SUNRPC: Add xdr_stream::rqst field

Having access to the controlling rpc_rqst means a trace point in the
XDR code can report:

 - the XID
 - the task ID and client ID
 - the p_name of RPC being processed

Subsequent patches will introduce such trace points.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/callback_xdr.c

@@ -943,10 +943,11 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp)
 	};
 	unsigned int nops = 0;
 
-	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
+	xdr_init_decode(&xdr_in, &rqstp->rq_arg,
+			rqstp->rq_arg.head[0].iov_base, NULL);
 
 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
-	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
+	xdr_init_encode(&xdr_out, &rqstp->rq_res, p, NULL);
 
 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
 	if (status == htonl(NFS4ERR_RESOURCE))

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -2036,7 +2036,7 @@ ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
 
 	dprintk("%s: Begin\n", __func__);
 
-	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL);
+	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL, NULL);
 
 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);

include/linux/sunrpc/xdr.h

@@ -217,6 +217,8 @@ struct xdr_stream {
 	struct kvec scratch;	/* Scratch buffer */
 	struct page **page_ptr;	/* pointer to the current page */
 	unsigned int nwords;	/* Remaining decode buffer length */
+
+	struct rpc_rqst *rqst;	/* For debugging */
 };
 
 /*
@@ -227,7 +229,8 @@ typedef void	(*kxdreproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
 typedef int	(*kxdrdproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
 		void *obj);
 
-extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
+extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf,
+			    __be32 *p, struct rpc_rqst *rqst);
 extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
 extern void xdr_commit_encode(struct xdr_stream *xdr);
 extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
@@ -235,7 +238,8 @@ extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen);
 extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
 		unsigned int base, unsigned int len);
 extern unsigned int xdr_stream_pos(const struct xdr_stream *xdr);
-extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
+extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf,
+			    __be32 *p, struct rpc_rqst *rqst);
 extern void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
 		struct page **pages, unsigned int len);
 extern void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen);

net/sunrpc/auth.c

@@ -798,7 +798,7 @@ static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
 {
 	struct xdr_stream xdr;
 
-	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
+	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data, rqstp);
 	encode(rqstp, &xdr, obj);
 }
 
@@ -823,7 +823,7 @@ rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
 {
 	struct xdr_stream xdr;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
+	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data, rqstp);
 	return decode(rqstp, &xdr, obj);
 }
 

net/sunrpc/auth_gss/auth_gss.c

@@ -1722,7 +1722,7 @@ static void gss_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
 {
 	struct xdr_stream xdr;
 
-	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, p);
+	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, p, rqstp);
 	encode(rqstp, &xdr, obj);
 }
 
@@ -1998,7 +1998,7 @@ gss_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
 {
 	struct xdr_stream xdr;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
+	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p, rqstp);
 	return decode(rqstp, &xdr, obj);
 }
 

net/sunrpc/xdr.c

@@ -483,6 +483,7 @@ EXPORT_SYMBOL_GPL(xdr_stream_pos);
  * @xdr: pointer to xdr_stream struct
  * @buf: pointer to XDR buffer in which to encode data
  * @p: current pointer inside XDR buffer
+ * @rqst: pointer to controlling rpc_rqst, for debugging
  *
  * Note: at the moment the RPC client only passes the length of our
  *	 scratch buffer in the xdr_buf's header kvec. Previously this
@@ -491,7 +492,8 @@ EXPORT_SYMBOL_GPL(xdr_stream_pos);
  *	 of the buffer length, and takes care of adjusting the kvec
  *	 length for us.
  */
-void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
+void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
+		     struct rpc_rqst *rqst)
 {
 	struct kvec *iov = buf->head;
 	int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
@@ -513,6 +515,7 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
 		buf->len += len;
 		iov->iov_len += len;
 	}
+	xdr->rqst = rqst;
 }
 EXPORT_SYMBOL_GPL(xdr_init_encode);
 
@@ -819,8 +822,10 @@ static bool xdr_set_next_buffer(struct xdr_stream *xdr)
  * @xdr: pointer to xdr_stream struct
  * @buf: pointer to XDR buffer from which to decode data
  * @p: current pointer inside XDR buffer
+ * @rqst: pointer to controlling rpc_rqst, for debugging
  */
-void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
+void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
+		     struct rpc_rqst *rqst)
 {
 	xdr->buf = buf;
 	xdr->scratch.iov_base = NULL;
@@ -836,6 +841,7 @@ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
 		xdr->nwords -= p - xdr->p;
 		xdr->p = p;
 	}
+	xdr->rqst = rqst;
 }
 EXPORT_SYMBOL_GPL(xdr_init_decode);
 
@@ -854,7 +860,7 @@ void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
 	buf->page_len =  len;
 	buf->buflen =  len;
 	buf->len = len;
-	xdr_init_decode(xdr, buf, NULL);
+	xdr_init_decode(xdr, buf, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
 

net/sunrpc/xprtrdma/backchannel.c

@@ -123,7 +123,7 @@ static int rpcrdma_bc_marshal_reply(struct rpc_rqst *rqst)
 
 	rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
 	xdr_init_encode(&req->rl_stream, &req->rl_hdrbuf,
-			req->rl_rdmabuf->rg_base);
+			req->rl_rdmabuf->rg_base, rqst);
 
 	p = xdr_reserve_space(&req->rl_stream, 28);
 	if (unlikely(!p))

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -748,7 +748,7 @@ rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
 
 	rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
 	xdr_init_encode(xdr, &req->rl_hdrbuf,
-			req->rl_rdmabuf->rg_base);
+			req->rl_rdmabuf->rg_base, rqst);
 
 	/* Fixed header fields */
 	ret = -EMSGSIZE;
@@ -1329,7 +1329,7 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
 
 	/* Fixed transport header fields */
 	xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
-			rep->rr_hdrbuf.head[0].iov_base);
+			rep->rr_hdrbuf.head[0].iov_base, NULL);
 	p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
 	if (unlikely(!p))
 		goto out_shortreply;