Commit 4629ed2e authored by David S. Miller's avatar David S. Miller
Browse files

Merge tag 'rxrpc-fixes-20200520' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs 



David Howells says:

====================
rxrpc: Fix retransmission timeout and ACK discard

Here are a couple of fixes and an extra tracepoint for AF_RXRPC:

 (1) Calculate the RTO pretty much as TCP does, rather than making
     something up, including an initial 4s timeout (which causes return
     probes from the fileserver to fail if a packet goes missing), and add
     backoff.

 (2) Fix the discarding of out-of-order received ACKs.  We mustn't let the
     hard-ACK point regress, nor do we want to do unnecessary
     retransmission because the soft-ACK list regresses.  This is not
     trivial, however, due to some loose wording in various old protocol
     specs, the ACK field that should be used for this sometimes has the
     wrong information in it.

 (3) Add a tracepoint to log a discarded ACK.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 79dde73c 441fdee1

fs/afs/fs_probe.c

+5 −13
Original line number Diff line number Diff line
@@ -32,9 +32,8 @@ void afs_fileserver_probe_result(struct afs_call *call) 
	struct afs_server *server = call->server;

	unsigned int server_index = call->server_index;

	unsigned int index = call->addr_ix;

	unsigned int rtt = UINT_MAX;

	unsigned int rtt_us;

	bool have_result = false;

	u64 _rtt;

	int ret = call->error;



	_enter("%pU,%u", &server->uuid, index);
@@ -93,15 +92,9 @@ responded: 
		}

	}



	/* Get the RTT and scale it to fit into a 32-bit value that represents

	 * over a minute of time so that we can access it with one instruction

	 * on a 32-bit system.

	 */

	_rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);

	_rtt /= 64;

	rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt;

	if (rtt < server->probe.rtt) {

		server->probe.rtt = rtt;

	rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall);

	if (rtt_us < server->probe.rtt) {

		server->probe.rtt = rtt_us;

		alist->preferred = index;

		have_result = true;

	}
@@ -113,8 +106,7 @@ out: 
	spin_unlock(&server->probe_lock);



	_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",

	       server_index, index, &alist->addrs[index].transport,

	       (unsigned int)rtt, ret);

	       server_index, index, &alist->addrs[index].transport, rtt_us, ret);



	have_result |= afs_fs_probe_done(server);

	if (have_result)

fs/afs/vl_probe.c

+5 −13
Original line number Diff line number Diff line
@@ -31,10 +31,9 @@ void afs_vlserver_probe_result(struct afs_call *call) 
	struct afs_addr_list *alist = call->alist;

	struct afs_vlserver *server = call->vlserver;

	unsigned int server_index = call->server_index;

	unsigned int rtt_us = 0;

	unsigned int index = call->addr_ix;

	unsigned int rtt = UINT_MAX;

	bool have_result = false;

	u64 _rtt;

	int ret = call->error;



	_enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);
@@ -93,15 +92,9 @@ responded: 
		}

	}



	/* Get the RTT and scale it to fit into a 32-bit value that represents

	 * over a minute of time so that we can access it with one instruction

	 * on a 32-bit system.

	 */

	_rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);

	_rtt /= 64;

	rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt;

	if (rtt < server->probe.rtt) {

		server->probe.rtt = rtt;

	rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall);

	if (rtt_us < server->probe.rtt) {

		server->probe.rtt = rtt_us;

		alist->preferred = index;

		have_result = true;

	}
@@ -113,8 +106,7 @@ out: 
	spin_unlock(&server->probe_lock);



	_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",

	       server_index, index, &alist->addrs[index].transport,

	       (unsigned int)rtt, ret);

	       server_index, index, &alist->addrs[index].transport, rtt_us, ret);



	have_result |= afs_vl_probe_done(server);

	if (have_result) {

include/net/af_rxrpc.h

+1 −1
Original line number Diff line number Diff line
@@ -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 *);

u64 rxrpc_kernel_get_rtt(struct socket *, struct rxrpc_call *);

u32 rxrpc_kernel_get_srtt(struct socket *, struct rxrpc_call *);

int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,

			       rxrpc_user_attach_call_t, unsigned long, gfp_t,

			       unsigned int);

include/trace/events/rxrpc.h

+42 −10
Original line number Diff line number Diff line
@@ -1112,18 +1112,17 @@ TRACE_EVENT(rxrpc_rtt_tx, 
TRACE_EVENT(rxrpc_rtt_rx,

