Hi Marek,
Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote @ Wed, 22 Aug 2012 14:04:26 +0200:
> Hi Hiroshi,
>
> On Wednesday, August 22, 2012 12:20 PM Hiroshi Doyu wrote:
>
> > The commit e9da6e9 "ARM: dma-mapping: remove custom consistent dma
> > region" breaks the compatibility with existing drivers. This causes
> > the following kernel oops(*1). That driver has called dma_pool_alloc()
> > to allocate memory from the interrupt context, and it hits
> > BUG_ON(in_interrpt()) in "get_vm_area_caller()". This patch seris
> > fixes this problem with making use of the pre-allocate atomic memory
> > pool which DMA is using in the same way as DMA does now.
> >
> > Any comment would be really appreciated.
>
> I was working on the similar patches, but You were faster. ;-)
Thank you for reviewing my patches.
> Basically the patch no 1 and 2 are fine, but I don't like the changes proposed in
> patch 3 and 4. You should not alter the attributes provided by the user nor make any
> assumptions that such attributes has been provided - drivers are allowed to call
> dma_alloc_attrs() directly. Please rework your patches to avoid such
> approach.
Sure. I'll send the series again later.
Instead of making use of DMA_ATTR_NO_KERNEL_MAPPING, I use the
following "__in_atomic_pool()" to see if buffer comes from atomic or
not at freeing.
>From cdf8621fd0876f3e56a55885c27e363893df2c98 Mon Sep 17 00:00:00 2001
From: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
Date: Wed, 22 Aug 2012 17:26:29 +0300
Subject: [PATCH 1/1] ARM: dma-mapping: Refactor out to introduce
__in_atomic_pool
Check the given range("start", "size") is included in "atomic_pool" or not.
Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
---
arch/arm/mm/dma-mapping.c | 20 +++++++++++++++-----
1 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 30bef80..26080ef 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -450,20 +450,30 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page)
return ptr;
}
-static int __free_from_pool(void *start, size_t size)
+static bool __in_atomic_pool(void *start, size_t size)
{
struct dma_pool *pool = &atomic_pool;
- unsigned long pageno, count;
- unsigned long flags;
if (start < pool->vaddr || start > pool->vaddr + pool->size)
- return 0;
+ return false;
if (start + size > pool->vaddr + pool->size) {
WARN(1, "freeing wrong coherent size from pool\n");
- return 0;
+ return false;
}
+ return true;
+}
+
+static int __free_from_pool(void *start, size_t size)
+{
+ struct dma_pool *pool = &atomic_pool;
+ unsigned long pageno, count;
+ unsigned long flags;
+
+ if (!__in_atomic_pool(start, size))
+ return 0;
+
pageno = (start - pool->vaddr) >> PAGE_SHIFT;
count = size >> PAGE_SHIFT;
--
1.7.5.4
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