2 files changed, 272 insertions, 60 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index c7c9bbb..e80f43d 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -62,17 +62,17 @@ enum rpcrdma_chunktype {
 };
 
 static const char transfertypes[][12] = {
-	"pure inline",	/* no chunks */
-	" read chunk",	/* some argument via rdma read */
-	"*read chunk",	/* entire request via rdma read */
-	"write chunk",	/* some result via rdma write */
+	"inline",	/* no chunks */
+	"read list",	/* some argument via rdma read */
+	"*read list",	/* entire request via rdma read */
+	"write list",	/* some result via rdma write */
 	"reply chunk"	/* entire reply via rdma write */
 };
 
 /* Returns size of largest RPC-over-RDMA header in a Call message
  *
- * The client marshals only one chunk list per Call message.
- * The largest list is the Read list.
+ * The largest Call header contains a full-size Read list and a
+ * minimal Reply chunk.
  */
 static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
 {
@@ -85,6 +85,11 @@ static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
 	maxsegs += 2;	/* segment for head and tail buffers */
 	size = maxsegs * sizeof(struct rpcrdma_read_chunk);
 
+	/* Minimal Read chunk size */
+	size += sizeof(__be32);	/* segment count */
+	size += sizeof(struct rpcrdma_segment);
+	size += sizeof(__be32);	/* list discriminator */
+
 	dprintk("RPC:       %s: max call header size = %u\n",
 		__func__, size);
 	return size;
@@ -431,6 +436,209 @@ out:
 	return n;
 }
 
