[PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

This code was using get_user_pages_fast(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages_fast() + put_page() calls to
pin_user_pages_fast() + unpin_user_pages() calls.

There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
    https://lwn.net/Articles/807108/

Cc: Xu Yilun <yilun.xu@intel.com>
Cc: Wu Hao <hao.wu@intel.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: linux-fpga@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---

Hi,

Changes since v1:

Changed the label from "put_pages", to "unpin_pages".

thanks,
John Hubbard
NVIDIA
 
 drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
index 62f924489db5..a31dd3a7e581 100644
--- a/drivers/fpga/dfl-afu-dma-region.c
+++ b/drivers/fpga/dfl-afu-dma-region.c
@@ -16,15 +16,6 @@
 
 #include "dfl-afu.h"
 
-static void put_all_pages(struct page **pages, int npages)
-{
-	int i;
-
-	for (i = 0; i < npages; i++)
-		if (pages[i])
-			put_page(pages[i]);
-}
-
 void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
 {
 	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
@@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
 		goto unlock_vm;
 	}
 
-	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
+	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
 				     region->pages);
 	if (pinned < 0) {
 		ret = pinned;
-		goto put_pages;
+		goto unpin_pages;
 	} else if (pinned != npages) {
 		ret = -EFAULT;
 		goto free_pages;
@@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
 
 	return 0;
 
-put_pages:
-	put_all_pages(region->pages, pinned);
+unpin_pages:
+	unpin_user_pages(region->pages, pinned);
 free_pages:
 	kfree(region->pages);
 unlock_vm:
@@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
 	long npages = region->length >> PAGE_SHIFT;
 	struct device *dev = &pdata->dev->dev;
 
-	put_all_pages(region->pages, npages);
+	unpin_user_pages(region->pages, npages);
 	kfree(region->pages);
 	account_locked_vm(current->mm, npages, false);
 
-- 
2.26.2

[PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

This code was using get_user_pages_fast(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages_fast() + put_page() calls to
pin_user_pages_fast() + unpin_user_pages() calls.

There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
    https://lwn.net/Articles/807108/

Cc: Xu Yilun <yilun.xu@intel.com>
Cc: Wu Hao <hao.wu@intel.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: linux-fpga@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---

Hi,

Changes since v1:

Changed the label from "put_pages", to "unpin_pages".

thanks,
John Hubbard
NVIDIA
 
 drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
index 62f924489db5..a31dd3a7e581 100644
--- a/drivers/fpga/dfl-afu-dma-region.c
+++ b/drivers/fpga/dfl-afu-dma-region.c
@@ -16,15 +16,6 @@
 
 #include "dfl-afu.h"
 
-static void put_all_pages(struct page **pages, int npages)
-{
-	int i;
-
-	for (i = 0; i < npages; i++)
-		if (pages[i])
-			put_page(pages[i]);
-}
-
 void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
 {
 	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
@@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
 		goto unlock_vm;
 	}
 
-	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
+	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
 				     region->pages);
 	if (pinned < 0) {
 		ret = pinned;
-		goto put_pages;
+		goto unpin_pages;
 	} else if (pinned != npages) {
 		ret = -EFAULT;
 		goto free_pages;
@@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
 
 	return 0;
 
-put_pages:
-	put_all_pages(region->pages, pinned);
+unpin_pages:
+	unpin_user_pages(region->pages, pinned);
 free_pages:
 	kfree(region->pages);
 unlock_vm:
@@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
 	long npages = region->length >> PAGE_SHIFT;
 	struct device *dev = &pdata->dev->dev;
 
-	put_all_pages(region->pages, npages);
+	unpin_user_pages(region->pages, npages);
 	kfree(region->pages);
 	account_locked_vm(current->mm, npages, false);
 
-- 
2.26.2

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

On 2020-05-19 13:14, John Hubbard wrote:
> This code was using get_user_pages_fast(), in a "Case 2" scenario
> (DMA/RDMA), using the categorization from [1]. That means that it's
> time to convert the get_user_pages_fast() + put_page() calls to
> pin_user_pages_fast() + unpin_user_pages() calls.
> 
> There is some helpful background in [2]: basically, this is a small
> part of fixing a long-standing disconnect between pinning pages, and
> file systems' use of those pages.
> 
> [1] Documentation/core-api/pin_user_pages.rst
> 
> [2] "Explicit pinning of user-space pages":
>      https://lwn.net/Articles/807108/
> 
> Cc: Xu Yilun <yilun.xu@intel.com>
> Cc: Wu Hao <hao.wu@intel.com>
> Cc: Moritz Fischer <mdf@kernel.org>
> Cc: linux-fpga@vger.kernel.org
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>


