[lttng-modules.git] / lib / ringbuffer / vfs.h

/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
 *
 * lib/ringbuffer/vfs.h
 *
 * Wait-free ring buffer VFS file operations.
 *
 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifndef _LIB_RING_BUFFER_VFS_H
#define _LIB_RING_BUFFER_VFS_H

#include <linux/fs.h>
#include <linux/poll.h>

/* VFS API */

extern const struct file_operations lib_ring_buffer_file_operations;

/*
 * Internal file operations.
 */

struct lib_ring_buffer;

int lib_ring_buffer_open(struct inode *inode, struct file *file,
		struct lib_ring_buffer *buf);
int lib_ring_buffer_release(struct inode *inode, struct file *file,
		struct lib_ring_buffer *buf);
unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait,
		struct lib_ring_buffer *buf);
ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
		struct pipe_inode_info *pipe, size_t len,
		unsigned int flags, struct lib_ring_buffer *buf);
int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma,
		struct lib_ring_buffer *buf);

/* Ring Buffer ioctl() and ioctl numbers */
long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg, struct lib_ring_buffer *buf);
#ifdef CONFIG_COMPAT
long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg, struct lib_ring_buffer *buf);
#endif

ssize_t vfs_lib_ring_buffer_file_splice_read(struct file *in, loff_t *ppos,
		struct pipe_inode_info *pipe, size_t len, unsigned int flags);
loff_t vfs_lib_ring_buffer_no_llseek(struct file *file, loff_t offset,
		int origin);
int vfs_lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma);
ssize_t vfs_lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
		struct pipe_inode_info *pipe, size_t len,
		unsigned int flags);

/*
 * Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and
 * consume sub-buffers sequentially.
 *
 * Reading sub-buffers without consuming them can be performed with:
 *
 * RING_BUFFER_SNAPSHOT
 * RING_BUFFER_SNAPSHOT_GET_CONSUMED
 * RING_BUFFER_SNAPSHOT_GET_PRODUCED
 *
 * to get the offset range to consume, and then by passing each sub-buffer
 * offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it
 * with RING_BUFFER_PUT_SUBBUF.
 *
 * Note that the "snapshot" API can be used to read the sub-buffer in reverse
 * order, which is useful for flight recorder snapshots.
 */

/* Get a snapshot of the current ring buffer producer and consumer positions */
#define RING_BUFFER_SNAPSHOT			_IO(0xF6, 0x00)
/* Get the consumer position (iteration start) */
#define RING_BUFFER_SNAPSHOT_GET_CONSUMED	_IOR(0xF6, 0x01, unsigned long)
/* Get the producer position (iteration end) */
#define RING_BUFFER_SNAPSHOT_GET_PRODUCED	_IOR(0xF6, 0x02, unsigned long)
/* Get exclusive read access to the specified sub-buffer position */
#define RING_BUFFER_GET_SUBBUF			_IOW(0xF6, 0x03, unsigned long)
/* Release exclusive sub-buffer access */
#define RING_BUFFER_PUT_SUBBUF			_IO(0xF6, 0x04)

/* Get exclusive read access to the next sub-buffer that can be read. */
#define RING_BUFFER_GET_NEXT_SUBBUF		_IO(0xF6, 0x05)
/* Release exclusive sub-buffer access, move consumer forward. */
#define RING_BUFFER_PUT_NEXT_SUBBUF		_IO(0xF6, 0x06)
/* returns the size of the current sub-buffer, without padding (for mmap). */
#define RING_BUFFER_GET_SUBBUF_SIZE		_IOR(0xF6, 0x07, unsigned long)
/* returns the size of the current sub-buffer, with padding (for splice). */
#define RING_BUFFER_GET_PADDED_SUBBUF_SIZE	_IOR(0xF6, 0x08, unsigned long)
/* returns the maximum size for sub-buffers. */
#define RING_BUFFER_GET_MAX_SUBBUF_SIZE		_IOR(0xF6, 0x09, unsigned long)
/* returns the length to mmap. */
#define RING_BUFFER_GET_MMAP_LEN		_IOR(0xF6, 0x0A, unsigned long)
/* returns the offset of the subbuffer belonging to the mmap reader. */
#define RING_BUFFER_GET_MMAP_READ_OFFSET	_IOR(0xF6, 0x0B, unsigned long)
/* Flush the current sub-buffer, if non-empty. */
#define RING_BUFFER_FLUSH			_IO(0xF6, 0x0C)
/* Get the current version of the metadata cache (after a get_next). */
#define RING_BUFFER_GET_METADATA_VERSION	_IOR(0xF6, 0x0D, uint64_t)
/*
 * Get a snapshot of the current ring buffer producer and consumer positions,
 * regardless of whether or not the two positions are contained within the same
 * sub-buffer.
 */
#define RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS	_IO(0xF6, 0x0E)
/* Flush the current sub-buffer, even if empty. */
#define RING_BUFFER_FLUSH_EMPTY			_IO(0xF6, 0x0F)
/*
 * Reset the position of what has been consumed from the metadata cache to 0
 * so it can be read again.
 */
#define RING_BUFFER_METADATA_CACHE_DUMP		_IO(0xF6, 0x10)
/* Clear ring buffer content. */
#define RING_BUFFER_CLEAR			_IO(0xF6, 0x11)

