linux-kernel - [PATCH tip/core/rcu 3/3] rcu: Eliminate the __kvfree

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Date:   Tue,  5 Jan 2021 17:01:25 -0800
From:   paulmck@...nel.org
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
        jiangshanlai@...il.com, akpm@...ux-foundation.org,
        mathieu.desnoyers@...icios.com, josh@...htriplett.org,
        tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
        dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
        oleg@...hat.com, joel@...lfernandes.org,
        "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH tip/core/rcu 3/3] rcu: Eliminate the __kvfree_rcu() macro

From: "Uladzislau Rezki (Sony)" <urezki@...il.com>

This commit open-codes the __kvfree_rcu() macro, thus saving a
few lines of code and improving readability.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 include/linux/rcupdate.h | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index b95373e..f1576cd 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -840,15 +840,6 @@ 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 for both single- and double-argument invocations.
@@ -866,7 +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 __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.
  *
@@ -912,8 +903,11 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 do {									\
 	typeof (ptr) ___p = (ptr);					\
 									\
-	if (___p)							\
-		__kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
+	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)					\
-- 
2.9.5