dma-mapping: remove CONFIG_DMA_REMAP

CONFIG_DMA_REMAP is used to build a few helpers around the core vmalloc code, and to use them in case there is a highmem page in dma-direct, and to make dma coherent allocations be able to use non-contiguous pages allocations for DMA allocations in the dma-iommu layer. Right now it needs to be explicitly selected by architectures, and is only done so by architectures that require remapping to deal with devices that are not DMA coherent. Make it unconditional for builds with CONFIG_MMU as it is very little extra code, but makes it much more likely that large DMA allocations succeed on x86. This fixes hot plugging a NVMe thunderbolt SSD for me, which tries to allocate a 1MB buffer that is otherwise hard to obtain due to memory fragmentation on a heavily used laptop.

Christoph Hellwig committed 4 years ago

Commit f5ff79f1 parent fba09096 files · +16 −29Browse files

Unified · Split

6 files

arch/arm/Kconfig +1 −1
arch/xtensa/Kconfig +1 −1
drivers/iommu/dma-iommu.c +5 −9
kernel/dma/Kconfig +1 −6
kernel/dma/Makefile +1 −1
kernel/dma/direct.c +7 −11

arch/arm/Kconfig+1−1

@@ -47,7 +47,7 @@ config ARM · 46 unmodified lines
47	47	select DMA_DECLARE_COHERENT
48	48	select DMA_GLOBAL_POOL if !MMU
49	49	select DMA_OPS
50		− select DMA_REMAP if MMU
	50	+ select DMA_NONCOHERENT_MMAP if MMU
51	51	select EDAC_SUPPORT
52	52	select EDAC_ATOMIC_SCRUB
53	53	select GENERIC_ALLOCATOR

arch/xtensa/Kconfig+1−1

@@ -17,7 +17,7 @@ config XTENSA · 16 unmodified lines
17	17	select BUILDTIME_TABLE_SORT
18	18	select CLONE_BACKWARDS
19	19	select COMMON_CLK
20		− select DMA_REMAP if MMU
	20	+ select DMA_NONCOHERENT_MMAP if MMU
21	21	select GENERIC_ATOMIC64
22	22	select GENERIC_IRQ_SHOW
23	23	select GENERIC_PCI_IOMAP

drivers/iommu/dma-iommu.c+5−9

@@ -852,7 +852,6 @@ out_unmap: · 851 unmodified lines
852	852	return NULL;
853	853	}
854	854
855		−#ifdef CONFIG_DMA_REMAP
856	855	static struct sg_table iommu_dma_alloc_noncontiguous(struct device dev,
857	856	size_t size, enum dma_data_direction dir, gfp_t gfp,
858	857	unsigned long attrs)
@@ -882,7 +881,6 @@ static void iommu_dma_free_noncontiguous(struct device *dev, size_t size, · 23 unmodified lines
882	881	sg_free_table(&sh->sgt);
883	882	kfree(sh);
884	883	}
885		−#endif /* CONFIG_DMA_REMAP */
886	884
887	885	static void iommu_dma_sync_single_for_cpu(struct device *dev,
888	886	dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
@@ -1276,7 +1274,7 @@ static void __iommu_dma_free(struct device dev, size_t size, void cpu_addr) · 387 unmodified lines
1276	1274	dma_free_from_pool(dev, cpu_addr, alloc_size))
1277	1275	return;
1278	1276
1279		− if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
	1277	+ if (is_vmalloc_addr(cpu_addr)) {
1280	1278	/*
1281	1279	* If it the address is remapped, then it's either non-coherent
1282	1280	* or highmem CMA, or an iommu_dma_alloc_remap() construction.
@@ -1318,7 +1316,7 @@ static void iommu_dma_alloc_pages(struct device dev, size_t size, · 35 unmodified lines
1318	1316	if (!page)
1319	1317	return NULL;
1320	1318
1321		− if (IS_ENABLED(CONFIG_DMA_REMAP) && (!coherent \|\| PageHighMem(page))) {
	1319	+ if (!coherent \|\| PageHighMem(page)) {
1322	1320	pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);
1323	1321
1324	1322	cpu_addr = dma_common_contiguous_remap(page, alloc_size,
@@ -1350,7 +1348,7 @@ static void iommu_dma_alloc(struct device dev, size_t size, · 25 unmodified lines
1350	1348
1351	1349	gfp \|= __GFP_ZERO;
1352	1350
1353		− if (IS_ENABLED(CONFIG_DMA_REMAP) && gfpflags_allow_blocking(gfp) &&
	1351	+ if (gfpflags_allow_blocking(gfp) &&
1354	1352	!(attrs & DMA_ATTR_FORCE_CONTIGUOUS)) {
1355	1353	return iommu_dma_alloc_remap(dev, size, handle, gfp,
1356	1354	dma_pgprot(dev, PAGE_KERNEL, attrs), attrs);
@@ -1391,7 +1389,7 @@ static int iommu_dma_mmap(struct device dev, struct vm_area_struct vma, · 34 unmodified lines
1391	1389	if (off >= nr_pages \|\| vma_pages(vma) > nr_pages - off)
1392	1390	return -ENXIO;
1393	1391
1394		− if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
	1392	+ if (is_vmalloc_addr(cpu_addr)) {
1395	1393	struct page **pages = dma_common_find_pages(cpu_addr);
1396	1394
1397	1395	if (pages)
@@ -1413,7 +1411,7 @@ static int iommu_dma_get_sgtable(struct device dev, struct sg_table sgt, · 15 unmodified lines
1413	1411	struct page *page;
1414	1412	int ret;
1415	1413
1416		− if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
	1414	+ if (is_vmalloc_addr(cpu_addr)) {
1417	1415	struct page **pages = dma_common_find_pages(cpu_addr);
1418	1416
1419	1417	if (pages) {
@@ -1445,10 +1443,8 @@ static const struct dma_map_ops iommu_dma_ops = { · 25 unmodified lines
1445	1443	.free = iommu_dma_free,
1446	1444	.alloc_pages = dma_common_alloc_pages,
1447	1445	.free_pages = dma_common_free_pages,
1448		−#ifdef CONFIG_DMA_REMAP
1449	1446	.alloc_noncontiguous = iommu_dma_alloc_noncontiguous,
1450	1447	.free_noncontiguous = iommu_dma_free_noncontiguous,
1451		−#endif
1452	1448	.mmap = iommu_dma_mmap,
1453	1449	.get_sgtable = iommu_dma_get_sgtable,
1454	1450	.map_page = iommu_dma_map_page,

