[PATCH 5.15 06/54] rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

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

[ Upstream commit 608723c41cd951fb32ade2f8371e61c270816175 ]

The kvfree_rcu() and kfree_rcu() APIs are hazardous in that if you forget
the second argument, it works, but might sleep.  This sleeping can be a
correctness bug from atomic contexts, and even in non-atomic contexts
it might introduce unacceptable latencies.  This commit therefore adds
kvfree_rcu_mightsleep() and kfree_rcu_mightsleep(), which will replace
the single-argument kvfree_rcu() and kfree_rcu(), respectively.

This commit enables a series of commits that switch from single-argument
kvfree_rcu() and kfree_rcu() to their _mightsleep() counterparts.  Once
all of these commits land, the single-argument versions will be removed.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Stable-dep-of: 511e64e13d8c ("can: gw: fix RCU/BH usage in cgw_create_job()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/rcupdate.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d908af5917339..978769e545b5f 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -979,6 +979,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 #define kvfree_rcu(...) KVFREE_GET_MACRO(__VA_ARGS__,		\
 	kvfree_rcu_arg_2, kvfree_rcu_arg_1)(__VA_ARGS__)
 
+#define kvfree_rcu_mightsleep(ptr) kvfree_rcu_arg_1(ptr)
+#define kfree_rcu_mightsleep(ptr) kvfree_rcu_mightsleep(ptr)
+
 #define KVFREE_GET_MACRO(_1, _2, NAME, ...) NAME
 #define kvfree_rcu_arg_2(ptr, rhf)					\
 do {									\
-- 
2.39.5