libceph: drop msg argument from ceph_osdc_callback_t

finish_read(), its only user, uses it to get to hdr.data_len, which is
what ->r_result is set to on success.  This gains us the ability to
safely call callbacks from contexts other than reply, e.g. map check.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

drivers/block/rbd.c

@@ -1828,13 +1828,12 @@ static void rbd_osd_call_callback(struct rbd_obj_request *obj_request)
 		obj_request_done_set(obj_request);
 }
 
-static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
-				struct ceph_msg *msg)
+static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
 {
 	struct rbd_obj_request *obj_request = osd_req->r_priv;
 	u16 opcode;
 
-	dout("%s: osd_req %p msg %p\n", __func__, osd_req, msg);
+	dout("%s: osd_req %p\n", __func__, osd_req);
 	rbd_assert(osd_req == obj_request->osd_req);
 	if (obj_request_img_data_test(obj_request)) {
 		rbd_assert(obj_request->img_request);

fs/ceph/addr.c

@@ -257,12 +257,12 @@ static int ceph_readpage(struct file *filp, struct page *page)
 /*
  * Finish an async read(ahead) op.
  */
-static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
+static void finish_read(struct ceph_osd_request *req)
 {
 	struct inode *inode = req->r_inode;
 	struct ceph_osd_data *osd_data;
-	int rc = req->r_result;
-	int bytes = le32_to_cpu(msg->hdr.data_len);
+	int rc = req->r_result <= 0 ? req->r_result : 0;
+	int bytes = req->r_result >= 0 ? req->r_result : 0;
 	int num_pages;
 	int i;
 
@@ -598,8 +598,7 @@ static void ceph_release_pages(struct page **pages, int num)
  * If we get an error, set the mapping error bit, but not the individual
  * page error bits.
  */
-static void writepages_finish(struct ceph_osd_request *req,
-			      struct ceph_msg *msg)
+static void writepages_finish(struct ceph_osd_request *req)
 {
 	struct inode *inode = req->r_inode;
 	struct ceph_inode_info *ci = ceph_inode(inode);

fs/ceph/file.c

@@ -616,8 +616,7 @@ static void ceph_aio_complete(struct inode *inode,
 	kfree(aio_req);
 }
 
-static void ceph_aio_complete_req(struct ceph_osd_request *req,
-				  struct ceph_msg *msg)
+static void ceph_aio_complete_req(struct ceph_osd_request *req)
 {
 	int rc = req->r_result;
 	struct inode *inode = req->r_inode;
@@ -740,7 +739,7 @@ static void ceph_aio_retry_work(struct work_struct *work)
 out:
 	if (ret < 0) {
 		req->r_result = ret;
-		ceph_aio_complete_req(req, NULL);
+		ceph_aio_complete_req(req);
 	}
 
 	ceph_put_snap_context(snapc);
@@ -961,7 +960,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 							      req, false);
 			if (ret < 0) {
 				req->r_result = ret;
-				ceph_aio_complete_req(req, NULL);
+				ceph_aio_complete_req(req);
 			}
 		}
 		return -EIOCBQUEUED;

include/linux/ceph/osd_client.h

@@ -20,8 +20,7 @@ struct ceph_osd_client;
 /*
  * completion callback for async writepages
  */
-typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *,
-				     struct ceph_msg *);
+typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *);
 typedef void (*ceph_osdc_unsafe_callback_t)(struct ceph_osd_request *, bool);
 
 #define CEPH_HOMELESS_OSD	-1

net/ceph/osd_client.c

@@ -2048,7 +2048,7 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
 		    result >= 0 && !(flags & CEPH_OSD_FLAG_ONDISK))
 			req->r_unsafe_callback(req, true);
 		if (req->r_callback)
-			req->r_callback(req, msg);
+			req->r_callback(req);
 		else
 			complete_all(&req->r_completion);
 	}
@@ -2072,7 +2072,7 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
 	req->r_result = -EIO;
 	__unregister_request(osdc, req);
 	if (req->r_callback)
-		req->r_callback(req, msg);
+		req->r_callback(req);
 	else
 		complete_all(&req->r_completion);
 	complete_request(req);