Hi Moritz and FPGA developers,

Is this OK? And if so, is it going into your git tree? Or should I
send it up through a different tree? (I'm new to the FPGA development
model).


thanks,
-- 
John Hubbard
NVIDIA



> ---
> 
> Hi,
> 
> Changes since v1:
> 
> Changed the label from "put_pages", to "unpin_pages".
> 
> thanks,
> John Hubbard
> NVIDIA
>   
>   drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
> index 62f924489db5..a31dd3a7e581 100644
> --- a/drivers/fpga/dfl-afu-dma-region.c
> +++ b/drivers/fpga/dfl-afu-dma-region.c
> @@ -16,15 +16,6 @@
>   
>   #include "dfl-afu.h"
>   
> -static void put_all_pages(struct page **pages, int npages)
> -{
> -	int i;
> -
> -	for (i = 0; i < npages; i++)
> -		if (pages[i])
> -			put_page(pages[i]);
> -}
> -
>   void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
>   {
>   	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
> @@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
>   		goto unlock_vm;
>   	}
>   
> -	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> +	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
>   				     region->pages);
>   	if (pinned < 0) {
>   		ret = pinned;
> -		goto put_pages;
> +		goto unpin_pages;
>   	} else if (pinned != npages) {
>   		ret = -EFAULT;
>   		goto free_pages;
> @@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
>   
>   	return 0;
>   
> -put_pages:
> -	put_all_pages(region->pages, pinned);
> +unpin_pages:
> +	unpin_user_pages(region->pages, pinned);
>   free_pages:
>   	kfree(region->pages);
>   unlock_vm:
> @@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
>   	long npages = region->length >> PAGE_SHIFT;
>   	struct device *dev = &pdata->dev->dev;
>   
> -	put_all_pages(region->pages, npages);
> +	unpin_user_pages(region->pages, npages);
>   	kfree(region->pages);
>   	account_locked_vm(current->mm, npages, false);
>   
> 

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

On 2020-05-19 13:14, John Hubbard wrote:
> This code was using get_user_pages_fast(), in a "Case 2" scenario
> (DMA/RDMA), using the categorization from [1]. That means that it's
> time to convert the get_user_pages_fast() + put_page() calls to
> pin_user_pages_fast() + unpin_user_pages() calls.
> 
> There is some helpful background in [2]: basically, this is a small
> part of fixing a long-standing disconnect between pinning pages, and
> file systems' use of those pages.
> 
> [1] Documentation/core-api/pin_user_pages.rst
> 
> [2] "Explicit pinning of user-space pages":
>      https://lwn.net/Articles/807108/
> 
> Cc: Xu Yilun <yilun.xu@intel.com>
> Cc: Wu Hao <hao.wu@intel.com>
> Cc: Moritz Fischer <mdf@kernel.org>
> Cc: linux-fpga@vger.kernel.org
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>


Hi Moritz and FPGA developers,

Is this OK? And if so, is it going into your git tree? Or should I
send it up through a different tree? (I'm new to the FPGA development
model).


