mmu_notifier: add the callback for mmu_notifier_invalidate_range()

Now that the mmu_notifier_invalidate_range() calls are in place, add the
callback to allow subsystems to register against it.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Jay Cornwall <Jay.Cornwall@amd.com>
Cc: Oded Gabbay <Oded.Gabbay@amd.com>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>

1 files changed, 32 insertions, 5 deletions

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 966da2b4b803..94d19f64cecf 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -98,11 +98,11 @@ struct mmu_notifier_ops {
         /*
          * invalidate_range_start() and invalidate_range_end() must be
          * paired and are called only when the mmap_sem and/or the
-         * locks protecting the reverse maps are held. The subsystem
-         * must guarantee that no additional references are taken to
-         * the pages in the range established between the call to
-         * invalidate_range_start() and the matching call to
-         * invalidate_range_end().
+         * locks protecting the reverse maps are held. If the subsystem
+         * can't guarantee that no additional references are taken to
+         * the pages in the range, it has to implement the
+         * invalidate_range() notifier to remove any references taken
+         * after invalidate_range_start().
          *
          * Invalidation of multiple concurrent ranges may be
          * optionally permitted by the driver. Either way the
@@ -144,6 +144,29 @@ struct mmu_notifier_ops {
         void (*invalidate_range_end)(struct mmu_notifier *mn,
                                      struct mm_struct *mm,
                                      unsigned long start, unsigned long end);
+
+        /*
+         * invalidate_range() is either called between
+         * invalidate_range_start() and invalidate_range_end() when the
+         * VM has to free pages that where unmapped, but before the
+         * pages are actually freed, or outside of _start()/_end() when
+         * a (remote) TLB is necessary.
+         *
+         * If invalidate_range() is used to manage a non-CPU TLB with
+         * shared page-tables, it not necessary to implement the
+         * invalidate_range_start()/end() notifiers, as
+         * invalidate_range() alread catches the points in time when an
+         * external TLB range needs to be flushed.
+         *
+         * The invalidate_range() function is called under the ptl
+         * spin-lock and not allowed to sleep.
+         *
+         * Note that this function might be called with just a sub-range
+         * of what was passed to invalidate_range_start()/end(), if
+         * called between those functions.
+         */
+        void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm,
+                                 unsigned long start, unsigned long end);
 };
 
 /*
@@ -190,6 +213,8 @@ extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
                                   unsigned long start, unsigned long end);
 extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
                                   unsigned long start, unsigned long end);
+extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
+                                  unsigned long start, unsigned long end);
 
 static inline void mmu_notifier_release(struct mm_struct *mm)
 {
@@ -245,6 +270,8 @@ static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
 static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
                                   unsigned long start, unsigned long end)
 {
+        if (mm_has_notifiers(mm))
+                __mmu_notifier_invalidate_range(mm, start, end);
 }
 
 static inline void mmu_notifier_mm_init(struct mm_struct *mm)