From 334680ab074cae5c7fa78ebcb04a9765bbf4fcea Mon Sep 17 00:00:00 2001
From: Emmanuel Vadot <manu@FreeBSD.org>
Date: Tue, 4 Aug 2020 15:25:22 +0000
Subject: [PATCH] linuxkpi: Add clear_bit_unlock

This calls clear_bit and adds a memory barrier.

Sponsored by: The FreeBSD Foundation

Reviewed by:	hselasky
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D25943
---
 sys/compat/linuxkpi/common/include/linux/bitops.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/compat/linuxkpi/common/include/linux/bitops.h b/sys/compat/linuxkpi/common/include/linux/bitops.h
index f3c62596bcf..7e259760f7c 100644
--- a/sys/compat/linuxkpi/common/include/linux/bitops.h
+++ b/sys/compat/linuxkpi/common/include/linux/bitops.h
@@ -275,6 +275,13 @@ find_next_zero_bit(const unsigned long *addr, unsigned long size,
 #define	test_bit(i, a)							\
     !!(READ_ONCE(((volatile const unsigned long *)(a))[BIT_WORD(i)]) & BIT_MASK(i))
 
+static inline void
+clear_bit_unlock(long bit, volatile unsigned long *var)
+{
+	clear_bit(bit, var);
+	wmb();
+}
+
 static inline int
 test_and_clear_bit(long bit, volatile unsigned long *var)
 {