kernel/dma/Kconfig+1−6

@@ -110,15 +110,10 @@ config DMA_GLOBAL_POOL · 109 unmodified lines
110	110	select DMA_DECLARE_COHERENT
111	111	bool
112	112
113		−config DMA_REMAP
114		− bool
115		− depends on MMU
116		− select DMA_NONCOHERENT_MMAP
117		−
118	113	config DMA_DIRECT_REMAP
119	114	bool
120		− select DMA_REMAP
121	115	select DMA_COHERENT_POOL
	116	+ select DMA_NONCOHERENT_MMAP
122	117
123	118	config DMA_CMA
124	119	bool "DMA Contiguous Memory Allocator"

kernel/dma/Makefile+1−1

@@ -8,5 +8,5 @@ obj-$(CONFIG_DMA_DECLARE_COHERENT) += coherent.o · 7 unmodified lines
8	8	obj-$(CONFIG_DMA_API_DEBUG) += debug.o
9	9	obj-$(CONFIG_SWIOTLB) += swiotlb.o
10	10	obj-$(CONFIG_DMA_COHERENT_POOL) += pool.o
11		−obj-$(CONFIG_DMA_REMAP) += remap.o
	11	+obj-$(CONFIG_MMU) += remap.o
12	12	obj-$(CONFIG_DMA_MAP_BENCHMARK) += map_benchmark.o

kernel/dma/direct.c+7−11

@@ -265,17 +265,13 @@ void dma_direct_alloc(struct device dev, size_t size, · 264 unmodified lines
265	265	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
266	266	if (!page)
267	267	return NULL;
	268	+
	269	+ /*
	270	+ * dma_alloc_contiguous can return highmem pages depending on a
	271	+ * combination the cma= arguments and per-arch setup. These need to be
	272	+ * remapped to return a kernel virtual address.
	273	+ */
268	274	if (PageHighMem(page)) {
269		− /*
270		− * Depending on the cma= arguments and per-arch setup,
271		− * dma_alloc_contiguous could return highmem pages.
272		− * Without remapping there is no way to return them here, so
273		− * log an error and fail.
274		− */
275		− if (!IS_ENABLED(CONFIG_DMA_REMAP)) {
276		− dev_info(dev, "Rejecting highmem page from CMA.\n");
277		− goto out_free_pages;
278		− }
279	275	remap = true;
280	276	set_uncached = false;
281	277	}
@@ -349,7 +345,7 @@ void dma_direct_free(struct device *dev, size_t size, · 67 unmodified lines
349	345	dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
350	346	return;
351	347
352		− if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
	348	+ if (is_vmalloc_addr(cpu_addr)) {
353	349	vunmap(cpu_addr);
354	350	} else {
355	351	if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))