From: Nicolas Saenz Julienne nsaenzjulienne@suse.de
[ Upstream commit d7e673ec2c8e0ea39c4c70fc490d67d7fbda869d ]
There is no guarantee to CMA's placement, so allocating a zone specific atomic pool from CMA might return memory from a completely different memory zone. To get around this double check CMA's placement before allocating from it.
Signed-off-by: Nicolas Saenz Julienne nsaenzjulienne@suse.de Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/dma/pool.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 5d071d4a3cbaa..06582b488e317 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -3,7 +3,9 @@ * Copyright (C) 2012 ARM Ltd. * Copyright (C) 2020 Google LLC */ +#include <linux/cma.h> #include <linux/debugfs.h> +#include <linux/dma-contiguous.h> #include <linux/dma-direct.h> #include <linux/dma-noncoherent.h> #include <linux/init.h> @@ -55,6 +57,29 @@ static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) pool_size_kernel += size; }
+static bool cma_in_zone(gfp_t gfp) +{ + unsigned long size; + phys_addr_t end; + struct cma *cma; + + cma = dev_get_cma_area(NULL); + if (!cma) + return false; + + size = cma_get_size(cma); + if (!size) + return false; + + /* CMA can't cross zone boundaries, see cma_activate_area() */ + end = cma_get_base(cma) + size - 1; + if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA)) + return end <= DMA_BIT_MASK(zone_dma_bits); + if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32)) + return end <= DMA_BIT_MASK(32); + return true; +} + static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, gfp_t gfp) { @@ -68,7 +93,11 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
do { pool_size = 1 << (PAGE_SHIFT + order); - page = alloc_pages(gfp, order); + if (cma_in_zone(gfp)) + page = dma_alloc_from_contiguous(NULL, 1 << order, + order, false); + if (!page) + page = alloc_pages(gfp, order); } while (!page && order-- > 0); if (!page) goto out;