Messages in this thread | | | Subject | Re: [PATCH v2] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages() | From | John Hubbard <> | Date | Fri, 22 May 2020 18:52:34 -0700 |
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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); > >
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