dma-pool: fix coherent pool allocations for IOMMU mappings

When allocating coherent pool memory for an IOMMU mapping we don't care
about the DMA mask.  Move the guess for the initial GFP mask into the
dma_direct_alloc_pages and pass dma_coherent_ok as a function pointer
argument so that it doesn't get applied to the IOMMU case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Amit Pundir <amit.pundir@linaro.org>

2 files changed, 57 insertions, 70 deletions

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index bb0041e99659..db6ef07aec3b 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -43,7 +43,7 @@ u64 dma_direct_get_required_mask(struct device *dev)
 	return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
 }
 
-gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
+static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
 				  u64 *phys_limit)
 {
 	u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);
@@ -68,7 +68,7 @@ gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
 	return 0;
 }
 
-bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
+static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 {
 	return phys_to_dma_direct(dev, phys) + size - 1 <=
 			min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
@@ -161,8 +161,13 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 	size = PAGE_ALIGN(size);
 
 	if (dma_should_alloc_from_pool(dev, gfp, attrs)) {
-		ret = dma_alloc_from_pool(dev, size, &page, gfp);
-		if (!ret)
+		u64 phys_mask;
+
+		gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
+				&phys_mask);
+		page = dma_alloc_from_pool(dev, size, &ret, gfp,
+				dma_coherent_ok);
+		if (!page)
 			return NULL;
 		goto done;
 	}
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 6bc74a2d5127..5d071d4a3cba 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -196,93 +196,75 @@ static int __init dma_atomic_pool_init(void)
 }
 postcore_initcall(dma_atomic_pool_init);
 
-static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev)
+static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
 {
-	u64 phys_mask;
-	gfp_t gfp;
-
-	gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
-					  &phys_mask);
-	if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)
+	if (prev == NULL) {
+		if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
+			return atomic_pool_dma32;
+		if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
+			return atomic_pool_dma;
+		return atomic_pool_kernel;
+	}
+	if (prev == atomic_pool_kernel)
+		return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
+	if (prev == atomic_pool_dma32)
 		return atomic_pool_dma;
-	if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)
-		return atomic_pool_dma32;
-	return atomic_pool_kernel;
+	return NULL;
 }
 
-static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool)
+static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
+		struct gen_pool *pool, void **cpu_addr,
+		bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
 {
-	if (bad_pool == atomic_pool_kernel)
-		return atomic_pool_dma32 ? : atomic_pool_dma;
+	unsigned long addr;
+	phys_addr_t phys;
 
-	if (bad_pool == atomic_pool_dma32)
-		return atomic_pool_dma;
+	addr = gen_pool_alloc(pool, size);
+	if (!addr)
+		return NULL;
 
-	return NULL;
-}
+	phys = gen_pool_virt_to_phys(pool, addr);
+	if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
+		gen_pool_free(pool, addr, size);
+		return NULL;
+	}
 
-static inline struct gen_pool *dma_guess_pool(struct device *dev,
-					      struct gen_pool *bad_pool)
-{
-	if (bad_pool)
-		return dma_get_safer_pool(bad_pool);
+	if (gen_pool_avail(pool) < atomic_pool_size)
+		schedule_work(&atomic_pool_work);
 
-	return dma_guess_pool_from_device(dev);
+	*cpu_addr = (void *)addr;
+	memset(*cpu_addr, 0, size);
+	return pfn_to_page(__phys_to_pfn(phys));
 }
 
-void *dma_alloc_from_pool(struct device *dev, size_t size,
-			  struct page **ret_page, gfp_t flags)
+struct page *dma_alloc_from_pool(struct device *dev, size_t size,
+		void **cpu_addr, gfp_t gfp,
+		bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
 {
 	struct gen_pool *pool = NULL;
-	unsigned long val = 0;
-	void *ptr = NULL;
-	phys_addr_t phys;
-
-	while (1) {
-		pool = dma_guess_pool(dev, pool);
-		if (!pool) {
-			WARN(1, "Failed to get suitable pool for %s\n",
-			     dev_name(dev));
-			break;
-		}
-
-		val = gen_pool_alloc(pool, size);
-		if (!val)
-			continue;
-
-		phys = gen_pool_virt_to_phys(pool, val);
-		if (dma_coherent_ok(dev, phys, size))
-			break;
-
-		gen_pool_free(pool, val, size);
-		val = 0;
-	}
-
-
-	if (val) {
-		*ret_page = pfn_to_page(__phys_to_pfn(phys));
-		ptr = (void *)val;
-		memset(ptr, 0, size);
+	struct page *page;
 
-		if (gen_pool_avail(pool) < atomic_pool_size)
-			schedule_work(&atomic_pool_work);
+	while ((pool = dma_guess_pool(pool, gfp))) {
+		page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
+					     phys_addr_ok);
+		if (page)
+			return page;
 	}
 
-	return ptr;
+	WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
+	return NULL;
 }
 
 bool dma_free_from_pool(struct device *dev, void *start, size_t size)
 {
 	struct gen_pool *pool = NULL;
 
-	while (1) {
-		pool = dma_guess_pool(dev, pool);
-		if (!pool)
-			return false;
-
-		if (gen_pool_has_addr(pool, (unsigned long)start, size)) {
-			gen_pool_free(pool, (unsigned long)start, size);
-			return true;
-		}
+	while ((pool = dma_guess_pool(pool, 0))) {
+		if (!gen_pool_has_addr(pool, (unsigned long)start, size))
+			continue;
+		gen_pool_free(pool, (unsigned long)start, size);
+		return true;
 	}
+
+	return false;
 }