[PATCH] [5/6] kfifo: Add kfifo_initialized

[Andi Kleen <andi@firstfloor.org>]

Simple inline that checks if kfifo_init() has been executed
on a fifo.

This is useful for walking all per CPU fifos, when some of them
might not have been brought up yet.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 include/linux/kfifo.h |   10 ++++++++++
 1 file changed, 10 insertions(+)

Index: linux/include/linux/kfifo.h
===================================================================
--- linux.orig/include/linux/kfifo.h
+++ linux/include/linux/kfifo.h
@@ -117,6 +117,16 @@ extern __must_check unsigned int kfifo_o
 extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo,
 				void *to, unsigned int len, unsigned offset);
 
+/**
+ * kfifo_initialized - Check if kfifo is initialized.
+ * @fifo: fifo to check
+ * Return %true if FIFO is initialized, otherwise %false.
+ * Assumes the fifo was 0 before.
+ */
+static inline bool kfifo_initialized(struct kfifo *fifo)
+{
+	return fifo->buffer != 0;
+}
 
 /**
  * kfifo_reset - removes the entire FIFO contents