[PATCH] seqlock: Use WRITE_ONCE() on sequence update

[Daniel Xu <dxu@xxxxxxxxx>]

WRITE_ONCE() is needed here to prevent store tears and other unwanted
compiler optimizations.

Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
---
 CodeSamples/defer/seqlock.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CodeSamples/defer/seqlock.h b/CodeSamples/defer/seqlock.h
index ec00177b..842d10a6 100644
--- a/CodeSamples/defer/seqlock.h
+++ b/CodeSamples/defer/seqlock.h
@@ -60,14 +60,14 @@ static inline int read_seqretry(seqlock_t *slp,		//\lnlbl{read_seqretry:b}
 static inline void write_seqlock(seqlock_t *slp)	//\lnlbl{write_seqlock:b}
 {
 	spin_lock(&slp->lock);
-	++slp->seq;
+	WRITE_ONCE(slp->seq, READ_ONCE(slp->seq) + 1);
 	smp_mb();
 }							//\lnlbl{write_seqlock:e}
 
 static inline void write_sequnlock(seqlock_t *slp)	//\lnlbl{write_sequnlock:b}
 {
 	smp_mb();					//\lnlbl{write_sequnlock:mb}
-	++slp->seq;					//\lnlbl{write_sequnlock:inc}
+	WRITE_ONCE(slp->seq, READ_ONCE(slp->seq) + 1);  //\lnlbl{write_sequnlock:inc}
 	spin_unlock(&slp->lock);
 }							//\lnlbl{write_sequnlock:e}
 //\end{snippet}
-- 
2.47.0