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From: Guillaume Tucker <guillaume.tucker@collabora.com>
To: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Tariq Toukan" <tariqt@mellanox.com>,
	"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
	"Toke Høiland-Jørgensen" <toke@toke.dk>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Tony Luck" <tony.luck@intel.com>,
	"Fenghua Yu" <fenghua.yu@intel.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Keith Busch" <keith.busch@intel.com>,
	"Jonathan Derrick" <jonathan.derrick@intel.com>,
	linux-pci@vger.kernel.org, linux-ia64@vger.kernel.org,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	"ezequiel Garcia" <ezequiel@collabora.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [15/15] dma-mapping: bypass indirect calls for dma-direct
Date: Tue, 18 Dec 2018 20:34:37 +0000
Message-ID: <2e779fa7-dc9f-7ed8-252a-5d20c5deca9c@collabora.com> (raw)
In-Reply-To: <20181207190720.18517-16-hch@lst.de>

On 07/12/2018 19:07, Christoph Hellwig wrote:
> Avoid expensive indirect calls in the fast path DMA mapping
> operations by directly calling the dma_direct_* ops if we are using
> the directly mapped DMA operations.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've run a semi-automated bisection on kernelci.org and found that this
patch appeared to cause some regressions in linux-next on the
rk3399-gru-kevin arm64 platform.  The bisection was run between
next-20181128 and its merge base in mainline master (6531e115b7ab) with
a plain defconfig.


The problems seem to start with this message:

[    3.242163] mmc1: Unable to allocate ADMA buffers - falling back to standard DMA

then we can see this kind of warnings:

[    3.424261] mmc1: asked for transfer of 512 bytes exceeds bounce buffer 0 bytes
[    3.432488] WARNING: CPU: 3 PID: 1596 at ../drivers/mmc/host/sdhci.c:1050 sdhci_send_command+0x8f0/0xfe8

see also:

[   16.046084] rk_iommu ff8f3f00.iommu: DMA map error for DT


The full kernel log is available here:

  https://lava.collabora.co.uk/scheduler/job/1395093


Reverting this patch makes the errors go away, but I haven't done any
further investigation so the actual problem may well lie somewhere else.

Hope this helps!

