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 <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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,
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;