From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753352AbcIOO4I (ORCPT <rfc822;w@1wt.eu>);
        Thu, 15 Sep 2016 10:56:08 -0400
Received: from mailout3.w1.samsung.com ([210.118.77.13]:17807 "EHLO
        mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751127AbcIOOyl (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 15 Sep 2016 10:54:41 -0400
X-AuditID: cbfec7f1-f79f46d0000008eb-8f-57dab62d06c6
Subject: Re: [PATCH v3] leds: Introduce userspace leds driver
To: Pavel Machek <pavel@ucw.cz>
Cc: David Lechner <david@lechnology.com>,
        Richard Purdie <rpurdie@rpsys.net>, linux-kernel@vger.kernel.org,
        linux-leds@vger.kernel.org, Marcel Holtmann <marcel@holtmann.org>
From: Jacek Anaszewski <j.anaszewski@samsung.com>
Message-id: <5e86399e-65a0-9251-d08e-ab8bfe1f5fbb@samsung.com>
Date: Thu, 15 Sep 2016 16:54:35 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
        Thunderbird/45.2.0
MIME-version: 1.0
In-reply-to: <20160915133558.GA29883@amd>
Content-type: text/plain; charset=windows-1252; format=flowed
Content-transfer-encoding: 7bit
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuphleLIzCtJLcpLzFFi42LZduznOV3dbbfCDV4tFbJY1CBmcXnXHDaL
        rW/WMVp8+/SL0eLuqaNsFrt3PWV1YPNYv3s5u8en/pOsHnvm/2D1WLH6O7vH501yAaxRXDYp
        qTmZZalF+nYJXBnr779nK5jDXrH6VDtLA+MF1i5GTg4JAROJCZMnsUPYYhIX7q1n62Lk4hAS
        WMoosf3rDiYI5zOjxLuGzcxdjBxgHZcvc0LElzFK/Jz5kh3CecYoMeXMQxaQUcICthLrNl5j
        ArFFBOQltvatYAYpYhbYyChx5fQyZpAEm4ChxM8Xr8GKeAXsJBp2ngRrZhFQlZizrAlsm6hA
        hMTuu6kQJYISPybfAyvhFNCU+HJpD5jNLOAo8WDRTlYIW15i85q3YLskBOaxSzR+2MkCcbWs
        xKYDzBBvukhMnPecEcIWlnh1fAvU+zISnR0HmSB6JzNKXDx2kxXCWc0osbGzkwWiylqi4f8v
        qM18EpO2TYcGC69ER5sQRImHRMuKf1DLHCU+tE6EhlAnk8TlGWfYJjDKz0Ly0CwkT8xC8sQC
        RuZVjCKppcW56anFRnrFibnFpXnpesn5uZsYgWnk9L/jH3cwvj9hdYhRgINRiYd3xdxb4UKs
        iWXFlbmHGCU4mJVEeJ9vAArxpiRWVqUW5ccXleakFh9ilOZgURLn3bPgSriQQHpiSWp2ampB
        ahFMlomDU6qBcb9AK0tYqHHAIpuKm7KnXqyeVCj1PvzgcYOGJWvXP34vd2vKrGbu9zGXrv3u
        UzSu/Bv4Y4Pylh2qXnkf7+ybLcbY8IFTMihI+EHW4sM7X7XpuLc9XT2/+cWZP1MX++fmCnps
        ZM6MSWbPz1jqciRFOndz/CfHc8+Xab5NvhawrUJywp2DD+fc81BiKc5INNRiLipOBACdoR3S
        HwMAAA==
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrDIsWRmVeSWpSXmKPExsVy+t/xy7oM226FGyzcqmaxqEHM4vKuOWwW
        W9+sY7T49ukXo8XdU0fZLHbvesrqwOaxfvdydo9P/SdZPfbM/8HqsWL1d3aPz5vkAlij3Gwy
        UhNTUosUUvOS81My89JtlUJD3HQtlBTyEnNTbZUidH1DgpQUyhJzSoE8IwM04OAc4B6spG+X
        4Jax/v57toI57BWrT7WzNDBeYO1i5OCQEDCRuHyZs4uRE8gUk7hwbz1bFyMXh5DAEkaJyYcu
