Clean up: rq_arg.head[0] already points to the RPC header. No need
to walk down the RPC-over-RDMA header again.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 31 ++++++++++---------------------
1 file changed, 10 insertions(+), 21 deletions(-)
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index c984b0a..41adbe7 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -549,35 +549,24 @@ static void rdma_read_complete(struct svc_rqst *rqstp,
rqstp->rq_arg.buflen = head->arg.buflen;
}
-/* By convention, backchannel calls arrive via rdma_msg type
- * messages, and never populate the chunk lists. This makes
- * the RPC/RDMA header small and fixed in size, so it is
- * straightforward to check the RPC header's direction field.
+/* Currently, this implementation does not support chunks in the
+ * backward direction. Thus only RDMA_MSG bc replies are accepted.
*/
static bool
-svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, struct rpcrdma_msg *rmsgp)
+svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, struct rpcrdma_msg *rmsgp,
+ struct xdr_buf *rq_arg)
{
- __be32 *p = (__be32 *)rmsgp;
+ __be32 *p = (__be32 *)rq_arg->head[0].iov_base;
+ /* Is there a backchannel transport associated with xprt? */
if (!xprt->xpt_bc_xprt)
return false;
-
+ /* Is there an RPC message in the inline buffer? */
if (rmsgp->rm_type != rdma_msg)
return false;
- if (rmsgp->rm_body.rm_chunks[0] != xdr_zero)
- return false;
- if (rmsgp->rm_body.rm_chunks[1] != xdr_zero)
+ /* Is that message a Call or a Reply? */
+ if (p[1] != cpu_to_be32(RPC_REPLY))
return false;
- if (rmsgp->rm_body.rm_chunks[2] != xdr_zero)
- return false;
-
- /* sanity */
- if (p[7] != rmsgp->rm_xid)
- return false;
- /* call direction */
- if (p[8] == cpu_to_be32(RPC_CALL))
- return false;
-
return true;
}
@@ -643,7 +632,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
goto out_drop;
rqstp->rq_xprt_hlen = ret;
- if (svc_rdma_is_backchannel_reply(xprt, rmsgp)) {
+ if (svc_rdma_is_backchannel_reply(xprt, rmsgp, &rqstp->rq_arg)) {
ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, rmsgp,
&rqstp->rq_arg);
svc_rdma_put_context(ctxt, 0);
--
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