From: Wen Gong <wgong@codeaurora.org>
To: Krishna Chaitanya <chaitanya.mgit@gmail.com>
Cc: Kalle Valo <kvalo@codeaurora.org>,
linux-wireless <linux-wireless@vger.kernel.org>,
ath10k <ath10k@lists.infradead.org>
Subject: Re: [RFC] ath10k: change to do napi_enable and napi_disable when insmod and rmmod for sdio
Date: Thu, 20 Aug 2020 18:20:46 +0800 [thread overview]
Message-ID: <17857699628b4627ac3c781d9a20c0d8@codeaurora.org> (raw)
In-Reply-To: <CABPxzYJLvrZKFeun0PmvE5NbXfke3orJnaXEY3e17xeBYkSqnw@mail.gmail.com>
On 2020-08-20 17:26, Krishna Chaitanya wrote:
> On Thu, Aug 20, 2020 at 2:49 PM Krishna Chaitanya
> <chaitanya.mgit@gmail.com> wrote:
>>
>> On Thu, Aug 20, 2020 at 2:03 PM Kalle Valo <kvalo@codeaurora.org>
>> wrote:
>> >
>> > Wen Gong <wgong@codeaurora.org> writes:
>> >
...
>> > I'm not really convinced that this is the right fix, but I'm no NAPI
>> > expert. Can anyone else help?
>> Calling napi_disable() twice can lead to hangs, but moving NAPI from
>> start/stop to
>> the probe isn't the right approach as the datapath is tied to
>> start/stop.
>>
>> Maybe check the state of NAPI before disable?
>>
>> if (test_bit(NAPI_STATE_SCHED, &ar->napi.napi.state))
>> napi_disable(&ar->napi)
>>
>> or maintain napi_state like this
>> https://patchwork.kernel.org/patch/10249365/
>>
>> Also, the most common cause for such issues (1st
>> napi_synchronize/napi_disable hang)
>> is that napi_poll is being scheduled, so, you might want to check that
>> napi_schedule isn't
>> called after stop.
>>
>> cd ath10k; git log --grep=napi shows plenty of such issues. the one
>> that matches closest is
>> c2cac2f74ab4bcf0db0dcf3a612f1e5b52d145c8, so, it could just be a
>> regression.
> Also, I see that napi_schedule() is being called from work_queue
> async_work_rx
> so we should cancel that work in hif_stop before calling
> napi_synchronize.
Yes, I will do that in a new patch.
next prev parent reply other threads:[~2020-08-20 10:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 3:55 [RFC] ath10k: change to do napi_enable and napi_disable when insmod and rmmod for sdio Wen Gong
2020-08-20 8:32 ` Kalle Valo
2020-08-20 9:19 ` Krishna Chaitanya
2020-08-20 9:26 ` Krishna Chaitanya
2020-08-20 10:20 ` Wen Gong [this message]
2020-08-20 10:14 ` Wen Gong
2020-08-20 10:52 ` Krishna Chaitanya
2020-08-20 14:37 ` Wen Gong
2020-08-20 16:08 ` Krishna Chaitanya
2020-08-20 16:32 ` Ben Greear
2020-08-20 17:00 ` Krishna Chaitanya
2020-08-20 17:07 ` Ben Greear
2020-08-20 17:41 ` Krishna Chaitanya
2020-08-20 17:42 ` Krishna Chaitanya
2020-08-20 17:53 ` Ben Greear
2020-08-20 20:15 ` Krishna Chaitanya
2020-08-20 20:59 ` Ben Greear
2020-08-21 2:45 ` Wen Gong
2020-08-24 4:35 ` Wen Gong
2020-09-07 16:07 ` Kalle Valo
2020-09-07 17:18 ` Ben Greear
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