediate;
+                   __entry->background = background;
+                   __entry->outcome    = outcome;
+                          ),
+
+           TP_printk("c=%p %s %s r=%08x i=%u b=%u%s",
+                     __entry->call,
+                     rxrpc_propose_ack_traces[__entry->why],
+                     rxrpc_ack_names[__entry->ack_reason],
+                     __entry->serial,
+                     __entry->immediate,
+                     __entry->background,
+                     rxrpc_propose_ack_outcomes[__entry->outcome])
+           );
+
 #endif /* _TRACE_RXRPC_H */
 
 /* This part must be outside protection */

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index e564eca..042dbcc 100644 (file)
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -689,8 +689,28 @@ enum rxrpc_timer_trace {
 
 extern const char rxrpc_timer_traces[rxrpc_timer__nr_trace][8];
 
+enum rxrpc_propose_ack_trace {
+       rxrpc_propose_ack_input_data,
+       rxrpc_propose_ack_ping_for_params,
+       rxrpc_propose_ack_respond_to_ack,
+       rxrpc_propose_ack_respond_to_ping,
+       rxrpc_propose_ack_retry_tx,
+       rxrpc_propose_ack_terminal_ack,
+       rxrpc_propose_ack__nr_trace
+};
+
+enum rxrpc_propose_ack_outcome {
+       rxrpc_propose_ack_use,
+       rxrpc_propose_ack_update,
+       rxrpc_propose_ack_subsume,
+       rxrpc_propose_ack__nr_outcomes
+};
+
+extern const char rxrpc_propose_ack_traces[rxrpc_propose_ack__nr_trace][8];
+extern const char *const rxrpc_propose_ack_outcomes[rxrpc_propose_ack__nr_outcomes];
+
 extern const char *const rxrpc_pkts[];
-extern const char *rxrpc_acks(u8 reason);
+extern const char const rxrpc_ack_names[RXRPC_ACK__INVALID + 1][4];
 
 #include <trace/events/rxrpc.h>
 
@@ -719,7 +739,8 @@ int rxrpc_reject_call(struct rxrpc_sock *);
  * call_event.c
  */
 void rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace);
-void rxrpc_propose_ACK(struct rxrpc_call *, u8, u16, u32, bool, bool);
+void rxrpc_propose_ACK(struct rxrpc_call *, u8, u16, u32, bool, bool,
+                      enum rxrpc_propose_ack_trace);
 void rxrpc_process_call(struct work_struct *);
 
 /*

diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 90e970b..fd5b113 100644 (file)
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -58,14 +58,13 @@ out:
  */
 static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
                                u16 skew, u32 serial, bool immediate,
-                               bool background)
+                               bool background,
+                               enum rxrpc_propose_ack_trace why)
 {
+       enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
        unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
        s8 prior = rxrpc_ack_priority[ack_reason];
 
-       _enter("{%d},%s,%%%x,%u",
-              call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
-
        /* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
         * numbers, but we don't alter the timeout.
         */
@@ -74,15 +73,18 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
               call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
        if (ack_reason == call->ackr_reason) {
                if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
+                       outcome = rxrpc_propose_ack_update;
                        call->ackr_serial = serial;
                        call->ackr_skew = skew;
                }
                if (!immediate)
-                       return;
+                       goto trace;
        } else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
                call->ackr_reason = ack_reason;
                call->ackr_serial = serial;
                call->ackr_skew = skew;
+       } else {
+               outcome = rxrpc_propose_ack_subsume;
        }
 
        switch (ack_reason) {
@@ -124,17 +126,22 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
                        rxrpc_set_timer(call, rxrpc_timer_set_for_ack);
                }
        }
+
+trace:
+       trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
+                               background, outcome);
 }
 
 /*
  * propose an ACK be sent, locking the call structure
  */
 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
-                      u16 skew, u32 serial, bool immediate, bool background)
+                      u16 skew, u32 serial, bool immediate, bool background,
+                      enum rxrpc_propose_ack_trace why)
 {
        spin_lock_bh(&call->lock);
        __rxrpc_propose_ACK(call, ack_reason, skew, serial,
-                           immediate, background);
+                           immediate, background, why);
        spin_unlock_bh(&call->lock);
 }
 

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 19b1e18..349698d 100644 (file)
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -49,7 +49,8 @@ static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
        if (call->peer->rtt_usage < 3 ||
            ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
                rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
-                                 true, true);
+                                 true, true,
+                                 rxrpc_propose_ack_ping_for_params);
 }
 
