Re: omap3isp cache error when unloading

Michael Jones
2011-03-04T14:39:01Z

Hi David,

On 03/04/2011 02:12 PM, David Cohen wrote:
> Hi,
>
> [snip]
>
>> Sorry, I should've mentioned: I'm using your media-0005-omap3isp branch
>> based on 2.6.38-rc5. I didn't have the problem with 2.6.37, either.
>> It's actually not related to mis-configuring the ISP pipeline like I
>> thought at first- it also happens after I have successfully captured images.
>>
>> I've since tracked down the problem, although I don't understand the
>> cache management well enough to be sure it's a proper fix, so hopefully
>> some new recipients on this can make suggestions/comments.
>>
>> The patch below solves the problem, which modifies a commit by Fernando
>> Guzman Lugo from December.
>>
>> -Michael
>>
>> From db35fb8edca2a4f8fd37197d77fd58676cb1dcac Mon Sep 17 00:00:00 2001
>> From: Michael Jones <michael.jones@matrix-vision.de>
>> Date: Thu, 3 Mar 2011 16:50:39 +0100
>> Subject: [PATCH] fix iovmm slab cache error on module unload
>>
>> modify "OMAP: iommu: create new api to set valid da range"
>>
>> This modifies commit c7f4ab26e3bcdaeb3e19ec658e3ad9092f1a6ceb.
>> ---
>> arch/arm/plat-omap/iovmm.c | 5 ++++-
>> 1 files changed, 4 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/plat-omap/iovmm.c b/arch/arm/plat-omap/iovmm.c
>> index 6dc1296..2fba6f1 100644
>> --- a/arch/arm/plat-omap/iovmm.c
>> +++ b/arch/arm/plat-omap/iovmm.c
>> @@ -280,7 +280,10 @@ static struct iovm_struct *alloc_iovm_area(struct iommu *obj, u32 da,
>> alignement = PAGE_SIZE;
>>
>> if (flags & IOVMF_DA_ANON) {
>> - start = obj->da_start;
>> + /*
>> + * Reserve the first page for NULL
>> + */
>> + start = obj->da_start + PAGE_SIZE;
>
> IMO if obj->da_start != 0, no need to add PAGE_SIZE. Otherwise, it
> does make sense to correct wrong obj->da_start == 0. Another thing is
> this piece of code is using alignement (alignment) variable instead of
> PAGE_SIZE (which is the same value).
>
> Br,
>
> David

I believe the following patch addresses your comments. I couldn't
resist also fixing the misspelling of alignment when I was using the
variable in my patch.

-Michael

>From 2712f2fd087ca782e964c912c7f1973e7d84f2b7 Mon Sep 17 00:00:00 2001
From: Michael Jones <michael.jones@matrix-vision.de>
Date: Fri, 4 Mar 2011 15:09:48 +0100
Subject: [PATCH] omap: iovmm: disallow mapping NULL address

commit c7f4ab26e3bcdaeb3e19ec658e3ad9092f1a6ceb allowed mapping
the NULL address if da_start==0, which would then not get unmapped.
Disallow this again. And spell variable 'alignment' correctly.

Signed-off-by: Michael Jones <michael.jones@matrix-vision.de>
---
arch/arm/plat-omap/iovmm.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm/plat-omap/iovmm.c b/arch/arm/plat-omap/iovmm.c
index 6dc1296..11c9b76 100644
--- a/arch/arm/plat-omap/iovmm.c
+++ b/arch/arm/plat-omap/iovmm.c
@@ -271,20 +271,24 @@ static struct iovm_struct *alloc_iovm_area(struct iommu *obj, u32 da,
size_t bytes, u32 flags)
{
struct iovm_struct *new, *tmp;
- u32 start, prev_end, alignement;
+ u32 start, prev_end, alignment;

if (!obj || !bytes)
return ERR_PTR(-EINVAL);

start = da;
- alignement = PAGE_SIZE;
+ alignment = PAGE_SIZE;

if (flags & IOVMF_DA_ANON) {
- start = obj->da_start;
+ /* Don't map address 0 */
+ if (obj->da_start)
+ start = obj->da_start;
+ else
+ start = obj->da_start + alignment;

if (flags & IOVMF_LINEAR)
- alignement = iopgsz_max(bytes);
- start = roundup(start, alignement);
+ alignment = iopgsz_max(bytes);
+ start = roundup(start, alignment);
} else if (start < obj->da_start || start > obj->da_end ||
obj->da_end - start < bytes) {
return ERR_PTR(-EINVAL);
@@ -304,7 +308,7 @@ static struct iovm_struct *alloc_iovm_area(struct iommu *obj, u32 da,
goto found;

if (tmp->da_end >= start && flags & IOVMF_DA_ANON)
- start = roundup(tmp->da_end + 1, alignement);
+ start = roundup(tmp->da_end + 1, alignment);

prev_end = tmp->da_end;
}
--
1.7.4.1

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