Subject: Re: [patch] ps3disk: passing wrong variable to bvec_kunmap_irq()

From: Jens Axboe <[email-masked]>
Date: Sun, 17 Oct 2010 08:49:29 +0200

On 2010-10-16 21:39, Geert Uytterhoeven wrote:
> On Mon, Oct 11, 2010 at 21:42, Jens Axboe <[email-masked]> wrote:
>> On 2010-10-11 21:13, Dan Carpenter wrote:
>>> This should pass "buf" to bvec_kunmap_irq() instead of "bv".  The api is
>>> like kmap_atomic() instead of kmap().
>>>
>>> Signed-off-by: Dan Carpenter <[email-masked]>
>>>
>>> diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
>>> index e9da874..03688c2 100644
>>> --- a/drivers/block/ps3disk.c
>>> +++ b/drivers/block/ps3disk.c
>>> @@ -113,7 +113,7 @@ static void ps3disk_scatter_gather(struct ps3_storage_device *dev,
>>>                       memcpy(buf, dev->bounce_buf+offset, size);
>>>               offset += size;
>>>               flush_kernel_dcache_page(bvec->bv_page);
>>> -             bvec_kunmap_irq(bvec, &flags);
>>> +             bvec_kunmap_irq(buf, &flags);
>>>               i++;
>>>       }
>>>  }
>>
>> Thanks applied, that bug is all too common.
> 
> Because  bvec_kunmap_irq() is a macro if !CONFIG_HIGHMEM, and thus there's no
> argument type checking on e.g. pp64, which doesn't support HIGHMEM?

It's a generic problem, not isolated to this case. The problem is that
the API isn't symmetric, and the unmap parts take a void * pointer.

-- 
Jens Axboe