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Subject[PATCH v2] seqlock: mark raw_read_seqcount and read_seqcount_retry as __always_inline
Date
With the function graph tracer, each traced function calls sched_clock()
to take a timestamp. As sched_clock() uses
raw_read_seqcount()/read_seqcount_retry(), we must ensure that these
do not in turn trigger the graph tracer.
Both functions is marked as inline. However, if CONFIG_OPTIMIZE_INLINING
is set that may make the two functions tracable which they shouldn't.

Rework so that functions raw_read_seqcount and read_seqcount_retry are
marked with __always_inline so they will be inlined even if
CONFIG_OPTIMIZE_INLINING is turned on.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
---
include/linux/seqlock.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index bcf4cf26b8c8..1b18e3df186e 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -127,7 +127,7 @@ static inline unsigned __read_seqcount_begin(const seqcount_t *s)
* seqcount without any lockdep checking and without checking or
* masking the LSB. Calling code is responsible for handling that.
*/
-static inline unsigned raw_read_seqcount(const seqcount_t *s)
+static __always_inline unsigned raw_read_seqcount(const seqcount_t *s)
{
unsigned ret = READ_ONCE(s->sequence);
smp_rmb();
@@ -215,7 +215,8 @@ static inline int __read_seqcount_retry(const seqcount_t *s, unsigned start)
* If the critical section was invalid, it must be ignored (and typically
* retried).
*/
-static inline int read_seqcount_retry(const seqcount_t *s, unsigned start)
+static
+__always_inline int read_seqcount_retry(const seqcount_t *s, unsigned start)
{
smp_rmb();
return __read_seqcount_retry(s, start);
--
2.20.1
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