lkml.org 
[lkml]   [2019]   [Apr]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] dma-mapping: remove an unnecessary NULL check
From
Date
On 24/04/2019 15:27, Christoph Hellwig wrote:
> On Wed, Apr 24, 2019 at 05:24:37PM +0300, Dan Carpenter wrote:
>> We already dereferenced "dev" when we called get_dma_ops() so this NULL
>> check is too late. We're not supposed to pass NULL "dev" pointers to
>> dma_alloc_attrs().
>
> Thanks, applied to the dma-mapping for-next tree.
>
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>> ---
>> There are still at least two drivers which do pass a NULL unfortunately.
>>
>> drivers/staging/comedi/drivers/comedi_isadma.c:195 comedi_isadma_alloc() error: NULL dereference inside function 'dma_alloc_coherent()'
>> drivers/staging/comedi/drivers/comedi_isadma.c:227 comedi_isadma_free() error: NULL dereference inside function 'dma_free_coherent()'
>
> This is staging code. Per official decree from Linus we can just
> ignore it, and I tend to do so to keep my sanity.

So for comedi_isadma, we can just replace the NULL with a pointer to a
static dummy device with a 24-bit coherent mask?

--
-=( Ian Abbott <abbotti@mev.co.uk> || Web: www.mev.co.uk )=-
-=( MEV Ltd. is a company registered in England & Wales. )=-
-=( Registered number: 02862268. Registered address: )=-
-=( 15 West Park Road, Bramhall, STOCKPORT, SK7 3JZ, UK. )=-

\
 
 \ /
  Last update: 2019-04-25 16:15    [W:0.071 / U:30.468 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site