[PATCH] drm/via: use get_user_pages_unlocked()

[PATCH] drm/via: use get_user_pages_unlocked()

[Lorenzo Stoakes]

Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
---
 drivers/gpu/drm/via/via_dmablit.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 1a3ad76..98aae98 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -238,13 +238,9 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 	vsg->pages = vzalloc(sizeof(struct page *) * vsg->num_pages);
 	if (NULL == vsg->pages)
 		return -ENOMEM;
-	down_read(&current->mm->mmap_sem);
-	ret = get_user_pages((unsigned long)xfer->mem_addr,
-			     vsg->num_pages,
-			     (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
-			     vsg->pages, NULL);
-
-	up_read(&current->mm->mmap_sem);
+	ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
+			vsg->num_pages, vsg->pages,
+			(vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);
 	if (ret != vsg->num_pages) {
 		if (ret < 0)
 			return ret;
-- 
2.10.2

Re: [PATCH] drm/via: use get_user_pages_unlocked()

[Lorenzo Stoakes]

Hi All,

Just a gentle ping on this one :)

Cheers, Lorenzo

On 1 November 2016 at 19:43, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
> Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
> and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.
>
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
> ---
>  drivers/gpu/drm/via/via_dmablit.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
> index 1a3ad76..98aae98 100644
> --- a/drivers/gpu/drm/via/via_dmablit.c
> +++ b/drivers/gpu/drm/via/via_dmablit.c
> @@ -238,13 +238,9 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>         vsg->pages = vzalloc(sizeof(struct page *) * vsg->num_pages);
>         if (NULL == vsg->pages)
>                 return -ENOMEM;
> -       down_read(&current->mm->mmap_sem);
> -       ret = get_user_pages((unsigned long)xfer->mem_addr,
> -                            vsg->num_pages,
> -                            (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
> -                            vsg->pages, NULL);
> -
> -       up_read(&current->mm->mmap_sem);
> +       ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
> +                       vsg->num_pages, vsg->pages,
> +                       (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);
>         if (ret != vsg->num_pages) {
>                 if (ret < 0)
>                         return ret;
> --
> 2.10.2
>



-- 
Lorenzo Stoakes
https://ljs.io

Re: [PATCH] drm/via: use get_user_pages_unlocked()

[Lorenzo Stoakes]

On 3 January 2017 at 20:23, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
> Hi All,
>
> Just a gentle ping on this one :)
>
> Cheers, Lorenzo
>
> On 1 November 2016 at 19:43, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
>> Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
>> and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.
>>
>> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
>> ---
>>  drivers/gpu/drm/via/via_dmablit.c | 10 +++-------
>>  1 file changed, 3 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
>> index 1a3ad76..98aae98 100644
>> --- a/drivers/gpu/drm/via/via_dmablit.c
>> +++ b/drivers/gpu/drm/via/via_dmablit.c
>> @@ -238,13 +238,9 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>>         vsg->pages = vzalloc(sizeof(struct page *) * vsg->num_pages);
>>         if (NULL == vsg->pages)
>>                 return -ENOMEM;
>> -       down_read(&current->mm->mmap_sem);
>> -       ret = get_user_pages((unsigned long)xfer->mem_addr,
>> -                            vsg->num_pages,
>> -                            (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
>> -                            vsg->pages, NULL);
>> -
>> -       up_read(&current->mm->mmap_sem);
>> +       ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
>> +                       vsg->num_pages, vsg->pages,
>> +                       (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);
>>         if (ret != vsg->num_pages) {
>>                 if (ret < 0)
>>                         return ret;
>> --
>> 2.10.2
>>

Adding Andrew, as this may be another less active corner of the corner, thanks!

-- 
Lorenzo Stoakes
https://ljs.io

Re: [PATCH] drm/via: use get_user_pages_unlocked()

[Lorenzo Stoakes]

On 6 January 2017 at 07:09, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
>
> Adding Andrew, as this may be another less active corner of the corner, thanks!

Hi all,

Thought I'd also give this one a gentle nudge now the merge window has
re-opened, Andrew - are you ok to pick this up? I've checked the patch
and it still applies, for convenience the raw patch is available at
https://marc.info/?l=linux-mm&m=147802942832515&q=raw - let me know if
there's anything else I can do on this or if you'd prefer a re-send.

