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authorChuck Lever <chuck.lever@oracle.com>2017-02-07 11:58:23 -0500
committerJ. Bruce Fields <bfields@redhat.com>2017-02-08 14:41:41 -0500
commit98fc21d3bfd55a36ce9eb7b32d1ce146f0d1696d (patch)
tree42a4f52ca9257d1274f8d6760c2687ab1031ba0b /net/sunrpc
parentcbaf58032efca401834518b905f528ac912449e4 (diff)
downloadop-kernel-dev-98fc21d3bfd55a36ce9eb7b32d1ce146f0d1696d.zip
op-kernel-dev-98fc21d3bfd55a36ce9eb7b32d1ce146f0d1696d.tar.gz
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 <chuck.lever@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_marshal.c18
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_sendto.c19
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_transport.c1
3 files changed, 14 insertions, 24 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_marshal.c b/net/sunrpc/xprtrdma/svc_rdma_marshal.c
index 4e72034..c7d15b1 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 <nul> 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 ba76f1617..515221b 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 ca2799a..174928f 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 +
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