libceph: change ceph_osdc_call() to take page vector for response

This will be used for loading object map.  rbd_obj_read_sync() isn't
suitable because object map must be accessed through class methods.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

drivers/block/rbd.c

@@ -4076,7 +4076,7 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 
 	ret = ceph_osdc_call(osdc, oid, oloc, RBD_DRV_NAME, method_name,
 			     CEPH_OSD_FLAG_READ, req_page, outbound_size,
-			     reply_page, &inbound_size);
+			     &reply_page, &inbound_size);
 	if (!ret) {
 		memcpy(inbound, page_address(reply_page), inbound_size);
 		ret = inbound_size;
@@ -5102,7 +5102,7 @@ static int __get_parent_info(struct rbd_device *rbd_dev,
 
 	ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
 			     "rbd", "parent_get", CEPH_OSD_FLAG_READ,
-			     req_page, sizeof(u64), reply_page, &reply_len);
+			     req_page, sizeof(u64), &reply_page, &reply_len);
 	if (ret)
 		return ret == -EOPNOTSUPP ? 1 : ret;
 
@@ -5114,7 +5114,7 @@ static int __get_parent_info(struct rbd_device *rbd_dev,
 
 	ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
 			     "rbd", "parent_overlap_get", CEPH_OSD_FLAG_READ,
-			     req_page, sizeof(u64), reply_page, &reply_len);
+			     req_page, sizeof(u64), &reply_page, &reply_len);
 	if (ret)
 		return ret;
 
@@ -5145,7 +5145,7 @@ static int __get_parent_info_legacy(struct rbd_device *rbd_dev,
 
 	ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
 			     "rbd", "get_parent", CEPH_OSD_FLAG_READ,
-			     req_page, sizeof(u64), reply_page, &reply_len);
+			     req_page, sizeof(u64), &reply_page, &reply_len);
 	if (ret)
 		return ret;
 

include/linux/ceph/osd_client.h

@@ -497,7 +497,7 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
 		   const char *class, const char *method,
 		   unsigned int flags,
 		   struct page *req_page, size_t req_len,
-		   struct page *resp_page, size_t *resp_len);
+		   struct page **resp_pages, size_t *resp_len);
 
 extern int ceph_osdc_readpages(struct ceph_osd_client *osdc,
 			       struct ceph_vino vino,

net/ceph/cls_lock_client.c

@@ -363,7 +363,7 @@ int ceph_cls_lock_info(struct ceph_osd_client *osdc,
 	dout("%s lock_name %s\n", __func__, lock_name);
 	ret = ceph_osdc_call(osdc, oid, oloc, "lock", "get_info",
 			     CEPH_OSD_FLAG_READ, get_info_op_page,
-			     get_info_op_buf_size, reply_page, &reply_len);
+			     get_info_op_buf_size, &reply_page, &reply_len);
 
 	dout("%s: status %d\n", __func__, ret);
 	if (ret >= 0) {

net/ceph/osd_client.c

@@ -5050,12 +5050,12 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
 		   const char *class, const char *method,
 		   unsigned int flags,
 		   struct page *req_page, size_t req_len,
-		   struct page *resp_page, size_t *resp_len)
+		   struct page **resp_pages, size_t *resp_len)
 {
 	struct ceph_osd_request *req;
 	int ret;
 
-	if (req_len > PAGE_SIZE || (resp_page && *resp_len > PAGE_SIZE))
+	if (req_len > PAGE_SIZE)
 		return -E2BIG;
 
 	req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_NOIO);
@@ -5073,8 +5073,8 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
 	if (req_page)
 		osd_req_op_cls_request_data_pages(req, 0, &req_page, req_len,
 						  0, false, false);
-	if (resp_page)
-		osd_req_op_cls_response_data_pages(req, 0, &resp_page,
+	if (resp_pages)
+		osd_req_op_cls_response_data_pages(req, 0, resp_pages,
 						   *resp_len, 0, false, false);
 
 	ret = ceph_osdc_alloc_messages(req, GFP_NOIO);
@@ -5085,7 +5085,7 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
 	ret = ceph_osdc_wait_request(osdc, req);
 	if (ret >= 0) {
 		ret = req->r_ops[0].rval;
-		if (resp_page)
+		if (resp_pages)
 			*resp_len = req->r_ops[0].outdata_len;
 	}