Merge branches 'doc.2021.01.06a', 'fixes.2021.01.04b', 'kfree_rcu.2021.01.04a', ...

[sfrench/cifs-2.6.git] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index de08264113111e0b43c531838489a6e3085f5326..ebd8dcca4997d2134ceae47ab9d2b8e1764d0453 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -33,6 +33,8 @@
 #define ULONG_CMP_GE(a, b)     (ULONG_MAX / 2 >= (a) - (b))
 #define ULONG_CMP_LT(a, b)     (ULONG_MAX / 2 < (a) - (b))
 #define ulong2long(a)          (*(long *)(&(a)))
+#define USHORT_CMP_GE(a, b)    (USHRT_MAX / 2 >= (unsigned short)((a) - (b)))
+#define USHORT_CMP_LT(a, b)    (USHRT_MAX / 2 < (unsigned short)((a) - (b)))
 
 /* Exported common interfaces */
 void call_rcu(struct rcu_head *head, rcu_callback_t func);
@@ -86,6 +88,12 @@ void rcu_sched_clock_irq(int user);
 void rcu_report_dead(unsigned int cpu);
 void rcutree_migrate_callbacks(int cpu);
 
+#ifdef CONFIG_TASKS_RCU_GENERIC
+void rcu_init_tasks_generic(void);
+#else
+static inline void rcu_init_tasks_generic(void) { }
+#endif
+
 #ifdef CONFIG_RCU_STALL_COMMON
 void rcu_sysrq_start(void);
 void rcu_sysrq_end(void);
@@ -104,8 +112,12 @@ static inline void rcu_user_exit(void) { }
 
 #ifdef CONFIG_RCU_NOCB_CPU
 void rcu_init_nohz(void);
+int rcu_nocb_cpu_offload(int cpu);
+int rcu_nocb_cpu_deoffload(int cpu);
 #else /* #ifdef CONFIG_RCU_NOCB_CPU */
 static inline void rcu_init_nohz(void) { }
+static inline int rcu_nocb_cpu_offload(int cpu) { return -EINVAL; }
+static inline int rcu_nocb_cpu_deoffload(int cpu) { return 0; }
 #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
 
 /**
@@ -840,19 +852,11 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
  */
 #define __is_kvfree_rcu_offset(offset) ((offset) < 4096)
 
-/*
- * Helper macro for kfree_rcu() to prevent argument-expansion eyestrain.
- */
-#define __kvfree_rcu(head, offset) \
-       do { \
-               BUILD_BUG_ON(!__is_kvfree_rcu_offset(offset)); \
-               kvfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \
-       } while (0)
-
 /**
  * kfree_rcu() - kfree an object after a grace period.
- * @ptr:       pointer to kfree
- * @rhf:       the name of the struct rcu_head within the type of @ptr.
+ * @ptr: pointer to kfree for both single- and double-argument invocations.
+ * @rhf: the name of the struct rcu_head within the type of @ptr,
+ *       but only for double-argument invocations.
  *
  * Many rcu callbacks functions just call kfree() on the base structure.
  * These functions are trivial, but their size adds up, and furthermore
@@ -865,7 +869,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
  * Because the functions are not allowed in the low-order 4096 bytes of
  * kernel virtual memory, offsets up to 4095 bytes can be accommodated.
  * If the offset is larger than 4095 bytes, a compile-time error will
- * be generated in __kvfree_rcu(). If this error is triggered, you can
+ * be generated in kvfree_rcu_arg_2(). If this error is triggered, you can
  * either fall back to use of call_rcu() or rearrange the structure to
  * position the rcu_head structure into the first 4096 bytes.
  *
@@ -875,13 +879,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
  * The BUILD_BUG_ON check must not involve any function calls, hence the
  * checks are done in macros here.
  */
-#define kfree_rcu(ptr, rhf)                                            \
-do {                                                                   \
-       typeof (ptr) ___p = (ptr);                                      \
-                                                                       \
-       if (___p)                                                       \
-               __kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
-} while (0)
+#define kfree_rcu kvfree_rcu
 
 /**
  * kvfree_rcu() - kvfree an object after a grace period.
@@ -913,7 +911,17 @@ do {                                                                       \
        kvfree_rcu_arg_2, kvfree_rcu_arg_1)(__VA_ARGS__)
 
 #define KVFREE_GET_MACRO(_1, _2, NAME, ...) NAME
-#define kvfree_rcu_arg_2(ptr, rhf) kfree_rcu(ptr, rhf)
+#define kvfree_rcu_arg_2(ptr, rhf)                                     \
+do {                                                                   \
+       typeof (ptr) ___p = (ptr);                                      \
+                                                                       \
+       if (___p) {                                                                     \
+               BUILD_BUG_ON(!__is_kvfree_rcu_offset(offsetof(typeof(*(ptr)), rhf)));   \
+               kvfree_call_rcu(&((___p)->rhf), (rcu_callback_t)(unsigned long)         \
+                       (offsetof(typeof(*(ptr)), rhf)));                               \
+       }                                                                               \
+} while (0)
+
 #define kvfree_rcu_arg_1(ptr)                                  \
 do {                                                           \
        typeof(ptr) ___p = (ptr);                               \