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>

1 files changed, 27 insertions, 54 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index d2a6e9589fab..9d21fcd7e188 100644
--- 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);