* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
@ 2019-01-14 16:38 ` Robin Murphy
0 siblings, 0 replies; 14+ messages in thread
From: Robin Murphy @ 2019-01-14 16:38 UTC (permalink / raw)
To: Thierry Reding, Marek Szyprowski
Cc: Bartlomiej Zolnierkiewicz, Russell King, linux-kernel,
Tobias Jakobi, iommu, Ben Skeggs, Christoph Hellwig,
linux-arm-kernel
On 14/01/2019 16:09, Thierry Reding wrote:
> On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
>> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>>
>> That patch broke IOMMU support for devices, which fails to probe for the
>> first time and use deferred probe approach. When non-NULL dma_ops is set
>> in arm_iommu_detach_device(), the given device later ignored by
>> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>>
>> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
>> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>> arch/arm/mm/dma-mapping.c | 12 ++++++------
>> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> Can you point out exactly what drivers break because of this change? We
> need to find a solution that works for everyone. Reverting is only
> marginally useful because somebody will just end up wanting to revert
> the revert because a different driver is now broken.
At first glance, it sounds like what we really want is for
arch_teardown_iommu_ops() to completely clear any ops that
arch_setup_dma_ops() installed - does the below suffice?
Robin.
----->8-----
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f1e2922e447c..1e3e08a1c456 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
return;
arm_teardown_iommu_dma_ops(dev);
+ /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
+ set_dma_ops(dev, NULL);
}
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^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
2019-01-14 16:38 ` Robin Murphy
@ 2019-01-14 20:20 ` Tobias Jakobi
-1 siblings, 0 replies; 14+ messages in thread
From: Tobias Jakobi @ 2019-01-14 20:20 UTC (permalink / raw)
To: Robin Murphy, Thierry Reding, Marek Szyprowski
Cc: iommu, linux-kernel, linux-arm-kernel, Christoph Hellwig,
Russell King, Ben Skeggs, Bartlomiej Zolnierkiewicz
Hello everyone,
first of all thanks to Marek for looking into this.
@Robin: This works for me. The drivers now probe and bind correctly again.
With best wishes,
Tobias
Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
>> On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
>>> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>>>
>>> That patch broke IOMMU support for devices, which fails to probe for the
>>> first time and use deferred probe approach. When non-NULL dma_ops is set
>>> in arm_iommu_detach_device(), the given device later ignored by
>>> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>>>
>>> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
>>> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in
>>> arm_iommu_detach_device()"
>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> ---
>>> arch/arm/mm/dma-mapping.c | 12 ++++++------
>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> Can you point out exactly what drivers break because of this change? We
>> need to find a solution that works for everyone. Reverting is only
>> marginally useful because somebody will just end up wanting to revert
>> the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that arch_setup_dma_ops()
> installed - does the below suffice?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
> + set_dma_ops(dev, NULL);
> }
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
@ 2019-01-14 20:20 ` Tobias Jakobi
0 siblings, 0 replies; 14+ messages in thread
From: Tobias Jakobi @ 2019-01-14 20:20 UTC (permalink / raw)
To: Robin Murphy, Thierry Reding, Marek Szyprowski
Cc: Bartlomiej Zolnierkiewicz, Russell King, linux-kernel, iommu,
Ben Skeggs, Christoph Hellwig, linux-arm-kernel
Hello everyone,
first of all thanks to Marek for looking into this.
@Robin: This works for me. The drivers now probe and bind correctly again.
With best wishes,
Tobias
Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
>> On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
>>> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>>>
>>> That patch broke IOMMU support for devices, which fails to probe for the
>>> first time and use deferred probe approach. When non-NULL dma_ops is set
>>> in arm_iommu_detach_device(), the given device later ignored by
>>> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>>>
>>> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
>>> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in
>>> arm_iommu_detach_device()"
>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> ---
>>> arch/arm/mm/dma-mapping.c | 12 ++++++------
>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> Can you point out exactly what drivers break because of this change? We
>> need to find a solution that works for everyone. Reverting is only
>> marginally useful because somebody will just end up wanting to revert
>> the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that arch_setup_dma_ops()
> installed - does the below suffice?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
> + set_dma_ops(dev, NULL);
> }
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
2019-01-14 16:38 ` Robin Murphy
(?)
