diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5d2ef1217d0c..ec8ba011fa7d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1548,8 +1548,24 @@ split_fallthrough: ptep = pte_offset_map_lock(mm, pmd, address, &ptl); pte = *ptep; - if (!pte_present(pte)) - goto no_page; + if (!pte_present(pte)) { + swp_entry_t entry; + /* + * KSM's break_ksm() relies upon recognizing a ksm page + * even while it is being migrated, so for that case we + * need migration_entry_wait(). + */ + if (likely(!(flags & FOLL_MIGRATION))) + goto no_page; + if (pte_none(pte) || pte_file(pte)) + goto no_page; + entry = pte_to_swp_entry(pte); + if (!is_migration_entry(entry)) + goto no_page; + pte_unmap_unlock(ptep, ptl); + migration_entry_wait(mm, pmd, address); + goto split_fallthrough; + } if ((flags & FOLL_NUMA) && pte_numa(pte)) goto no_page; if ((flags & FOLL_WRITE) && !pte_write(pte)) |