thp: fix copy_page_rep GPF by testing is_huge_zero_pmd once only

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7de1bf8..95d1acb 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -883,9 +883,6 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
                goto out_unlock;
        }
 
-       /* mmap_sem prevents this happening but warn if that changes */
-       WARN_ON(pmd_trans_migrating(pmd));
-
        if (unlikely(pmd_trans_splitting(pmd))) {
                /* split huge page running from under us */
                spin_unlock(src_ptl);
@@ -1157,7 +1154,7 @@ alloc:
                new_page = NULL;
 
        if (unlikely(!new_page)) {
-               if (is_huge_zero_pmd(orig_pmd)) {
+               if (!page) {
                        ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
                                        address, pmd, orig_pmd, haddr);
                } else {
@@ -1184,7 +1181,7 @@ alloc:
 
        count_vm_event(THP_FAULT_ALLOC);
 
-       if (is_huge_zero_pmd(orig_pmd))
+       if (!page)
                clear_huge_page(new_page, haddr, HPAGE_PMD_NR);
        else
                copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
@@ -1210,7 +1207,7 @@ alloc:
                page_add_new_anon_rmap(new_page, vma, haddr);
                set_pmd_at(mm, haddr, pmd, entry);
                update_mmu_cache_pmd(vma, address, pmd);
-               if (is_huge_zero_pmd(orig_pmd)) {
+               if (!page) {
                        add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
                        put_huge_zero_page();
                } else {