+static inline __be32 *
+xdr_encode_rdma_segment(__be32 *iptr, struct rpcrdma_mr_seg *seg)
+{
+	*iptr++ = cpu_to_be32(seg->mr_rkey);
+	*iptr++ = cpu_to_be32(seg->mr_len);
+	return xdr_encode_hyper(iptr, seg->mr_base);
+}
+
+/* XDR-encode the Read list. Supports encoding a list of read
+ * segments that belong to a single read chunk.
+ *
+ * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
+ *
+ *  Read chunklist (a linked list):
+ *   N elements, position P (same P for all chunks of same arg!):
+ *    1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
+ *
+ * Returns a pointer to the XDR word in the RDMA header following
+ * the end of the Read list, or an error pointer.
+ */
+static __be32 *
+rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
+			 struct rpcrdma_req *req, struct rpc_rqst *rqst,
+			 __be32 *iptr, enum rpcrdma_chunktype rtype)
+{
+	struct rpcrdma_mr_seg *seg = req->rl_nextseg;
+	unsigned int pos;
+	int n, nsegs;
+
+	if (rtype == rpcrdma_noch) {
+		*iptr++ = xdr_zero;	/* item not present */
+		return iptr;
+	}
+
+	pos = rqst->rq_snd_buf.head[0].iov_len;
+	if (rtype == rpcrdma_areadch)
+		pos = 0;
+	nsegs = rpcrdma_convert_iovs(&rqst->rq_snd_buf, pos, rtype, seg,
+				     RPCRDMA_MAX_SEGS - req->rl_nchunks);
+	if (nsegs < 0)
+		return ERR_PTR(nsegs);
+
+	do {
+		n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, false);
+		if (n <= 0)
+			return ERR_PTR(n);
+
+		*iptr++ = xdr_one;	/* item present */
+
+		/* All read segments in this chunk
+		 * have the same "position".
+		 */
+		*iptr++ = cpu_to_be32(pos);
+		iptr = xdr_encode_rdma_segment(iptr, seg);
+
+		dprintk("RPC: %5u %s: read segment pos %u "
+			"%d@0x%016llx:0x%08x (%s)\n",
+			rqst->rq_task->tk_pid, __func__, pos,
+			seg->mr_len, (unsigned long long)seg->mr_base,
+			seg->mr_rkey, n < nsegs ? "more" : "last");
+
+		r_xprt->rx_stats.read_chunk_count++;
+		req->rl_nchunks++;
+		seg += n;
+		nsegs -= n;
+	} while (nsegs);
+	req->rl_nextseg = seg;
+
+	/* Finish Read list */
+	*iptr++ = xdr_zero;	/* Next item not present */
+	return iptr;
+}
+
+/* XDR-encode the Write list. Supports encoding a list containing
+ * one array of plain segments that belong to a single write chunk.
+ *
+ * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
+ *
+ *  Write chunklist (a list of (one) counted array):
+ *   N elements:
+ *    1 - N - HLOO - HLOO - ... - HLOO - 0
+ *
+ * Returns a pointer to the XDR word in the RDMA header following
+ * the end of the Write list, or an error pointer.
+ */
+static __be32 *
+rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
+			  struct rpc_rqst *rqst, __be32 *iptr,
+			  enum rpcrdma_chunktype wtype)
+{
+	struct rpcrdma_mr_seg *seg = req->rl_nextseg;
+	int n, nsegs, nchunks;
+	__be32 *segcount;
+
+	if (wtype != rpcrdma_writech) {
+		*iptr++ = xdr_zero;	/* no Write list present */
+		return iptr;
+	}
+
+	nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf,
+				     rqst->rq_rcv_buf.head[0].iov_len,
+				     wtype, seg,
+				     RPCRDMA_MAX_SEGS - req->rl_nchunks);
+	if (nsegs < 0)
+		return ERR_PTR(nsegs);
+
