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dma-pool: Only allocate from CMA when in same memory zone

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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>
This commit is contained in:
Nicolas Saenz Julienne 2020-08-14 12:26:23 +02:00 committed by Christoph Hellwig
parent 9420139f51
commit d7e673ec2c
1 changed files with 30 additions and 1 deletions
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31
kernel/dma/pool.c
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@ -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;