@ 2019-01-15 15:29 ` Thierry Reding
-1 siblings, 0 replies; 14+ messages in thread
From: Thierry Reding @ 2019-01-15 15:29 UTC (permalink / raw)
To: Robin Murphy
Cc: Marek Szyprowski, iommu, linux-kernel, linux-arm-kernel,
Christoph Hellwig, Russell King, Ben Skeggs, Tobias Jakobi,
Bartlomiej Zolnierkiewicz
[-- Attachment #1: Type: text/plain, Size: 1919 bytes --]
On Mon, Jan 14, 2019 at 04:38:20PM +0000, Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
> > On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
> > > This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
> > >
> > > That patch broke IOMMU support for devices, which fails to probe for the
> > > first time and use deferred probe approach. When non-NULL dma_ops is set
> > > in arm_iommu_detach_device(), the given device later ignored by
> > > arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
> > >
> > > Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
> > > Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
> > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > > ---
> > > arch/arm/mm/dma-mapping.c | 12 ++++++------
> > > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > Can you point out exactly what drivers break because of this change? We
> > need to find a solution that works for everyone. Reverting is only
> > marginally useful because somebody will just end up wanting to revert
> > the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that
> arch_setup_dma_ops() installed - does the below suffice?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
> + set_dma_ops(dev, NULL);
> }
Seems to work fine on Tegra:
Tested-by: Thierry Reding <treding@nvidia.com>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
@ 2019-01-15 15:29 ` Thierry Reding
0 siblings, 0 replies; 14+ messages in thread
From: Thierry Reding @ 2019-01-15 15:29 UTC (permalink / raw)
To: Robin Murphy
Cc: Bartlomiej Zolnierkiewicz, Russell King, linux-kernel,
Tobias Jakobi, iommu, Ben Skeggs, Christoph Hellwig,
linux-arm-kernel, Marek Szyprowski
[-- Attachment #1.1: Type: text/plain, Size: 1919 bytes --]
On Mon, Jan 14, 2019 at 04:38:20PM +0000, Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
> > On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
> > > This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
> > >
> > > That patch broke IOMMU support for devices, which fails to probe for the
> > > first time and use deferred probe approach. When non-NULL dma_ops is set
> > > in arm_iommu_detach_device(), the given device later ignored by
> > > arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
> > >
> > > Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
> > > Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
> > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > > ---
> > > arch/arm/mm/dma-mapping.c | 12 ++++++------
> > > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > Can you point out exactly what drivers break because of this change? We
> > need to find a solution that works for everyone. Reverting is only
> > marginally useful because somebody will just end up wanting to revert
> > the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that
> arch_setup_dma_ops() installed - does the below suffice?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
> + set_dma_ops(dev, NULL);
> }
Seems to work fine on Tegra:
Tested-by: Thierry Reding <treding@nvidia.com>
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_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
@ 2019-01-15 15:29 ` Thierry Reding
0 siblings, 0 replies; 14+ messages in thread
From: Thierry Reding @ 2019-01-15 15:29 UTC (permalink / raw)
To: Robin Murphy
Cc: Marek Szyprowski, iommu, linux-kernel, linux-arm-kernel,
Christoph Hellwig, Russell King, Ben Skeggs, Tobias Jakobi,
Bartlomiej Zolnierkiewicz
[-- Attachment #1: Type: text/plain, Size: 1919 bytes --]
On Mon, Jan 14, 2019 at 04:38:20PM +0000, Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
> > On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
> > > This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
> > >
> > > That patch broke IOMMU support for devices, which fails to probe for the
> > > first time and use deferred probe approach. When non-NULL dma_ops is set
> > > in arm_iommu_detach_device(), the given device later ignored by
> > > arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
> > >
> > > Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
> > > Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
> > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > > ---
> > > arch/arm/mm/dma-mapping.c | 12 ++++++------
> > > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > Can you point out exactly what drivers break because of this change? We
