Commit 19fed0da authored by John Hubbard's avatar John Hubbard Committed by Linus Torvalds
Browse files

vfio, mm: pin_user_pages (FOLL_PIN) and put_user_page() conversion

1. Change vfio from get_user_pages_remote(), to

2. Because all FOLL_PIN-acquired pages must be released via
   put_user_page(), also convert the put_page() call over to

Note that this effectively changes the code's behavior in
vfio_iommu_type1.c: put_pfn(): it now ultimately calls
set_page_dirty_lock(), instead of set_page_dirty().  This is probably
more accurate.

As Christoph Hellwig put it, "set_page_dirty() is only safe if we are
dealing with a file backed page where we have reference on the inode it
hangs off." [1]



Signed-off-by: default avatarJohn Hubbard <>
Tested-by: default avatarAlex Williamson <>
Acked-by: default avatarAlex Williamson <>
Cc: Aneesh Kumar K.V <>
Cc: Björn Töpel <>
Cc: Christoph Hellwig <>
Cc: Daniel Vetter <>
Cc: Dan Williams <>
Cc: Hans Verkuil <>
Cc: Ira Weiny <>
Cc: Jan Kara <>
Cc: Jason Gunthorpe <>
Cc: Jason Gunthorpe <>
Cc: Jens Axboe <>
Cc: Jerome Glisse <>
Cc: Jonathan Corbet <>
Cc: Kirill A. Shutemov <>
Cc: Leon Romanovsky <>
Cc: Mauro Carvalho Chehab <>
Cc: Mike Rapoport <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 1f815afc
......@@ -309,9 +309,8 @@ static int put_pfn(unsigned long pfn, int prot)
if (!is_invalid_reserved_pfn(pfn)) {
struct page *page = pfn_to_page(pfn);
if (prot & IOMMU_WRITE)
put_user_pages_dirty_lock(&page, 1, prot & IOMMU_WRITE);
return 1;
return 0;
......@@ -329,7 +328,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
flags |= FOLL_WRITE;
ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags | FOLL_LONGTERM,
ret = pin_user_pages_remote(NULL, mm, vaddr, 1, flags | FOLL_LONGTERM,
page, NULL, NULL);
if (ret == 1) {
*pfn = page_to_pfn(page[0]);
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