libceph: pass reply buffer length through ceph_osdc_call()

To spare checking for "this reply fits into a page, but does it fit
into my buffer?" in some callers, osd_req_op_cls_response_data_pages()
needs to know how big it is.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

2 files changed, 6 insertions, 3 deletions

diff --git a/net/ceph/cls_lock_client.c b/net/ceph/cls_lock_client.c
index 50f040fdb2a9..f13a1ea87459 100644
--- a/net/ceph/cls_lock_client.c
+++ b/net/ceph/cls_lock_client.c
@@ -278,7 +278,7 @@ int ceph_cls_lock_info(struct ceph_osd_client *osdc,
         int get_info_op_buf_size;
         int name_len = strlen(lock_name);
         struct page *get_info_op_page, *reply_page;
-        size_t reply_len;
+        size_t reply_len = PAGE_SIZE;
         void *p, *end;
         int ret;
 
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 3a2417bb6ff0..ac4753421d0c 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -4023,7 +4023,7 @@ 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
+ * @resp_len: in/out param for reply length
  */
 int ceph_osdc_call(struct ceph_osd_client *osdc,
                    struct ceph_object_id *oid,
@@ -4036,6 +4036,9 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
         struct ceph_osd_request *req;
         int ret;
 
+        if (req_len > PAGE_SIZE || (resp_page && *resp_len > PAGE_SIZE))
+                return -E2BIG;
+
         req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_NOIO);
         if (!req)
                 return -ENOMEM;
@@ -4054,7 +4057,7 @@ int ceph_osdc_call(struct ceph_osd_client *osdc,
                                                   0, false, false);
         if (resp_page)
                 osd_req_op_cls_response_data_pages(req, 0, &resp_page,
-                                                   PAGE_SIZE, 0, false, false);
+                                                   *resp_len, 0, false, false);
 
         ceph_osdc_start_request(osdc, req, false);
         ret = ceph_osdc_wait_request(osdc, req);