Hi,
I have merged this to a 5.8 tree along with "dma-pool: Fix atomic pool selection" and tested it in various ACPI/DT combinations, particularly on the RPI4. It seems to be working fine.
So thanks for your time and effort clearing this up! tested-by: Jeremy Linton <jeremy.lin...@arm.com> On 7/10/20 9:10 AM, Nicolas Saenz Julienne wrote:
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. Fixes: c84dc6e68a1d ("dma-pool: add additional coherent pools to map to gfp mask") Reported-by: Jeremy Linton <jeremy.lin...@arm.com> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulie...@suse.de> --- This is a code intensive alternative to "dma-pool: Do not allocate pool memory from CMA"[1]. [1] https://lkml.org/lkml/2020/7/8/1108 kernel/dma/pool.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 8cfa01243ed2..ccf3eeb77e00 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -3,6 +3,7 @@ * Copyright (C) 2012 ARM Ltd. * Copyright (C) 2020 Google LLC */ +#include <linux/cma.h> #include <linux/debugfs.h> #include <linux/dma-direct.h> #include <linux/dma-noncoherent.h> @@ -56,6 +57,39 @@ 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)+{ + u64 zone_dma_end, zone_dma32_end; + phys_addr_t base, end; + unsigned long size; + struct cma *cma; + + cma = dev_get_cma_area(NULL); + if (!cma) + return false; + + size = cma_get_size(cma); + if (!size) + return false; + base = cma_get_base(cma) - memblock_start_of_DRAM(); + end = base + size - 1; + + zone_dma_end = IS_ENABLED(CONFIG_ZONE_DMA) ? DMA_BIT_MASK(zone_dma_bits) : 0; + zone_dma32_end = IS_ENABLED(CONFIG_ZONE_DMA32) ? DMA_BIT_MASK(32) : 0; + + /* CMA can't cross zone boundaries, see cma_activate_area() */ + if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp & GFP_DMA && + end <= zone_dma_end) + return true; + else if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp & GFP_DMA32 && + base > zone_dma_end && end <= zone_dma32_end) + return true; + else if (base > zone_dma32_end) + return true; + + return false; +} + static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, gfp_t gfp) { @@ -70,7 +104,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, do { pool_size = 1 << (PAGE_SHIFT + order);- if (dev_get_cma_area(NULL))+ if (cma_in_zone(gfp)) page = dma_alloc_from_contiguous(NULL, 1 << order, order, false); else
