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From: "Sven Peter" <sven@svenpeter.dev>
To: "Rouven Czerwinski" <r.czerwinski@pengutronix.de>,
	"Will Deacon" <will@kernel.org>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Rob Herring" <robh+dt@kernel.org>
Cc: "Arnd Bergmann" <arnd@kernel.org>,
	devicetree@vger.kernel.org, "Hector Martin" <marcan@marcan.st>,
	linux-kernel@vger.kernel.org, "Marc Zyngier" <maz@kernel.org>,
	"Mohamed Mediouni" <mohamed.mediouni@caramail.com>,
	"Stan Skowronek" <stan@corellium.com>,
	linux-arm-kernel@lists.infradead.org,
	"Mark Kettenis" <mark.kettenis@xs4all.nl>,
	"Petr Mladek via iommu" <iommu@lists.linux-foundation.org>,
	"Alexander Graf" <graf@amazon.com>
Subject: Re: [PATCH v3 3/3] iommu: dart: Add DART iommu driver
Date: Sat, 05 Jun 2021 14:28:27 +0200	[thread overview]
Message-ID: <89b391d1-c076-491a-97c0-d08593c006e7@www.fastmail.com> (raw)
In-Reply-To: <d50ad9392f7719c01f752e73a00d4dc83b1a5c5c.camel@pengutronix.de>

Hi Rouven,

On Sat, Jun 5, 2021, at 13:50, Rouven Czerwinski wrote:
> Hi Sven,
> 
> just a small comment, see inline.
> 
> On Thu, 2021-06-03 at 10:50 +0200, Sven Peter wrote:
> > +
> > +/* must be called with held dart_domain->lock */
> 
> You can remove this comment, include lockdep.h and…
> 
> > +static int apple_dart_finalize_domain(struct iommu_domain *domain)
> > +{
> > +	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
> > +	struct apple_dart *dart = dart_domain->dart;
> > +	struct io_pgtable_cfg pgtbl_cfg;
> > +
> 
> 	lockdep_assert_held(&dart_domain->lock);
> 
> A lockdep enabled kernel will warn if this function is called without
> the lock held, otherwise this gets optimized out. Same for the similar
> comments below.
> 

That looks very useful, thanks! Will use it for v4.

I only found assert_spin_locked originally but didn't want to have that
performance overhead for code that (I hope :-)) correctly uses these functions
with a held lock right now.


Thanks,


Sven


WARNING: multiple messages have this Message-ID (diff)
From: Sven Peter via iommu <iommu@lists.linux-foundation.org>
To: "Rouven Czerwinski" <r.czerwinski@pengutronix.de>,
	"Will Deacon" <will@kernel.org>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Rob Herring" <robh+dt@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>,
	devicetree@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	Hector Martin <marcan@marcan.st>,
	linux-kernel@vger.kernel.org,
	Petr Mladek via iommu <iommu@lists.linux-foundation.org>,
	Alexander Graf <graf@amazon.com>,
	Mohamed Mediouni <mohamed.mediouni@caramail.com>,
	Mark Kettenis <mark.kettenis@xs4all.nl>,
	linux-arm-kernel@lists.infradead.org,
	Stan Skowronek <stan@corellium.com>
Subject: Re: [PATCH v3 3/3] iommu: dart: Add DART iommu driver
Date: Sat, 05 Jun 2021 14:28:27 +0200	[thread overview]
Message-ID: <89b391d1-c076-491a-97c0-d08593c006e7@www.fastmail.com> (raw)
In-Reply-To: <d50ad9392f7719c01f752e73a00d4dc83b1a5c5c.camel@pengutronix.de>

Hi Rouven,

On Sat, Jun 5, 2021, at 13:50, Rouven Czerwinski wrote:
> Hi Sven,
> 
> just a small comment, see inline.
> 
> On Thu, 2021-06-03 at 10:50 +0200, Sven Peter wrote:
> > +
> > +/* must be called with held dart_domain->lock */
> 
> You can remove this comment, include lockdep.h and…
> 
> > +static int apple_dart_finalize_domain(struct iommu_domain *domain)
> > +{
> > +	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
> > +	struct apple_dart *dart = dart_domain->dart;
> > +	struct io_pgtable_cfg pgtbl_cfg;
> > +
> 
> 	lockdep_assert_held(&dart_domain->lock);
> 
> A lockdep enabled kernel will warn if this function is called without
> the lock held, otherwise this gets optimized out. Same for the similar
> comments below.
> 

That looks very useful, thanks! Will use it for v4.