Best wishes,
Guillaume

> ---
>  arch/alpha/include/asm/dma-mapping.h |   2 +-
>  arch/arc/mm/cache.c                  |   2 +-
>  arch/arm/include/asm/dma-mapping.h   |   2 +-
>  arch/arm/mm/dma-mapping-nommu.c      |  14 +---
>  arch/arm64/mm/dma-mapping.c          |   3 -
>  arch/ia64/hp/common/hwsw_iommu.c     |   2 +-
>  arch/ia64/hp/common/sba_iommu.c      |   4 +-
>  arch/ia64/kernel/dma-mapping.c       |   1 -
>  arch/mips/include/asm/dma-mapping.h  |   2 +-
>  arch/parisc/kernel/setup.c           |   4 -
>  arch/sparc/include/asm/dma-mapping.h |   4 +-
>  arch/x86/kernel/pci-dma.c            |   2 +-
>  drivers/gpu/drm/vmwgfx/vmwgfx_drv.c  |   2 +-
>  drivers/iommu/amd_iommu.c            |  13 +---
>  include/asm-generic/dma-mapping.h    |   2 +-
>  include/linux/dma-direct.h           |  17 ----
>  include/linux/dma-mapping.h          | 111 +++++++++++++++++++++++----
>  include/linux/dma-noncoherent.h      |   5 +-
>  kernel/dma/direct.c                  |  37 ++-------
>  kernel/dma/mapping.c                 |  40 ++++++----
>  20 files changed, 150 insertions(+), 119 deletions(-)
> 
> diff --git a/arch/alpha/include/asm/dma-mapping.h b/arch/alpha/include/asm/dma-mapping.h
> index 8beeafd4f68e..0ee6a5c99b16 100644
> --- a/arch/alpha/include/asm/dma-mapping.h
> +++ b/arch/alpha/include/asm/dma-mapping.h
> @@ -7,7 +7,7 @@ extern const struct dma_map_ops alpha_pci_ops;
>  static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>  {
>  #ifdef CONFIG_ALPHA_JENSEN
> -	return &dma_direct_ops;
> +	return NULL;
>  #else
>  	return &alpha_pci_ops;
>  #endif
> diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
> index f2701c13a66b..e188bb3ede53 100644
> --- a/arch/arc/mm/cache.c
> +++ b/arch/arc/mm/cache.c
> @@ -1280,7 +1280,7 @@ void __init arc_cache_init_master(void)
>  	/*
>  	 * In case of IOC (say IOC+SLC case), pointers above could still be set
>  	 * but end up not being relevant as the first function in chain is not
> -	 * called at all for @dma_direct_ops
> +	 * called at all for devices using coherent DMA.
>  	 *     arch_sync_dma_for_cpu() -> dma_cache_*() -> __dma_cache_*()
>  	 */
>  }
> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> index 965b7c846ecb..31d3b96f0f4b 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -18,7 +18,7 @@ extern const struct dma_map_ops arm_coherent_dma_ops;
>  
>  static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>  {
> -	return IS_ENABLED(CONFIG_MMU) ? &arm_dma_ops : &dma_direct_ops;
> +	return IS_ENABLED(CONFIG_MMU) ? &arm_dma_ops : NULL;
>  }
>  
>  #ifdef __arch_page_to_dma
> diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
> index 712416ecd8e6..f304b10e23a4 100644
> --- a/arch/arm/mm/dma-mapping-nommu.c
> +++ b/arch/arm/mm/dma-mapping-nommu.c
> @@ -22,7 +22,7 @@
>  #include "dma.h"
>  
>  /*
> - *  dma_direct_ops is used if
> + *  The generic direct mapping code is used if
>   *   - MMU/MPU is off
>   *   - cpu is v7m w/o cache support
>   *   - device is coherent
> @@ -209,16 +209,9 @@ const struct dma_map_ops arm_nommu_dma_ops = {
>  };
>  EXPORT_SYMBOL(arm_nommu_dma_ops);
>  
> -static const struct dma_map_ops *arm_nommu_get_dma_map_ops(bool coherent)
> -{
> -	return coherent ? &dma_direct_ops : &arm_nommu_dma_ops;
> -}
> -
>  void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>  			const struct iommu_ops *iommu, bool coherent)
>  {
> -	const struct dma_map_ops *dma_ops;
> -
>  	if (IS_ENABLED(CONFIG_CPU_V7M)) {
>  		/*
>  		 * Cache support for v7m is optional, so can be treated as
> @@ -234,7 +227,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>  		dev->archdata.dma_coherent = (get_cr() & CR_M) ? coherent : true;
>  	}
>  
> -	dma_ops = arm_nommu_get_dma_map_ops(dev->archdata.dma_coherent);
> -
> -	set_dma_ops(dev, dma_ops);
> +	if (!dev->archdata.dma_coherent)
> +		set_dma_ops(dev, &arm_nommu_dma_ops);
>  }
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index ab1e417204d0..95eda81e3f2d 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -462,9 +462,6 @@ static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>  void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>  			const struct iommu_ops *iommu, bool coherent)
>  {
> -	if (!dev->dma_ops)
> -		dev->dma_ops = &dma_direct_ops;
> -
>  	dev->dma_coherent = coherent;
>  	__iommu_setup_dma_ops(dev, dma_base, size, iommu);
>  
> diff --git a/arch/ia64/hp/common/hwsw_iommu.c b/arch/ia64/hp/common/hwsw_iommu.c
> index f40ca499b246..8840ed97712f 100644
