[v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()
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Message ID 20200525221754.433023-1-jhubbard@nvidia.com
State Mainlined, archived
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Series
  • [v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()
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Commit Message

John Hubbard May 25, 2020, 10:17 p.m. UTC
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,

This is the same logical change as in v2, but it is applied to
char-misc-next, in order to avoid a merge problem with Souptick's
commit c9d7e3da1f3c ("fpga: dfl: afu: Corrected error handling levels <Souptick Joarder>")

thanks,
John Hubbard
NVIDIA


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

Comments

Wu, Hao May 27, 2020, 12:10 a.m. UTC | #1
> -----Original Message-----
> From: John Hubbard <jhubbard@nvidia.com>
> Sent: Tuesday, May 26, 2020 6:18 AM
> To: LKML <linux-kernel@vger.kernel.org>
> Cc: John Hubbard <jhubbard@nvidia.com>; Xu, Yilun <yilun.xu@intel.com>;
> Wu, Hao <hao.wu@intel.com>; Moritz Fischer <mdf@kernel.org>; linux-
> fpga@vger.kernel.org
> Subject: [PATCH v3] fpga: dfl: afu: convert get_user_pages() -->
> pin_user_pages()
> 
> 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,
> 
> This is the same logical change as in v2, but it is applied to
> char-misc-next, in order to avoid a merge problem with Souptick's
> commit c9d7e3da1f3c ("fpga: dfl: afu: Corrected error handling levels
> <Souptick Joarder>")

Thanks a lot! 

Acked-by: Wu Hao <hao.wu@intel.com>

Thanks
Hao

> 
> 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 5942343a5d6e..0b817b722920 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);
> @@ -57,22 +48,22 @@ 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 free_pages;
>  	} else if (pinned != npages) {
>  		ret = -EFAULT;
> -		goto put_pages;
> +		goto unpin_pages;
>  	}
> 
>  	dev_dbg(dev, "%d pages pinned\n", pinned);
> 
>  	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
Moritz Fischer May 31, 2020, 9:27 p.m. UTC | #2
On Wed, May 27, 2020 at 12:10:21AM +0000, Wu, Hao wrote:
> > -----Original Message-----
> > From: John Hubbard <jhubbard@nvidia.com>
> > Sent: Tuesday, May 26, 2020 6:18 AM
> > To: LKML <linux-kernel@vger.kernel.org>
> > Cc: John Hubbard <jhubbard@nvidia.com>; Xu, Yilun <yilun.xu@intel.com>;
> > Wu, Hao <hao.wu@intel.com>; Moritz Fischer <mdf@kernel.org>; linux-
> > fpga@vger.kernel.org
> > Subject: [PATCH v3] fpga: dfl: afu: convert get_user_pages() -->
> > pin_user_pages()
> > 
> > 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,
> > 
> > This is the same logical change as in v2, but it is applied to
> > char-misc-next, in order to avoid a merge problem with Souptick's
> > commit c9d7e3da1f3c ("fpga: dfl: afu: Corrected error handling levels
> > <Souptick Joarder>")
> 
> Thanks a lot! 
> 
> Acked-by: Wu Hao <hao.wu@intel.com>
> 
> Thanks
> Hao
> 
> > 
> > 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 5942343a5d6e..0b817b722920 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);
> > @@ -57,22 +48,22 @@ 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 free_pages;
> >  	} else if (pinned != npages) {
> >  		ret = -EFAULT;
> > -		goto put_pages;
> > +		goto unpin_pages;
> >  	}
> > 
> >  	dev_dbg(dev, "%d pages pinned\n", pinned);
> > 
> >  	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
> 
Applied to for-next.

Thanks,
Moritz

Patch
diff mbox series

diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
index 5942343a5d6e..0b817b722920 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);
@@ -57,22 +48,22 @@  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 free_pages;
 	} else if (pinned != npages) {
 		ret = -EFAULT;
-		goto put_pages;
+		goto unpin_pages;
 	}
 
 	dev_dbg(dev, "%d pages pinned\n", pinned);
 
 	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);