[7/7] dma-mapping: Simplify arch_setup_dma_ops()

Commit Message

Robin Murphy Nov. 29, 2023, 5:43 p.m. UTC

The dma_base, size and iommu arguments are only used by ARM, and can
now easily be deduced from the device itself, so there's no need to pass
them through the callchain as well.

Signed-off-by: Robin Murphy <[e-mail]>
---
 arch/arc/mm/dma.c               |  3 +--
 arch/arm/mm/dma-mapping-nommu.c |  3 +--
 arch/arm/mm/dma-mapping.c       | 12 ++++++++----
 arch/arm64/mm/dma-mapping.c     |  3 +--
 arch/mips/mm/dma-noncoherent.c  |  3 +--
 arch/riscv/mm/dma-noncoherent.c |  3 +--
 drivers/acpi/scan.c             |  3 +--
 drivers/hv/hv_common.c          |  6 +-----
 drivers/of/device.c             |  4 +---
 include/linux/dma-map-ops.h     |  6 ++----
 10 files changed, 18 insertions(+), 28 deletions(-)

Comments

Christoph Hellwig Dec. 4, 2023, 8:44 a.m. UTC | #1

On Wed, Nov 29, 2023 at 05:43:04PM +0000, Robin Murphy wrote:
> The dma_base, size and iommu arguments are only used by ARM, and can
> now easily be deduced from the device itself, so there's no need to pass
> them through the callchain as well.

This looks even better than the patch form Jason that only removed the
iommu argument:

Reviewed-by: Christoph Hellwig <[e-mail]>

I wonder if it makes sense to also remove the coherent argument
by setting up dev->dma_coherent in the caller.  That would require
a pretty careful audit as we're doing a few weird things in that
area, though.

Robin Murphy Dec. 4, 2023, 12:54 p.m. UTC | #2

On 04/12/2023 8:44 am, Christoph Hellwig wrote:
> On Wed, Nov 29, 2023 at 05:43:04PM +0000, Robin Murphy wrote:
>> The dma_base, size and iommu arguments are only used by ARM, and can
>> now easily be deduced from the device itself, so there's no need to pass
>> them through the callchain as well.
> 
> This looks even better than the patch form Jason that only removed the
> iommu argument:
> 
> Reviewed-by: Christoph Hellwig <[e-mail]>
> 
> I wonder if it makes sense to also remove the coherent argument
> by setting up dev->dma_coherent in the caller.  That would require
> a pretty careful audit as we're doing a few weird things in that
> area, though.

Yeah, it crossed my mind too, but then I remembered we have at least the 
ARM stuff which may have already set a platform-specific value for 
dev->dma_coherent to take precedence over the firmware value, thus still 
needs to differentiate between the two at this point. Leaving the 
established argument in place seems neater IMO than having to go back to 
arch-specific mechanisms for that and any other similar tricks.

Thanks,
Robin.

Patch

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 2a7fbbb83b70..6b85e94f3275 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -90,8 +90,7 @@  void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 /*
  * Plug in direct dma map ops.
  */
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-			const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	/*
 	 * IOC hardware snoops all DMA traffic keeping the caches consistent
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index cfd9c933d2f0..97db5397c320 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -33,8 +33,7 @@  void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 	}
 }
 
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-			const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	if (IS_ENABLED(CONFIG_CPU_V7M)) {
 		/*
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 5409225b4abc..70a2131f9b09 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1716,7 +1716,12 @@  static void arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
 				    const struct iommu_ops *iommu, bool coherent)
 {
 	struct dma_iommu_mapping *mapping;
+	u64 dma_base = 0, size = SZ_4GB;
 
+	if (dev->dma_range_map) {
+		dma_base = dma_range_map_min(dev->dma_range_map);
+		size = dma_range_map_max(dev->dma_range_map) - dma_base;
+	}
 	mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
 	if (IS_ERR(mapping)) {
 		pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
@@ -1756,8 +1761,7 @@  static void arm_teardown_iommu_dma_ops(struct device *dev) { }
 