> --- a/arch/ia64/hp/common/hwsw_iommu.c
> +++ b/arch/ia64/hp/common/hwsw_iommu.c
> @@ -38,7 +38,7 @@ static inline int use_swiotlb(struct device *dev)
>  const struct dma_map_ops *hwsw_dma_get_ops(struct device *dev)
>  {
>  	if (use_swiotlb(dev))
> -		return &dma_direct_ops;
> +		return NULL;
>  	return &sba_dma_ops;
>  }
>  EXPORT_SYMBOL(hwsw_dma_get_ops);
> diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
> index 5ee74820a0f6..5a361e51cb1e 100644
> --- a/arch/ia64/hp/common/sba_iommu.c
> +++ b/arch/ia64/hp/common/sba_iommu.c
> @@ -2078,7 +2078,7 @@ sba_init(void)
>  	 * a successful kdump kernel boot is to use the swiotlb.
>  	 */
>  	if (is_kdump_kernel()) {
> -		dma_ops = &dma_direct_ops;
> +		dma_ops = NULL;
>  		if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
>  			panic("Unable to initialize software I/O TLB:"
>  				  " Try machvec=dig boot option");
> @@ -2100,7 +2100,7 @@ sba_init(void)
>  		 * If we didn't find something sba_iommu can claim, we
>  		 * need to setup the swiotlb and switch to the dig machvec.
>  		 */
> -		dma_ops = &dma_direct_ops;
> +		dma_ops = NULL;
>  		if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
>  			panic("Unable to find SBA IOMMU or initialize "
>  			      "software I/O TLB: Try machvec=dig boot option");
> diff --git a/arch/ia64/kernel/dma-mapping.c b/arch/ia64/kernel/dma-mapping.c
> index 80cd3e1ea95a..ad7d9963de34 100644
> --- a/arch/ia64/kernel/dma-mapping.c
> +++ b/arch/ia64/kernel/dma-mapping.c
> @@ -36,7 +36,6 @@ long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr,
>  
>  void __init swiotlb_dma_init(void)
>  {
> -	dma_ops = &dma_direct_ops;
>  	swiotlb_init(1);
>  }
>  #endif
> diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
> index 69f914667f3e..20dfaad3a55d 100644
> --- a/arch/mips/include/asm/dma-mapping.h
> +++ b/arch/mips/include/asm/dma-mapping.h
> @@ -11,7 +11,7 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>  #if defined(CONFIG_MACH_JAZZ)
>  	return &jazz_dma_ops;
>  #else
> -	return &dma_direct_ops;
> +	return NULL;
>  #endif
>  }
>  
> diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
> index cd227f1cf629..54818cd78bd0 100644
> --- a/arch/parisc/kernel/setup.c
> +++ b/arch/parisc/kernel/setup.c
> @@ -99,10 +99,6 @@ void __init dma_ops_init(void)
>  
>  	case pcxl2:
>  		pa7300lc_init();
> -	case pcxl: /* falls through */
> -	case pcxs:
> -	case pcxt:
> -		hppa_dma_ops = &dma_direct_ops;
>  		break;
>  	default:
>  		break;
> diff --git a/arch/sparc/include/asm/dma-mapping.h b/arch/sparc/include/asm/dma-mapping.h
> index b0bb2fcaf1c9..59f5a0f17316 100644
> --- a/arch/sparc/include/asm/dma-mapping.h
> +++ b/arch/sparc/include/asm/dma-mapping.h
> @@ -14,11 +14,11 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>  {
>  #ifdef CONFIG_SPARC_LEON
>  	if (sparc_cpu_model == sparc_leon)
> -		return &dma_direct_ops;
> +		return NULL;
>  #endif
>  #if defined(CONFIG_SPARC32) && defined(CONFIG_PCI)
>  	if (bus == &pci_bus_type)
> -		return &dma_direct_ops;
> +		return NULL;
>  #endif
>  	return dma_ops;
>  }
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index f4562fcec681..d460998ae828 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -17,7 +17,7 @@
>  
>  static bool disable_dac_quirk __read_mostly;
>  
> -const struct dma_map_ops *dma_ops = &dma_direct_ops;
> +const struct dma_map_ops *dma_ops;
>  EXPORT_SYMBOL(dma_ops);
>  
>  #ifdef CONFIG_IOMMU_DEBUG
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> index 61a84b958d67..50637f372e9f 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> @@ -581,7 +581,7 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
>  
>  	dev_priv->map_mode = vmw_dma_map_populate;
>  
> -	if (dma_ops->sync_single_for_cpu)
> +	if (dma_ops && dma_ops->sync_single_for_cpu)
>  		dev_priv->map_mode = vmw_dma_alloc_coherent;
>  #ifdef CONFIG_SWIOTLB
>  	if (swiotlb_nr_tbl() == 0)
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index c5d6c7c42b0a..567221cca13c 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2184,7 +2184,7 @@ static int amd_iommu_add_device(struct device *dev)
>  				dev_name(dev));
>  
>  		iommu_ignore_device(dev);
> -		dev->dma_ops = &dma_direct_ops;
> +		dev->dma_ops = NULL;
>  		goto out;
>  	}
>  	init_iommu_group(dev);
> @@ -2770,17 +2770,6 @@ int __init amd_iommu_init_dma_ops(void)
>  	swiotlb        = (iommu_pass_through || sme_me_mask) ? 1 : 0;
>  	iommu_detected = 1;
>  
> -	/*
