Commit f5821c76 authored by Chuck Lever's avatar Chuck Lever Committed by J. Bruce Fields

svcrdma: Clean up RPC-over-RDMA backchannel reply processing

Replace C structure-based XDR decoding with pointer arithmetic.
Pointer arithmetic is considered more portable.
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 4757d90b
...@@ -204,7 +204,7 @@ static inline void svc_rdma_count_mappings(struct svcxprt_rdma *rdma, ...@@ -204,7 +204,7 @@ static inline void svc_rdma_count_mappings(struct svcxprt_rdma *rdma,
/* svc_rdma_backchannel.c */ /* svc_rdma_backchannel.c */
extern int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, extern int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt,
struct rpcrdma_msg *rmsgp, __be32 *rdma_resp,
struct xdr_buf *rcvbuf); struct xdr_buf *rcvbuf);
/* svc_rdma_marshal.c */ /* svc_rdma_marshal.c */
......
...@@ -12,7 +12,17 @@ ...@@ -12,7 +12,17 @@
#undef SVCRDMA_BACKCHANNEL_DEBUG #undef SVCRDMA_BACKCHANNEL_DEBUG
int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, struct rpcrdma_msg *rmsgp, /**
* svc_rdma_handle_bc_reply - Process incoming backchannel reply
* @xprt: controlling backchannel transport
* @rdma_resp: pointer to incoming transport header
* @rcvbuf: XDR buffer into which to decode the reply
*
* Returns:
* %0 if @rcvbuf is filled in, xprt_complete_rqst called,
* %-EAGAIN if server should call ->recvfrom again.
*/
int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, __be32 *rdma_resp,
struct xdr_buf *rcvbuf) struct xdr_buf *rcvbuf)
{ {
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
...@@ -27,13 +37,13 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, struct rpcrdma_msg *rmsgp, ...@@ -27,13 +37,13 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, struct rpcrdma_msg *rmsgp,
p = (__be32 *)src->iov_base; p = (__be32 *)src->iov_base;
len = src->iov_len; len = src->iov_len;
xid = rmsgp->rm_xid; xid = *rdma_resp;
#ifdef SVCRDMA_BACKCHANNEL_DEBUG #ifdef SVCRDMA_BACKCHANNEL_DEBUG
pr_info("%s: xid=%08x, length=%zu\n", pr_info("%s: xid=%08x, length=%zu\n",
__func__, be32_to_cpu(xid), len); __func__, be32_to_cpu(xid), len);
pr_info("%s: RPC/RDMA: %*ph\n", pr_info("%s: RPC/RDMA: %*ph\n",
__func__, (int)RPCRDMA_HDRLEN_MIN, rmsgp); __func__, (int)RPCRDMA_HDRLEN_MIN, rdma_resp);
pr_info("%s: RPC: %*ph\n", pr_info("%s: RPC: %*ph\n",
__func__, (int)len, p); __func__, (int)len, p);
#endif #endif
...@@ -53,7 +63,7 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, struct rpcrdma_msg *rmsgp, ...@@ -53,7 +63,7 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, struct rpcrdma_msg *rmsgp,
goto out_unlock; goto out_unlock;
memcpy(dst->iov_base, p, len); memcpy(dst->iov_base, p, len);
credits = be32_to_cpu(rmsgp->rm_credit); credits = be32_to_cpup(rdma_resp + 2);
if (credits == 0) if (credits == 0)
credits = 1; /* don't deadlock */ credits = 1; /* don't deadlock */
else if (credits > r_xprt->rx_buf.rb_bc_max_requests) else if (credits > r_xprt->rx_buf.rb_bc_max_requests)
......
...@@ -613,28 +613,30 @@ static void svc_rdma_send_error(struct svcxprt_rdma *xprt, ...@@ -613,28 +613,30 @@ static void svc_rdma_send_error(struct svcxprt_rdma *xprt,
* the RPC/RDMA header small and fixed in size, so it is * the RPC/RDMA header small and fixed in size, so it is
* straightforward to check the RPC header's direction field. * straightforward to check the RPC header's direction field.
*/ */
static bool static bool svc_rdma_is_backchannel_reply(struct svc_xprt *xprt,
svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, struct rpcrdma_msg *rmsgp) __be32 *rdma_resp)
{ {
__be32 *p = (__be32 *)rmsgp; __be32 *p;
if (!xprt->xpt_bc_xprt) if (!xprt->xpt_bc_xprt)
return false; return false;
if (rmsgp->rm_type != rdma_msg) p = rdma_resp + 3;
if (*p++ != rdma_msg)
return false; return false;
if (rmsgp->rm_body.rm_chunks[0] != xdr_zero)
if (*p++ != xdr_zero)
return false; return false;
if (rmsgp->rm_body.rm_chunks[1] != xdr_zero) if (*p++ != xdr_zero)
return false; return false;
if (rmsgp->rm_body.rm_chunks[2] != xdr_zero) if (*p++ != xdr_zero)
return false; return false;
/* sanity */ /* XID sanity */
if (p[7] != rmsgp->rm_xid) if (*p++ != *rdma_resp)
return false; return false;
/* call direction */ /* call direction */
if (p[8] == cpu_to_be32(RPC_CALL)) if (*p == cpu_to_be32(RPC_CALL))
return false; return false;
return true; return true;
...@@ -700,8 +702,9 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) ...@@ -700,8 +702,9 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
goto out_drop; goto out_drop;
rqstp->rq_xprt_hlen = ret; rqstp->rq_xprt_hlen = ret;
if (svc_rdma_is_backchannel_reply(xprt, rmsgp)) { if (svc_rdma_is_backchannel_reply(xprt, &rmsgp->rm_xid)) {
ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, rmsgp, ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt,
&rmsgp->rm_xid,
&rqstp->rq_arg); &rqstp->rq_arg);
svc_rdma_put_context(ctxt, 0); svc_rdma_put_context(ctxt, 0);
if (ret) if (ret)
......
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