I only found assert_spin_locked originally but didn't want to have that
performance overhead for code that (I hope :-)) correctly uses these functions
with a held lock right now.


Thanks,


Sven

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: "Sven Peter" <sven@svenpeter.dev>
To: "Rouven Czerwinski" <r.czerwinski@pengutronix.de>,
	"Will Deacon" <will@kernel.org>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Rob Herring" <robh+dt@kernel.org>
Cc: "Arnd Bergmann" <arnd@kernel.org>,
	devicetree@vger.kernel.org, "Hector Martin" <marcan@marcan.st>,
	linux-kernel@vger.kernel.org, "Marc Zyngier" <maz@kernel.org>,
	"Mohamed Mediouni" <mohamed.mediouni@caramail.com>,
	"Stan Skowronek" <stan@corellium.com>,
	linux-arm-kernel@lists.infradead.org,
	"Mark Kettenis" <mark.kettenis@xs4all.nl>,
	"Petr Mladek via iommu" <iommu@lists.linux-foundation.org>,
	"Alexander Graf" <graf@amazon.com>
Subject: Re: [PATCH v3 3/3] iommu: dart: Add DART iommu driver
Date: Sat, 05 Jun 2021 14:28:27 +0200	[thread overview]
Message-ID: <89b391d1-c076-491a-97c0-d08593c006e7@www.fastmail.com> (raw)
In-Reply-To: <d50ad9392f7719c01f752e73a00d4dc83b1a5c5c.camel@pengutronix.de>

Hi Rouven,

On Sat, Jun 5, 2021, at 13:50, Rouven Czerwinski wrote:
> Hi Sven,
> 
> just a small comment, see inline.
> 
> On Thu, 2021-06-03 at 10:50 +0200, Sven Peter wrote:
> > +
> > +/* must be called with held dart_domain->lock */
> 
> You can remove this comment, include lockdep.h and…
> 
> > +static int apple_dart_finalize_domain(struct iommu_domain *domain)
> > +{
> > +	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
> > +	struct apple_dart *dart = dart_domain->dart;
> > +	struct io_pgtable_cfg pgtbl_cfg;
> > +
> 
> 	lockdep_assert_held(&dart_domain->lock);
> 
> A lockdep enabled kernel will warn if this function is called without
> the lock held, otherwise this gets optimized out. Same for the similar
> comments below.
> 

That looks very useful, thanks! Will use it for v4.

I only found assert_spin_locked originally but didn't want to have that
performance overhead for code that (I hope :-)) correctly uses these functions
with a held lock right now.


Thanks,


Sven


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-06-05 12:29 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-03  8:50 [PATCH v3 0/3] Apple M1 DART IOMMU driver Sven Peter
2021-06-03  8:50 ` Sven Peter
2021-06-03  8:50 ` Sven Peter via iommu
2021-06-03  8:50 ` [PATCH v3 1/3] iommu: io-pgtable: add DART pagetable format Sven Peter
2021-06-03  8:50   ` Sven Peter
2021-06-03  8:50   ` Sven Peter via iommu
2021-06-03  8:50 ` [PATCH v3 2/3] dt-bindings: iommu: add DART iommu bindings Sven Peter
2021-06-03  8:50   ` Sven Peter
2021-06-03  8:50   ` Sven Peter via iommu
2021-06-10 16:52   ` Rob Herring
2021-06-10 16:52     ` Rob Herring
2021-06-10 16:52     ` Rob Herring
2021-06-12 12:24     ` Sven Peter
2021-06-12 12:24       ` Sven Peter
2021-06-12 12:24       ` Sven Peter via iommu
2021-06-03  8:50 ` [PATCH v3 3/3] iommu: dart: Add DART iommu driver Sven Peter
2021-06-03  8:50   ` Sven Peter
2021-06-03  8:50   ` Sven Peter via iommu
2021-06-05 11:50   ` Rouven Czerwinski
2021-06-05 11:50     ` Rouven Czerwinski
2021-06-05 11:50     ` Rouven Czerwinski
2021-06-05 12:28     ` Sven Peter [this message]
2021-06-05 12:28       ` Sven Peter
2021-06-05 12:28       ` Sven Peter via iommu

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