> -	 * In case we don't initialize SWIOTLB (actually the common case
> -	 * when AMD IOMMU is enabled and SME is not active), make sure there
> -	 * are global dma_ops set as a fall-back for devices not handled by
> -	 * this driver (for example non-PCI devices). When SME is active,
> -	 * make sure that swiotlb variable remains set so the global dma_ops
> -	 * continue to be SWIOTLB.
> -	 */
> -	if (!swiotlb)
> -		dma_ops = &dma_direct_ops;
> -
>  	if (amd_iommu_unmap_flush)
>  		pr_info("AMD-Vi: IO/TLB flush on unmap enabled\n");
>  	else
> diff --git a/include/asm-generic/dma-mapping.h b/include/asm-generic/dma-mapping.h
> index 880a292d792f..c13f46109e88 100644
> --- a/include/asm-generic/dma-mapping.h
> +++ b/include/asm-generic/dma-mapping.h
> @@ -4,7 +4,7 @@
>  
>  static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
>  {
> -	return &dma_direct_ops;
> +	return NULL;
>  }
>  
>  #endif /* _ASM_GENERIC_DMA_MAPPING_H */
> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index 3b0a3ea3876d..b7338702592a 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -60,22 +60,5 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
>  struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
>  		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
>  void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page);
> -dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
> -		unsigned long offset, size_t size, enum dma_data_direction dir,
> -		unsigned long attrs);
> -void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
> -		size_t size, enum dma_data_direction dir, unsigned long attrs);
> -int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
> -		enum dma_data_direction dir, unsigned long attrs);
> -void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
> -		int nents, enum dma_data_direction dir, unsigned long attrs);
> -void dma_direct_sync_single_for_device(struct device *dev,
> -		dma_addr_t addr, size_t size, enum dma_data_direction dir);
> -void dma_direct_sync_sg_for_device(struct device *dev,
> -		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
> -void dma_direct_sync_single_for_cpu(struct device *dev,
> -		dma_addr_t addr, size_t size, enum dma_data_direction dir);
> -void dma_direct_sync_sg_for_cpu(struct device *dev,
> -		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
>  int dma_direct_supported(struct device *dev, u64 mask);
>  #endif /* _LINUX_DMA_DIRECT_H */
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 269ee27fc3d9..f422aec0f53c 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -134,7 +134,6 @@ struct dma_map_ops {
>  
>  #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
>  
> -extern const struct dma_map_ops dma_direct_ops;
>  extern const struct dma_map_ops dma_virt_ops;
>  extern const struct dma_map_ops dma_dummy_ops;
>  
> @@ -222,6 +221,69 @@ static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
>  }
>  #endif
>  
> +static inline bool dma_is_direct(const struct dma_map_ops *ops)
> +{
> +	return likely(!ops);
> +}
> +
> +/*
> + * All the dma_direct_* declarations are here just for the indirect call bypass,
> + * and must not be used directly drivers!
> + */
> +dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
> +		unsigned long offset, size_t size, enum dma_data_direction dir,
> +		unsigned long attrs);
> +int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
> +		enum dma_data_direction dir, unsigned long attrs);
> +
> +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
> +    defined(CONFIG_SWIOTLB)
> +void dma_direct_sync_single_for_device(struct device *dev,
> +		dma_addr_t addr, size_t size, enum dma_data_direction dir);
> +void dma_direct_sync_sg_for_device(struct device *dev,
> +		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
> +#else
> +static inline void dma_direct_sync_single_for_device(struct device *dev,
> +		dma_addr_t addr, size_t size, enum dma_data_direction dir)
> +{
> +}
> +static inline void dma_direct_sync_sg_for_device(struct device *dev,
> +		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
> +{
> +}
> +#endif
> +
> +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
> +    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
> +    defined(CONFIG_SWIOTLB)
> +void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
> +		size_t size, enum dma_data_direction dir, unsigned long attrs);
> +void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
> +		int nents, enum dma_data_direction dir, unsigned long attrs);
