linux-kernel - Re: [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in stir421x_fw

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Message-ID: <ecf21a6e-0e99-55dc-54be-3bd633bedbc5@gmail.com>
Date:   Wed, 11 Apr 2018 16:11:00 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     devel@...verdev.osuosl.org, samuel@...tiz.org,
        netdev@...r.kernel.org, johan@...nel.org,
        linux-kernel@...r.kernel.org, arvind.yadav.cs@...il.com,
        davem@...emloft.net
Subject: Re: [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in
 stir421x_fw_upload



On 2018/4/11 16:03, Greg KH wrote:
> On Wed, Apr 11, 2018 at 03:17:10PM +0800, Jia-Ju Bai wrote:
>>
>> On 2018/4/11 14:41, Greg KH wrote:
>>> On Wed, Apr 11, 2018 at 09:29:34AM +0800, Jia-Ju Bai wrote:
>>>> stir421x_fw_upload() is never called in atomic context.
>>>>
>>>> The call chain ending up at stir421x_fw_upload() is:
>>>> [1] stir421x_fw_upload() <- stir421x_patch_device() <- irda_usb_probe()
>>>>
>>>> irda_usb_probe() is set as ".probe" in struct usb_driver.
>>>> This function is not called in atomic context.
>>>>
>>>> Despite never getting called from atomic context, stir421x_fw_upload()
>>>> calls mdelay() to busily wait.
>>>> This is not necessary and can be replaced with usleep_range() to
>>>> avoid busy waiting.
>>>>
>>>> This is found by a static analysis tool named DCNS written by myself.
>>>> And I also manually check it.
>>>>
>>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
>>>> ---
>>>>    drivers/staging/irda/drivers/irda-usb.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>> Please, at the very least, work off of Linus's tree.  There is no
>>> drivers/staging/irda/ anymore :)
>>>
>> Okay, sorry.
>> Could you please recommend me a right tree or its git address?
> Have you looked in the MAINTAINERS file?  Worst case, always use
> linux-next.
>
> greg k-h

Oh, sorry, I did notice the git tree in the MAINTAINERS file.
I always used linux-stable.
Thanks for telling me this :)


Best wishes,
Jia-Ju Bai