From: jonathanh@nvidia•com (Jon Hunter)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V5 08/14] PM / Domains: Add function to remove a pm-domain
Date: Wed, 3 Feb 2016 10:51:40 +0000 [thread overview]
Message-ID: <56B1DBBC.5020509@nvidia.com> (raw)
In-Reply-To: <CAPDyKFqJLdoee4a9819XukXTmYyd3pue452K_zbiV6XhfA=fTw@mail.gmail.com>
On 02/02/16 15:35, Ulf Hansson wrote:
> On 28 January 2016 at 17:33, Jon Hunter <jonathanh@nvidia•com> wrote:
>> The genpd framework allows users to add power-domains via the
>> pm_genpd_init() function, however, there is no corresponding function
>> to remove a power-domain. For most devices this may be fine as the power
>> domains are never removed, however, for devices that wish to populate
>> the power-domains from within a driver, having the ability to remove a
>> power domain if the probing of the device fails or the driver is unloaded
>> is necessary. Therefore, add a function to remove a power-domain. Please
>> note that the power domain can only be removed if there are no devices
>> using the power-domain and it is not linked to another domain.
>>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia•com>
>> ---
>> drivers/base/power/domain.c | 26 ++++++++++++++++++++++++++
>> include/linux/pm_domain.h | 5 +++++
>> 2 files changed, 31 insertions(+)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index 45e3641b427d..b4120121bcac 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -1529,6 +1529,32 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
>> }
>> EXPORT_SYMBOL_GPL(pm_genpd_init);
>>
>> +/**
>> + * pm_genpd_remove - Remove a generic I/O PM domain object.
>> + * @genpd: PM domain object to remove.
>> + */
>> +int pm_genpd_remove(struct generic_pm_domain *genpd)
>> +{
>> + if (IS_ERR_OR_NULL(genpd))
>> + return -EINVAL;
>> +
>> + mutex_lock(&genpd->lock);
>
> pm_genpd_summary_show() first locks the gpd_list_lock, then the genpd lock.
>
> Please preserve that order here as well, to prevent potential deadlocks.
Ok, yes good point.
>> +
>> + if (!list_empty(&genpd->master_links)
>> + || !list_empty(&genpd->slave_links) || genpd->device_count) {
>> + mutex_unlock(&genpd->lock);
>> + return -EBUSY;
>> + }
>> +
>> + mutex_lock_nested(&gpd_list_lock, SINGLE_DEPTH_NESTING);
>
> Why the nesting, can this really cause lockdep warnings?
Hmmm, yes I don't believe that is needed here as it should be a
different class. Will fix.
>> + list_del(&genpd->gpd_list_node);
>> + mutex_unlock(&gpd_list_lock);
>> + mutex_unlock(&genpd->lock);
>
> Before returning, you need to make sure there isn't a scheduled work
> for powering off the genpd.
> That might happen for example happen via genpd_poweroff_unused().
>
> Otherwise, the caller of pm_genpd_remove() might free the memory while
> the genpd struct is still in use...
>
> I assume a cancel_delayed_work_sync() should do the trick here.
Good point. I will address that too.
Jon
next prev parent reply other threads:[~2016-02-03 10:51 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-28 16:33 [PATCH V5 00/14] Add generic PM domain support for Tegra Jon Hunter
2016-01-28 16:33 ` [PATCH V5 01/14] soc: tegra: pmc: Restore base address on probe failure Jon Hunter
2016-01-28 16:33 ` [PATCH V5 02/14] soc: tegra: pmc: Protect public functions from potential race conditions Jon Hunter
2016-01-29 16:20 ` Mathieu Poirier
2016-02-01 13:42 ` Jon Hunter
2016-01-28 16:33 ` [PATCH V5 03/14] soc: tegra: pmc: Change powergate and rail IDs to be an unsigned type Jon Hunter
2016-01-28 16:33 ` [PATCH V5 04/14] soc: tegra: pmc: Fix testing of powergate state Jon Hunter
2016-01-28 16:33 ` [PATCH V5 05/14] soc: tegra: pmc: Wait for powergate state to change Jon Hunter
2016-01-29 16:58 ` Mathieu Poirier
2016-02-01 13:44 ` Jon Hunter
2016-02-03 9:20 ` Jon Hunter
2016-02-03 15:58 ` Mathieu Poirier
2016-01-28 16:33 ` [PATCH V5 06/14] soc: tegra: pmc: Fix checking of valid partitions Jon Hunter
2016-01-29 17:08 ` Mathieu Poirier
2016-02-01 13:45 ` Jon Hunter
2016-01-28 16:33 ` [PATCH V5 07/14] soc: tegra: pmc: Ensure partitions can be toggled on/off by PMC Jon Hunter
2016-01-28 16:33 ` [PATCH V5 08/14] PM / Domains: Add function to remove a pm-domain Jon Hunter
2016-02-02 15:35 ` Ulf Hansson
2016-02-03 10:51 ` Jon Hunter [this message]
2016-01-28 16:33 ` [PATCH V5 09/14] Documentation: DT: bindings: Update NVIDIA PMC for Tegra Jon Hunter
2016-01-29 16:08 ` Rob Herring
2016-01-28 16:33 ` [PATCH V5 10/14] Documentation: DT: bindings: Add power domain info for NVIDIA PMC Jon Hunter
2016-01-29 16:06 ` Rob Herring
2016-02-03 11:02 ` Jon Hunter
2016-02-03 15:48 ` Rob Herring
2016-02-10 10:57 ` Jon Hunter
2016-02-10 14:06 ` Rob Herring
2016-01-28 16:33 ` [PATCH V5 11/14] soc: tegra: pmc: Add generic PM domain support Jon Hunter
2016-02-04 15:44 ` Ulf Hansson
2016-02-10 18:01 ` Jon Hunter
2016-02-10 18:25 ` Ulf Hansson
2016-02-11 9:13 ` Jon Hunter
2016-02-11 9:57 ` Ulf Hansson
2016-02-11 10:13 ` Jon Hunter
2016-02-11 10:26 ` Jon Hunter
2016-02-11 10:37 ` Ulf Hansson
2016-02-11 10:52 ` Jon Hunter
2016-02-11 10:28 ` Ulf Hansson
2016-02-11 16:38 ` Jon Hunter
2016-02-18 15:06 ` Ulf Hansson
2016-02-12 23:14 ` Kevin Hilman
2016-02-15 11:27 ` Jon Hunter
2016-02-18 16:00 ` Ulf Hansson
2016-02-18 16:31 ` Jon Hunter
2016-02-24 0:03 ` Kevin Hilman
2016-01-28 16:33 ` [PATCH V5 12/14] clk: tegra210: Add the APB2APE audio clock Jon Hunter
2016-02-02 14:37 ` Thierry Reding
2016-01-28 16:33 ` [PATCH V5 13/14] ARM64: tegra: Add audio PM domain device node for Tegra210 Jon Hunter
2016-01-28 16:33 ` [PATCH V5 14/14] ARM64: tegra: select PM_GENERIC_DOMAINS Jon Hunter
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=56B1DBBC.5020509@nvidia.com \
--to=jonathanh@nvidia$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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