mm/migrate: preserve soft dirty in remove_migration_pte()

The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry.  This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ralph Campbell 2020-09-04 16:36:07 -07:00 committed by Linus Torvalds
parent 6128763fc3
commit 3d321bf82c

View File

@ -249,6 +249,8 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
if (unlikely(is_device_private_page(new))) {
entry = make_device_private_entry(new, pte_write(pte));
pte = swp_entry_to_pte(entry);
if (pte_swp_soft_dirty(*pvmw.pte))
pte = pte_swp_mksoft_dirty(pte);
if (pte_swp_uffd_wp(*pvmw.pte))
pte = pte_swp_mkuffd_wp(pte);
}