> +void dma_direct_sync_single_for_cpu(struct device *dev,
> +		dma_addr_t addr, size_t size, enum dma_data_direction dir);
> +void dma_direct_sync_sg_for_cpu(struct device *dev,
> +		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
> +#else
> +static inline void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
> +		size_t size, enum dma_data_direction dir, unsigned long attrs)
> +{
> +}
> +static inline void dma_direct_unmap_sg(struct device *dev,
> +		struct scatterlist *sgl, int nents, enum dma_data_direction dir,
> +		unsigned long attrs)
> +{
> +}
> +static inline void dma_direct_sync_single_for_cpu(struct device *dev,
> +		dma_addr_t addr, size_t size, enum dma_data_direction dir)
> +{
> +}
> +static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
> +		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
> +{
> +}
> +#endif
> +
>  static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
>  					      size_t size,
>  					      enum dma_data_direction dir,
> @@ -232,9 +294,12 @@ static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
>  
>  	BUG_ON(!valid_dma_direction(dir));
>  	debug_dma_map_single(dev, ptr, size);
> -	addr = ops->map_page(dev, virt_to_page(ptr),
> -			     offset_in_page(ptr), size,
> -			     dir, attrs);
> +	if (dma_is_direct(ops))
> +		addr = dma_direct_map_page(dev, virt_to_page(ptr),
> +				offset_in_page(ptr), size, dir, attrs);
> +	else
> +		addr = ops->map_page(dev, virt_to_page(ptr),
> +				offset_in_page(ptr), size, dir, attrs);
>  	debug_dma_map_page(dev, virt_to_page(ptr),
>  			   offset_in_page(ptr), size,
>  			   dir, addr, true);
> @@ -249,7 +314,9 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->unmap_page)
> +	if (dma_is_direct(ops))
> +		dma_direct_unmap_page(dev, addr, size, dir, attrs);
> +	else if (ops->unmap_page)
>  		ops->unmap_page(dev, addr, size, dir, attrs);
>  	debug_dma_unmap_page(dev, addr, size, dir, true);
>  }
> @@ -272,7 +339,10 @@ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
>  	int ents;
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	ents = ops->map_sg(dev, sg, nents, dir, attrs);
> +	if (dma_is_direct(ops))
> +		ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
> +	else
> +		ents = ops->map_sg(dev, sg, nents, dir, attrs);
>  	BUG_ON(ents < 0);
>  	debug_dma_map_sg(dev, sg, nents, ents, dir);
>  
> @@ -287,7 +357,9 @@ static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg
>  
>  	BUG_ON(!valid_dma_direction(dir));
>  	debug_dma_unmap_sg(dev, sg, nents, dir);
> -	if (ops->unmap_sg)
> +	if (dma_is_direct(ops))
> +		dma_direct_unmap_sg(dev, sg, nents, dir, attrs);
> +	else if (ops->unmap_sg)
>  		ops->unmap_sg(dev, sg, nents, dir, attrs);
>  }
>  
> @@ -301,7 +373,10 @@ static inline dma_addr_t dma_map_page_attrs(struct device *dev,
>  	dma_addr_t addr;
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	addr = ops->map_page(dev, page, offset, size, dir, attrs);
> +	if (dma_is_direct(ops))
> +		addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
> +	else
> +		addr = ops->map_page(dev, page, offset, size, dir, attrs);
>  	debug_dma_map_page(dev, page, offset, size, dir, addr, false);
>  
>  	return addr;
> @@ -322,7 +397,7 @@ static inline dma_addr_t dma_map_resource(struct device *dev,
>  	BUG_ON(pfn_valid(PHYS_PFN(phys_addr)));
>  
>  	addr = phys_addr;
> -	if (ops->map_resource)
> +	if (ops && ops->map_resource)
>  		addr = ops->map_resource(dev, phys_addr, size, dir, attrs);
>  
>  	debug_dma_map_resource(dev, phys_addr, size, dir, addr);
> @@ -337,7 +412,7 @@ static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->unmap_resource)
> +	if (ops && ops->unmap_resource)
>  		ops->unmap_resource(dev, addr, size, dir, attrs);
>  	debug_dma_unmap_resource(dev, addr, size, dir);
>  }
> @@ -349,7 +424,9 @@ static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->sync_single_for_cpu)
> +	if (dma_is_direct(ops))
> +		dma_direct_sync_single_for_cpu(dev, addr, size, dir);
> +	else if (ops->sync_single_for_cpu)
>  		ops->sync_single_for_cpu(dev, addr, size, dir);
>  	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
>  }
> @@ -368,7 +445,9 @@ static inline void dma_sync_single_for_device(struct device *dev,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->sync_single_for_device)
> +	if (dma_is_direct(ops))
> +		dma_direct_sync_single_for_device(dev, addr, size, dir);
> +	else if (ops->sync_single_for_device)
>  		ops->sync_single_for_device(dev, addr, size, dir);
