mmu_notifier: allow range invalidation to exclude a specific mmu_notifier

This patch allow to invalidate a range while excluding call to a specific
mmu_notifier which allow for a subsystem to invalidate a range for everyone
but itself.

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>

2 files changed, 73 insertions, 9 deletions

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 1a20145cfd55..794d626eae65 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -291,11 +291,15 @@ extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
 					  struct page *page,
 					  enum mmu_event event);
 extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
-					struct mmu_notifier_range *range);
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude);
 extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
-					struct mmu_notifier_range *range);
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude);
 extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
-				  unsigned long start, unsigned long end);
+					    unsigned long start,
+					    unsigned long end,
+					    const struct mmu_notifier *exclude);
 extern bool mmu_notifier_range_is_valid(struct mm_struct *mm,
 					unsigned long start,
 					unsigned long end);
@@ -348,21 +352,49 @@ static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
 					struct mmu_notifier_range *range)
 {
 	if (mm_has_notifiers(mm))
-		__mmu_notifier_invalidate_range_start(mm, range);
+		__mmu_notifier_invalidate_range_start(mm, range, NULL);
 }
 
 static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
 					struct mmu_notifier_range *range)
 {
 	if (mm_has_notifiers(mm))
-		__mmu_notifier_invalidate_range_end(mm, range);
+		__mmu_notifier_invalidate_range_end(mm, range, NULL);
 }
 
 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);
+		__mmu_notifier_invalidate_range(mm, start, end, NULL);
+}
+
+static inline void mmu_notifier_invalidate_range_start_excluding(
+					struct mm_struct *mm,
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude)
+{
+	if (mm_has_notifiers(mm))
+		__mmu_notifier_invalidate_range_start(mm, range, exclude);
+}
+
+static inline void mmu_notifier_invalidate_range_end_excluding(
+					struct mm_struct *mm,
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude)
+{
+	if (mm_has_notifiers(mm))
+		__mmu_notifier_invalidate_range_end(mm, range, exclude);
+}
+
+static inline void mmu_notifier_invalidate_range_excluding(
+					struct mm_struct *mm,
+					unsigned long start,
+					unsigned long end,
+					const struct mmu_notifier *exclude)
+{
+	if (mm_has_notifiers(mm))
+		__mmu_notifier_invalidate_range(mm, start, end, exclude);
 }
 
 static inline void mmu_notifier_mm_init(struct mm_struct *mm)
@@ -512,6 +544,28 @@ static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
 {
 }
 
+static inline void mmu_notifier_invalidate_range_start_excluding(
+					struct mm_struct *mm,
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude)
+{
+}
+
+static inline void mmu_notifier_invalidate_range_end_excluding(
+					struct mm_struct *mm,
+					struct mmu_notifier_range *range,
+					const struct mmu_notifier *exclude)
+{
+}
+
+static inline void mmu_notifier_invalidate_range_excluding(
+					struct mm_struct *mm,
+					unsigned long start,
+					unsigned long end,
+					const struct mmu_notifier *exclude)
+{
+}
+
 static inline void mmu_notifier_mm_init(struct mm_struct *mm)
 {
 }
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 2ed6d0da7e07..c673ba9cbca1 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -175,7 +175,8 @@ void __mmu_notifier_invalidate_page(struct mm_struct *mm,
 }
 
 void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
-					   struct mmu_notifier_range *range)
+					   struct mmu_notifier_range *range,
+					   const struct mmu_notifier *exclude)
 
 {
 	struct mmu_notifier *mn;
@@ -188,6 +189,8 @@ void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
 
 	id = srcu_read_lock(&srcu);
 	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+		if (mn == exclude)
+			continue;
 		if (mn->ops->invalidate_range_start)
 			mn->ops->invalidate_range_start(mn, mm, range);
 	}
@@ -196,13 +199,16 @@ void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
 EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range_start);
 
 void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
-					 struct mmu_notifier_range *range)
+					 struct mmu_notifier_range *range,
+					 const struct mmu_notifier *exclude)
 {
 	struct mmu_notifier *mn;
 	int id;
 
 	id = srcu_read_lock(&srcu);
 	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+		if (mn == exclude)
+			continue;
 		/*
 		 * Call invalidate_range here too to avoid the need for the
 		 * subsystem of having to register an invalidate_range_end
@@ -233,13 +239,17 @@ void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
 EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range_end);
 
 void __mmu_notifier_invalidate_range(struct mm_struct *mm,
-				  unsigned long start, unsigned long end)
+				     unsigned long start,
+				     unsigned long end,
+				     const struct mmu_notifier *exclude)
 {
 	struct mmu_notifier *mn;
 	int id;
 
 	id = srcu_read_lock(&srcu);
 	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+		if (mn == exclude)
+			continue;
 		if (mn->ops->invalidate_range)
 			mn->ops->invalidate_range(mn, mm, start, end);
 	}