netdev - Re: [PATCH] netxen: Fix a sleep-in-atomic bug in netxen_nic_pci_mem_access

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Message-ID: <594A131F.9040300@163.com>
Date:   Wed, 21 Jun 2017 14:33:03 +0800
From:   Jia-Ju Bai <baijiaju1990@....com>
To:     Kalle Valo <kvalo@...eaurora.org>
CC:     David Miller <davem@...emloft.net>, manish.chopra@...ium.com,
        rahul.verma@...ium.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] netxen: Fix a sleep-in-atomic bug in netxen_nic_pci_mem_access_direct

On 06/21/2017 02:11 PM, Kalle Valo wrote:
> David Miller<davem@...emloft.net>  writes:
>
>> From: Jia-Ju Bai<baijiaju1990@....com>
>> Date: Mon, 19 Jun 2017 10:48:53 +0800
>>
>>> The driver may sleep under a spin lock, and the function call path is:
>>> netxen_nic_pci_mem_access_direct (acquire the lock by spin_lock)
>>>    ioremap -->  may sleep
>>>
>>> To fix it, the lock is released before "ioremap", and the lock is
>>> acquired again after this function.
>>>
>>> Signed-off-by: Jia-Ju Bai<baijiaju1990@....com>
>> This style of change you are making is really starting to be a
>> problem.
>>
>> You can't just drop locks like this, especially without explaining
>> why it's ok, and why the mutual exclusion this code was trying to
>> achieve is still going to be OK afterwards.
>>
>> In fact, I see zero analysis of the locking situation here, why
>> it was needed in the first place, and why your change is OK in
>> that context.
>>
>> Any locking change is delicate, and you must put the greatest of
>> care and consideration into it.
>>
>> Just putting "unlock/lock" around the sleeping operation shows a
>> very low level of consideration for the implications of the change
>> you are making.
>>
>> This isn't like making whitespace fixes, sorry...
> We already tried to explain this to Jia-Ju during review of a wireless
> patch:
>
> https://patchwork.kernel.org/patch/9756585/
>
> Jia-Ju, you should listen to feedback. If you continue submitting random
> patches like this makes it hard for maintainers to trust your patches
> anymore.
>
Hi,

I am quite sorry for my incorrect patches, and I will listen carefully 
to your advice.
In fact, for some bugs and patches which I have reported before, I have 
not received the feedback of them, so I resent them a few days ago, 
including this patch.
Sorry for my mistake again.

Thanks,
Jia-Ju Bai