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authorDavid S. Miller <davem@davemloft.net>2017-10-20 10:42:09 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-20 10:42:09 +0300
commit9854d758f7215ceea7da625cb421e0674846b53c (patch)
tree08ed51abc3e56216076e43efbf496e816b64b454 /Documentation/networking
parent37320537318934878cc02d8e6103e1be5696fe9f (diff)
parentbc5e3a546d553e5223851fc199e69040eb70f68b (diff)
downloadlinux-9854d758f7215ceea7da625cb421e0674846b53c.tar.xz
Merge tag 'rxrpc-next-20171018' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
David Howells says: ==================== rxrpc: Add bits for kernel services Here are some patches that add a few things for kernel services to use: (1) Allow service upgrade to be requested and allow the resultant actual service ID to be obtained. (2) Allow the RTT time of a call to be obtained. (3) Allow a kernel service to find out if a call is still alive on a server between transmitting a request and getting the reply. (4) Allow data transmission to ignore signals if transmission progress is being made in reasonable time. This is also usable by userspace by passing MSG_WAITALL to sendmsg()[*]. [*] I'm not sure this is the right interface for this or whether a sockopt should be used instead. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/rxrpc.txt53
1 files changed, 51 insertions, 2 deletions
diff --git a/Documentation/networking/rxrpc.txt b/Documentation/networking/rxrpc.txt
index 810620153a44..b5407163d53b 100644
--- a/Documentation/networking/rxrpc.txt
+++ b/Documentation/networking/rxrpc.txt
@@ -280,6 +280,18 @@ Interaction with the user of the RxRPC socket:
nominated by a socket option.
+Notes on sendmsg:
+
+ (*) MSG_WAITALL can be set to tell sendmsg to ignore signals if the peer is
+ making progress at accepting packets within a reasonable time such that we
+ manage to queue up all the data for transmission. This requires the
+ client to accept at least one packet per 2*RTT time period.
+
+ If this isn't set, sendmsg() will return immediately, either returning
+ EINTR/ERESTARTSYS if nothing was consumed or returning the amount of data
+ consumed.
+
+
Notes on recvmsg:
(*) If there's a sequence of data messages belonging to a particular call on
@@ -782,7 +794,9 @@ The kernel interface functions are as follows:
struct key *key,
unsigned long user_call_ID,
s64 tx_total_len,
- gfp_t gfp);
+ gfp_t gfp,
+ rxrpc_notify_rx_t notify_rx,
+ bool upgrade);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
@@ -803,6 +817,13 @@ The kernel interface functions are as follows:
allows the kernel to encrypt directly to the packet buffers, thereby
saving a copy. The value may not be less than -1.
+ notify_rx is a pointer to a function to be called when events such as
+ incoming data packets or remote aborts happen.
+
+ upgrade should be set to true if a client operation should request that
+ the server upgrade the service to a better one. The resultant service ID
+ is returned by rxrpc_kernel_recv_data().
+
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
@@ -850,7 +871,8 @@ The kernel interface functions are as follows:
size_t size,
size_t *_offset,
bool want_more,
- u32 *_abort)
+ u32 *_abort,
+ u16 *_service)
This is used to receive data from either the reply part of a client call
or the request part of a service call. buf and size specify how much
@@ -873,6 +895,9 @@ The kernel interface functions are as follows:
If a remote ABORT is detected, the abort code received will be stored in
*_abort and ECONNABORTED will be returned.
+ The service ID that the call ended up with is returned into *_service.
+ This can be used to see if a call got a service upgrade.
+
(*) Abort a call.
void rxrpc_kernel_abort_call(struct socket *sock,
@@ -1020,6 +1045,30 @@ The kernel interface functions are as follows:
It returns 0 if the call was requeued and an error otherwise.
+ (*) Get call RTT.
+
+ u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call);
+
+ Get the RTT time to the peer in use by a call. The value returned is in
+ nanoseconds.
+
+ (*) Check call still alive.
+
+ u32 rxrpc_kernel_check_life(struct socket *sock,
+ struct rxrpc_call *call);
+
+ This returns a number that is updated when ACKs are received from the peer
+ (notably including PING RESPONSE ACKs which we can elicit by sending PING
+ ACKs to see if the call still exists on the server). The caller should
+ compare the numbers of two calls to see if the call is still alive after
+ waiting for a suitable interval.
+
+ This allows the caller to work out if the server is still contactable and
+ if the call is still alive on the server whilst waiting for the server to
+ process a client operation.
+
+ This function may transmit a PING ACK.
+
=======================
CONFIGURABLE PARAMETERS