thanks,
-- 
John Hubbard
NVIDIA



> ---
> 
> Hi,
> 
> Changes since v1:
> 
> Changed the label from "put_pages", to "unpin_pages".
> 
> thanks,
> John Hubbard
> NVIDIA
>   
>   drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
> index 62f924489db5..a31dd3a7e581 100644
> --- a/drivers/fpga/dfl-afu-dma-region.c
> +++ b/drivers/fpga/dfl-afu-dma-region.c
> @@ -16,15 +16,6 @@
>   
>   #include "dfl-afu.h"
>   
> -static void put_all_pages(struct page **pages, int npages)
> -{
> -	int i;
> -
> -	for (i = 0; i < npages; i++)
> -		if (pages[i])
> -			put_page(pages[i]);
> -}
> -
>   void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
>   {
>   	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
> @@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
>   		goto unlock_vm;
>   	}
>   
> -	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> +	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
>   				     region->pages);
>   	if (pinned < 0) {
>   		ret = pinned;
> -		goto put_pages;
> +		goto unpin_pages;
>   	} else if (pinned != npages) {
>   		ret = -EFAULT;
>   		goto free_pages;
> @@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
>   
>   	return 0;
>   
> -put_pages:
> -	put_all_pages(region->pages, pinned);
> +unpin_pages:
> +	unpin_user_pages(region->pages, pinned);
>   free_pages:
>   	kfree(region->pages);
>   unlock_vm:
> @@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
>   	long npages = region->length >> PAGE_SHIFT;
>   	struct device *dev = &pdata->dev->dev;
>   
> -	put_all_pages(region->pages, npages);
> +	unpin_user_pages(region->pages, npages);
>   	kfree(region->pages);
>   	account_locked_vm(current->mm, npages, false);
>   
> 

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[Moritz Fischer]

On Fri, May 22, 2020 at 06:52:34PM -0700, John Hubbard wrote:
> On 2020-05-19 13:14, John Hubbard wrote:
> > This code was using get_user_pages_fast(), in a "Case 2" scenario
> > (DMA/RDMA), using the categorization from [1]. That means that it's
> > time to convert the get_user_pages_fast() + put_page() calls to
> > pin_user_pages_fast() + unpin_user_pages() calls.
> > 
> > There is some helpful background in [2]: basically, this is a small
> > part of fixing a long-standing disconnect between pinning pages, and
> > file systems' use of those pages.
> > 
> > [1] Documentation/core-api/pin_user_pages.rst
> > 
> > [2] "Explicit pinning of user-space pages":
> >      https://lwn.net/Articles/807108/
> > 
> > Cc: Xu Yilun <yilun.xu@intel.com>
> > Cc: Wu Hao <hao.wu@intel.com>
> > Cc: Moritz Fischer <mdf@kernel.org>
> > Cc: linux-fpga@vger.kernel.org
> > Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> 
> 
> Hi Moritz and FPGA developers,
> 
> Is this OK? And if so, is it going into your git tree? Or should I
> send it up through a different tree? (I'm new to the FPGA development
> model).

I can take it, sorry for sluggish response.

Cheers,
Moritz

> 
> 
> thanks,
> -- 
> John Hubbard
> NVIDIA
> 
> 
> 
> > ---
> > 
> > Hi,
> > 
> > Changes since v1:
> > 
> > Changed the label from "put_pages", to "unpin_pages".
> > 
> > thanks,
> > John Hubbard
> > NVIDIA
> >   drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
> >   1 file changed, 5 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
> > index 62f924489db5..a31dd3a7e581 100644
> > --- a/drivers/fpga/dfl-afu-dma-region.c
> > +++ b/drivers/fpga/dfl-afu-dma-region.c
> > @@ -16,15 +16,6 @@
> >   #include "dfl-afu.h"
> > -static void put_all_pages(struct page **pages, int npages)
> > -{
> > -	int i;
> > -
> > -	for (i = 0; i < npages; i++)
> > -		if (pages[i])
> > -			put_page(pages[i]);
> > -}
> > -
> >   void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
> >   {
> >   	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
> > @@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
> >   		goto unlock_vm;
> >   	}
> > -	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> > +	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> >   				     region->pages);
> >   	if (pinned < 0) {
> >   		ret = pinned;
> > -		goto put_pages;
> > +		goto unpin_pages;
> >   	} else if (pinned != npages) {
> >   		ret = -EFAULT;
> >   		goto free_pages;
> > @@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
> >   	return 0;
> > -put_pages:
> > -	put_all_pages(region->pages, pinned);
> > +unpin_pages:
> > +	unpin_user_pages(region->pages, pinned);
> >   free_pages:
> >   	kfree(region->pages);
> >   unlock_vm:
> > @@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
> >   	long npages = region->length >> PAGE_SHIFT;
> >   	struct device *dev = &pdata->dev->dev;
> > -	put_all_pages(region->pages, npages);
> > +	unpin_user_pages(region->pages, npages);
> >   	kfree(region->pages);
> >   	account_locked_vm(current->mm, npages, false);
> > 
> 

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[Moritz Fischer]

