Hi Christoph,
Gentle ping
Can you give some suggestions on the limitations of dma_mmap_coherent api?
Best regards
Sherry
> Subject: RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space
> as noncached
>
> Hi David, thanks for your information.
> Hi Christoph
Hi David, thanks for your information.
Hi Christoph, please see my comments below.
> Subject: RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space
> as noncached
>
> From: Christoph Hellwig
> > Sent: 29 September 2020 11:29
> ...
> > You can't call remap_p
From: Christoph Hellwig
> Sent: 29 September 2020 11:29
...
> You can't call remap_pfn_range on memory returned from
> dma_alloc_coherent (which btw is not marked uncached on many platforms).
>
> You need to use the dma_mmap_coherent helper instead.
H. I've a driver that does that.
Hi Christoph,
> On Tue, Sep 29, 2020 at 04:44:25PM +0800, Sherry Sun wrote:
> > Mapping kernel space memory to user space as noncached, since user
> > space need check the updates of avail_idx and device page flags timely.
> >
> > Signed-off-by: Joakim Zhang
> > Signed-off-by: Sherry Sun
> >
On Tue, Sep 29, 2020 at 04:44:25PM +0800, Sherry Sun wrote:
> Mapping kernel space memory to user space as noncached, since user space
> need check the updates of avail_idx and device page flags timely.
>
> Signed-off-by: Joakim Zhang
> Signed-off-by: Sherry Sun
> ---
>
5 matches
Mail list logo