+	*iptr++ = xdr_one;	/* Write list present */
+	segcount = iptr++;	/* save location of segment count */
+
+	nchunks = 0;
+	do {
+		n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true);
+		if (n <= 0)
+			return ERR_PTR(n);
+
+		iptr = xdr_encode_rdma_segment(iptr, seg);
+
+		dprintk("RPC: %5u %s: write segment "
+			"%d@0x016%llx:0x%08x (%s)\n",
+			rqst->rq_task->tk_pid, __func__,
+			seg->mr_len, (unsigned long long)seg->mr_base,
+			seg->mr_rkey, n < nsegs ? "more" : "last");
+
+		r_xprt->rx_stats.write_chunk_count++;
+		r_xprt->rx_stats.total_rdma_request += seg->mr_len;
+		req->rl_nchunks++;
+		nchunks++;
+		seg   += n;
+		nsegs -= n;
+	} while (nsegs);
+	req->rl_nextseg = seg;
+
+	/* Update count of segments in this Write chunk */
+	*segcount = cpu_to_be32(nchunks);
+
+	/* Finish Write list */
+	*iptr++ = xdr_zero;	/* Next item not present */
+	return iptr;
+}
+
+/* XDR-encode the Reply chunk. Supports encoding an array of plain
+ * segments that belong to a single write (reply) chunk.
+ *
+ * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
+ *
+ *  Reply chunk (a counted array):
+ *   N elements:
+ *    1 - N - HLOO - HLOO - ... - HLOO
+ *
+ * Returns a pointer to the XDR word in the RDMA header following
+ * the end of the Reply chunk, or an error pointer.
+ */
+static __be32 *
+rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
+			   struct rpcrdma_req *req, struct rpc_rqst *rqst,
+			   __be32 *iptr, enum rpcrdma_chunktype wtype)
+{
+	struct rpcrdma_mr_seg *seg = req->rl_nextseg;
+	int n, nsegs, nchunks;
+	__be32 *segcount;
+
+	if (wtype != rpcrdma_replych) {
+		*iptr++ = xdr_zero;	/* no Reply chunk present */
+		return iptr;
+	}
+
+	nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf, 0, wtype, seg,
+				     RPCRDMA_MAX_SEGS - req->rl_nchunks);
+	if (nsegs < 0)
+		return ERR_PTR(nsegs);
+
+	*iptr++ = xdr_one;	/* Reply chunk present */
+	segcount = iptr++;	/* save location of segment count */
+
+	nchunks = 0;
+	do {
+		n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true);
+		if (n <= 0)
+			return ERR_PTR(n);
+
+		iptr = xdr_encode_rdma_segment(iptr, seg);
+
+		dprintk("RPC: %5u %s: reply segment "
+			"%d@0x%016llx:0x%08x (%s)\n",
+			rqst->rq_task->tk_pid, __func__,
+			seg->mr_len, (unsigned long long)seg->mr_base,
+			seg->mr_rkey, n < nsegs ? "more" : "last");
+
+		r_xprt->rx_stats.reply_chunk_count++;
+		r_xprt->rx_stats.total_rdma_request += seg->mr_len;
+		req->rl_nchunks++;
+		nchunks++;
+		seg   += n;
+		nsegs -= n;
+	} while (nsegs);
+	req->rl_nextseg = seg;
+
+	/* Update count of segments in the Reply chunk */
+	*segcount = cpu_to_be32(nchunks);
+
+	return iptr;
+}
+
 /*
  * Copy write data inline.
  * This function is used for "small" requests. Data which is passed
@@ -508,24 +716,18 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 	struct rpc_xprt *xprt = rqst->rq_xprt;
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
-	char *base;
-	size_t rpclen;
-	ssize_t hdrlen;
 	enum rpcrdma_chunktype rtype, wtype;
 	struct rpcrdma_msg *headerp;
+	unsigned int pos;
+	ssize_t hdrlen;
+	size_t rpclen;
+	__be32 *iptr;
 
