linux-kernel - Re: [PATCH] serdev: Restore serdev_device_write

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Message-ID: <b62674e7-5c50-585b-eade-7cef0a400d02@i2se.com>
Date:   Thu, 4 May 2017 18:22:31 +0200
From:   Stefan Wahren <stefan.wahren@...e.com>
To:     Johan Hovold <johan@...nel.org>, Rob Herring <robh@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Sebastian Reichel <sre@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Andrey Smirnov <andrew.smirnov@...il.com>,
        "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] serdev: Restore serdev_device_write_buf for atomic
 context

Am 02.05.2017 um 15:18 schrieb Johan Hovold:
> On Tue, May 02, 2017 at 07:41:34AM -0500, Rob Herring wrote:
>> On Tue, May 2, 2017 at 4:06 AM, Johan Hovold <johan@...nel.org> wrote:
>>> On Fri, Apr 28, 2017 at 01:47:21PM +0200, Stefan Wahren wrote:
>>>> Starting with commit 6fe729c4bdae ("serdev: Add serdev_device_write
>>>> subroutine") the function serdev_device_write_buf cannot be used in
>>>> atomic context anymore (mutex_lock is sleeping). So restore the old
>>>> behavior.
>>> Yeah, preventing use in atomic context seems unnecessary, although any
>>> clients writing must now deal with serialisation themselves (as before,
>>> and as they should).
>> We could just remove the mutex for serdev_device_write and always make
>> the client responsible for serialization.
> That sounds reasonable.

So it's unwanted to have 2 write functions (non-atomic, atomic)?

Stefan