mm/rmap: update to new mmu_notifier semantic v2

Replace all mmu_notifier_invalidate_page() calls by *_invalidate_range()
and make sure it is bracketed by calls to *_invalidate_range_start()/end().

Note that because we can not presume the pmd value or pte value we have
to assume the worst and unconditionaly report an invalidation as
happening.

Changed since v2:
  - try_to_unmap_one() only one call to mmu_notifier_invalidate_range()
  - compute end with PAGE_SIZE << compound_order(page)
  - fix PageHuge() case in try_to_unmap_one()

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Bernhard Held <berny156@gmx.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: axie <axie@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 32 insertions, 3 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index c8993c63eb25..c570f82e6827 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -887,11 +887,21 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
                 .address = address,
                 .flags = PVMW_SYNC,
         };
+        unsigned long start = address, end;
         int *cleaned = arg;
 
+        /*
+         * We have to assume the worse case ie pmd for invalidation. Note that
+         * the page can not be free from this function.
+         */
+        end = min(vma->vm_end, start + (PAGE_SIZE << compound_order(page)));
+        mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
+
         while (page_vma_mapped_walk(&pvmw)) {
+                unsigned long cstart, cend;
                 int ret = 0;
-                address = pvmw.address;
+
+                cstart = address = pvmw.address;
                 if (pvmw.pte) {
                         pte_t entry;
                         pte_t *pte = pvmw.pte;
@@ -904,6 +914,7 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
                         entry = pte_wrprotect(entry);
                         entry = pte_mkclean(entry);
                         set_pte_at(vma->vm_mm, address, pte, entry);
+                        cend = cstart + PAGE_SIZE;
                         ret = 1;
                 } else {
 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
@@ -918,6 +929,8 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
                         entry = pmd_wrprotect(entry);
                         entry = pmd_mkclean(entry);
                         set_pmd_at(vma->vm_mm, address, pmd, entry);
+                        cstart &= PMD_MASK;
+                        cend = cstart + PMD_SIZE;
                         ret = 1;
 #else
                         /* unexpected pmd-mapped page? */
@@ -926,11 +939,13 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
                 }
 
                 if (ret) {
-                        mmu_notifier_invalidate_page(vma->vm_mm, address);
+                        mmu_notifier_invalidate_range(vma->vm_mm, cstart, cend);
                         (*cleaned)++;
                 }
         }
 
+        mmu_notifier_invalidate_range_end(vma->vm_mm, start, end);
+
         return true;
 }
 
@@ -1324,6 +1339,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
         pte_t pteval;
         struct page *subpage;
         bool ret = true;
+        unsigned long start = address, end;
         enum ttu_flags flags = (enum ttu_flags)arg;
 
         /* munlock has nothing to gain from examining un-locked vmas */
@@ -1335,6 +1351,14 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                                 flags & TTU_MIGRATION, page);
         }
 
+        /*
+         * We have to assume the worse case ie pmd for invalidation. Note that
+         * the page can not be free in this function as call of try_to_unmap()
+         * must hold a reference on the page.
+         */
+        end = min(vma->vm_end, start + (PAGE_SIZE << compound_order(page)));
+        mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
+
         while (page_vma_mapped_walk(&pvmw)) {
                 /*
                  * If the page is mlock()d, we cannot swap it out.
@@ -1445,6 +1469,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                         if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) {
                                 WARN_ON_ONCE(1);
                                 ret = false;
+                                /* We have to invalidate as we cleared the pte */
                                 page_vma_mapped_walk_done(&pvmw);
                                 break;
                         }
@@ -1490,8 +1515,12 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 discard:
                 page_remove_rmap(subpage, PageHuge(page));
                 put_page(page);
-                mmu_notifier_invalidate_page(mm, address);
+                mmu_notifier_invalidate_range(mm, address,
+                                              address + PAGE_SIZE);
         }
+
+        mmu_notifier_invalidate_range_end(vma->vm_mm, start, end);
+
         return ret;
 }