libceph: add ceph_osdc_call() single-page helper

Add a convenience function to osd_client to send Ceph OSD
'class' ops. The interface assumes that the request and
reply data each consist of single pages.

Signed-off-by: Douglas Fuller <dfuller@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>

1 files changed, 51 insertions, 0 deletions

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index dd51ec8ce97f..fbc6b7090c65 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -4027,6 +4027,57 @@ void ceph_osdc_maybe_request_map(struct ceph_osd_client *osdc)
 EXPORT_SYMBOL(ceph_osdc_maybe_request_map);
 
 /*
+ * Execute an OSD class method on an object.
+ *
+ * @flags: CEPH_OSD_FLAG_*
+ * @resp_len: out param for reply length
+ */
+int ceph_osdc_call(struct ceph_osd_client *osdc,
+                   struct ceph_object_id *oid,
+                   struct ceph_object_locator *oloc,
+                   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 ceph_osd_request *req;
+        int ret;
+
+        req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_NOIO);
+        if (!req)
+                return -ENOMEM;
+
+        ceph_oid_copy(&req->r_base_oid, oid);
+        ceph_oloc_copy(&req->r_base_oloc, oloc);
+        req->r_flags = flags;
+
+        ret = ceph_osdc_alloc_messages(req, GFP_NOIO);
+        if (ret)
+                goto out_put_req;
+
+        osd_req_op_cls_init(req, 0, CEPH_OSD_OP_CALL, class, method);
+        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,
+                                                   PAGE_SIZE, 0, false, false);
+
+        ceph_osdc_start_request(osdc, req, false);
+        ret = ceph_osdc_wait_request(osdc, req);
+        if (ret >= 0) {
+                ret = req->r_ops[0].rval;
+                if (resp_page)
+                        *resp_len = req->r_ops[0].outdata_len;
+        }
+
+out_put_req:
+        ceph_osdc_put_request(req);
+        return ret;
+}
+EXPORT_SYMBOL(ceph_osdc_call);
+
+/*
  * init, shutdown
  */
 int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client)