svc: Add xpo_accept transport function

Previously, the accept logic looked into the socket state to determine
whether to call accept or recv when data-ready was indicated on an endpoint.
Since some transports don't use sockets, this logic now uses a flag
bit (SK_LISTENER) to identify listening endpoints. A transport function
(xpo_accept) allows each transport to define its own accept processing.
A transport's initialization logic is reponsible for setting the
SK_LISTENER bit. I didn't see any way to do this in transport independent
logic since the passive side of a UDP connection doesn't listen and
always recv's.

In the svc_recv function, if the SK_LISTENER bit is set, the transport
xpo_accept function is called to handle accept processing.

Note that all functions are defined even if they don't make sense
for a given transport. For example, accept doesn't mean anything for
UDP. The function is defined anyway and bug checks if called. The
UDP transport should never set the SK_LISTENER bit.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

2 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 85df97acc2d0..31a44f441fd1 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -10,6 +10,7 @@
 #include <linux/sunrpc/svc.h>
 
 struct svc_xprt_ops {
+        struct svc_xprt *(*xpo_accept)(struct svc_xprt *);
         int             (*xpo_has_wspace)(struct svc_xprt *);
         int             (*xpo_recvfrom)(struct svc_rqst *);
         void            (*xpo_prep_reply_hdr)(struct svc_rqst *);
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 08e78d0a364f..9882ce0ee33c 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -36,6 +36,7 @@ struct svc_sock {
 #define SK_DEFERRED     8                       /* request on sk_deferred */
 #define SK_OLD          9                       /* used for temp socket aging mark+sweep */
 #define SK_DETACHED     10                      /* detached from tempsocks list */
+#define SK_LISTENER     11                      /* listening endpoint */
 
         atomic_t                sk_reserved;    /* space on outq that is reserved */