From 3d321bf82c4be8e33261754a5775bc65fc5d2184 Mon Sep 17 00:00:00 2001 From: Ralph Campbell <rcampbell@nvidia.com> Date: Fri, 4 Sep 2020 16:36:07 -0700 Subject: [PATCH] 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> --- mm/migrate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 1d791d420725..941b89383cf3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -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); } -- GitLab