linux-kernel - [PATCH tip/core/rcu 05/10] rcu: Fix kfree

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Date:   Wed,  3 Mar 2021 16:00:14 -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,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH tip/core/rcu 05/10] rcu: Fix kfree_rcu() docbook errors

From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>

After commit 5130b8fd0690 ("rcu: Introduce kfree_rcu() single-argument macro"),
kernel-doc now emits two warnings:

	./include/linux/rcupdate.h:884: warning: Excess function parameter 'ptr' description in 'kfree_rcu'
	./include/linux/rcupdate.h:884: warning: Excess function parameter 'rhf' description in 'kfree_rcu'

This commit added some macro magic in order to call two different versions
of kfree_rcu(), the first having just one argument and the second having
two arguments.  That makes it difficult to document the kfree_rcu() arguments
in the docboook header.

In order to make clearer that this macro accepts optional arguments,
this commit uses macro concatenation so that this macro changes from:
	#define kfree_rcu kvfree_rcu

to:
	#define kfree_rcu(ptr, rhf...) kvfree_rcu(ptr, ## rhf)

That not only helps kernel-doc understand the macro arguments, but also
provides a better C definition that makes clearer that the first argument
is mandatory and the second one is optional.

Fixes: 5130b8fd0690 ("rcu: Introduce kfree_rcu() single-argument macro")
Tested-by: Uladzislau Rezki (Sony) <urezki@...il.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 include/linux/rcupdate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index bd04f72..5cc6dea 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -881,7 +881,7 @@ 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 kvfree_rcu
+#define kfree_rcu(ptr, rhf...) kvfree_rcu(ptr, ## rhf)
 
 /**
  * kvfree_rcu() - kvfree an object after a grace period.
-- 
2.9.5