Re: [PATCH 1/2] xen/arm, arm64: fix xen_dma_ops after 815dd18 "Consolidate get_dma_ops..."

[Juergen Gross <jgross@suse.com>]

On 19/04/17 19:25, Stefano Stabellini wrote:
> Hello Russell,
> 
> Can I have your acked-by on the following fix (original patch is
> 1492117462-19886-1-git-send-email-sstabellini@kernel.org)?

Stefano, through which tree should this go? ARM or Xen or other?


Juergen

> 
> Thanks,
> 
> Stefano
> 
> 
> On Tue, 18 Apr 2017, Catalin Marinas wrote:
>> On Thu, Apr 13, 2017 at 02:04:21PM -0700, Stefano Stabellini wrote:
>>> The following commit:
>>>
>>>   commit 815dd18788fe0d41899f51b91d0560279cf16b0d
>>>   Author: Bart Van Assche <bart.vanassche@sandisk.com>
>>>   Date:   Fri Jan 20 13:04:04 2017 -0800
>>>
>>>       treewide: Consolidate get_dma_ops() implementations
>>>
>>> rearranges get_dma_ops in a way that xen_dma_ops are not returned when
>>> running on Xen anymore, dev->dma_ops is returned instead (see
>>> arch/arm/include/asm/dma-mapping.h:get_arch_dma_ops and
>>> include/linux/dma-mapping.h:get_dma_ops).
>>>
>>> Fix the problem by storing dev->dma_ops in dev_archdata, and setting
>>> dev->dma_ops to xen_dma_ops. This way, xen_dma_ops is returned naturally
>>> by get_dma_ops. The Xen code can retrieve the original dev->dma_ops from
>>> dev_archdata when needed. It also allows us to remove __generic_dma_ops
>>> from common headers.
>>>
>>> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
>>> Tested-by: Julien Grall <julien.grall@arm.com>
>>> Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
>>> CC: linux@armlinux.org.uk
>>> CC: catalin.marinas@arm.com
>>> CC: will.deacon@arm.com
>>> CC: boris.ostrovsky@oracle.com
>>> CC: jgross@suse.com
>>> CC: Julien Grall <julien.grall@arm.com>
>>
>> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
>>
>>
>>> diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
>>> index 220ba20..36ec9c8 100644
>>> --- a/arch/arm/include/asm/device.h
>>> +++ b/arch/arm/include/asm/device.h
>>> @@ -16,6 +16,9 @@ struct dev_archdata {
>>>  #ifdef CONFIG_ARM_DMA_USE_IOMMU
>>>  	struct dma_iommu_mapping	*mapping;
>>>  #endif
>>> +#ifdef CONFIG_XEN
>>> +	const struct dma_map_ops *dev_dma_ops;
>>> +#endif
>>>  	bool dma_coherent;
>>>  };
>>>  
>>> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
>>> index 7166569..680d3f3 100644
>>> --- a/arch/arm/include/asm/dma-mapping.h
>>> +++ b/arch/arm/include/asm/dma-mapping.h
>>> @@ -16,19 +16,9 @@
>>>  extern const struct dma_map_ops arm_dma_ops;
>>>  extern const struct dma_map_ops arm_coherent_dma_ops;
>>>  
>>> -static inline const struct dma_map_ops *__generic_dma_ops(struct device *dev)
>>> -{
>>> -	if (dev && dev->dma_ops)
>>> -		return dev->dma_ops;
>>> -	return &arm_dma_ops;
>>> -}
>>> -
>>>  static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>>>  {
>>> -	if (xen_initial_domain())
>>> -		return xen_dma_ops;
>>> -	else
>>> -		return __generic_dma_ops(NULL);
>>> +	return &arm_dma_ops;
>>>  }
>>>  
>>>  #define HAVE_ARCH_DMA_SUPPORTED 1
>>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>>> index 63eabb0..a614459 100644
>>> --- a/arch/arm/mm/dma-mapping.c
>>> +++ b/arch/arm/mm/dma-mapping.c
>>> @@ -2396,6 +2396,13 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>>>  		dma_ops = arm_get_dma_map_ops(coherent);
