From 98fc21d3bfd55a36ce9eb7b32d1ce146f0d1696d Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 7 Feb 2017 11:58:23 -0500 Subject: svcrdma: Clean up RPC-over-RDMA Reply header encoder Replace C structure-based XDR decoding with pointer arithmetic. Pointer arithmetic is considered more portable, and is used throughout the kernel's existing XDR encoders. The gcc optimizer generates similar assembler code either way. Byte-swapping before a memory store on x86 typically results in an instruction pipeline stall. Avoid byte-swapping when encoding a new header. svcrdma currently doesn't alter a connection's credit grant value after the connection has been accepted, so it is effectively a constant. Cache the byte-swapped value in a separate field. Christoph suggested pulling the header encoding logic into the only function that uses it. Signed-off-by: Chuck Lever Reviewed-by: Christoph Hellwig Signed-off-by: J. Bruce Fields --- net/sunrpc/xprtrdma/svc_rdma_marshal.c | 18 +----------------- net/sunrpc/xprtrdma/svc_rdma_sendto.c | 19 ++++++++++++------- net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 + 3 files changed, 14 insertions(+), 24 deletions(-) (limited to 'net/sunrpc') diff --git a/net/sunrpc/xprtrdma/svc_rdma_marshal.c b/net/sunrpc/xprtrdma/svc_rdma_marshal.c index 4e7203439e2f..c7d15b1126ce 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_marshal.c +++ b/net/sunrpc/xprtrdma/svc_rdma_marshal.c @@ -249,7 +249,7 @@ int svc_rdma_xdr_encode_error(struct svcxprt_rdma *xprt, *va++ = rmsgp->rm_xid; *va++ = rmsgp->rm_vers; - *va++ = cpu_to_be32(xprt->sc_max_requests); + *va++ = xprt->sc_fc_credits; *va++ = rdma_error; *va++ = cpu_to_be32(err); if (err == ERR_VERS) { @@ -329,19 +329,3 @@ void svc_rdma_xdr_encode_array_chunk(struct rpcrdma_write_array *ary, seg->rs_offset = rs_offset; seg->rs_length = cpu_to_be32(write_len); } - -void svc_rdma_xdr_encode_reply_header(struct svcxprt_rdma *xprt, - struct rpcrdma_msg *rdma_argp, - struct rpcrdma_msg *rdma_resp, - enum rpcrdma_proc rdma_type) -{ - rdma_resp->rm_xid = rdma_argp->rm_xid; - rdma_resp->rm_vers = rdma_argp->rm_vers; - rdma_resp->rm_credit = cpu_to_be32(xprt->sc_max_requests); - rdma_resp->rm_type = cpu_to_be32(rdma_type); - - /* Encode chunks lists */ - rdma_resp->rm_body.rm_chunks[0] = xdr_zero; - rdma_resp->rm_body.rm_chunks[1] = xdr_zero; - rdma_resp->rm_body.rm_chunks[2] = xdr_zero; -} diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index ba76f1617965..515221b16d09 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -560,12 +560,12 @@ int svc_rdma_sendto(struct svc_rqst *rqstp) struct rpcrdma_msg *rdma_argp; struct rpcrdma_msg *rdma_resp; struct rpcrdma_write_array *wr_ary, *rp_ary; - enum rpcrdma_proc reply_type; int ret; int inline_bytes; struct page *res_page; struct svc_rdma_req_map *vec; u32 inv_rkey; + __be32 *p; dprintk("svcrdma: sending response for rqstp=%p\n", rqstp); @@ -597,12 +597,17 @@ int svc_rdma_sendto(struct svc_rqst *rqstp) if (!res_page) goto err0; rdma_resp = page_address(res_page); - if (rp_ary) - reply_type = RDMA_NOMSG; - else - reply_type = RDMA_MSG; - svc_rdma_xdr_encode_reply_header(rdma, rdma_argp, - rdma_resp, reply_type); + + p = &rdma_resp->rm_xid; + *p++ = rdma_argp->rm_xid; + *p++ = rdma_argp->rm_vers; + *p++ = rdma->sc_fc_credits; + *p++ = rp_ary ? rdma_nomsg : rdma_msg; + + /* Start with empty chunks */ + *p++ = xdr_zero; + *p++ = xdr_zero; + *p = xdr_zero; /* Send any write-chunk data and build resp write-list */ if (wr_ary) { diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index ca2799af05a6..174928fe5f83 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -1002,6 +1002,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) newxprt->sc_max_req_size = svcrdma_max_req_size; newxprt->sc_max_requests = min_t(u32, dev->attrs.max_qp_wr, svcrdma_max_requests); + newxprt->sc_fc_credits = cpu_to_be32(newxprt->sc_max_requests); newxprt->sc_max_bc_requests = min_t(u32, dev->attrs.max_qp_wr, svcrdma_max_bc_requests); newxprt->sc_rq_depth = newxprt->sc_max_requests + -- cgit v1.2.3