From: Stephen Boyd <sboyd@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH 06/12] PM / OPP: Add 'struct kref' to struct dev_pm_opp
Date: Thu, 19 Jan 2017 12:01:00 -0800 [thread overview]
Message-ID: <20170119200100.GB7829@codeaurora.org> (raw)
In-Reply-To: <20170113085639.GE9953@vireshk-i7>
On 01/13, Viresh Kumar wrote:
> On 13-01-17, 00:52, Stephen Boyd wrote:
> > What still doesn't make sense is how an individual OPP could go
> > away without the table that the OPP lives in also going away.
>
> dev_pm_opp_remove() is one such option, which can remove OPPs
> individually. Over that, while remove tables we remove all the OPPs
> one by one. So that really does happen.
>
> > If
> > an OPP is going away while a driver has a reference to it, then
> > the driver using that OPP should probably not be using it.
>
> That is being protected with this patch now and the drivers can use
> them freely.
>
> > TL;DR
> > letting drivers use OPP pointers outside of the OPP core feels
> > racy.
>
> Hmm, we don't update the OPP a lot after creating it today. But that's
> a different problem to solve, if we really see a race there.
>
Ok. We still have work to do to fix the race between drivers
using dev_pm_opp pointers and other drivers updating the data
those pointers point to like voltage, enable/disable, etc. This
isn't making anything worse than it already is though, so:
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2017-01-19 20:10 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 10:37 [PATCH 00/12] PM / OPP: Use kref and move away from RCU locking Viresh Kumar
2016-12-07 10:37 ` [PATCH 01/12] PM / OPP: Add per OPP table mutex Viresh Kumar
2017-01-09 23:11 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 02/12] PM / OPP: Add 'struct kref' to OPP table Viresh Kumar
2017-01-09 23:36 ` Stephen Boyd
2017-01-10 4:23 ` Viresh Kumar
2017-01-13 8:54 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 03/12] PM / OPP: Return opp_table from dev_pm_opp_set_*() routines Viresh Kumar
2017-01-09 23:37 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 04/12] PM / OPP: Take reference of the OPP table while adding/removing OPPs Viresh Kumar
2017-01-09 23:38 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 05/12] PM / OPP: Use dev_pm_opp_get_opp_table() instead of _add_opp_table() Viresh Kumar
2017-01-09 23:43 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 06/12] PM / OPP: Add 'struct kref' to struct dev_pm_opp Viresh Kumar
2017-01-09 23:44 ` Stephen Boyd
2017-01-10 4:26 ` Viresh Kumar
2017-01-13 8:52 ` Stephen Boyd
2017-01-13 8:56 ` Viresh Kumar
2017-01-19 20:01 ` Stephen Boyd [this message]
2016-12-07 10:37 ` [PATCH 07/12] PM / OPP: Update OPP users to put reference Viresh Kumar
2016-12-07 13:23 ` Chanwoo Choi
2016-12-08 4:00 ` Viresh Kumar
2017-01-21 7:42 ` Chanwoo Choi
2016-12-07 10:37 ` [PATCH 08/12] PM / OPP: Take kref from _find_opp_table() Viresh Kumar
2017-01-09 23:49 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 09/12] PM / OPP: Move away from RCU locking Viresh Kumar
2017-01-09 23:57 ` Stephen Boyd
2017-01-10 4:28 ` Viresh Kumar
2016-12-07 10:37 ` [PATCH 10/12] PM / OPP: Simplify _opp_set_availability() Viresh Kumar
2017-01-10 0:00 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 11/12] PM / OPP: Simplify dev_pm_opp_get_max_volt_latency() Viresh Kumar
2017-01-09 22:40 ` Stephen Boyd
2016-12-07 10:37 ` [PATCH 12/12] PM / OPP: Update Documentation to remove RCU specific bits Viresh Kumar
2017-01-09 22:39 ` Stephen Boyd
2017-01-10 4:39 ` Viresh Kumar
2017-01-13 8:44 ` Stephen Boyd
2016-12-07 23:14 ` [PATCH 00/12] PM / OPP: Use kref and move away from RCU locking Rafael J. Wysocki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170119200100.GB7829@codeaurora.org \
--to=sboyd@codeaurora.org \
--cc=linaro-kernel@lists.linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=nm@ti.com \
--cc=rjw@rjwysocki.net \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
--cc=vireshk@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).