On Sat, May 16, 2020 at 06:18:37PM -0700, 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: Wu Hao <hao.wu@xxxxxxxxx> > Cc: Moritz Fischer <mdf@xxxxxxxxxx> > Cc: linux-fpga@xxxxxxxxxxxxxxx > Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> > --- > drivers/fpga/dfl-afu-dma-region.c | 15 +++------------ > 1 file changed, 3 insertions(+), 12 deletions(-) > > diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c > index 62f924489db5..84f696d5ba82 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); > @@ -57,7 +48,7 @@ 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; > @@ -72,7 +63,7 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata, > return 0; > > put_pages: How about we also change the tag to "unpin_pages"? Others look good to me. Thanks, Yilun. > - put_all_pages(region->pages, pinned); > + 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); > > > base-commit: 3d1c1e5931ce45b3a3f309385bbc00c78e9951c6 > -- > 2.26.2
