[patch v2 1/4] percpu_counter: change return value and add comments

[shaohua . li]

the percpu_counter_*_positive() API SMP and UP aren't consistent. Add comments
to explain it.
Also if count < 0, returns 0 instead of 1 for *read_positive().

Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>

---
 include/linux/percpu_counter.h |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Index: linux/include/linux/percpu_counter.h
===================================================================
--- linux.orig/include/linux/percpu_counter.h	2011-04-13 13:10:13.000000000 +0800
+++ linux/include/linux/percpu_counter.h	2011-04-13 13:21:21.000000000 +0800
@@ -75,7 +75,7 @@ static inline s64 percpu_counter_read_po
 	barrier();		/* Prevent reloads of fbc->count */
 	if (ret >= 0)
 		return ret;
-	return 1;
+	return 0;
 }
 
 static inline int percpu_counter_initialized(struct percpu_counter *fbc)
@@ -135,6 +135,10 @@ static inline s64 percpu_counter_read(st
 
 static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
 {
+	/*
+	 * percpu_counter is intended to track positive number. In UP case, the
+	 * number should never be negative.
+	 */
 	return fbc->count;
 }
 

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