Best, Lorenzo

> On 3 January 2017 at 20:23, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
>> Hi All,
>>
>> Just a gentle ping on this one :)
>>
>> Cheers, Lorenzo
>>
>> On 1 November 2016 at 19:43, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
>>> Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
>>> and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.
>>>
>>> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
>>> ---
>>>  drivers/gpu/drm/via/via_dmablit.c | 10 +++-------
>>>  1 file changed, 3 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
>>> index 1a3ad76..98aae98 100644
>>> --- a/drivers/gpu/drm/via/via_dmablit.c
>>> +++ b/drivers/gpu/drm/via/via_dmablit.c
>>> @@ -238,13 +238,9 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>>>         vsg->pages = vzalloc(sizeof(struct page *) * vsg->num_pages);
>>>         if (NULL == vsg->pages)
>>>                 return -ENOMEM;
>>> -       down_read(&current->mm->mmap_sem);
>>> -       ret = get_user_pages((unsigned long)xfer->mem_addr,
>>> -                            vsg->num_pages,
>>> -                            (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
>>> -                            vsg->pages, NULL);
>>> -
>>> -       up_read(&current->mm->mmap_sem);
>>> +       ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
>>> +                       vsg->num_pages, vsg->pages,
>>> +                       (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);
>>>         if (ret != vsg->num_pages) {
>>>                 if (ret < 0)
>>>                         return ret;
>>> --
>>> 2.10.2
>>>

-- 
Lorenzo Stoakes
https://ljs.io

Re: [PATCH] drm/via: use get_user_pages_unlocked()

[Daniel Vetter]

On Mon, Feb 20, 2017 at 06:46:54PM +0000, Lorenzo Stoakes wrote:
> On 6 January 2017 at 07:09, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
> >
> > Adding Andrew, as this may be another less active corner of the corner, thanks!
> 
> Hi all,
> 
> Thought I'd also give this one a gentle nudge now the merge window has
> re-opened, Andrew - are you ok to pick this up? I've checked the patch
> and it still applies, for convenience the raw patch is available at
> https://marc.info/?l=linux-mm&m=147802942832515&q=raw - let me know if
> there's anything else I can do on this or if you'd prefer a re-send.

Somehow your original patch never made it to dri-devel :( The via driver
is entirely unmaintained, but if you resubmit I'll smash it into drm-misc
for 4.12. Merge window is long over already for 4.11, subsystems need to
have their stuff ready _before_ it starts.

Cheers, Daniel
> 
> Best, Lorenzo
> 
> > On 3 January 2017 at 20:23, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
> >> Hi All,
> >>
> >> Just a gentle ping on this one :)
> >>
> >> Cheers, Lorenzo
> >>
> >> On 1 November 2016 at 19:43, Lorenzo Stoakes <lstoakes@gmail.com> wrote:
> >>> Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
> >>> and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.
> >>>
> >>> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
> >>> ---
> >>>  drivers/gpu/drm/via/via_dmablit.c | 10 +++-------
> >>>  1 file changed, 3 insertions(+), 7 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
> >>> index 1a3ad76..98aae98 100644
> >>> --- a/drivers/gpu/drm/via/via_dmablit.c
> >>> +++ b/drivers/gpu/drm/via/via_dmablit.c
> >>> @@ -238,13 +238,9 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
> >>>         vsg->pages = vzalloc(sizeof(struct page *) * vsg->num_pages);
> >>>         if (NULL == vsg->pages)
> >>>                 return -ENOMEM;
> >>> -       down_read(&current->mm->mmap_sem);
> >>> -       ret = get_user_pages((unsigned long)xfer->mem_addr,
> >>> -                            vsg->num_pages,
> >>> -                            (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
> >>> -                            vsg->pages, NULL);
> >>> -
> >>> -       up_read(&current->mm->mmap_sem);
> >>> +       ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
> >>> +                       vsg->num_pages, vsg->pages,
> >>> +                       (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);
> >>>         if (ret != vsg->num_pages) {
> >>>                 if (ret < 0)
> >>>                         return ret;
> >>> --
> >>> 2.10.2
> >>>
> 
> -- 
> Lorenzo Stoakes
> https://ljs.io
> 
> --
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch