diff mbox series

[mm-unstable,v1,15/20] media: pci/ivtv: remove FOLL_FORCE usage

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

Commit Message

David Hildenbrand Nov. 16, 2022, 10:26 a.m. UTC 
  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(-)

Comments

Hans Verkuil Nov. 23, 2022, 1:18 p.m. UTC | #1 
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 mbox series

Patch

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) {