[v2,09/18] drm/via: set FOLL_PIN via pin_user_pages_fast()
diff mbox series

Message ID 20191103211813.213227-10-jhubbard@nvidia.com
State New
Headers show
Series
  • mm/gup: track dma-pinned pages: FOLL_PIN, FOLL_LONGTERM
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Commit Message

John Hubbard Nov. 3, 2019, 9:18 p.m. UTC
Convert drm/via to use the new pin_user_pages_fast() call, which sets
FOLL_PIN. Setting FOLL_PIN is now required for code that requires
tracking of pinned pages, and therefore for any code that calls
put_user_page().

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/gpu/drm/via/via_dmablit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jerome Glisse Nov. 4, 2019, 5:44 p.m. UTC | #1
On Sun, Nov 03, 2019 at 01:18:04PM -0800, John Hubbard wrote:
> Convert drm/via to use the new pin_user_pages_fast() call, which sets
> FOLL_PIN. Setting FOLL_PIN is now required for code that requires
> tracking of pinned pages, and therefore for any code that calls
> put_user_page().
> 
> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>

Please be more explicit that via_dmablit.c is already using put_user_page()
as i am expecting that any conversion to pin_user_pages*() must be pair with
a put_user_page(). I find above commit message bit unclear from that POV.

Reviewed-by: Jérôme Glisse <jglisse@redhat.com>


> ---
>  drivers/gpu/drm/via/via_dmablit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
> index 3db000aacd26..37c5e572993a 100644
> --- a/drivers/gpu/drm/via/via_dmablit.c
> +++ b/drivers/gpu/drm/via/via_dmablit.c
> @@ -239,7 +239,7 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>  	vsg->pages = vzalloc(array_size(sizeof(struct page *), vsg->num_pages));
>  	if (NULL == vsg->pages)
>  		return -ENOMEM;
> -	ret = get_user_pages_fast((unsigned long)xfer->mem_addr,
> +	ret = pin_user_pages_fast((unsigned long)xfer->mem_addr,
>  			vsg->num_pages,
>  			vsg->direction == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
>  			vsg->pages);
> -- 
> 2.23.0
>
John Hubbard Nov. 4, 2019, 6:22 p.m. UTC | #2
On 11/4/19 9:44 AM, Jerome Glisse wrote:
> On Sun, Nov 03, 2019 at 01:18:04PM -0800, John Hubbard wrote:
>> Convert drm/via to use the new pin_user_pages_fast() call, which sets
>> FOLL_PIN. Setting FOLL_PIN is now required for code that requires
>> tracking of pinned pages, and therefore for any code that calls
>> put_user_page().
>>
>> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
>> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> 
> Please be more explicit that via_dmablit.c is already using put_user_page()
> as i am expecting that any conversion to pin_user_pages*() must be pair with
> a put_user_page(). I find above commit message bit unclear from that POV.
> 

OK. This one, and the fs/io_uring (patch 9) and net/xdp (patch 10) were all
cases that had put_user_page() pre-existing. I will add something like the 
following to each commit description, for v3:

In partial anticipation of this work, the drm/via driver was already 
calling put_user_page() instead of put_page(). Therefore, in order to
convert from the get_user_pages()/put_page() model, to the
pin_user_pages()/put_user_page() model, the only change required
is to change get_user_pages() to pin_user_pages().

thanks,

John Hubbard
NVIDIA

> Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
> 
> 
>> ---
>>  drivers/gpu/drm/via/via_dmablit.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
>> index 3db000aacd26..37c5e572993a 100644
>> --- a/drivers/gpu/drm/via/via_dmablit.c
>> +++ b/drivers/gpu/drm/via/via_dmablit.c
>> @@ -239,7 +239,7 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>>  	vsg->pages = vzalloc(array_size(sizeof(struct page *), vsg->num_pages));
>>  	if (NULL == vsg->pages)
>>  		return -ENOMEM;
>> -	ret = get_user_pages_fast((unsigned long)xfer->mem_addr,
>> +	ret = pin_user_pages_fast((unsigned long)xfer->mem_addr,
>>  			vsg->num_pages,
>>  			vsg->direction == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
>>  			vsg->pages);
>> -- 
>> 2.23.0
>>
> 
>

Patch
diff mbox series

diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 3db000aacd26..37c5e572993a 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -239,7 +239,7 @@  via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 	vsg->pages = vzalloc(array_size(sizeof(struct page *), vsg->num_pages));
 	if (NULL == vsg->pages)
 		return -ENOMEM;
-	ret = get_user_pages_fast((unsigned long)xfer->mem_addr,
+	ret = pin_user_pages_fast((unsigned long)xfer->mem_addr,
 			vsg->num_pages,
 			vsg->direction == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
 			vsg->pages);