>  	debug_dma_sync_single_for_device(dev, addr, size, dir);
>  }
> @@ -387,7 +466,9 @@ dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->sync_sg_for_cpu)
> +	if (dma_is_direct(ops))
> +		dma_direct_sync_sg_for_cpu(dev, sg, nelems, dir);
> +	else if (ops->sync_sg_for_cpu)
>  		ops->sync_sg_for_cpu(dev, sg, nelems, dir);
>  	debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
>  }
> @@ -399,7 +480,9 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->sync_sg_for_device)
> +	if (dma_is_direct(ops))
> +		dma_direct_sync_sg_for_device(dev, sg, nelems, dir);
> +	else if (ops->sync_sg_for_device)
>  		ops->sync_sg_for_device(dev, sg, nelems, dir);
>  	debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
>  
> diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
> index 306557331d7d..69b36ed31a99 100644
> --- a/include/linux/dma-noncoherent.h
> +++ b/include/linux/dma-noncoherent.h
> @@ -38,7 +38,10 @@ pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
>  void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size,
>  		enum dma_data_direction direction);
>  #else
> -#define arch_dma_cache_sync NULL
> +static inline void arch_dma_cache_sync(struct device *dev, void *vaddr,
> +		size_t size, enum dma_data_direction direction)
> +{
> +}
>  #endif /* CONFIG_DMA_NONCOHERENT_CACHE_SYNC */
>  
>  #ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 85d8286a0ba2..79da61b49fa4 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -223,6 +223,7 @@ void dma_direct_sync_single_for_device(struct device *dev,
>  	if (!dev_is_dma_coherent(dev))
>  		arch_sync_dma_for_device(dev, paddr, size, dir);
>  }
> +EXPORT_SYMBOL(dma_direct_sync_single_for_device);
>  
>  void dma_direct_sync_sg_for_device(struct device *dev,
>  		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
> @@ -240,6 +241,7 @@ void dma_direct_sync_sg_for_device(struct device *dev,
>  					dir);
>  	}
>  }
> +EXPORT_SYMBOL(dma_direct_sync_sg_for_device);
>  #endif
>  
>  #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
> @@ -258,6 +260,7 @@ void dma_direct_sync_single_for_cpu(struct device *dev,
>  	if (unlikely(is_swiotlb_buffer(paddr)))
>  		swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
>  }
> +EXPORT_SYMBOL(dma_direct_sync_single_for_cpu);
>  
>  void dma_direct_sync_sg_for_cpu(struct device *dev,
>  		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
> @@ -277,6 +280,7 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
>  	if (!dev_is_dma_coherent(dev))
>  		arch_sync_dma_for_cpu_all(dev);
>  }
> +EXPORT_SYMBOL(dma_direct_sync_sg_for_cpu);
>  
>  void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
>  		size_t size, enum dma_data_direction dir, unsigned long attrs)
> @@ -289,6 +293,7 @@ void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
>  	if (unlikely(is_swiotlb_buffer(phys)))
>  		swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
>  }
> +EXPORT_SYMBOL(dma_direct_unmap_page);
>  
>  void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
>  		int nents, enum dma_data_direction dir, unsigned long attrs)
> @@ -300,11 +305,7 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
>  		dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir,
>  			     attrs);
>  }
> -#else
> -void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
> -		int nents, enum dma_data_direction dir, unsigned long attrs)
> -{
> -}
> +EXPORT_SYMBOL(dma_direct_unmap_sg);
>  #endif
>  
>  static inline bool dma_direct_possible(struct device *dev, dma_addr_t dma_addr,
> @@ -331,6 +332,7 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
>  		arch_sync_dma_for_device(dev, phys, size, dir);
>  	return dma_addr;
>  }
> +EXPORT_SYMBOL(dma_direct_map_page);
>  
>  int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
>  		enum dma_data_direction dir, unsigned long attrs)
> @@ -352,6 +354,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
>  	dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
>  	return 0;
>  }
> +EXPORT_SYMBOL(dma_direct_map_sg);
>  
>  /*
>   * Because 32-bit DMA masks are so common we expect every architecture to be
> @@ -372,27 +375,3 @@ int dma_direct_supported(struct device *dev, u64 mask)
>  
>  	return mask >= phys_to_dma(dev, min_mask);
>  }
> -
> -const struct dma_map_ops dma_direct_ops = {
> -	.alloc			= dma_direct_alloc,
> -	.free			= dma_direct_free,
> -	.map_page		= dma_direct_map_page,
> -	.map_sg			= dma_direct_map_sg,
