rbd: combine rbd sync watch/unwatch functions

The rbd_req_sync_watch() and rbd_req_sync_unwatch() functions are
nearly identical.  Combine them into a single function with a flag
indicating whether a watch is to be initiated or torn down.

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

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index d2a6e95..9d21fcd 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1429,74 +1429,48 @@ static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
 }
 
 /*
- * Request sync osd watch
+ * Request sync osd watch/unwatch.  The value of "start" determines
+ * whether a watch request is being initiated or torn down.
  */
-static int rbd_req_sync_watch(struct rbd_device *rbd_dev)
+static int rbd_req_sync_watch(struct rbd_device *rbd_dev, int start)
 {
        struct ceph_osd_req_op *op;
-       struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+       struct ceph_osd_request **linger_req = NULL;
+       __le64 version = 0;
        int ret;
 
        op = rbd_create_rw_op(CEPH_OSD_OP_WATCH, 0);
        if (!op)
                return -ENOMEM;
 
-       ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0,
-                                    (void *)rbd_dev, &rbd_dev->watch_event);
-       if (ret < 0)
-               goto fail;
-
-       op->watch.ver = cpu_to_le64(rbd_dev->header.obj_version);
-       op->watch.cookie = cpu_to_le64(rbd_dev->watch_event->cookie);
-       op->watch.flag = 1;
-
-       ret = rbd_req_sync_op(rbd_dev,
-                             CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
-                             op,
-                             rbd_dev->header_name,
-                             0, 0, NULL,
-                             &rbd_dev->watch_request, NULL);
-
-       if (ret < 0)
-               goto fail_event;
-
-       rbd_destroy_op(op);
-       return 0;
-
-fail_event:
-       ceph_osdc_cancel_event(rbd_dev->watch_event);
-       rbd_dev->watch_event = NULL;
-fail:
-       rbd_destroy_op(op);
-       return ret;
-}
-
-/*
- * Request sync osd unwatch
- */
-static int rbd_req_sync_unwatch(struct rbd_device *rbd_dev)
-{
-       struct ceph_osd_req_op *op;
-       int ret;
+       if (start) {
+               struct ceph_osd_client *osdc;
 
-       op = rbd_create_rw_op(CEPH_OSD_OP_WATCH, 0);
-       if (!op)
-               return -ENOMEM;
+               osdc = &rbd_dev->rbd_client->client->osdc;
+               ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0, rbd_dev,
+                                               &rbd_dev->watch_event);
+               if (ret < 0)
+                       goto done;
+               version = cpu_to_le64(rbd_dev->header.obj_version);
+               linger_req = &rbd_dev->watch_request;
+       }
 
-       op->watch.ver = 0;
+       op->watch.ver = version;
        op->watch.cookie = cpu_to_le64(rbd_dev->watch_event->cookie);
-       op->watch.flag = 0;
+       op->watch.flag = (u8) start ? 1 : 0;
 
        ret = rbd_req_sync_op(rbd_dev,
                              CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
-                             op,
-                             rbd_dev->header_name,
-                             0, 0, NULL, NULL, NULL);
-
+                             op, rbd_dev->header_name,
+                             0, 0, NULL, linger_req, NULL);
 
+       if (!start || ret < 0) {
+               ceph_osdc_cancel_event(rbd_dev->watch_event);
+               rbd_dev->watch_event = NULL;
+       }
+done:
        rbd_destroy_op(op);
-       ceph_osdc_cancel_event(rbd_dev->watch_event);
-       rbd_dev->watch_event = NULL;
+
        return ret;
 }
 
@@ -3033,7 +3007,7 @@ static int rbd_init_watch_dev(struct rbd_device *rbd_dev)
        int ret, rc;
 
        do {
-               ret = rbd_req_sync_watch(rbd_dev);
+               ret = rbd_req_sync_watch(rbd_dev, 1);
                if (ret == -ERANGE) {
                        rc = rbd_dev_refresh(rbd_dev, NULL);
                        if (rc < 0)
@@ -3752,8 +3726,7 @@ static void rbd_dev_release(struct device *dev)
                                                    rbd_dev->watch_request);
        }
        if (rbd_dev->watch_event)
-               rbd_req_sync_unwatch(rbd_dev);
-
+               rbd_req_sync_watch(rbd_dev, 0);
 
        /* clean up and free blkdev */
        rbd_free_disk(rbd_dev);