Messages in this thread Patch in this message | | | From | Julia Cartwright <> | Subject | [PATCH RT 21/22] seqlock: provide the same ordering semantics as mainline | Date | Mon, 6 Aug 2018 04:17:37 -0500 |
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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: stable-rt@vger.kernel.org Signed-off-by: Julia Cartwright <julia@ni.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> (cherry picked from commit afa4c06b89a3c0fb7784ff900ccd707bef519cb7) Signed-off-by: Julia Cartwright <julia@ni.com> --- 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
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