From: Armin Wolf <W_Armin@gmx.de>
To: "Guenter Roeck" <linux@roeck-us.net>, "Pali Rohár" <pali@kernel.org>
Cc: jdelvare@suse.com, linux-hwmon@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] hwmon: (dell-smm) Unify i8k_ioctl() and i8k_ioctl_unlocked()
Date: Mon, 22 Nov 2021 19:50:14 +0100 [thread overview]
Message-ID: <e336f501-fe07-7b49-bc65-d6ca443491ca@gmx.de> (raw)
In-Reply-To: <c23caeab-dd27-4c95-2e25-9eb0ff7b33f6@roeck-us.net>
Am 22.11.21 um 18:55 schrieb Guenter Roeck:
> On 11/22/21 8:01 AM, Pali Rohár wrote:
>> On Saturday 20 November 2021 18:03:19 Armin Wolf wrote:
>>> The only purpose of i8k_ioctl() is to call i8k_ioctl_unlocked()
>>> with i8k_mutex held. Judging from the hwmon code, this mutex
>>> only needs to be held when setting the fan speed/mode.
>>
>> Really? I think that there is no difference between setting and getting
>> fan speed/mode. At least I do not see why 'set' needs mutex and 'get' do
>> not need it. Some more explanation is needed...
>>
> I8K_SET_FAN sets the fan speed and returns the current status. Without
> locking, the returned status may not match or be associated with the
> previous
> set operation.
>
> Maybe that doesn't matter, and the synchronization is not needed. If so,
> you can probably remove the locking entirely.
>
> Guenter
That is the reason i kept the locking code. Since i do not want to break
the ioctl interfacein any way, removing the locking code seems too risky
to me.
Armin
next prev parent reply other threads:[~2021-11-22 18:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 17:03 [PATCH 0/2] hwmon: (dell-smm) Improve ioctl handler Armin Wolf
2021-11-20 17:03 ` [PATCH 1/2] hwmon: (dell-smm) Simplify " Armin Wolf
2021-11-23 16:13 ` Pali Rohár
2021-11-29 20:57 ` Armin Wolf
2021-12-09 16:52 ` Pali Rohár
2021-11-20 17:03 ` [PATCH 2/2] hwmon: (dell-smm) Unify i8k_ioctl() and i8k_ioctl_unlocked() Armin Wolf
2021-11-22 16:01 ` Pali Rohár
2021-11-22 17:55 ` Guenter Roeck
2021-11-22 18:50 ` Armin Wolf [this message]
2021-11-22 19:10 ` Pali Rohár
2021-11-22 19:28 ` Guenter Roeck
2021-11-22 19:43 ` Pali Rohár
2021-11-23 16:00 ` Guenter Roeck
2021-11-23 16:02 ` Pali Rohár
2021-11-23 16:04 ` Pali Rohár
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