> -#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
> -    defined(CONFIG_SWIOTLB)
> -	.sync_single_for_device	= dma_direct_sync_single_for_device,
> -	.sync_sg_for_device	= dma_direct_sync_sg_for_device,
> -#endif
> -#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
> -    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
> -    defined(CONFIG_SWIOTLB)
> -	.sync_single_for_cpu	= dma_direct_sync_single_for_cpu,
> -	.sync_sg_for_cpu	= dma_direct_sync_sg_for_cpu,
> -	.unmap_page		= dma_direct_unmap_page,
> -	.unmap_sg		= dma_direct_unmap_sg,
> -#endif
> -	.get_required_mask	= dma_direct_get_required_mask,
> -	.dma_supported		= dma_direct_supported,
> -	.cache_sync		= arch_dma_cache_sync,
> -};
> -EXPORT_SYMBOL(dma_direct_ops);
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index 0b18cfbdde95..fc84c81029d9 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
> @@ -7,6 +7,7 @@
>   */
>  #include <linux/memblock.h> /* for max_pfn */
>  #include <linux/acpi.h>
> +#include <linux/dma-direct.h>
>  #include <linux/dma-noncoherent.h>
>  #include <linux/export.h>
>  #include <linux/gfp.h>
> @@ -229,8 +230,8 @@ int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
>  		unsigned long attrs)
>  {
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
> -	BUG_ON(!ops);
> -	if (ops->get_sgtable)
> +
> +	if (!dma_is_direct(ops) && ops->get_sgtable)
>  		return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size,
>  					attrs);
>  	return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size,
> @@ -293,8 +294,8 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
>  		unsigned long attrs)
>  {
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
> -	BUG_ON(!ops);
> -	if (ops->mmap)
> +
> +	if (!dma_is_direct(ops) && ops->mmap)
>  		return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
>  	return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
>  }
> @@ -324,6 +325,8 @@ u64 dma_get_required_mask(struct device *dev)
>  {
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
> +	if (dma_is_direct(ops))
> +		return dma_direct_get_required_mask(dev);
>  	if (ops->get_required_mask)
>  		return ops->get_required_mask(dev);
>  	return dma_default_get_required_mask(dev);
> @@ -341,7 +344,6 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  	void *cpu_addr;
>  
> -	BUG_ON(!ops);
>  	WARN_ON_ONCE(dev && !dev->coherent_dma_mask);
>  
>  	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
> @@ -352,10 +354,14 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  
>  	if (!arch_dma_alloc_attrs(&dev))
>  		return NULL;
> -	if (!ops->alloc)
> +
> +	if (dma_is_direct(ops))
> +		cpu_addr = dma_direct_alloc(dev, size, dma_handle, flag, attrs);
> +	else if (ops->alloc)
> +		cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs);
> +	else
>  		return NULL;
>  
> -	cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs);
>  	debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr);
>  	return cpu_addr;
>  }
> @@ -366,8 +372,6 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
>  {
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
> -	BUG_ON(!ops);
> -
>  	if (dma_release_from_dev_coherent(dev, get_order(size), cpu_addr))
>  		return;
>  	/*
> @@ -379,11 +383,14 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
>  	 */
>  	WARN_ON(irqs_disabled());
>  
> -	if (!ops->free || !cpu_addr)
> +	if (!cpu_addr)
>  		return;
>  
>  	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
> -	ops->free(dev, size, cpu_addr, dma_handle, attrs);
> +	if (dma_is_direct(ops))
> +		dma_direct_free(dev, size, cpu_addr, dma_handle, attrs);
> +	else if (ops->free)
> +		ops->free(dev, size, cpu_addr, dma_handle, attrs);
>  }
>  EXPORT_SYMBOL(dma_free_attrs);
>  
> @@ -397,9 +404,9 @@ int dma_supported(struct device *dev, u64 mask)
>  {
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
> -	if (!ops)
> -		return 0;
> -	if (!ops->dma_supported)
> +	if (dma_is_direct(ops))
> +		return dma_direct_supported(dev, mask);
> +	if (ops->dma_supported)
>  		return 1;
>  	return ops->dma_supported(dev, mask);
>  }
> @@ -437,7 +444,10 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
>  	const struct dma_map_ops *ops = get_dma_ops(dev);
>  
>  	BUG_ON(!valid_dma_direction(dir));
> -	if (ops->cache_sync)
> +
> +	if (dma_is_direct(ops))
> +		arch_dma_cache_sync(dev, vaddr, size, dir);
> +	else if (ops->cache_sync)
>  		ops->cache_sync(dev, vaddr, size, dir);
>  }
>  EXPORT_SYMBOL(dma_cache_sync);
> 


