1 files changed, 41 insertions, 1 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 120536f4c6eb..621b200d9b87 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -24,7 +24,7 @@
 #include <linux/compiler.h>
 #include <linux/atomic.h>
 #include <linux/irqflags.h>
-#include <linux/preempt.h>
+#include <linux/sched.h>
 #include <linux/bottom_half.h>
 #include <linux/lockdep.h>
 #include <linux/cleanup.h>
@@ -713,6 +713,24 @@ do {									      \
 				(c) || rcu_read_lock_sched_held(), \
 				__rcu)
 
+/**
+ * rcu_dereference_all_check() - rcu_dereference_all with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * This is similar to rcu_dereference_check(), but allows protection
+ * by all forms of vanilla RCU readers, including preemption disabled,
+ * bh-disabled, and interrupt-disabled regions of code.  Note that "vanilla
+ * RCU" excludes SRCU and the various Tasks RCU flavors.  Please note
+ * that this macro should not be backported to any Linux-kernel version
+ * preceding v5.0 due to changes in synchronize_rcu() semantics prior
+ * to that version.
+ */
+#define rcu_dereference_all_check(p, c) \
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), \
+				(c) || rcu_read_lock_any_held(), \
+				__rcu)
+
 /*
  * The tracing infrastructure traces RCU (we want that), but unfortunately
  * some of the RCU checks causes tracing to lock up the system.
@@ -768,6 +786,14 @@ do {									      \
 #define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0)
 
 /**
+ * rcu_dereference_all() - fetch RCU-all-protected pointer for dereferencing
+ * @p: The pointer to read, prior to dereferencing
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define rcu_dereference_all(p) rcu_dereference_all_check(p, 0)
+
+/**
  * rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism
  * @p: The pointer to hand off
  *
@@ -962,6 +988,20 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 	preempt_enable_notrace();
 }
 
+static __always_inline void rcu_read_lock_dont_migrate(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RCU))
+		migrate_disable();
+	rcu_read_lock();
+}
+
+static inline void rcu_read_unlock_migrate(void)
+{
+	rcu_read_unlock();
+	if (IS_ENABLED(CONFIG_PREEMPT_RCU))
+		migrate_enable();
+}
+
 /**
  * RCU_INIT_POINTER() - initialize an RCU protected pointer
  * @p: The pointer to be initialized.