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	if (test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state))
 		return rpcrdma_bc_marshal_reply(rqst);
 #endif
 
-	/*
-	 * rpclen gets amount of data in first buffer, which is the
-	 * pre-registered buffer.
-	 */
-	base = rqst->rq_svec[0].iov_base;
-	rpclen = rqst->rq_svec[0].iov_len;
-
 	headerp = rdmab_to_msg(req->rl_rdmabuf);
 	/* don't byte-swap XID, it's already done in request */
 	headerp->rm_xid = rqst->rq_xid;
@@ -565,8 +767,12 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 	 */
 	if (rpcrdma_args_inline(r_xprt, rqst)) {
 		rtype = rpcrdma_noch;
+		rpcrdma_inline_pullup(rqst);
+		rpclen = rqst->rq_svec[0].iov_len;
 	} else if (rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
 		rtype = rpcrdma_readch;
+		rpclen = rqst->rq_svec[0].iov_len;
+		rpclen += rpcrdma_tail_pullup(&rqst->rq_snd_buf);
 	} else {
 		r_xprt->rx_stats.nomsg_call_count++;
 		headerp->rm_type = htonl(RDMA_NOMSG);
@@ -574,52 +780,49 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 		rpclen = 0;
 	}
 
-	/* The following simplification is not true forever */
-	if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
-		wtype = rpcrdma_noch;
-	if (rtype != rpcrdma_noch && wtype != rpcrdma_noch) {
-		dprintk("RPC:       %s: cannot marshal multiple chunk lists\n",
-			__func__);
-		return -EIO;
-	}
-
-	hdrlen = RPCRDMA_HDRLEN_MIN;
-
-	/*
-	 * Pull up any extra send data into the preregistered buffer.
-	 * When padding is in use and applies to the transfer, insert
-	 * it and change the message type.
+	/* This implementation supports the following combinations
+	 * of chunk lists in one RPC-over-RDMA Call message:
+	 *
+	 *   - Read list
+	 *   - Write list
+	 *   - Reply chunk
+	 *   - Read list + Reply chunk
+	 *
+	 * It might not yet support the following combinations:
+	 *
+	 *   - Read list + Write list
+	 *
+	 * It does not support the following combinations:
+	 *
+	 *   - Write list + Reply chunk
+	 *   - Read list + Write list + Reply chunk
+	 *
+	 * This implementation supports only a single chunk in each
+	 * Read or Write list. Thus for example the client cannot
+	 * send a Call message with a Position Zero Read chunk and a
+	 * regular Read chunk at the same time.
 	 */
-	if (rtype == rpcrdma_noch) {
-
-		rpcrdma_inline_pullup(rqst);
-
-		headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
-		headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
-		headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
-		/* new length after pullup */
-		rpclen = rqst->rq_svec[0].iov_len;
-	} else if (rtype == rpcrdma_readch)
-		rpclen += rpcrdma_tail_pullup(&rqst->rq_snd_buf);
-	if (rtype != rpcrdma_noch) {
-		hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_snd_buf,
-					       headerp, rtype);
-		wtype = rtype;	/* simplify dprintk */
-
-	} else if (wtype != rpcrdma_noch) {
-		hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_rcv_buf,
-					       headerp, wtype);
-	}
-	if (hdrlen < 0)
-		return hdrlen;
+	req->rl_nchunks = 0;
+	req->rl_nextseg = req->rl_segments;
+	iptr = headerp->rm_body.rm_chunks;
+	iptr = rpcrdma_encode_read_list(r_xprt, req, rqst, iptr, rtype);
+	if (IS_ERR(iptr))
+		goto out_unmap;
+	iptr = rpcrdma_encode_write_list(r_xprt, req, rqst, iptr, wtype);
+	if (IS_ERR(iptr))
+		goto out_unmap;
+	iptr = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, iptr, wtype);
+	if (IS_ERR(iptr))
+		goto out_unmap;
+	hdrlen = (unsigned char *)iptr - (unsigned char *)headerp;
 
 	if (hdrlen + rpclen > RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
 		goto out_overflow;
 
-	dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd"
-		" headerp 0x%p base 0x%p lkey 0x%x\n",
-		__func__, transfertypes[wtype], hdrlen, rpclen,
-		headerp, base, rdmab_lkey(req->rl_rdmabuf));
+	dprintk("RPC: %5u %s: %s/%s: hdrlen %zd rpclen %zd\n",
+		rqst->rq_task->tk_pid, __func__,
+		transfertypes[rtype], transfertypes[wtype],
+		hdrlen, rpclen);
 
 	req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
 	req->rl_send_iov[0].length = hdrlen;
@@ -637,12 +840,18 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 	return 0;
 
 out_overflow:
-	pr_err("rpcrdma: send overflow: hdrlen %zd rpclen %zu %s\n",
-		hdrlen, rpclen, transfertypes[wtype]);
+	pr_err("rpcrdma: send overflow: hdrlen %zd rpclen %zu %s/%s\n",
+		hdrlen, rpclen, transfertypes[rtype], transfertypes[wtype]);
 	/* Terminate this RPC. Chunks registered above will be
 	 * released by xprt_release -> xprt_rmda_free .
 	 */
 	return -EIO;
+
+out_unmap:
+	for (pos = 0; req->rl_nchunks--;)
+		pos += r_xprt->rx_ia.ri_ops->ro_unmap(r_xprt,
+						      &req->rl_segments[pos]);
+	return PTR_ERR(iptr);
 }
 
 /*
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 4349e03..61999b6 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -184,7 +184,9 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb)
  */
 
 #define RPCRDMA_MAX_DATA_SEGS	((1 * 1024 * 1024) / PAGE_SIZE)
-#define RPCRDMA_MAX_SEGS 	(RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
+
+/* data segments + head/tail for Call + head/tail for Reply */
+#define RPCRDMA_MAX_SEGS 	(RPCRDMA_MAX_DATA_SEGS + 4)
 
 struct rpcrdma_buffer;
 
@@ -298,6 +300,7 @@ struct rpcrdma_req {
 	struct rpcrdma_regbuf	*rl_rdmabuf;
 	struct rpcrdma_regbuf	*rl_sendbuf;
 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
+	struct rpcrdma_mr_seg	*rl_nextseg;
 
 	struct ib_cqe		rl_cqe;
 	struct list_head	rl_all;