libublk: ctrl: improve document & comment

Signed-off-by: Ming Lei <[email protected]>

src/ctrl.rs

@@ -19,6 +19,8 @@ const CTRL_PATH: &str = "/dev/ublk-control";
 
 const MAX_BUF_SZ: u32 = 32_u32 << 20;
 
+// per-thread control uring
+//
 std::thread_local! {
     pub(crate) static CTRL_URING: RefCell<IoUring::<squeue::Entry128>> =
         RefCell::new(IoUring::<squeue::Entry128>::builder()
@@ -1408,13 +1410,14 @@ impl UblkCtrl {
     }
 
     /// Run ublk daemon and kick off the ublk device, and `/dev/ublkbN` will be
-    /// created and visible to userspace.
+    /// created and exposed to userspace.
     ///
     /// # Arguments:
     ///
     /// * `tgt_fn`: target initialization handler
-    /// * `q_fn`: queue handler for setting up the queue and its handler
-    /// * `device_fn`: handler called after device is started, run in current
+    /// * `q_fn`: queue handler for setting up the queue and its handler,
+    ///     all IO logical is implemented in queue handler
+    /// * `device_fn`: called after device is started, run in current
     ///     context
     ///
     /// This one is the preferred interface for creating ublk daemon, and

src/uring_async.rs

@@ -109,10 +109,7 @@ fn ublk_process_queue_io(
     nr_waits: usize,
 ) -> Result<i32, UblkError> {
     let res = q.flush_and_wake_io_tasks(|data, cqe, _| ublk_wake_task(data, cqe), nr_waits);
-
-    if res.is_ok() {
-        while exe.try_tick() {}
-    }
+    while exe.try_tick() {}
 
     res
 }