| Message ID | 20200525221754.433023-1-jhubbard@nvidia.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | [v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages() | expand |
> -----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
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
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);
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(-)