include/linux/kfifo.h

Source file repositories/reference/linux-study-clean/include/linux/kfifo.h

File Facts

System
Linux kernel
Corpus path
include/linux/kfifo.h
Extension
.h
Size
30622 bytes
Lines
1001
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct __kfifo {
	unsigned int	in;
	unsigned int	out;
	unsigned int	mask;
	unsigned int	esize;
	void		*data;
};

#define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) \
	union { \
		struct __kfifo	kfifo; \
		datatype	*type; \
		const datatype	*const_type; \
		char		(*rectype)[recsize]; \
		ptrtype		*ptr; \
		ptrtype const	*ptr_const; \
	}

#define __STRUCT_KFIFO(type, size, recsize, ptrtype) \
{ \
	__STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
	type		buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \
}

#define STRUCT_KFIFO(type, size) \
	struct __STRUCT_KFIFO(type, size, 0, type)

#define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) \
{ \
	__STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
	type		buf[0]; \
}

#define STRUCT_KFIFO_PTR(type) \
	struct __STRUCT_KFIFO_PTR(type, 0, type)

/*
 * define compatibility "struct kfifo" for dynamic allocated fifos
 */
struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void);

#define STRUCT_KFIFO_REC_1(size) \
	struct __STRUCT_KFIFO(unsigned char, size, 1, void)

#define STRUCT_KFIFO_REC_2(size) \
	struct __STRUCT_KFIFO(unsigned char, size, 2, void)

/*
 * define kfifo_rec types
 */
struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void);
struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void);

/*
 * helper macro to distinguish between real in place fifo where the fifo
 * array is a part of the structure and the fifo type where the array is
 * outside of the fifo structure.
 */
#define	__is_kfifo_ptr(fifo) \
	(sizeof(*fifo) == sizeof(STRUCT_KFIFO_PTR(typeof(*(fifo)->type))))

/**
 * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object
 * @fifo: name of the declared fifo
 * @type: type of the fifo elements
 */
#define DECLARE_KFIFO_PTR(fifo, type)	STRUCT_KFIFO_PTR(type) fifo

/**
 * DECLARE_KFIFO - macro to declare a fifo object
 * @fifo: name of the declared fifo
 * @type: type of the fifo elements
 * @size: the number of elements in the fifo, this must be a power of 2
 */
#define DECLARE_KFIFO(fifo, type, size)	STRUCT_KFIFO(type, size) fifo

/**
 * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO
 * @fifo: name of the declared fifo datatype
 */
#define INIT_KFIFO(fifo) \
(void)({ \
	typeof(&(fifo)) __tmp = &(fifo); \
	struct __kfifo *__kfifo = &__tmp->kfifo; \
	__kfifo->in = 0; \
	__kfifo->out = 0; \
	__kfifo->mask = __is_kfifo_ptr(__tmp) ? 0 : ARRAY_SIZE(__tmp->buf) - 1;\
	__kfifo->esize = sizeof(*__tmp->buf); \
	__kfifo->data = __is_kfifo_ptr(__tmp) ?  NULL : __tmp->buf; \
})

Annotation

Implementation Notes