On Fri, May 22, 2020 at 06:52:34PM -0700, John Hubbard wrote:
> On 2020-05-19 13:14, John Hubbard wrote:
> > This code was using get_user_pages_fast(), in a "Case 2" scenario
> > (DMA/RDMA), using the categorization from [1]. That means that it's
> > time to convert the get_user_pages_fast() + put_page() calls to
> > pin_user_pages_fast() + unpin_user_pages() calls.
> > 
> > There is some helpful background in [2]: basically, this is a small
> > part of fixing a long-standing disconnect between pinning pages, and
> > file systems' use of those pages.
> > 
> > [1] Documentation/core-api/pin_user_pages.rst
> > 
> > [2] "Explicit pinning of user-space pages":
> >      https://lwn.net/Articles/807108/
> > 
> > Cc: Xu Yilun <yilun.xu@intel.com>
> > Cc: Wu Hao <hao.wu@intel.com>
> > Cc: Moritz Fischer <mdf@kernel.org>
> > Cc: linux-fpga@vger.kernel.org
> > Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> 
> 
> Hi Moritz and FPGA developers,
> 
> Is this OK? And if so, is it going into your git tree? Or should I
> send it up through a different tree? (I'm new to the FPGA development
> model).

I can take it, sorry for sluggish response.

Cheers,
Moritz

> 
> 
> thanks,
> -- 
> John Hubbard
> NVIDIA
> 
> 
> 
> > ---
> > 
> > Hi,
> > 
> > Changes since v1:
> > 
> > Changed the label from "put_pages", to "unpin_pages".
> > 
> > thanks,
> > John Hubbard
> > NVIDIA
> >   drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
> >   1 file changed, 5 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
> > index 62f924489db5..a31dd3a7e581 100644
> > --- a/drivers/fpga/dfl-afu-dma-region.c
> > +++ b/drivers/fpga/dfl-afu-dma-region.c
> > @@ -16,15 +16,6 @@
> >   #include "dfl-afu.h"
> > -static void put_all_pages(struct page **pages, int npages)
> > -{
> > -	int i;
> > -
> > -	for (i = 0; i < npages; i++)
> > -		if (pages[i])
> > -			put_page(pages[i]);
> > -}
> > -
> >   void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
> >   {
> >   	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
> > @@ -57,11 +48,11 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
> >   		goto unlock_vm;
> >   	}
> > -	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> > +	pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
> >   				     region->pages);
> >   	if (pinned < 0) {
> >   		ret = pinned;
> > -		goto put_pages;
> > +		goto unpin_pages;
> >   	} else if (pinned != npages) {
> >   		ret = -EFAULT;
> >   		goto free_pages;
> > @@ -71,8 +62,8 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
> >   	return 0;
> > -put_pages:
> > -	put_all_pages(region->pages, pinned);
> > +unpin_pages:
> > +	unpin_user_pages(region->pages, pinned);
> >   free_pages:
> >   	kfree(region->pages);
> >   unlock_vm:
> > @@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
> >   	long npages = region->length >> PAGE_SHIFT;
> >   	struct device *dev = &pdata->dev->dev;
> > -	put_all_pages(region->pages, npages);
> > +	unpin_user_pages(region->pages, npages);
> >   	kfree(region->pages);
> >   	account_locked_vm(current->mm, npages, false);
> > 
> 

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

On 2020-05-23 13:57, Moritz Fischer wrote:
> On Fri, May 22, 2020 at 06:52:34PM -0700, John Hubbard wrote:
>> On 2020-05-19 13:14, John Hubbard wrote:
>>> This code was using get_user_pages_fast(), in a "Case 2" scenario
>>> (DMA/RDMA), using the categorization from [1]. That means that it's
>>> time to convert the get_user_pages_fast() + put_page() calls to
>>> pin_user_pages_fast() + unpin_user_pages() calls.
>>>
>>> There is some helpful background in [2]: basically, this is a small
>>> part of fixing a long-standing disconnect between pinning pages, and
>>> file systems' use of those pages.
>>>
>>> [1] Documentation/core-api/pin_user_pages.rst
>>>
>>> [2] "Explicit pinning of user-space pages":
>>>       https://lwn.net/Articles/807108/
>>>
>>> Cc: Xu Yilun <yilun.xu@intel.com>
>>> Cc: Wu Hao <hao.wu@intel.com>
>>> Cc: Moritz Fischer <mdf@kernel.org>
>>> Cc: linux-fpga@vger.kernel.org
>>> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
>>
>>
>> Hi Moritz and FPGA developers,
>>
>> Is this OK? And if so, is it going into your git tree? Or should I
>> send it up through a different tree? (I'm new to the FPGA development
>> model).
> 
> I can take it, sorry for sluggish response.
> 

