| Message ID | 20221116102659.70287-16-david@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/gup: remove FOLL_FORCE usage from drivers (reliable R/O long-term pinning) | expand |
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) {
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) {
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. 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(-)