Re: [PATCH mm-unstable v1 15/20] media: pci/ivtv: remove FOLL_FORCE usage
From: Hans Verkuil <hidden>
Date: 2022-11-23 13:34:28
Also in:
dri-devel, linux-alpha, linux-arm-kernel, linux-fsdevel, linux-kselftest, linux-media, linux-mips, linux-mm, linux-perf-users, linux-rdma, linux-samsung-soc, linux-security-module, linux-um, lkml, sparclinux
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 <redacted> Regards, Hans
quoted hunk ↗ jump to hunk
Cc: Andy Walls <awalls@md.metrocast.net> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: David Hildenbrand <redacted> --- 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) {