rcu: Rename *_kfree_callback/*_kfree_rcu_offset/kfree_call_*

The following changes are introduced:

1. Rename rcu_invoke_kfree_callback() to rcu_invoke_kvfree_callback(),
as well as the associated trace events, so the rcu_kfree_callback(),
becomes rcu_kvfree_callback(). The reason is to be aligned with kvfree()
notation.

2. Rename __is_kfree_rcu_offset to __is_kvfree_rcu_offset. All RCU
paths use kvfree() now instead of kfree(), thus rename it.

3. Rename kfree_call_rcu() to the kvfree_call_rcu(). The reason is,
it is capable of freeing vmalloc() memory now. Do the same with
__kfree_rcu() macro, it becomes __kvfree_rcu(), the goal is the
same.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

include/linux/rcupdate.h

@@ -828,17 +828,17 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 
 /*
  * Does the specified offset indicate that the corresponding rcu_head
- * structure can be handled by kfree_rcu()?
+ * structure can be handled by kvfree_rcu()?
  */
-#define __is_kfree_rcu_offset(offset) ((offset) < 4096)
+#define __is_kvfree_rcu_offset(offset) ((offset) < 4096)
 
 /*
  * Helper macro for kfree_rcu() to prevent argument-expansion eyestrain.
  */
-#define __kfree_rcu(head, offset) \
+#define __kvfree_rcu(head, offset) \
 	do { \
-		BUILD_BUG_ON(!__is_kfree_rcu_offset(offset)); \
-		kfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \
+		BUILD_BUG_ON(!__is_kvfree_rcu_offset(offset)); \
+		kvfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \
 	} while (0)
 
 /**
@@ -857,7 +857,7 @@ 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 __kfree_rcu().  If this error is triggered, you can
+ * be generated in __kvfree_rcu(). 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.
  *
@@ -872,7 +872,7 @@ do {									\
 	typeof (ptr) ___p = (ptr);					\
 									\
 	if (___p)							\
-		__kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
+		__kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
 } while (0)
 
 /*

include/linux/rcutiny.h

@@ -34,7 +34,7 @@ static inline void synchronize_rcu_expedited(void)
 	synchronize_rcu();
 }
 
-static inline void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
 {
 	call_rcu(head, func);
 }

include/linux/rcutree.h

@@ -33,7 +33,7 @@ static inline void rcu_virt_note_context_switch(int cpu)
 }
 
 void synchronize_rcu_expedited(void);
-void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
 
 void rcu_barrier(void);
 bool rcu_eqs_special_set(int cpu);

include/trace/events/rcu.h

@@ -506,13 +506,13 @@ TRACE_EVENT_RCU(rcu_callback,
 
 /*
  * Tracepoint for the registration of a single RCU callback of the special
- * kfree() form.  The first argument is the RCU type, the second argument
+ * kvfree() form.  The first argument is the RCU type, the second argument
  * is a pointer to the RCU callback, the third argument is the offset
  * of the callback within the enclosing RCU-protected data structure,
  * the fourth argument is the number of lazy callbacks queued, and the
  * fifth argument is the total number of callbacks queued.
  */
-TRACE_EVENT_RCU(rcu_kfree_callback,
+TRACE_EVENT_RCU(rcu_kvfree_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset,
 		 long qlen),
@@ -596,12 +596,12 @@ TRACE_EVENT_RCU(rcu_invoke_callback,
 
 /*
  * Tracepoint for the invocation of a single RCU callback of the special
- * kfree() form.  The first argument is the RCU flavor, the second
+ * kvfree() form.  The first argument is the RCU flavor, the second
  * argument is a pointer to the RCU callback, and the third argument
  * is the offset of the callback within the enclosing RCU-protected
  * data structure.
  */
-TRACE_EVENT_RCU(rcu_invoke_kfree_callback,
+TRACE_EVENT_RCU(rcu_invoke_kvfree_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset),
 

kernel/rcu/tiny.c

@@ -85,8 +85,8 @@ static inline bool rcu_reclaim_tiny(struct rcu_head *head)
 	unsigned long offset = (unsigned long)head->func;
 
 	rcu_lock_acquire(&rcu_callback_map);
-	if (__is_kfree_rcu_offset(offset)) {
-		trace_rcu_invoke_kfree_callback("", head, offset);
+	if (__is_kvfree_rcu_offset(offset)) {
+		trace_rcu_invoke_kvfree_callback("", head, offset);
 		kvfree((void *)head - offset);
 		rcu_lock_release(&rcu_callback_map);
 		return true;

kernel/rcu/tree.c

@@ -2905,8 +2905,8 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
 		return; // Enqueued onto ->nocb_bypass, so just leave.
 	// If no-CBs CPU gets here, rcu_nocb_try_bypass() acquired ->nocb_lock.
 	rcu_segcblist_enqueue(&rdp->cblist, head);
-	if (__is_kfree_rcu_offset((unsigned long)func))
-		trace_rcu_kfree_callback(rcu_state.name, head,
+	if (__is_kvfree_rcu_offset((unsigned long)func))
+		trace_rcu_kvfree_callback(rcu_state.name, head,
 					 (unsigned long)func,
 					 rcu_segcblist_n_cbs(&rdp->cblist));
 	else
@@ -3146,7 +3146,7 @@ static void kfree_rcu_work(struct work_struct *work)
 					bkvhead[i]->records);
 			} else { // vmalloc() / vfree().
 				for (j = 0; j < bkvhead[i]->nr_records; j++) {
-					trace_rcu_invoke_kfree_callback(
+					trace_rcu_invoke_kvfree_callback(
 						rcu_state.name,
 						bkvhead[i]->records[j], 0);
 
@@ -3179,9 +3179,9 @@ static void kfree_rcu_work(struct work_struct *work)
 		next = head->next;
 		debug_rcu_head_unqueue((struct rcu_head *)ptr);
 		rcu_lock_acquire(&rcu_callback_map);
-		trace_rcu_invoke_kfree_callback(rcu_state.name, head, offset);
+		trace_rcu_invoke_kvfree_callback(rcu_state.name, head, offset);
 
-		if (!WARN_ON_ONCE(!__is_kfree_rcu_offset(offset)))
+		if (!WARN_ON_ONCE(!__is_kvfree_rcu_offset(offset)))
 			kvfree(ptr);
 
 		rcu_lock_release(&rcu_callback_map);
@@ -3344,12 +3344,12 @@ kvfree_call_rcu_add_ptr_to_bulk(struct kfree_rcu_cpu *krcp, void *ptr)
  * one, that is used only when the main path can not be maintained temporary,
  * due to memory pressure.
  *
- * Each kfree_call_rcu() request is added to a batch. The batch will be drained
+ * Each kvfree_call_rcu() request is added to a batch. The batch will be drained
  * every KFREE_DRAIN_JIFFIES number of jiffies. All the objects in the batch will
  * be free'd in workqueue context. This allows us to: batch requests together to
  * reduce the number of grace periods during heavy kfree_rcu()/kvfree_rcu() load.
  */
-void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
 {
 	unsigned long flags;
 	struct kfree_rcu_cpu *krcp;
@@ -3388,7 +3388,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
 unlock_return:
 	krc_this_cpu_unlock(krcp, flags);
 }
-EXPORT_SYMBOL_GPL(kfree_call_rcu);
+EXPORT_SYMBOL_GPL(kvfree_call_rcu);
 
 static unsigned long
 kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)