+ dax-revert-userfaultfd-change.patch added to -mm tree

+ dax-revert-userfaultfd-change.patch added to -mm tree

[akpm]

The patch titled
     Subject: dax: revert userfaultfd change
has been added to the -mm tree.  Its filename is
     dax-revert-userfaultfd-change.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/dax-revert-userfaultfd-change.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/dax-revert-userfaultfd-change.patch

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: dax: revert userfaultfd change

Undo the chagne whcih "userfaultfd: call handle_userfault() for
userfaultfd_missing() faults" made to set_huge_zero_page().  DAX will need
that return value.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff -puN mm/huge_memory.c~dax-revert-userfaultfd-change mm/huge_memory.c
--- a/mm/huge_memory.c~dax-revert-userfaultfd-change
+++ a/mm/huge_memory.c
@@ -794,16 +794,19 @@ static inline gfp_t alloc_hugepage_gfpma
 }
 
 /* Caller must hold page table lock. */
-static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 		struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
 		struct page *zero_page)
 {
 	pmd_t entry;
+	if (!pmd_none(*pmd))
+		return false;
 	entry = mk_pmd(zero_page, vma->vm_page_prot);
 	entry = pmd_mkhuge(entry);
 	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	set_pmd_at(mm, haddr, pmd, entry);
 	atomic_long_inc(&mm->nr_ptes);
+	return true;
 }
 
 int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

arch-alpha-kernel-systblss-remove-debug-check.patch
openrisc-fix-config_uid16-setting.patch
kernel-kthreadc-kthread_create_on_node-clarify-documentation.patch
scripts-spellingtxt-adding-misspelled-word-for-check-fix.patch
mm.patch
userfaultfd-change-the-read-api-to-return-a-uffd_msg-fix-2.patch
userfaultfd-change-the-read-api-to-return-a-uffd_msg-fix-2-fix.patch
userfaultfd-avoid-mmap_sem-read-recursion-in-mcopy_atomic-fix.patch
genalloc-add-name-arg-to-gen_pool_get-and-devm_gen_pool_create-fix.patch
dax-revert-userfaultfd-change.patch
thp-prepare-for-dax-huge-pages-fix.patch
mm-page-refine-the-calculation-of-highest-possible-node-id.patch
pagemap-add-mmap-exclusive-bit-for-marking-pages-mapped-only-here-fix.patch
mm-show-proportional-swap-share-of-the-mapping-fix.patch
mm-improve-__gfp_noretry-comment-based-on-implementation-fix.patch
memcg-export-struct-mem_cgroup-fix.patch
include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated.patch
x86-add-pmd_-for-thp-fix.patch
sparc-add-pmd_-for-thp-fix.patch
mm-support-madvisemadv_free-fix-2.patch
mm-dont-split-thp-page-when-syscall-is-called-fix-3.patch
mm-move-lazy-free-pages-to-inactive-list-fix-fix.patch
mm-move-lazy-free-pages-to-inactive-list-fix-fix-fix.patch
define-kallsyms_cmp_symbol_t-as-function-type-to-simplify-the-code-fix.patch
linux-next.patch
linux-next-rejects.patch
drivers-gpu-drm-i915-intel_spritec-fix-build.patch
drivers-gpu-drm-i915-intel_tvc-fix-build.patch
net-netfilter-ipset-work-around-gcc-444-initializer-bug.patch
fs-seq_file-convert-int-seq_vprint-seq_printf-etc-returns-to-void-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
journal_add_journal_head-debug.patch
journal_add_journal_head-debug-fix.patch
kernel-forkc-export-kernel_thread-to-modules.patch
mutex-subsystem-synchro-test-module.patch
slab-leaks3-default-y.patch