	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,

		     rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,

		     s64 rtt, u8 nr, s64 avg),

		     u32 rtt, u32 rto),



	    TP_ARGS(call, why, send_serial, resp_serial, rtt, nr, avg),

	    TP_ARGS(call, why, send_serial, resp_serial, rtt, rto),



	    TP_STRUCT__entry(

		    __field(unsigned int,		call		)

		    __field(enum rxrpc_rtt_rx_trace,	why		)

		    __field(u8,				nr		)

		    __field(rxrpc_serial_t,		send_serial	)

		    __field(rxrpc_serial_t,		resp_serial	)

		    __field(s64,			rtt		)

		    __field(u64,			avg		)

		    __field(u32,			rtt		)

		    __field(u32,			rto		)

			     ),



	    TP_fast_assign(
@@ -1132,18 +1131,16 @@ TRACE_EVENT(rxrpc_rtt_rx, 
		    __entry->send_serial = send_serial;

		    __entry->resp_serial = resp_serial;

		    __entry->rtt = rtt;

		    __entry->nr = nr;

		    __entry->avg = avg;

		    __entry->rto = rto;

			   ),



	    TP_printk("c=%08x %s sr=%08x rr=%08x rtt=%lld nr=%u avg=%lld",

	    TP_printk("c=%08x %s sr=%08x rr=%08x rtt=%u rto=%u",

		      __entry->call,

		      __print_symbolic(__entry->why, rxrpc_rtt_rx_traces),

		      __entry->send_serial,

		      __entry->resp_serial,

		      __entry->rtt,

		      __entry->nr,

		      __entry->avg)

		      __entry->rto)

	    );



TRACE_EVENT(rxrpc_timer,
@@ -1544,6 +1541,41 @@ TRACE_EVENT(rxrpc_notify_socket, 
		      __entry->serial)

	    );



TRACE_EVENT(rxrpc_rx_discard_ack,

	    TP_PROTO(unsigned int debug_id, rxrpc_serial_t serial,

		     rxrpc_seq_t first_soft_ack, rxrpc_seq_t call_ackr_first,

		     rxrpc_seq_t prev_pkt, rxrpc_seq_t call_ackr_prev),



	    TP_ARGS(debug_id, serial, first_soft_ack, call_ackr_first,

		    prev_pkt, call_ackr_prev),



	    TP_STRUCT__entry(

		    __field(unsigned int,	debug_id	)

		    __field(rxrpc_serial_t,	serial		)

		    __field(rxrpc_seq_t,	first_soft_ack)

		    __field(rxrpc_seq_t,	call_ackr_first)

		    __field(rxrpc_seq_t,	prev_pkt)

		    __field(rxrpc_seq_t,	call_ackr_prev)

			     ),



	    TP_fast_assign(

		    __entry->debug_id		= debug_id;

		    __entry->serial		= serial;

		    __entry->first_soft_ack	= first_soft_ack;

		    __entry->call_ackr_first	= call_ackr_first;

		    __entry->prev_pkt		= prev_pkt;

		    __entry->call_ackr_prev	= call_ackr_prev;

			   ),



	    TP_printk("c=%08x r=%08x %08x<%08x %08x<%08x",

		      __entry->debug_id,

		      __entry->serial,

		      __entry->first_soft_ack,

		      __entry->call_ackr_first,

		      __entry->prev_pkt,

		      __entry->call_ackr_prev)

	    );



#endif /* _TRACE_RXRPC_H */



/* This part must be outside protection */

net/rxrpc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ rxrpc-y := \ 
	peer_event.o \

	peer_object.o \

	recvmsg.o \

	rtt.o \

	security.o \

	sendmsg.o \

	skbuff.o \

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