> > need to find a solution that works for everyone. Reverting is only
> > marginally useful because somebody will just end up wanting to revert
> > the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that
> arch_setup_dma_ops() installed - does the below suffice?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */
> + set_dma_ops(dev, NULL);
> }
Seems to work fine on Tegra:
Tested-by: Thierry Reding <treding@nvidia.com>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
2019-01-14 16:38 ` Robin Murphy
@ 2019-01-16 10:36 ` Marek Szyprowski
-1 siblings, 0 replies; 14+ messages in thread
From: Marek Szyprowski @ 2019-01-16 10:36 UTC (permalink / raw)
To: Robin Murphy, Thierry Reding
Cc: iommu, linux-kernel, linux-arm-kernel, Christoph Hellwig,
Russell King, Ben Skeggs, Tobias Jakobi,
Bartlomiej Zolnierkiewicz
Hi Robin,
On 2019-01-14 17:38, Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
>> On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
>>> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>>>
>>> That patch broke IOMMU support for devices, which fails to probe for
>>> the
>>> first time and use deferred probe approach. When non-NULL dma_ops is
>>> set
>>> in arm_iommu_detach_device(), the given device later ignored by
>>> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>>>
>>> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
>>> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in
>>> arm_iommu_detach_device()"
>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> ---
>>> arch/arm/mm/dma-mapping.c | 12 ++++++------
>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> Can you point out exactly what drivers break because of this change? We
>> need to find a solution that works for everyone. Reverting is only
>> marginally useful because somebody will just end up wanting to revert
>> the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that
> arch_setup_dma_ops() installed - does the below suffice?
I've initially also thought about similar fix, but then I found the
commit 1874619a7df4b14b23b14877e705ae15325773e3, which was the source of
this problem.
Robin: do you plan to send this fix as a complete patch or do you want
me to resend it with the above commit message and your's suggested-by?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon
> re-probe */
> + set_dma_ops(dev, NULL);
> }
>
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
@ 2019-01-16 10:36 ` Marek Szyprowski
0 siblings, 0 replies; 14+ messages in thread
From: Marek Szyprowski @ 2019-01-16 10:36 UTC (permalink / raw)
To: Robin Murphy, Thierry Reding
Cc: Bartlomiej Zolnierkiewicz, Russell King, linux-kernel,
Tobias Jakobi, iommu, Ben Skeggs, Christoph Hellwig,
linux-arm-kernel
Hi Robin,
On 2019-01-14 17:38, Robin Murphy wrote:
> On 14/01/2019 16:09, Thierry Reding wrote:
>> On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
>>> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>>>
>>> That patch broke IOMMU support for devices, which fails to probe for
>>> the
>>> first time and use deferred probe approach. When non-NULL dma_ops is
>>> set
>>> in arm_iommu_detach_device(), the given device later ignored by
>>> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>>>
>>> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
>>> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in
>>> arm_iommu_detach_device()"
>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> ---
>>> arch/arm/mm/dma-mapping.c | 12 ++++++------
>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> Can you point out exactly what drivers break because of this change? We
>> need to find a solution that works for everyone. Reverting is only
>> marginally useful because somebody will just end up wanting to revert
>> the revert because a different driver is now broken.
>
> At first glance, it sounds like what we really want is for
> arch_teardown_iommu_ops() to completely clear any ops that
> arch_setup_dma_ops() installed - does the below suffice?
I've initially also thought about similar fix, but then I found the
commit 1874619a7df4b14b23b14877e705ae15325773e3, which was the source of
this problem.
Robin: do you plan to send this fix as a complete patch or do you want
me to resend it with the above commit message and your's suggested-by?
>
> Robin.
>
> ----->8-----
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f1e2922e447c..1e3e08a1c456 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev)
> return;
>
> arm_teardown_iommu_dma_ops(dev);
> + /* Let arch_setup_dma_ops() start again from scratch upon
> re-probe */
> + set_dma_ops(dev, NULL);
> }
>
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread