kfifo: add kfifo_initialized

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 <[email protected]>
Acked-by: Stefani Seibold <[email protected]>
Cc: Roland Dreier <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: Andy Walls <[email protected]>
Cc: Vikram Dhillon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 7ad6d32dd673..c8618243ca5a 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -116,6 +116,16 @@ extern __must_check unsigned int kfifo_out(struct kfifo *fifo,
 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