libceph: format class info at init time

An object class method is formatted using a pagelist which contains
the class name, the method name, and the data concatenated into an
osd request's outbound data.

Currently when a class op is initialized in osd_req_op_cls_init(),
the lengths of and pointers to these three items are recorded.
Later, when the op is getting formatted into the request message, a
new pagelist is created and that is when these items get copied into
the pagelist.

This patch makes it so the pagelist to hold these items is created
when the op is initialized instead.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

net/ceph/osd_client.c

@@ -399,28 +399,39 @@ void osd_req_op_cls_init(struct ceph_osd_request *osd_req, unsigned int which,
 			const void *request_data, size_t request_data_size)
 {
 	struct ceph_osd_req_op *op = osd_req_op_init(osd_req, which, opcode);
+	struct ceph_pagelist *pagelist;
 	size_t payload_len = 0;
 	size_t size;
 
 	BUG_ON(opcode != CEPH_OSD_OP_CALL);
 
+	pagelist = kmalloc(sizeof (*pagelist), GFP_NOFS);
+	BUG_ON(!pagelist);
+	ceph_pagelist_init(pagelist);
+
 	op->cls.class_name = class;
 	size = strlen(class);
 	BUG_ON(size > (size_t) U8_MAX);
 	op->cls.class_len = size;
+	ceph_pagelist_append(pagelist, class, size);
 	payload_len += size;
 
 	op->cls.method_name = method;
 	size = strlen(method);
 	BUG_ON(size > (size_t) U8_MAX);
 	op->cls.method_len = size;
+	ceph_pagelist_append(pagelist, method, size);
 	payload_len += size;
 
 	op->cls.request_data = request_data;
 	BUG_ON(request_data_size > (size_t) U32_MAX);
 	op->cls.request_data_len = (u32) request_data_size;
+	ceph_pagelist_append(pagelist, request_data, request_data_size);
 	payload_len += request_data_size;
 
+	op->cls.request_info = &osd_req->r_data_out;
+	ceph_osd_data_pagelist_init(op->cls.request_info, pagelist);
+
 	op->cls.argc = 0;	/* currently unused */
 
 	op->payload_len = payload_len;
@@ -456,7 +467,6 @@ static u64 osd_req_encode_op(struct ceph_osd_request *req,
 {
 	struct ceph_osd_req_op *src;
 	u64 request_data_len = 0;
-	struct ceph_pagelist *pagelist;
 
 	BUG_ON(which >= req->r_num_ops);
 	src = &req->r_ops[which];
@@ -485,23 +495,14 @@ static u64 osd_req_encode_op(struct ceph_osd_request *req,
 			WARN_ON(src->extent.osd_data != &req->r_data_in);
 		break;
 	case CEPH_OSD_OP_CALL:
-		pagelist = kmalloc(sizeof (*pagelist), GFP_NOFS);
-		BUG_ON(!pagelist);
-		ceph_pagelist_init(pagelist);
-
 		dst->cls.class_len = src->cls.class_len;
 		dst->cls.method_len = src->cls.method_len;
 		dst->cls.indata_len = cpu_to_le32(src->cls.request_data_len);
-		ceph_pagelist_append(pagelist, src->cls.class_name,
-				     src->cls.class_len);
-		ceph_pagelist_append(pagelist, src->cls.method_name,
-				     src->cls.method_len);
-		ceph_pagelist_append(pagelist, src->cls.request_data,
-				     src->cls.request_data_len);
-		ceph_osd_data_pagelist_init(&req->r_data_out, pagelist);
-
 		WARN_ON(src->cls.response_data != &req->r_data_in);
-		request_data_len = pagelist->length;
+		WARN_ON(src->cls.request_info != &req->r_data_out);
+		BUG_ON(src->cls.request_info->type !=
+					CEPH_OSD_DATA_TYPE_PAGELIST);
+		request_data_len = src->cls.request_info->pagelist->length;
 		break;
 	case CEPH_OSD_OP_STARTSYNC:
 		break;