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From: Johan Hovold <johan@kernel.org>
To: Jia-Ju Bai <baijiaju1990@gmail.com>
Cc: devel@driverdev.osuosl.org, samuel@sortiz.org,
	gregkh@linuxfoundation.org, johan@kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	arvind.yadav.cs@gmail.com, davem@davemloft.net
Subject: Re: [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in stir421x_fw_upload
Date: Wed, 11 Apr 2018 09:07:42 +0200	[thread overview]
Message-ID: <20180411070742.GE10795@localhost> (raw)
In-Reply-To: <1523410174-1553-1-git-send-email-baijiaju1990@gmail.com>

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@gmail.com>

This all looks good (also note the call to usb_control_msg(), which may
sleep, just above the mdelay()).

Reviewed-by: Johan Hovold <johan@kernel.org>

Thanks,
Johan
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      parent reply	other threads:[~2018-04-11  7:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-11  1:29 [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in stir421x_fw_upload Jia-Ju Bai
2018-04-11  6:41 ` Greg KH
2018-04-11  7:17   ` Jia-Ju Bai
2018-04-11  8:03     ` Greg KH
2018-04-11  8:11       ` Jia-Ju Bai
2018-04-11  8:17         ` Greg KH
2018-04-11  8:20           ` Jia-Ju Bai
2018-04-11 14:26             ` David Miller
2018-04-11 14:30               ` Jia-Ju Bai
2018-04-11  7:07 ` Johan Hovold [this message]

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