4.9.115-rt94-rc1 stable review patch.
If you have any objection to the inclusion of this patch, let me know.
--- 8< --- 8< --- 8< ---
The mainline implementation of read_seqbegin() orders prior loads w.r.t.
the read-side critical section. Fixup the RT writer-boosting
implementation to provide the same guarantee.
Also, while we're here, update the usage of ACCESS_ONCE() to use
READ_ONCE().
Fixes: e69f15cf77c23 ("seqlock: Prevent rt starvation")
Cc: [email protected]
Signed-off-by: Julia Cartwright <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
(cherry picked from commit afa4c06b89a3c0fb7784ff900ccd707bef519cb7)
Signed-off-by: Julia Cartwright <[email protected]>
---
include/linux/seqlock.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 3d7223ffdd3b..de04d6d0face 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -461,6 +461,7 @@ static inline unsigned read_seqbegin(seqlock_t *sl)
spin_unlock_wait(&sl->lock);
goto repeat;
}
+ smp_rmb();
return ret;
}
#endif
--
2.18.0
