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Date:   Tue, 8 Sep 2020 03:45:24 +0000
From:   Wen Gong <wgong@codeaurora.org>
To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     ath10k@lists.infradead.org, linux-wireless@vger.kernel.org
Subject: Re: [PATCH v3] ath10k: add flag to protect napi operation to avoid
 dead loop hang
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 <87d02x1rqb.fsf@codeaurora.org>
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On 2020-09-08 00:22, Kalle Valo wrote:
> Wen Gong <wgong@codeaurora.org> writes:
[...]
> Just like with the recent firmware restart patch, isn't 
> ar->napi_enabled
> racy? Wouldn't test_and_set_bit() and test_and_clear_bit() be safer?
> 
> Or are we holding a lock? But then that should be documented with
> lockdep_assert_held().
yes, ath10k_hif_start is only called from ath10k_core_start, it has 
"lockdep_assert_held(&ar->conf_mutex)",
and ath10k_hif_stop is only called from ath10k_core_stop, it also has 
"lockdep_assert_held(&ar->conf_mutex)".
then it will not 2 thread both enter ath10k_hif_start/ath10k_hif_stop 
meanwhile.