WRITE_ONCE() is needed here to prevent store tears and other unwanted compiler optimizations.
Signed-off-by: Daniel Xu <[email protected]> --- 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
