Merge pull request #64351 from ifed01/wip-ifed-discard-threads-better-lifecycle

blk/kernel: improve DiscardThread life cycle.

Reviewed-by: Yite Gu <guyite@bytedance.com>

diff --cc src/blk/kernel/KernelDevice.cc
Simple merge

diff --cc src/blk/kernel/KernelDevice.h
index 149b8b4aa4130e08ebdccc4d77adbdddd5ea0850,f10458b4aff7717e39963bf0516a819aabda96ec..b444b645bc34f5ba69d97e9c4376df3a25ac68d3
--- 1/src/blk/kernel/KernelDevice.h
--- 2/src/blk/kernel/KernelDevice.h
+++ b/src/blk/kernel/KernelDevice.h
@@@ -94,11 -94,9 +94,11 @@@ private
    virtual void  _pre_close() { }  // hook for child implementations
  
    void _aio_thread();
-   void _discard_thread(uint64_t tid);
+   void _discard_thread(DiscardThread* thr);
    bool _queue_discard(interval_set<uint64_t> &to_release);
 -  bool try_discard(interval_set<uint64_t> &to_release, bool async = true) override;
 +  bool try_discard(interval_set<uint64_t> &to_release,
 +                   bool async = true,
 +                   bool force = false) override;
  
    int _aio_start();
    void _aio_stop();