new kfifo API

diff -u -N -r linux-2.6.31-rc4-kfifo4/include/linux/kfifo.h linux-2.6.31-rc4-kfifo5/include/linux/kfifo.h
@@ -32,6 +32,28 @@
 	unsigned int out;	/* data is extracted from off. (out % size) */
 };
 
+#define KFIFO_INIT(s, b) \
+	(struct kfifo) { \
+		.size	= s, \
+		.in	= 0, \
+		.out	= 0, \
+		.buffer = b \
+	}
+
+
+#define DECLARE_KFIFO(name, size) \
+union { \
+	struct kfifo name; \
+	unsigned char name##_buffer[size + sizeof(struct kfifo)]; \
+}
+
+#define DEFINE_KFIFO(name, size) \
+	DECLARE_KFIFO(name, size) = KFIFO_INIT(name, size)
+
+#define INIT_KFIFO(name) \
+	name = KFIFO_INIT(sizeof(name##_buffer) - sizeof(struct kfifo), \
+				name##_buffer)
+
 extern void kfifo_init(struct kfifo *fifo,
 			unsigned char *buffer, unsigned int size);
 extern __must_check int kfifo_alloc(struct kfifo *fifo,

@@ -52,6 +74,24 @@
 }
 
 /**
+ * kfifo_reset_in - skip input FIFO contents
+ * @fifo: the fifo to be emptied.
+ */
+static inline void kfifo_reset_in(struct kfifo *fifo)
+{
+	fifo->in = fifo->out;
+}
+
+/**
+ * kfifo_reset_in - skip output FIFO contents
+ * @fifo: the fifo to be emptied.
+ */
+static inline void kfifo_reset_out(struct kfifo *fifo)
+{
+	fifo->out = fifo->in;
+}
+
+/**
  * kfifo_in_locked - puts some data into the FIFO using a spinlock for locking
  * @fifo: the fifo to be used.
  * @buffer: the data to be added.

@@ -122,4 +162,40 @@
 	return fifo->in - out;
 }
 
+/**
+ * kfifo_size - returns the size of the fifo in bytes
+ * @fifo: the fifo to be used.
+ */
+static inline __must_check unsigned int kfifo_size(struct kfifo *fifo)
+{
+	return fifo->size;
+}
+
+/**
+ * kfifo_is_empty - returns true if the fifo is empty
+ * @fifo: the fifo to be used.
+ */
+static inline __must_check int kfifo_is_empty(struct kfifo *fifo)
+{
+	return fifo->in == fifo->out;
+}
+
+/**
+ * kfifo_is_full - returns true if the fifo is full
+ * @fifo: the fifo to be used.
+ */
+static inline __must_check int kfifo_is_full(struct kfifo *fifo)
+{
+	return kfifo_len(fifo) == kfifo_size(fifo);
+}
+
+/**
+ * kfifo_avail - returns the number of bytes available in the FIFO
+ * @fifo: the fifo to be used.
+ */
+static inline __must_check unsigned int kfifo_avail(struct kfifo *fifo)
+{
+	return kfifo_size(fifo) - kfifo_len(fifo);
+}
+
 #endif