svc: Add xprt header len to svc_deferred_req

A transport may have a header that precedes the RPC message. Save the size of this header in the svc_deferred_req so that when the RPC is revisited, the deferred recv function doesn't need to re-parse the header to determine it's length.

In addition, a misleading comment related to the transport header for TCP/UDP has been rewritten.

Signed-off-by Tom Tucker <[email protected]>

---

 include/linux/sunrpc/svc.h |    1 +
 net/sunrpc/svc_xprt.c      |    1 +
 net/sunrpc/svcsock.c       |    2 +-
 3 files changed, 3 insertions(+), 1 deletions(-)

include/linux/sunrpc/svc.h +1 -0

index ea07e3d..f2ada2a 100644
@@ -323,6 +323,7 @@ struct svc_deferred_req {
 	size_t			addrlen;
 	union svc_addr_u	daddr;	/* where reply must come from */
 	struct cache_deferred_req handle;
+	int			xprt_hlen;
 	int			argslen;
 	__be32			args[0];
 };

net/sunrpc/svc_xprt.c +0 -0

index 080ecf5..b580d4c 100644

Quoted 39 lines · Tom Tucker

A transport may have a header that precedes the RPC message. Save the size of this header in the svc_deferred_req so that when the RPC is revisited, the deferred recv function doesn't need to re-parse the header to determine it's length.

In addition, a misleading comment related to the transport header for TCP/UDP has been rewritten.

Signed-off-by Tom Tucker <[email protected]>

---

 include/linux/sunrpc/svc.h |    1 +
 net/sunrpc/svc_xprt.c      |    1 +
 net/sunrpc/svcsock.c       |    2 +-
 3 files changed, 3 insertions(+), 1 deletions(-)

include/linux/sunrpc/svc.h +1 -0

index ea07e3d..f2ada2a 100644
@@ -323,6 +323,7 @@ struct svc_deferred_req {
 	size_t			addrlen;
 	union svc_addr_u	daddr;	/* where reply must come from */
 	struct cache_deferred_req handle;
+	int			xprt_hlen;
 	int			argslen;
 	__be32			args[0];
 };

net/sunrpc/svc_xprt.c +1 -0

index 080ecf5..b580d4c 100644
@@ -884,6 +884,7 @@ static struct cache_deferred_req *svc_de
 		dr->addrlen = rqstp->rq_addrlen;
 		dr->daddr = rqstp->rq_daddr;
 		dr->argslen = (rqstp->rq_arg.len + rqstp->rq_xprt_hlen) >> 2;
+		dr->xprt_hlen = rqstp->rq_xprt_hlen;
 

net/sunrpc/svc_xprt.c static struct cache_deferred_req *svc_de · line 890

Quoted 2 lines

net/sunrpc/svc_xprt.c +0 -0

 		/* back up head to the start of the buffer and copy */
 		skip = (rqstp->rq_arg.len + rqstp->rq_xprt_hlen) -

Are you planning on restoring rqstp->rq_xprt_hlen from dr->xprt_hlen in svc_deferred_recv() ?

Greg.

Quoted 4 lines · Greg Banks

Quoted 1 line · Tom Tucker

Are you planning on restoring rqstp->rq_xprt_hlen from dr->xprt_hlen in svc_deferred_recv() ?

Well that's a really good question. I'm assuming RPC are never deferred more than one. That seems naive looking at the code.