raw_read_seqcount opens a read critical section of the given seqcount
without any lockdep checking and without checking or masking the
LSB. Calling code is responsible for handling that.
Preparatory patch to provide a NMI safe clock monotonic accessor
function.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
---
include/linux/seqlock.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
Index: tip/include/linux/seqlock.h
===================================================================
--- tip.orig/include/linux/seqlock.h
+++ tip/include/linux/seqlock.h
@@ -117,6 +117,22 @@ repeat:
}
/**
+ * raw_read_seqcount - Read the raw seqcount
+ * @s: pointer to seqcount_t
+ * Returns: count to be passed to read_seqcount_retry
+ *
+ * raw_read_seqcount opens a read critical section of the given
+ * 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)
+{
+ unsigned ret = ACCESS_ONCE(s->sequence);
+ smp_rmb();
+ return ret;
+}
+
+/**
* raw_read_seqcount_begin - start seq-read critical section w/o lockdep
* @s: pointer to seqcount_t
* Returns: count to be passed to read_seqcount_retry
--
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