1 files changed, 27 insertions, 0 deletions

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 8cf350325dc6..cc359636cfa3 100644
--- a/include/linux/seqlock.h
+++ b/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
@@ -218,6 +234,17 @@ static inline void raw_write_seqcount_end(seqcount_t *s)
 }
 
 /*
+ * raw_write_seqcount_latch - redirect readers to even/odd copy
+ * @s: pointer to seqcount_t
+ */
+static inline void raw_write_seqcount_latch(seqcount_t *s)
+{
+       smp_wmb();      /* prior stores before incrementing "sequence" */
+       s->sequence++;
+       smp_wmb();      /* increment "sequence" before following stores */
+}
+
+/*
  * Sequence counter only version assumes that callers are using their
  * own mutexing.
  */