[PATCH] mm/thp: fix call to mmu_notifier in set_pmd_migration_entry()

[jglisse]

From: Jérôme Glisse <jgli...@redhat.com>

Inside set_pmd_migration_entry() we are holding page table locks and
thus we can not sleep so we can not call invalidate_range_start/end()

So remove call to mmu_notifier_invalidate_range_start/end() and add
call to mmu_notifier_invalidate_range(). Note that we are already
calling mmu_notifier_invalidate_range_start/end() inside the function
calling set_pmd_migration_entry() (see try_to_unmap_one()).

Signed-off-by: Jérôme Glisse <jgli...@redhat.com>
Reported-by: Andrea Arcangeli <aarca...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Zi Yan <zi....@cs.rutgers.edu>
Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: David Nellans <dnell...@nvidia.com>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Mel Gorman <mgor...@techsingularity.net>
Cc: Minchan Kim <minc...@kernel.org>
Cc: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Vlastimil Babka <vba...@suse.cz>
Cc: Michal Hocko <mho...@kernel.org>
Cc: Andrea Arcangeli <aarca...@redhat.com>
---
 mm/huge_memory.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 533f9b00147d..93cb80fe12cb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2885,9 +2885,6 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk 
*pvmw,
        if (!(pvmw->pmd && !pvmw->pte))
                return;
 
-       mmu_notifier_invalidate_range_start(mm, address,
-                       address + HPAGE_PMD_SIZE);
-
        flush_cache_range(vma, address, address + HPAGE_PMD_SIZE);
        pmdval = *pvmw->pmd;
        pmdp_invalidate(vma, address, pvmw->pmd);
@@ -2898,11 +2895,9 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk 
*pvmw,
        if (pmd_soft_dirty(pmdval))
                pmdswp = pmd_swp_mksoft_dirty(pmdswp);
        set_pmd_at(mm, address, pvmw->pmd, pmdswp);
+       mmu_notifier_invalidate_range(mm, address, address + HPAGE_PMD_SIZE);
        page_remove_rmap(page, true);
        put_page(page);
-
-       mmu_notifier_invalidate_range_end(mm, address,
-                       address + HPAGE_PMD_SIZE);
 }
 
 void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
-- 
2.17.2