Re: [PATCH 4/4] drivers: dma-contiguous: add initialization from device tree

From: Marek Szyprowski
Date: Mon Jul 07 2014 - 06:36:48 EST


Hello,

On 2014-07-04 07:52, Joonsoo Kim wrote:
-----Original Message-----
From: Marek Szyprowski [mailto:m.szyprowski@xxxxxxxxxxx]
Sent: Wednesday, July 02, 2014 7:49 PM

Subject: [PATCH 4/4] drivers: dma-contiguous: add initialization from
device tree

Add a code to create CMA region from reserved memory and add support for
handling 'shared-dma-pool' reserved-memory device tree nodes.

Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/base/dma-contiguous.c | 67
+++++++++++++++++++++++++++++++++++++++++
include/linux/cma.h | 3 ++
mm/cma.c | 69
++++++++++++++++++++++++++++++++-----------
3 files changed, 122 insertions(+), 17 deletions(-)


...

+/**
* cma_declare_contiguous() - reserve custom contiguous area
* @base: Base address of the reserved area optional, use 0 for any
* @size: Size of the reserved area (in bytes),
@@ -162,18 +210,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
phys_addr_t alignment, unsigned int order_per_bit,
bool fixed, struct cma **res_cma)
{
- struct cma *cma;
- int ret = 0;
+ int ret;

pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
__func__, (unsigned long)size, (unsigned long)base,
(unsigned long)limit, (unsigned long)alignment);

- if (cma_area_count == ARRAY_SIZE(cma_areas)) {
- pr_err("Not enough slots for CMA reserved regions!\n");
- return -ENOSPC;
- }
-
Hello, Marek.

After this change, if we have not enough cma_areas, memory will leak.
I think that we need separate function to check constraint and this
function should be called before reserving memory in
cma_declare_contiguous().

Well, I will leave this check to avoid memory leak then.

BTW, this mail doesn't appear in LKML. What happens? :)

I have no idea, I will send second version then.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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