From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Alexander Aring <alex.aring@gmail.com>
Cc: Kevin Hilman <khilman@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>,
Florian Fainelli <f.fainelli@gmail.com>,
Pawel Moll <pawel.moll@arm.com>,
Stephen Warren <swarren@wwwdotorg.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org, Jon Hunter <jonathanh@nvidia.com>,
Eric Anholt <eric@anholt.net>, Rob Herring <robh+dt@kernel.org>,
Lee Jones <lee@kernel.org>, Pavel Machek <pavel@ucw.cz>,
Len Brown <len.brown@intel.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
linux-arm-kernel@lists.infradead.org,
linux-rpi-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/5] power: domain: add pm_genpd_exit
Date: Wed, 9 Dec 2015 10:54:57 +0000 [thread overview]
Message-ID: <20151209105457.GG8644@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20151209104752.GB1036@omega>
On Wed, Dec 09, 2015 at 11:47:58AM +0100, Alexander Aring wrote:
> Example: the error case is while probing, how we react on a -EBUSY there
> "in an error case" -> simple ignore it? But then nobody see that the use
> of this function is wrong.
The proper way to deal with functionality that can only be registered
but never removed is to report the error, but never fail during probing,
and never allow removal (empty removal function.)
If you return a failure code during probe, you end up in an inconsistent
situation where you have facilities registered, but resources that those
facilities require will be undone when probe() returns a failure, and
that can potentially lead to kernel oops or scribbling over someone
elses device or memory.
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/5] power: domain: add pm_genpd_exit
Date: Wed, 9 Dec 2015 10:54:57 +0000 [thread overview]
Message-ID: <20151209105457.GG8644@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20151209104752.GB1036@omega>
On Wed, Dec 09, 2015 at 11:47:58AM +0100, Alexander Aring wrote:
> Example: the error case is while probing, how we react on a -EBUSY there
> "in an error case" -> simple ignore it? But then nobody see that the use
> of this function is wrong.
The proper way to deal with functionality that can only be registered
but never removed is to report the error, but never fail during probing,
and never allow removal (empty removal function.)
If you return a failure code during probe, you end up in an inconsistent
situation where you have facilities registered, but resources that those
facilities require will be undone when probe() returns a failure, and
that can potentially lead to kernel oops or scribbling over someone
elses device or memory.
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-12-09 10:55 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-04 17:45 [PATCH v2 0/5] Raspberry Pi power domains v2 Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` [PATCH v2 1/5] power: domain: add pm_genpd_exit Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-07 10:04 ` Jon Hunter
2015-12-07 10:04 ` Jon Hunter
2015-12-07 10:04 ` Jon Hunter
2015-12-08 18:59 ` Kevin Hilman
2015-12-08 18:59 ` Kevin Hilman
2015-12-08 18:59 ` Kevin Hilman
2015-12-09 10:47 ` Alexander Aring
2015-12-09 10:47 ` Alexander Aring
2015-12-09 10:54 ` Russell King - ARM Linux [this message]
2015-12-09 10:54 ` Russell King - ARM Linux
2015-12-14 9:49 ` Ulf Hansson
2015-12-14 9:49 ` Ulf Hansson
2015-12-14 9:49 ` Ulf Hansson
2015-12-04 17:45 ` [PATCH v2 2/5] ARM: bcm2835: Define two new packets from the latest firmware Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` [PATCH v2 3/5] ARM: bcm2835: add rpi power domain driver Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-07 23:35 ` Kevin Hilman
2015-12-07 23:35 ` Kevin Hilman
2015-12-08 1:04 ` Eric Anholt
2015-12-08 1:04 ` Eric Anholt
2015-12-08 18:19 ` Kevin Hilman
2015-12-08 18:19 ` Kevin Hilman
2015-12-11 18:13 ` Stefan Wahren
2015-12-11 18:13 ` Stefan Wahren
2015-12-11 18:13 ` Stefan Wahren
2015-12-04 17:45 ` [PATCH v2 4/5] dt-bindings: add rpi power domain driver bindings Eric Anholt
2015-12-04 17:45 ` Eric Anholt
2015-12-04 17:45 ` [PATCH v2 5/5] ARM: bcm2835: Add the Raspberry Pi power domain driver to the DT Eric Anholt
2015-12-04 17:45 ` Eric Anholt
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