From 9d532f286914add61e02312881733a90355f153c Mon Sep 17 00:00:00 2001 From: John Hubbard Date: Mon, 27 Jul 2020 13:43:38 -0600 Subject: [PATCH] vfio/spapr_tce: convert get_user_pages() --> pin_user_pages() This code was using get_user_pages*(), in a "Case 2" scenario (DMA/RDMA), using the categorization from [1]. That means that it's time to convert the get_user_pages*() + put_page() calls to pin_user_pages*() + 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: Alex Williamson Cc: Cornelia Huck Cc: kvm@vger.kernel.org Signed-off-by: John Hubbard Signed-off-by: Alex Williamson --- drivers/vfio/vfio_iommu_spapr_tce.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index 16b3adc508db..fe888b5dcc00 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -383,7 +383,7 @@ static void tce_iommu_unuse_page(struct tce_container *container, struct page *page; page = pfn_to_page(hpa >> PAGE_SHIFT); - put_page(page); + unpin_user_page(page); } static int tce_iommu_prereg_ua_to_hpa(struct tce_container *container, @@ -486,7 +486,7 @@ static int tce_iommu_use_page(unsigned long tce, unsigned long *hpa) struct page *page = NULL; enum dma_data_direction direction = iommu_tce_direction(tce); - if (get_user_pages_fast(tce & PAGE_MASK, 1, + if (pin_user_pages_fast(tce & PAGE_MASK, 1, direction != DMA_TO_DEVICE ? FOLL_WRITE : 0, &page) != 1) return -EFAULT; -- 2.39.5