RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached

2020-10-19 Thread Sherry Sun
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

RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached

2020-10-12 Thread Sherry Sun
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

RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached

2020-09-29 Thread David Laight
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.

RE: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached

2020-09-29 Thread Sherry Sun
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 > >

Re: [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached

2020-09-29 Thread Christoph Hellwig
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 > --- >