kmalloc/malloc for dma ?

[Ran Shalit]

On Wed, Mar 9, 2016 at 11:16 AM, Ran Shalit <ranshalit at gmail.com> wrote:
> Hello,
>
> I have some sample code which uses 2 test application:
> 1. test application in kernel , which allocates buffer using kmalloc
> (GFP_KERNEL)
> 2. test application in userspace which allocates buffer using malloc
just to add that in the case (2) of userspace, the kernel driver use
copy_from_user before dma transfer.

>
> In both cases the buffers are DMA through PCI.
> I don't understand how is it that the buffers are allocated with
> malloc/kmalloc for DMA.
> Is there any idea ?
>
> Regards,
> Ran