From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: amit.pundir@linaro.org, hch@lst.de, linux-kernel@vger.kernel.org,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>
Cc: rientjes@google.com, jeremy.linton@arm.com,
linux-rpi-kernel@lists.infradead.org,
Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
iommu@lists.linux-foundation.org
Subject: [PATCH v3 2/2] dma-pool: Only allocate from CMA when in same memory zone
Date: Thu, 6 Aug 2020 20:47:55 +0200 [thread overview]
Message-ID: <20200806184756.32075-3-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20200806184756.32075-1-nsaenzjulienne@suse.de>
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>
[hch: rebased, added a fallback to the page allocator, allow dipping into
lower CMA pools]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
Changes since v2:
- Go back to v1 behavior
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 5d071d4a3cba..30d28d761490 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) - memblock_start_of_DRAM() + 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;
--
2.28.0
next prev parent reply other threads:[~2020-08-06 18:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 18:47 [PATCH v3 0/2] dma-pool fixes Nicolas Saenz Julienne
2020-08-06 18:47 ` [PATCH v3 1/2] dma-pool: fix coherent pool allocations for IOMMU mappings Nicolas Saenz Julienne
2020-08-06 18:47 ` Nicolas Saenz Julienne [this message]
2020-08-07 0:16 ` [PATCH v3 2/2] dma-pool: Only allocate from CMA when in same memory zone kernel test robot
2020-08-07 5:21 ` Christoph Hellwig
2020-08-07 8:50 ` Nicolas Saenz Julienne
2020-08-08 6:33 ` Christoph Hellwig
2020-08-14 6:06 ` Christoph Hellwig
2020-08-14 10:03 ` Nicolas Saenz Julienne
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