Re: omap3isp cache error when unloading

David Cohen
2011-03-04T15:45:12Z

On Fri, Mar 4, 2011 at 4:39 PM, Michael Jones
<michael.jones@matrix-vision.de> wrote:
> Hi David,

Hi Michael,

>
> 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;

It seems to be fine for me now. Let's see what Hiroshi says.

Regards,

David

>
>                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
>
>
>
> MATRIX VISION GmbH, Talstrasse 16, DE-71570 Oppenweiler
> Registergericht: Amtsgericht Stuttgart, HRB 271090
> Geschaeftsfuehrer: Gerhard Thullner, Werner Armingeon, Uwe Furtner
>