 /*
@@ -382,7 +383,8 @@ skip:
 ack:
        if (ack)
                rxrpc_propose_ACK(call, ack, skew, ack_serial,
-                                 immediate_ack, true);
+                                 immediate_ack, true,
+                                 rxrpc_propose_ack_input_data);
 
        if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
                rxrpc_notify_socket(call);
@@ -539,6 +541,7 @@ static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
                            u16 skew)
 {
+       u8 ack_reason;
        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
        union {
                struct rxrpc_ackpacket ack;
@@ -561,8 +564,10 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
        first_soft_ack = ntohl(buf.ack.firstPacket);
        hard_ack = first_soft_ack - 1;
        nr_acks = buf.ack.nAcks;
+       ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
+                     buf.ack.reason : RXRPC_ACK__INVALID);
 
-       trace_rxrpc_rx_ack(call, first_soft_ack, buf.ack.reason, nr_acks);
+       trace_rxrpc_rx_ack(call, first_soft_ack, ack_reason, nr_acks);
 
        _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
               sp->hdr.serial,
@@ -570,7 +575,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
               first_soft_ack,
               ntohl(buf.ack.previousPacket),
               acked_serial,
-              rxrpc_acks(buf.ack.reason),
+              rxrpc_ack_names[ack_reason],
               buf.ack.nAcks);
 
        if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
@@ -583,10 +588,12 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
        if (buf.ack.reason == RXRPC_ACK_PING) {
                _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
                rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
-                                 skew, sp->hdr.serial, true, true);
+                                 skew, sp->hdr.serial, true, true,
+                                 rxrpc_propose_ack_respond_to_ping);
        } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
                rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
-                                 skew, sp->hdr.serial, true, true);
+                                 skew, sp->hdr.serial, true, true,
+                                 rxrpc_propose_ack_respond_to_ack);
        }
 
        offset = sp->offset + nr_acks + 3;

diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index fa9942f..1ca1483 100644 (file)
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -91,17 +91,10 @@ const s8 rxrpc_ack_priority[] = {
        [RXRPC_ACK_PING]                = 9,
 };
 
-const char *rxrpc_acks(u8 reason)
-{
-       static const char *const str[] = {
-               "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
-               "IDL", "-?-"
-       };
-
-       if (reason >= ARRAY_SIZE(str))
-               reason = ARRAY_SIZE(str) - 1;
-       return str[reason];
-}
+const char const rxrpc_ack_names[RXRPC_ACK__INVALID + 1][4] = {
+       "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
+       "IDL", "-?-"
+};
 
 const char rxrpc_skb_traces[rxrpc_skb__nr_trace][7] = {
        [rxrpc_skb_rx_cleaned]          = "Rx CLN",
@@ -202,3 +195,18 @@ const char rxrpc_timer_traces[rxrpc_timer__nr_trace][8] = {
        [rxrpc_timer_set_for_send]              = "SetTx ",
        [rxrpc_timer_set_for_resend]            = "SetRTx",
 };
+
+const char rxrpc_propose_ack_traces[rxrpc_propose_ack__nr_trace][8] = {
+       [rxrpc_propose_ack_input_data]          = "DataIn ",
+       [rxrpc_propose_ack_ping_for_params]     = "Params ",
+       [rxrpc_propose_ack_respond_to_ack]      = "Rsp2Ack",
+       [rxrpc_propose_ack_respond_to_ping]     = "Rsp2Png",
+       [rxrpc_propose_ack_retry_tx]            = "RetryTx",
+       [rxrpc_propose_ack_terminal_ack]        = "ClTerm ",
+};
+
+const char *const rxrpc_propose_ack_outcomes[rxrpc_propose_ack__nr_outcomes] = {
+       [rxrpc_propose_ack_use]                 = "",
+       [rxrpc_propose_ack_update]              = " Update",
+       [rxrpc_propose_ack_subsume]             = " Subsume",
+};

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index e47fbd1..0c563e3 100644 (file)
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -210,7 +210,8 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
                        rxrpc_propose_ACK(call, pkt->ack.reason,
                                          ntohs(pkt->ack.maxSkew),
                                          ntohl(pkt->ack.serial),
-                                         true, true);
+                                         true, true,
+                                         rxrpc_propose_ack_retry_tx);
                        break;
                case RXRPC_PACKET_TYPE_ABORT:
                        break;

diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 99e4c0a..8c7f3de 100644 (file)
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -141,7 +141,8 @@ static void rxrpc_end_rx_phase(struct rxrpc_call *call)
        ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
 
        if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
-               rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, true, false);
+               rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, true, false,
+                                 rxrpc_propose_ack_terminal_ack);
                rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
        }