svcrdma: Add common XDR decoders for RDMA and Read segments

Clean up: De-duplicate some code.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

include/linux/sunrpc/rpc_rdma.h

@@ -124,4 +124,41 @@ rpcrdma_decode_buffer_size(u8 val)
 	return ((unsigned int)val + 1) << 10;
 }
 
+/**
+ * xdr_decode_rdma_segment - Decode contents of an RDMA segment
+ * @p: Pointer to the undecoded RDMA segment
+ * @handle: Upon return, the RDMA handle
+ * @length: Upon return, the RDMA length
+ * @offset: Upon return, the RDMA offset
+ *
+ * Return value:
+ *   Pointer to the XDR item that follows the RDMA segment
+ */
+static inline __be32 *xdr_decode_rdma_segment(__be32 *p, u32 *handle,
+					      u32 *length, u64 *offset)
+{
+	*handle = be32_to_cpup(p++);
+	*length = be32_to_cpup(p++);
+	return xdr_decode_hyper(p, offset);
+}
+
+/**
+ * xdr_decode_read_segment - Decode contents of a Read segment
+ * @p: Pointer to the undecoded Read segment
+ * @position: Upon return, the segment's position
+ * @handle: Upon return, the RDMA handle
+ * @length: Upon return, the RDMA length
+ * @offset: Upon return, the RDMA offset
+ *
+ * Return value:
+ *   Pointer to the XDR item that follows the Read segment
+ */
+static inline __be32 *xdr_decode_read_segment(__be32 *p, u32 *position,
+					      u32 *handle, u32 *length,
+					      u64 *offset)
+{
+	*position = be32_to_cpup(p++);
+	return xdr_decode_rdma_segment(p, handle, length, offset);
+}
+
 #endif				/* _LINUX_SUNRPC_RPC_RDMA_H */

net/sunrpc/xprtrdma/frwr_ops.c

@@ -40,7 +40,6 @@
  * New MRs are created on demand.
  */
 
-#include <linux/sunrpc/rpc_rdma.h>
 #include <linux/sunrpc/svc_rdma.h>
 
 #include "xprt_rdma.h"

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -1176,10 +1176,7 @@ static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
 	if (unlikely(!p))
 		return -EIO;
 
-	handle = be32_to_cpup(p++);
-	*length = be32_to_cpup(p++);
-	xdr_decode_hyper(p, &offset);
-
+	xdr_decode_rdma_segment(p, &handle, length, &offset);
 	trace_xprtrdma_decode_seg(handle, *length, offset);
 	return 0;
 }

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

@@ -466,9 +466,7 @@ static bool xdr_check_write_chunk(struct svc_rdma_recv_ctxt *rctxt, u32 maxlen)
 		if (!p)
 			return false;
 
-		handle = be32_to_cpup(p++);
-		length = be32_to_cpup(p++);
-		xdr_decode_hyper(p, &offset);
+		xdr_decode_rdma_segment(p, &handle, &length, &offset);
 		trace_svcrdma_decode_wseg(handle, length, offset);
 
 		total += length;

net/sunrpc/xprtrdma/svc_rdma_rw.c

@@ -7,6 +7,7 @@
 
 #include <rdma/rw.h>
 
+#include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/rpc_rdma.h>
 #include <linux/sunrpc/svc_rdma.h>
 
@@ -441,34 +442,32 @@ svc_rdma_build_writes(struct svc_rdma_write_info *info,
 	seg = info->wi_segs + info->wi_seg_no * rpcrdma_segment_maxsz;
 	do {
 		unsigned int write_len;
-		u32 seg_length, seg_handle;
-		u64 seg_offset;
+		u32 handle, length;
+		u64 offset;
 
 		if (info->wi_seg_no >= info->wi_nsegs)
 			goto out_overflow;
 
-		seg_handle = be32_to_cpup(seg);
-		seg_length = be32_to_cpup(seg + 1);
-		xdr_decode_hyper(seg + 2, &seg_offset);
-		seg_offset += info->wi_seg_off;
+		xdr_decode_rdma_segment(seg, &handle, &length, &offset);
+		offset += info->wi_seg_off;
 
-		write_len = min(remaining, seg_length - info->wi_seg_off);
+		write_len = min(remaining, length - info->wi_seg_off);
 		ctxt = svc_rdma_get_rw_ctxt(rdma,
 					    (write_len >> PAGE_SHIFT) + 2);
 		if (!ctxt)
 			return -ENOMEM;
 
 		constructor(info, write_len, ctxt);
-		ret = svc_rdma_rw_ctx_init(rdma, ctxt, seg_offset, seg_handle,
+		ret = svc_rdma_rw_ctx_init(rdma, ctxt, offset, handle,
 					   DMA_TO_DEVICE);
 		if (ret < 0)
 			return -EIO;
 
-		trace_svcrdma_send_wseg(seg_handle, write_len, seg_offset);
+		trace_svcrdma_send_wseg(handle, write_len, offset);
 
 		list_add(&ctxt->rw_list, &cc->cc_rwctxts);
 		cc->cc_sqecount += ret;
-		if (write_len == seg_length - info->wi_seg_off) {
+		if (write_len == length - info->wi_seg_off) {
 			seg += 4;
 			info->wi_seg_no++;
 			info->wi_seg_off = 0;
@@ -689,21 +688,17 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp,
 	ret = -EINVAL;
 	info->ri_chunklen = 0;
 	while (*p++ != xdr_zero && be32_to_cpup(p++) == info->ri_position) {
-		u32 rs_handle, rs_length;
-		u64 rs_offset;
+		u32 handle, length;
+		u64 offset;
 
-		rs_handle = be32_to_cpup(p++);
-		rs_length = be32_to_cpup(p++);
-		p = xdr_decode_hyper(p, &rs_offset);
-
-		ret = svc_rdma_build_read_segment(info, rqstp,
-						  rs_handle, rs_length,
-						  rs_offset);
+		p = xdr_decode_rdma_segment(p, &handle, &length, &offset);
+		ret = svc_rdma_build_read_segment(info, rqstp, handle, length,
+						  offset);
 		if (ret < 0)
 			break;
 
-		trace_svcrdma_send_rseg(rs_handle, rs_length, rs_offset);
-		info->ri_chunklen += rs_length;
+		trace_svcrdma_send_rseg(handle, length, offset);
+		info->ri_chunklen += length;
 	}
 
 	return ret;

net/sunrpc/xprtrdma/svc_rdma_sendto.c

@@ -106,7 +106,6 @@
 #include <rdma/rdma_cm.h>
 
 #include <linux/sunrpc/debug.h>
-#include <linux/sunrpc/rpc_rdma.h>
 #include <linux/sunrpc/svc_rdma.h>
 
 #include "xprt_rdma.h"
@@ -375,9 +374,7 @@ static ssize_t svc_rdma_encode_write_segment(__be32 *src,
 	if (!p)
 		return -EMSGSIZE;
 
-	handle = be32_to_cpup(src++);
-	length = be32_to_cpup(src++);
-	xdr_decode_hyper(src, &offset);
+	xdr_decode_rdma_segment(src, &handle, &length, &offset);
 
 	*p++ = cpu_to_be32(handle);
 	if (*remaining < length) {

net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -55,7 +55,6 @@
 
 #include <linux/sunrpc/addr.h>
 #include <linux/sunrpc/debug.h>
-#include <linux/sunrpc/rpc_rdma.h>
 #include <linux/sunrpc/svc_xprt.h>
 #include <linux/sunrpc/svc_rdma.h>