        sUM4zxglNsw/xAxSJSxgK7Fu4zUmEFtEQF5ia98KZoiiTiaJU9e6GEEcZoGNjBKf+9aDdbAJ
        GEr8fPEarINXwE6iYedJFhCbRUBVYs6yJrAaUYEIiVurPjJC1AhK/Jh8D6yGU0BT4sulPWA2
        M9DmBe/XQdnyEpvXvGWewCgwC0nLLCRls5CULWBkXsUoklpanJueW2yoV5yYW1yal66XnJ+7
        iREYU9uO/dy8g/HSxuBDjAIcjEo8vAGzb4ULsSaWFVfmHmKU4GBWEuHdtgUoxJuSWFmVWpQf
        X1Sak1p8iNEU6ImJzFKiyfnAeM8riTc0MTS3NDQytrAwNzJSEuct+XAlXEggPbEkNTs1tSC1
        CKaPiYNTqoGRJ2S9+UO15SI3X/QtPGGQ+vyhRaLS/bcXD+x/k/n5WfxLy/zO6Q/vT0lwaxS+
        OCdPxjns9spN7EU7tvxZ8vrH9AuzpMOX3V6WLOb5TFbkSpDLKQ0b5XTlkMW9HqWTttmvNqvw
        Zdokuejrir1T5L5nPt/dp8167Uu48HSnJV6OQYks176c2Xv8jxJLcUaioRZzUXEiAPylSVe/        AgAA
X-MTR: 20000000000000000@CPGS
X-CMS-MailID: 20160915145436eucas1p2b855bcd9bd41664459120e43b1208202
X-Msg-Generator: CA
X-Sender-IP: 182.198.249.179
X-Local-Sender: =?UTF-8?B?SmFjZWsgQW5hc3pld3NraRtTUlBPTC1TeXN0ZW0gRlcgIChN?=
        =?UTF-8?B?Qikb7IK87ISx7KCE7J6QG1NlbmlvciBTb2Z0d2FyZSBFbmdpbmVlcg==?=
X-Global-Sender: =?UTF-8?B?SmFjZWsgQW5hc3pld3NraRtTUlBPTC1TeXN0ZW0gRlcgIChN?=
        =?UTF-8?B?QikbU2Ftc3VuZyBFbGVjdHJvbmljcxtTZW5pb3IgU29mdHdhcmUgRW5naW5l?=
        =?UTF-8?B?ZXI=?=
X-Sender-Code: =?UTF-8?B?QzEwG0VIURtDMTBDRDAyQ0QwMjc1MjY=?=
CMS-TYPE: 201P
X-HopCount: 7
X-CMS-RootMailID: 20160912081846eucas1p255044e49034685ad44400d6830ef0b95
X-RootMTR: 20160912081846eucas1p255044e49034685ad44400d6830ef0b95
References: <1473439776-15655-1-git-send-email-david@lechnology.com>
 <CGME20160912081846eucas1p255044e49034685ad44400d6830ef0b95@eucas1p2.samsung.com>
 <80597ded-f4b4-2990-3eae-e72276296d1a@samsung.com>
 <20160915130831.GJ13132@amd> <20160915133558.GA29883@amd>
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Pavel,

On 09/15/2016 03:35 PM, Pavel Machek wrote:
> Hi!
>
>>>> +	if (copy_from_user(&udev->user_dev, buffer,
>>>> +			   sizeof(struct uleds_user_dev))) {
>>>> +		ret = -EFAULT;
>>>> +		goto out;
>>>> +	}
>>>> +
>>>> +	if (!udev->user_dev.name[0]) {
>>>> +		ret = -EINVAL;
>>>> +		goto out;
>>>> +	}
>>>> +
>>>> +	ret = led_classdev_register(NULL, &udev->led_cdev);
>>>> +	if (ret < 0)
>>>> +		goto out;
>>
>> No sanity checking on the name -> probably a security hole. Do not
>> push this upstream before this is fixed.
>
> And actually... is it possible to have more then one userspace LED
> with this interface? I do have RGB LED connect on /dev/ttyUSB0, and I
> guess userspace driver would be appropriate, but it needs 3
> channels...

Each new successful write to /dev/uleds creates a new LED class device.

See Documentation/leds/uleds.txt.

-- 
Best regards,
Jacek Anaszewski