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: David Howells <dhowells@redhat.com>
diff --git a/Documentation/networking/rxrpc.txt b/Documentation/networking/rxrpc.txt
index b540716..6787999 100644
--- a/Documentation/networking/rxrpc.txt
+++ b/Documentation/networking/rxrpc.txt
@@ -1069,6 +1069,17 @@
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
diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index f53edb3..c4c9125 100644
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -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_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 */
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 816b19a..eaf19eb 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -715,3 +715,46 @@
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);
