Commit 2070a3e4 authored by David Howells's avatar David Howells
Browse files

rxrpc: Allow the reply time to be obtained on a client call 



Allow the timestamp on the sk_buff holding the first DATA packet of a reply
to be queried.  This can then be used as a base for the expiry time
calculation on the callback promise duration indicated by an operation
result.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 5a790b73

Documentation/networking/rxrpc.txt

+11 −0
Original line number Diff line number Diff line
@@ -1069,6 +1069,17 @@ The kernel interface functions are as follows: 


     This function may transmit a PING ACK.



 (*) Get reply timestamp.



	bool rxrpc_kernel_get_reply_time(struct socket *sock,

					 struct rxrpc_call *call,

					 ktime_t *_ts)



     This allows the timestamp on the first DATA packet of the reply of a

     client call to be queried, provided that it is still in the Rx ring.  If

     successful, the timestamp will be stored into *_ts and true will be

     returned; false will be returned otherwise.





=======================

CONFIGURABLE PARAMETERS

include/net/af_rxrpc.h

+3 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define _NET_RXRPC_H



#include <linux/rxrpc.h>

#include <linux/ktime.h>



struct key;

struct sock;
@@ -77,5 +78,7 @@ int rxrpc_kernel_retry_call(struct socket *, struct rxrpc_call *, 
int rxrpc_kernel_check_call(struct socket *, struct rxrpc_call *,

			    enum rxrpc_call_completion *, u32 *);

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

bool rxrpc_kernel_get_reply_time(struct socket *, struct rxrpc_call *,

				 ktime_t *);



#endif /* _NET_RXRPC_H */

net/rxrpc/recvmsg.c

+43 −0
Original line number Diff line number Diff line
@@ -715,3 +715,46 @@ call_complete: 
	goto out;

}

EXPORT_SYMBOL(rxrpc_kernel_recv_data);



/**

 * rxrpc_kernel_get_reply_time - Get timestamp on first reply packet

 * @sock: The socket that the call exists on

 * @call: The call to query

 * @_ts: Where to put the timestamp

 *

 * Retrieve the timestamp from the first DATA packet of the reply if it is

 * in the ring.  Returns true if successful, false if not.

 */

bool rxrpc_kernel_get_reply_time(struct socket *sock, struct rxrpc_call *call,

				 ktime_t *_ts)

{

	struct sk_buff *skb;

	rxrpc_seq_t hard_ack, top, seq;

	bool success = false;



	mutex_lock(&call->user_mutex);



	if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_RECV_REPLY)

		goto out;



	hard_ack = call->rx_hard_ack;

	if (hard_ack != 0)

		goto out;



	seq = hard_ack + 1;

	top = smp_load_acquire(&call->rx_top);

	if (after(seq, top))

		goto out;



	skb = call->rxtx_buffer[seq & RXRPC_RXTX_BUFF_MASK];

	if (!skb)

		goto out;



	*_ts = skb_get_ktime(skb);

	success = true;



out:

	mutex_unlock(&call->user_mutex);

	return success;

}

EXPORT_SYMBOL(rxrpc_kernel_get_reply_time);

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