Re: [PATCH] uvcvideo: Apply flags from device to actual properties

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Edgar,

On Wednesday, 3 January 2018 08:07:44 EET Edgar Thier wrote:
> Hi Emmanuel,

If we pick names randomly I'll call you David :-)

> >>> +	int flags = 0;
> >>> +
> >>> +	data = kmalloc(2, GFP_KERNEL);
> > 
> > Isn't 1 byte enough ?
> 
> To quote from Kieran further up this thread:
> 
> >> kmalloc seems a bit of an overhead for 2 bytes (only one of which is
> >> used). Can this use local stack storage?
> >> 
> >> (Laurent, looks like you originally wrote the code that did that, was
> >> there a reason for the kmalloc for 2 bytes?)
> > 
> > Aha - OK, Just spoke with Laurent and - yes this is needed, as we can't
> > DMA to the stack  - I hadn't realised the 'data' was being DMA'd ..

I don't dispute the fact that we need to kmalloc the memory, but I think we 
only need to kmalloc one byte, not two. The existing 2 bytes allocation comes 
from the size of the GET_LEN reply. Now that you only issue a GET_INFO here, 
one byte is enough.

> >> All these are small issues. Let me try to address them, I'll send you an
> >> updated patch shortly.
> 
> I'll be waiting.

-- 
Regards,

Laurent Pinchart