extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
+/**
+ * xdr_stream_remaining - Return the number of bytes remaining in the stream
+ * @xdr: pointer to struct xdr_stream
+ *
+ * Return value:
+ * Number of bytes remaining in @xdr before xdr->end
+ */
+static inline size_t
+xdr_stream_remaining(const struct xdr_stream *xdr)
+{
+ return xdr->nwords << 2;
+}
+
ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
size_t maxlen, gfp_t gfp_flags);
/**
* @xprt: transport receiving the call
* @rep: receive buffer containing the call
*
- * Called in the RPC reply handler, which runs in a tasklet.
- * Be quick about it.
- *
* Operational assumptions:
* o Backchannel credits are ignored, just as the NFS server
* forechannel currently does
struct rpcrdma_rep *rep)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
- struct rpcrdma_msg *headerp;
struct svc_serv *bc_serv;
struct rpcrdma_req *req;
struct rpc_rqst *rqst;
size_t size;
__be32 *p;
- headerp = rdmab_to_msg(rep->rr_rdmabuf);
+ p = xdr_inline_decode(&rep->rr_stream, 0);
+ size = xdr_stream_remaining(&rep->rr_stream);
+
#ifdef RPCRDMA_BACKCHANNEL_DEBUG
pr_info("RPC: %s: callback XID %08x, length=%u\n",
- __func__, be32_to_cpu(headerp->rm_xid), rep->rr_len);
- pr_info("RPC: %s: %*ph\n", __func__, rep->rr_len, headerp);
+ __func__, be32_to_cpup(p), size);
+ pr_info("RPC: %s: %*ph\n", __func__, size, p);
#endif
- /* Sanity check:
- * Need at least enough bytes for RPC/RDMA header, as code
- * here references the header fields by array offset. Also,
- * backward calls are always inline, so ensure there
- * are some bytes beyond the RPC/RDMA header.
- */
- if (rep->rr_len < RPCRDMA_HDRLEN_MIN + 24)
- goto out_short;
- p = (__be32 *)((unsigned char *)headerp + RPCRDMA_HDRLEN_MIN);
- size = rep->rr_len - RPCRDMA_HDRLEN_MIN;
-
/* Grab a free bc rqst */
spin_lock(&xprt->bc_pa_lock);
if (list_empty(&xprt->bc_pa_list)) {
/* Prepare rqst */
rqst->rq_reply_bytes_recvd = 0;
rqst->rq_bytes_sent = 0;
- rqst->rq_xid = headerp->rm_xid;
+ rqst->rq_xid = *p;
rqst->rq_private_buf.len = size;
set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
buf->len = size;
/* The receive buffer has to be hooked to the rpcrdma_req
- * so that it can be reposted after the server is done
- * parsing it but just before sending the backward
- * direction reply.
+ * so that it is not released while the req is pointing
+ * to its buffer, and so that it can be reposted after
+ * the Upper Layer is done decoding it.
*/
req = rpcr_to_rdmar(rqst);
dprintk("RPC: %s: attaching rep %p to req %p\n",
* when the connection is re-established.
*/
return;
-
-out_short:
- pr_warn("RPC/RDMA short backward direction call\n");
-
- if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep))
- xprt_disconnect_done(xprt);
- else
- pr_warn("RPC: %s: reposting rep %p\n",
- __func__, rep);
}
}
}
-#if defined(CONFIG_SUNRPC_BACKCHANNEL)
/* 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.
*/
static bool
-rpcrdma_is_bcall(struct rpcrdma_msg *headerp)
+rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
+ __be32 xid, __be32 proc)
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
{
- __be32 *p = (__be32 *)headerp;
+ struct xdr_stream *xdr = &rep->rr_stream;
+ __be32 *p;
- if (headerp->rm_type != rdma_msg)
+ if (proc != rdma_msg)
return false;
- if (headerp->rm_body.rm_chunks[0] != xdr_zero)
+
+ /* Peek at stream contents without advancing. */
+ p = xdr_inline_decode(xdr, 0);
+
+ /* Chunk lists */
+ if (*p++ != xdr_zero)
return false;
- if (headerp->rm_body.rm_chunks[1] != xdr_zero)
+ if (*p++ != xdr_zero)
return false;
- if (headerp->rm_body.rm_chunks[2] != xdr_zero)
+ if (*p++ != xdr_zero)
return false;
- /* sanity */
- if (p[7] != headerp->rm_xid)
+ /* RPC header */
+ if (*p++ != xid)
return false;
- /* call direction */
- if (p[8] != cpu_to_be32(RPC_CALL))
+ if (*p != cpu_to_be32(RPC_CALL))
return false;
+ /* Now that we are sure this is a backchannel call,
+ * advance to the RPC header.
+ */
+ p = xdr_inline_decode(xdr, 3 * sizeof(*p));
+ if (unlikely(!p))
+ goto out_short;
+
+ rpcrdma_bc_receive_call(r_xprt, rep);
+ return true;
+
+out_short:
+ pr_warn("RPC/RDMA short backward direction call\n");
+ if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep))
+ xprt_disconnect_done(&r_xprt->rx_xprt);
return true;
}
+#else /* CONFIG_SUNRPC_BACKCHANNEL */
+{
+ return false;
+}
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
/* Process received RPC/RDMA messages.
proc = *p++;
headerp = rdmab_to_msg(rep->rr_rdmabuf);
-#if defined(CONFIG_SUNRPC_BACKCHANNEL)
- if (rpcrdma_is_bcall(headerp))
- goto out_bcall;
-#endif
+ if (rpcrdma_is_bcall(r_xprt, rep, xid, proc))
+ return;
/* Match incoming rpcrdma_rep to an rpcrdma_req to
* get context for handling any incoming chunks.
}
return;
-#if defined(CONFIG_SUNRPC_BACKCHANNEL)
-out_bcall:
- rpcrdma_bc_receive_call(r_xprt, rep);
- return;
-#endif
-
/* If the incoming reply terminated a pending RPC, the next
* RPC call will post a replacement receive buffer as it is
* being marshaled.
projects / linux.git / commitdiff