  parent reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-07 19:07 [RFC] avoid indirect calls for DMA direct mappings v2 Christoph Hellwig
2018-12-07 19:07 ` [PATCH 01/15] swiotlb: remove SWIOTLB_MAP_ERROR Christoph Hellwig
2018-12-07 19:07 ` [PATCH 02/15] swiotlb: remove dma_mark_clean Christoph Hellwig
2019-01-02 21:53   ` Tony Luck
2019-01-03  7:23     ` Christoph Hellwig
2019-01-03 17:35       ` Tony Luck
2019-01-04  8:09         ` Christoph Hellwig
2018-12-07 19:07 ` [PATCH 03/15] dma-direct: improve addressability error reporting Christoph Hellwig
2018-12-07 19:07 ` [PATCH 04/15] dma-direct: use dma_direct_map_page to implement dma_direct_map_sg Christoph Hellwig
2018-12-07 19:07 ` [PATCH 05/15] dma-direct: merge swiotlb_dma_ops into the dma_direct code Christoph Hellwig
2018-12-07 19:07 ` [PATCH 06/15] dma-mapping: simplify the dma_sync_single_range_for_{cpu,device} implementation Christoph Hellwig
2018-12-07 19:07 ` [PATCH 07/15] dma-mapping: merge dma_unmap_page_attrs and dma_unmap_single_attrs Christoph Hellwig
2018-12-07 19:07 ` [PATCH 08/15] dma-mapping: move dma_get_required_mask to kernel/dma Christoph Hellwig
2018-12-07 19:07 ` [PATCH 09/15] dma-mapping: move various slow path functions out of line Christoph Hellwig
2018-12-07 19:07 ` [PATCH 10/15] dma-mapping: move dma_cache_sync " Christoph Hellwig
2018-12-07 19:07 ` [PATCH 11/15] dma-mapping: always build the direct mapping code Christoph Hellwig
2018-12-07 19:07 ` [PATCH 12/15] dma-mapping: factor out dummy DMA ops Christoph Hellwig
2018-12-07 19:07 ` [PATCH 13/15] ACPI / scan: Refactor _CCA enforcement Christoph Hellwig
2018-12-14 21:15   ` Bjorn Helgaas
2018-12-07 19:07 ` [PATCH 14/15] vmd: use the proper dma_* APIs instead of direct methods calls Christoph Hellwig
2018-12-14 21:17   ` Bjorn Helgaas
2018-12-14 21:34     ` Derrick, Jonathan
2018-12-07 19:07 ` [PATCH 15/15] dma-mapping: bypass indirect calls for dma-direct Christoph Hellwig
2018-12-14 14:11   ` Marek Szyprowski
2018-12-14 14:24     ` Christoph Hellwig
2018-12-14 14:32       ` Marek Szyprowski
2018-12-15 17:46   ` [15/15] " Guenter Roeck
2018-12-16  9:02     ` Christoph Hellwig
2018-12-18 20:34   ` Guillaume Tucker [this message]
2018-12-18 20:42     ` Robin Murphy
2018-12-19  6:42       ` Christoph Hellwig
2018-12-20 16:44   ` [PATCH 15/15] " Thierry Reding
2018-12-20 16:46     ` Christoph Hellwig
2018-12-08 16:06 ` [RFC] avoid indirect calls for DMA direct mappings v2 Jesper Dangaard Brouer
2018-12-08 16:50   ` Christoph Hellwig
2018-12-10 21:51 ` Luck, Tony
2018-12-11  6:51   ` Christoph Hellwig
2018-12-11 16:42     ` Luck, Tony
2018-12-11 17:13     ` Luck, Tony
2018-12-11 17:15       ` Christoph Hellwig
2018-12-13 20:08 ` Christoph Hellwig

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