[v3 1/4] ARM: dma-mapping: atomic_pool with struct page **pages

[Hiroshi Doyu]

struct page **pages is necessary to align with non atomic path in
__iommu_get_pages(). atomic_pool() has the intialized **pages instead
of just *page.

Signed-off-by: Hiroshi Doyu <hdoyu at nvidia.com>
---
 arch/arm/mm/dma-mapping.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 601da7a..b14ee64 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -296,7 +296,7 @@ struct dma_pool {
 	unsigned long *bitmap;
 	unsigned long nr_pages;
 	void *vaddr;
-	struct page *page;
+	struct page **pages;
 };
 
 static struct dma_pool atomic_pool = {
@@ -335,12 +335,16 @@ static int __init atomic_pool_init(void)
 	unsigned long nr_pages = pool->size >> PAGE_SHIFT;
 	unsigned long *bitmap;
 	struct page *page;
+	struct page **pages;
 	void *ptr;
 	int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
+	size_t size = nr_pages * sizeof(struct page *);
 
-	bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+	size += bitmap_size;
+	bitmap = kzalloc(size, GFP_KERNEL);
 	if (!bitmap)
 		goto no_bitmap;
+	pages = (void *)bitmap + bitmap_size;
 
 	if (IS_ENABLED(CONFIG_CMA))
 		ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
@@ -348,9 +352,14 @@ static int __init atomic_pool_init(void)
 		ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
 					   &page, NULL);
 	if (ptr) {
+		int i;
+
+		for (i = 0; i < nr_pages; i++)
+			pages[i] = page + i;
+
 		spin_lock_init(&pool->lock);
 		pool->vaddr = ptr;
-		pool->page = page;
+		pool->pages = pages;
 		pool->bitmap = bitmap;
 		pool->nr_pages = nr_pages;
 		pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n",
@@ -481,7 +490,7 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page)
 	if (pageno < pool->nr_pages) {
 		bitmap_set(pool->bitmap, pageno, count);
 		ptr = pool->vaddr + PAGE_SIZE * pageno;
-		*ret_page = pool->page + pageno;
+		*ret_page = pool->pages[pageno];
 	} else {
 		pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too small!\n"
 			    "Please increase it with coherent_pool= kernel parameter!\n",
-- 
1.7.5.4