>>>  
>>>  	set_dma_ops(dev, dma_ops);
>>> +
>>> +#ifdef CONFIG_XEN
>>> +	if (xen_initial_domain()) {
>>> +		dev->archdata.dev_dma_ops = dev->dma_ops;
>>> +		dev->dma_ops = xen_dma_ops;
>>> +	}
>>> +#endif
>>>  }
>>>  
>>>  void arch_teardown_dma_ops(struct device *dev)
>>> diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
>>> index 73d5bab..5a5fa47 100644
>>> --- a/arch/arm64/include/asm/device.h
>>> +++ b/arch/arm64/include/asm/device.h
>>> @@ -20,6 +20,9 @@ struct dev_archdata {
>>>  #ifdef CONFIG_IOMMU_API
>>>  	void *iommu;			/* private IOMMU data */
>>>  #endif
>>> +#ifdef CONFIG_XEN
>>> +	const struct dma_map_ops *dev_dma_ops;
>>> +#endif
>>>  	bool dma_coherent;
>>>  };
>>>  
>>> diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
>>> index 505756c..5392dbe 100644
>>> --- a/arch/arm64/include/asm/dma-mapping.h
>>> +++ b/arch/arm64/include/asm/dma-mapping.h
>>> @@ -27,11 +27,8 @@
>>>  #define DMA_ERROR_CODE	(~(dma_addr_t)0)
>>>  extern const struct dma_map_ops dummy_dma_ops;
>>>  
>>> -static inline const struct dma_map_ops *__generic_dma_ops(struct device *dev)
>>> +static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>>>  {
>>> -	if (dev && dev->dma_ops)
>>> -		return dev->dma_ops;
>>> -
>>>  	/*
>>>  	 * We expect no ISA devices, and all other DMA masters are expected to
>>>  	 * have someone call arch_setup_dma_ops at device creation time.
>>> @@ -39,14 +36,6 @@ static inline const struct dma_map_ops *__generic_dma_ops(struct device *dev)
>>>  	return &dummy_dma_ops;
>>>  }
>>>  
>>> -static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>>> -{
>>> -	if (xen_initial_domain())
>>> -		return xen_dma_ops;
>>> -	else
>>> -		return __generic_dma_ops(NULL);
>>> -}
>>> -
>>>  void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>>>  			const struct iommu_ops *iommu, bool coherent);
>>>  #define arch_setup_dma_ops	arch_setup_dma_ops
>>> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
>>> index 81cdb2e..7f8b37e 100644
>>> --- a/arch/arm64/mm/dma-mapping.c
>>> +++ b/arch/arm64/mm/dma-mapping.c
>>> @@ -977,4 +977,11 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>>>  
>>>  	dev->archdata.dma_coherent = coherent;
>>>  	__iommu_setup_dma_ops(dev, dma_base, size, iommu);
>>> +
>>> +#ifdef CONFIG_XEN
>>> +	if (xen_initial_domain()) {
>>> +		dev->archdata.dev_dma_ops = dev->dma_ops;
>>> +		dev->dma_ops = xen_dma_ops;
>>> +	}
>>> +#endif
>>>  }
>>> diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h
>>> index 95ce6ac..b0a2bfc 100644
>>> --- a/include/xen/arm/page-coherent.h
>>> +++ b/include/xen/arm/page-coherent.h
>>> @@ -2,8 +2,16 @@
>>>  #define _ASM_ARM_XEN_PAGE_COHERENT_H
>>>  
>>>  #include <asm/page.h>
>>> +#include <asm/dma-mapping.h>
>>>  #include <linux/dma-mapping.h>
>>>  
>>> +static inline const struct dma_map_ops *__generic_dma_ops(struct device *dev)
>>> +{
>>> +	if (dev && dev->archdata.dev_dma_ops)
>>> +		return dev->archdata.dev_dma_ops;
>>> +	return get_arch_dma_ops(NULL);
>>> +}
>>> +
>>>  void __xen_dma_map_page(struct device *hwdev, struct page *page,
>>>  	     dma_addr_t dev_addr, unsigned long offset, size_t size,
>>>  	     enum dma_data_direction dir, unsigned long attrs);
>