Commit 3d321bf8 authored Sep 04, 2020 by Ralph Campbell Committed by Linus Torvalds Sep 05, 2020

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>

parent 6128763f

mm/migrate.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}

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