backport-include/linux/kfifo.h

#ifndef BACKPORT_LINUX_KFIFO_H
#define BACKPORT_LINUX_KFIFO_H

#include <linux/version.h>
#include_next <linux/kfifo.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(3,13,0)
#undef kfifo_put
/**
 * kfifo_put - put data into the fifo
 * @fifo: address of the fifo to be used
 * @val: the data to be added
 *
 * This macro copies the given value into the fifo.
 * It returns 0 if the fifo was full. Otherwise it returns the number
 * processed elements.
 *
 * Note that with only one concurrent reader and one concurrent
 * writer, you don't need extra locking to use these macro.
 */
#define	kfifo_put(fifo, val) \
({ \
	typeof((fifo) + 1) __tmp = (fifo); \
	typeof((&val) + 1) __val = (&val); \
	unsigned int __ret; \
	const size_t __recsize = sizeof(*__tmp->rectype); \
	struct __kfifo *__kfifo = &__tmp->kfifo; \
	if (0) { \
		typeof(__tmp->ptr_const) __dummy __attribute__ ((unused)); \
		__dummy = (typeof(__val))NULL; \
	} \
	if (__recsize) \
		__ret = __kfifo_in_r(__kfifo, __val, sizeof(*__val), \
			__recsize); \
	else { \
		__ret = !kfifo_is_full(__tmp); \
		if (__ret) { \
			(__is_kfifo_ptr(__tmp) ? \
			((typeof(__tmp->type))__kfifo->data) : \
			(__tmp->buf) \
			)[__kfifo->in & __tmp->kfifo.mask] = \
				*(typeof(__tmp->type))__val; \
			smp_wmb(); \
			__kfifo->in++; \
		} \
	} \
	__ret; \
})
#endif

#endif /* BACKPORT_LINUX_KFIFO_H */