 #endif	/* CONFIG_ARM_DMA_USE_IOMMU */
 
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-			const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	/*
 	 * Due to legacy code that sets the ->dma_coherent flag from a bus
@@ -1776,8 +1780,8 @@  void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 	if (dev->dma_ops)
 		return;
 
-	if (iommu)
-		arm_setup_iommu_dma_ops(dev, dma_base, size, iommu, coherent);
+	if (device_iommu_mapped(dev))
+		arm_setup_iommu_dma_ops(dev);
 
 	xen_setup_dma_ops(dev);
 	dev->archdata.dma_ops_setup = true;
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 96ff791199e8..0b320a25a471 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -46,8 +46,7 @@  void arch_teardown_dma_ops(struct device *dev)
 }
 #endif
 
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-			const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	int cls = cache_line_size_of_cpu();
 
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index 3c4fc97b9f39..ab4f2a75a7d0 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -137,8 +137,7 @@  void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 #endif
 
 #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-		const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	dev->dma_coherent = coherent;
 }
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index 4e4e469b8dd6..cb89d7e0ba88 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -128,8 +128,7 @@  void arch_dma_prep_coherent(struct page *page, size_t size)
 	ALT_CMO_OP(FLUSH, flush_addr, size, riscv_cbom_block_size);
 }
 
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-		const struct iommu_ops *iommu, bool coherent)
+void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	WARN_TAINT(!coherent && riscv_cbom_block_size > ARCH_DMA_MINALIGN,
 		   TAINT_CPU_OUT_OF_SPEC,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index ee88a727f200..cad171fc31e8 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1640,8 +1640,7 @@  int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
 	if (PTR_ERR(iommu) == -EPROBE_DEFER)
 		return -EPROBE_DEFER;
 
-	arch_setup_dma_ops(dev, 0, U64_MAX,
-				iommu, attr == DEV_DMA_COHERENT);
+	arch_setup_dma_ops(dev, attr == DEV_DMA_COHERENT);
 
 	return 0;
 }
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 4372f5d146ab..0e2decd1167a 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -484,11 +484,7 @@  EXPORT_SYMBOL_GPL(hv_query_ext_cap);
 
 void hv_setup_dma_ops(struct device *dev, bool coherent)
 {
-	/*
-	 * Hyper-V does not offer a vIOMMU in the guest
-	 * VM, so pass 0/NULL for the IOMMU settings
-	 */
-	arch_setup_dma_ops(dev, 0, 0, NULL, coherent);
+	arch_setup_dma_ops(dev, coherent);
 }
 EXPORT_SYMBOL_GPL(hv_setup_dma_ops);
 
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 66879edb4a61..3394751015d3 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -96,7 +96,6 @@  int of_dma_configure_id(struct device *dev, struct device_node *np,
 	const struct iommu_ops *iommu;
 	const struct bus_dma_region *map = NULL;
 	struct device_node *bus_np;
-	u64 dma_start = 0;
 	u64 mask, end = 0;
 	bool coherent;
 	int ret;
@@ -118,7 +117,6 @@  int of_dma_configure_id(struct device *dev, struct device_node *np,
 			return ret == -ENODEV ? 0 : ret;
 	} else {
 		/* Determine the overall bounds of all DMA regions */
-		dma_start = dma_range_map_min(map);
 		end = dma_range_map_max(map);
 	}
 
@@ -167,7 +165,7 @@  int of_dma_configure_id(struct device *dev, struct device_node *np,
 	dev_dbg(dev, "device is%sbehind an iommu\n",
 		iommu ? " " : " not ");
 
-	arch_setup_dma_ops(dev, dma_start, end - dma_start + 1, iommu, coherent);
+	arch_setup_dma_ops(dev, coherent);
 
 	if (!iommu)
 		of_dma_set_restricted_buffer(dev, np);
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index a52e508d1869..023f265eae2e 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -426,11 +426,9 @@  bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
 #endif
 
 #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
-void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-		const struct iommu_ops *iommu, bool coherent);
+void arch_setup_dma_ops(struct device *dev, bool coherent);
 #else
-static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
-		u64 size, const struct iommu_ops *iommu, bool coherent)
+static inline void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 }
 #endif /* CONFIG_ARCH_HAS_SETUP_DMA_OPS */