Messages in this thread | | | Date | Wed, 23 Nov 2022 14:18:31 +0100 | Subject | Re: [PATCH mm-unstable v1 15/20] media: pci/ivtv: remove FOLL_FORCE usage | From | Hans Verkuil <> |
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On 16/11/2022 11:26, David Hildenbrand wrote: > FOLL_FORCE is really only for ptrace access. R/O pinning a page is > supposed to fail if the VMA misses proper access permissions (no VM_READ). > > Let's just remove FOLL_FORCE usage here; there would have to be a pretty > good reason to allow arbitrary drivers to R/O pin pages in a PROT_NONE > VMA. Most probably, FOLL_FORCE usage is just some legacy leftover.
I'm pretty sure about that as well, so:
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Regards,
Hans
> > Cc: Andy Walls <awalls@md.metrocast.net> > Cc: Mauro Carvalho Chehab <mchehab@kernel.org> > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > drivers/media/pci/ivtv/ivtv-udma.c | 2 +- > drivers/media/pci/ivtv/ivtv-yuv.c | 5 ++--- > 2 files changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/pci/ivtv/ivtv-udma.c b/drivers/media/pci/ivtv/ivtv-udma.c > index 210be8290f24..99b9f55ca829 100644 > --- a/drivers/media/pci/ivtv/ivtv-udma.c > +++ b/drivers/media/pci/ivtv/ivtv-udma.c > @@ -115,7 +115,7 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, > > /* Pin user pages for DMA Xfer */ > err = pin_user_pages_unlocked(user_dma.uaddr, user_dma.page_count, > - dma->map, FOLL_FORCE); > + dma->map, 0); > > if (user_dma.page_count != err) { > IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n", > diff --git a/drivers/media/pci/ivtv/ivtv-yuv.c b/drivers/media/pci/ivtv/ivtv-yuv.c > index 4ba10c34a16a..582146f8d70d 100644 > --- a/drivers/media/pci/ivtv/ivtv-yuv.c > +++ b/drivers/media/pci/ivtv/ivtv-yuv.c > @@ -63,12 +63,11 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, > > /* Pin user pages for DMA Xfer */ > y_pages = pin_user_pages_unlocked(y_dma.uaddr, > - y_dma.page_count, &dma->map[0], FOLL_FORCE); > + y_dma.page_count, &dma->map[0], 0); > uv_pages = 0; /* silence gcc. value is set and consumed only if: */ > if (y_pages == y_dma.page_count) { > uv_pages = pin_user_pages_unlocked(uv_dma.uaddr, > - uv_dma.page_count, &dma->map[y_pages], > - FOLL_FORCE); > + uv_dma.page_count, &dma->map[y_pages], 0); > } > > if (y_pages != y_dma.page_count || uv_pages != uv_dma.page_count) {
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