That's great news, thanks Moritz! Sorry to be pushy, just didn't want it
to get lost. :)

thanks,
-- 
John Hubbard
NVIDIA

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

On 2020-05-23 13:57, Moritz Fischer wrote:
> On Fri, May 22, 2020 at 06:52:34PM -0700, John Hubbard wrote:
>> On 2020-05-19 13:14, John Hubbard wrote:
>>> This code was using get_user_pages_fast(), in a "Case 2" scenario
>>> (DMA/RDMA), using the categorization from [1]. That means that it's
>>> time to convert the get_user_pages_fast() + put_page() calls to
>>> pin_user_pages_fast() + unpin_user_pages() calls.
>>>
>>> There is some helpful background in [2]: basically, this is a small
>>> part of fixing a long-standing disconnect between pinning pages, and
>>> file systems' use of those pages.
>>>
>>> [1] Documentation/core-api/pin_user_pages.rst
>>>
>>> [2] "Explicit pinning of user-space pages":
>>>       https://lwn.net/Articles/807108/
>>>
>>> Cc: Xu Yilun <yilun.xu@intel.com>
>>> Cc: Wu Hao <hao.wu@intel.com>
>>> Cc: Moritz Fischer <mdf@kernel.org>
>>> Cc: linux-fpga@vger.kernel.org
>>> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
>>
>>
>> Hi Moritz and FPGA developers,
>>
>> Is this OK? And if so, is it going into your git tree? Or should I
>> send it up through a different tree? (I'm new to the FPGA development
>> model).
> 
> I can take it, sorry for sluggish response.
> 

That's great news, thanks Moritz! Sorry to be pushy, just didn't want it
to get lost. :)

thanks,
-- 
John Hubbard
NVIDIA

RE: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[Wu, Hao]

> >> Hi Moritz and FPGA developers,
> >>
> >> Is this OK? And if so, is it going into your git tree? Or should I
> >> send it up through a different tree? (I'm new to the FPGA development
> >> model).
> >
> > I can take it, sorry for sluggish response.
> >
> 
> That's great news, thanks Moritz! Sorry to be pushy, just didn't want it
> to get lost. :)

Thanks John for this patch, and thanks Moritz for taking care of this.
Sorry for late response, one thing here we may need to be careful is
a recent bug fixing patch, that fixing patch has been merged by Greg
in char-misc-next tree, and may have some conflict with this one.

https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/commit/?h=char-misc-next&id=c9d7e3da1f3c4cf5dddfc5d7ce4d76d013aba1cc
fpga: dfl: afu: Corrected error handling levels

I guess we need to rebase this patch on top of it?
Moritz, do you have any suggestion?

Thanks
Hao

> 
> thanks,
> --
> John Hubbard
> NVIDIA

Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()

[John Hubbard]

On 2020-05-24 19:25, Wu, Hao wrote:
>>>> Hi Moritz and FPGA developers,
>>>>
>>>> Is this OK? And if so, is it going into your git tree? Or should I
>>>> send it up through a different tree? (I'm new to the FPGA development
>>>> model).
>>>
>>> I can take it, sorry for sluggish response.
>>>
>>
>> That's great news, thanks Moritz! Sorry to be pushy, just didn't want it
>> to get lost. :)
> 
> Thanks John for this patch, and thanks Moritz for taking care of this.
> Sorry for late response, one thing here we may need to be careful is
> a recent bug fixing patch, that fixing patch has been merged by Greg
> in char-misc-next tree, and may have some conflict with this one.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/commit/?h=char-misc-next&id=c9d7e3da1f3c4cf5dddfc5d7ce4d76d013aba1cc
> fpga: dfl: afu: Corrected error handling levels
> 
> I guess we need to rebase this patch on top of it?
> Moritz, do you have any suggestion?
> 

I'll send you a v2, rebased on top of the latest char-misc.git, no problem.

thanks,
-- 
John Hubbard
NVIDIA