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Date:   Mon, 14 Aug 2023 11:18:06 +0200 (CEST)
From:   Jiri Kosina <jikos@kernel.org>
To:     Nikita Zhandarovich <n.zhandarovich@fintech.ru>
cc:     =?ISO-8859-15?Q?Filipe_La=EDns?= <lains@riseup.net>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org
Subject: Re: [PATCH] HID: logitech-dj: Fix error handling in
 logi_dj_recv_switch_to_dj_mode()
In-Reply-To: <20230613101635.77820-1-n.zhandarovich@fintech.ru>
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References: <20230613101635.77820-1-n.zhandarovich@fintech.ru>
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On Tue, 13 Jun 2023, Nikita Zhandarovich wrote:

> Presently, if a call to logi_dj_recv_send_report() fails, we do
> not learn about the error until after sending short
> HID_OUTPUT_REPORT with hid_hw_raw_request().
> To handle this somewhat unlikely issue, return on error in
> logi_dj_recv_send_report() (minding ugly sleep workaround) and
> take into account the result of hid_hw_raw_request().
> 
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
> 
> Fixes: 6a9ddc897883 ("HID: logitech-dj: enable notifications on connect/disconnect")
> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
> ---
>  drivers/hid/hid-logitech-dj.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
> index 62180414efcc..e6a8b6d8eab7 100644
> --- a/drivers/hid/hid-logitech-dj.c
> +++ b/drivers/hid/hid-logitech-dj.c
> @@ -1285,6 +1285,9 @@ static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
>  		 * 50 msec should gives enough time to the receiver to be ready.
>  		 */
>  		msleep(50);
> +
> +		if (retval)
> +			return retval;
>  	}
>  
>  	/*
> @@ -1306,7 +1309,7 @@ static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
>  	buf[5] = 0x09;
>  	buf[6] = 0x00;
>  
> -	hid_hw_raw_request(hdev, REPORT_ID_HIDPP_SHORT, buf,
> +	retval = hid_hw_raw_request(hdev, REPORT_ID_HIDPP_SHORT, buf,
>  			HIDPP_REPORT_SHORT_LENGTH, HID_OUTPUT_REPORT,
>  			HID_REQ_SET_REPORT);

Looks good to me. Benjamin, could you please Ack/apply it?

Thanks,

-- 
Jiri Kosina
SUSE Labs