Re: [PATCH] qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()

On Tue, 20 Jul 2021 02:02:26 +0000, Justin He wrote:

quoted

quoted

For instance:
_qed_mcp_cmd_and_union()
  In while loop
    spin_lock_bh()
    qed_mcp_has_pending_cmd() (assume false), will break the loop  

I agree till here.
  

quoted

  if (cnt >= max_retries) {
...
    return -EAGAIN; <-- here returns -EAGAIN without invoking bh unlock
  }
 

Because of break, cnt has not been increased.
   - cnt is still less than max_retries.
  - if (cnt >= max_retries) will not be *true*, leading to spin_unlock_bh().
Hence pairing completed.  

Sorry, indeed. Let me check other possibilities.
@David S. Miller Sorry for the inconvenience, could you please revert it
in netdev tree?

Please submit a revert patch with the conclusions from the discussion
included in the commit message.