[PATCH 8/8] dma-mapping: remove CONFIG_ARCH_NO_COHERENT_DMA_MMAP

[Christoph Hellwig <hch@lst.de>]

CONFIG_ARCH_NO_COHERENT_DMA_MMAP is now functionally identical to
!CONFIG_MMU, so remove the separate symbol.  The only difference is that
arm did not set it for !CONFIG_MMU, but arm uses a separate dma mapping
implementation including its own mmap method, which is handled by moving
the CONFIG_MMU check in dma_can_mmap so that is only applies to the
dma-direct case, just as the other ifdefs for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/Kconfig            |  3 ---
 arch/c6x/Kconfig        |  1 -
 arch/m68k/Kconfig       |  1 -
 arch/microblaze/Kconfig |  1 -
 arch/sh/Kconfig         |  1 -
 arch/xtensa/Kconfig     |  1 -
 kernel/dma/mapping.c    | 12 +++++-------
 7 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index a7b57dd42c26..ec2834206d08 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -790,9 +790,6 @@ config COMPAT_32BIT_TIME
 	  This is relevant on all 32-bit architectures, and 64-bit architectures
 	  as part of compat syscall handling.
 
-config ARCH_NO_COHERENT_DMA_MMAP
-	bool
-
 config ARCH_NO_PREEMPT
 	bool
 
diff --git a/arch/c6x/Kconfig b/arch/c6x/Kconfig
index b4fb61c83494..e65e8d82442a 100644
--- a/arch/c6x/Kconfig
+++ b/arch/c6x/Kconfig
@@ -20,7 +20,6 @@ config C6X
 	select OF_EARLY_FLATTREE
 	select GENERIC_CLOCKEVENTS
 	select MODULES_USE_ELF_RELA
-	select ARCH_NO_COHERENT_DMA_MMAP
 	select MMU_GATHER_NO_RANGE if MMU
 
 config MMU
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index c518d695c376..614b355ae338 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -8,7 +8,6 @@ config M68K
 	select ARCH_HAS_DMA_PREP_COHERENT if HAS_DMA && MMU && !COLDFIRE
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
 	select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
-	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
 	select ARCH_NO_PREEMPT if !COLDFIRE
 	select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
 	select DMA_DIRECT_REMAP if HAS_DMA && MMU && !COLDFIRE
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index d411de05b628..632c9477a0f6 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -9,7 +9,6 @@ config MICROBLAZE
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_MIGHT_HAVE_PC_PARPORT
-	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT
 	select TIMER_OF
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 6b1b5941b618..f356ee674d89 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -5,7 +5,6 @@ config SUPERH
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_MIGHT_HAVE_PC_PARPORT
-	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
 	select HAVE_PATA_PLATFORM
 	select CLKDEV_LOOKUP
 	select DMA_DECLARE_COHERENT
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index ebc135bda921..70653aed3005 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -5,7 +5,6 @@ config XTENSA
 	select ARCH_HAS_BINFMT_FLAT if !MMU
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_WANT_FRAME_POINTERS
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 64d1de59e133..fc17016b0871 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -186,7 +186,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		unsigned long attrs)
 {
-#ifndef CONFIG_ARCH_NO_COHERENT_DMA_MMAP
+#ifdef CONFIG_MMU
 	unsigned long user_count = vma_pages(vma);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	unsigned long off = vma->vm_pgoff;
@@ -217,7 +217,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 			user_count << PAGE_SHIFT, vma->vm_page_prot);
 #else
 	return -ENXIO;
-#endif /* !CONFIG_ARCH_NO_COHERENT_DMA_MMAP */
+#endif /* CONFIG_MMU */
 }
 
 /**
@@ -231,12 +231,10 @@ bool dma_can_mmap(struct device *dev)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 
-	if (IS_ENABLED(CONFIG_ARCH_NO_COHERENT_DMA_MMAP))
-		return false;
-
 	if (dma_is_direct(ops)) {
-		return dev_is_dma_coherent(dev) ||
-			IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN);
+		return IS_ENABLED(CONFIG_MMU) &&
+		       (dev_is_dma_coherent(dev) ||
+			IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN));
 	}
 
 	return ops->mmap != NULL;
-- 
2.20.1