#ifdef CONFIG_COMPAT
/* Get a snapshot of the current ring buffer producer and consumer positions */
#define RING_BUFFER_COMPAT_SNAPSHOT		RING_BUFFER_SNAPSHOT
/* Get the consumer position (iteration start) */
#define RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED \
	_IOR(0xF6, 0x01, compat_ulong_t)
/* Get the producer position (iteration end) */
#define RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED \
	_IOR(0xF6, 0x02, compat_ulong_t)
/* Get exclusive read access to the specified sub-buffer position */
#define RING_BUFFER_COMPAT_GET_SUBBUF		_IOW(0xF6, 0x03, compat_ulong_t)
/* Release exclusive sub-buffer access */
#define RING_BUFFER_COMPAT_PUT_SUBBUF		RING_BUFFER_PUT_SUBBUF

/* Get exclusive read access to the next sub-buffer that can be read. */
#define RING_BUFFER_COMPAT_GET_NEXT_SUBBUF	RING_BUFFER_GET_NEXT_SUBBUF
/* Release exclusive sub-buffer access, move consumer forward. */
#define RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF	RING_BUFFER_PUT_NEXT_SUBBUF
/* returns the size of the current sub-buffer, without padding (for mmap). */
#define RING_BUFFER_COMPAT_GET_SUBBUF_SIZE	_IOR(0xF6, 0x07, compat_ulong_t)
/* returns the size of the current sub-buffer, with padding (for splice). */
#define RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE \
	_IOR(0xF6, 0x08, compat_ulong_t)
/* returns the maximum size for sub-buffers. */
#define RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE	_IOR(0xF6, 0x09, compat_ulong_t)
/* returns the length to mmap. */
#define RING_BUFFER_COMPAT_GET_MMAP_LEN		_IOR(0xF6, 0x0A, compat_ulong_t)
/* returns the offset of the subbuffer belonging to the mmap reader. */
#define RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET	_IOR(0xF6, 0x0B, compat_ulong_t)
/* Flush the current sub-buffer, if non-empty. */
#define RING_BUFFER_COMPAT_FLUSH		RING_BUFFER_FLUSH
/* Get the current version of the metadata cache (after a get_next). */
#define RING_BUFFER_COMPAT_GET_METADATA_VERSION	RING_BUFFER_GET_METADATA_VERSION
/*
 * Get a snapshot of the current ring buffer producer and consumer positions,
 * regardless of whether or not the two positions are contained within the same
 * sub-buffer.
 */
#define RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS	\
	RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS
/* Flush the current sub-buffer, even if empty. */
#define RING_BUFFER_COMPAT_FLUSH_EMPTY			\
	RING_BUFFER_FLUSH_EMPTY
/* Clear ring buffer content. */
#define RING_BUFFER_COMPAT_CLEAR			\
	RING_BUFFER_CLEAR
#endif /* CONFIG_COMPAT */

#endif /* _LIB_RING_BUFFER_VFS_H */
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
9f36eaed	2	*
886d51a3	3	* lib/ringbuffer/vfs.h
f3bc08c5 MD	4	*
	5	* Wait-free ring buffer VFS file operations.
	6	*
886d51a3	7	* Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
f3bc08c5 MD	8	*/
f3bc08c5 MD	9
9f36eaed MJ	10	#ifndef _LIB_RING_BUFFER_VFS_H
	11	#define _LIB_RING_BUFFER_VFS_H
	12
f3bc08c5 MD	13	#include <linux/fs.h>
	14	#include <linux/poll.h>
	15
	16	/* VFS API */
	17
	18	extern const struct file_operations lib_ring_buffer_file_operations;
	19
	20	/*
	21	* Internal file operations.
	22	*/
	23
d83004aa JD	24	struct lib_ring_buffer;
	25
	26	int lib_ring_buffer_open(struct inode inode, struct file file,
	27	struct lib_ring_buffer *buf);
	28	int lib_ring_buffer_release(struct inode inode, struct file file,
	29	struct lib_ring_buffer *buf);
	30	unsigned int lib_ring_buffer_poll(struct file filp, poll_table wait,
	31	struct lib_ring_buffer *buf);
f3bc08c5	32	ssize_t lib_ring_buffer_splice_read(struct file in, loff_t ppos,
d83004aa JD	33	struct pipe_inode_info *pipe, size_t len,
	34	unsigned int flags, struct lib_ring_buffer *buf);
	35	int lib_ring_buffer_mmap(struct file filp, struct vm_area_struct vma,
	36	struct lib_ring_buffer *buf);
f3bc08c5 MD	37
f3bc08c5 MD	38	/* Ring Buffer ioctl() and ioctl numbers */
d83004aa JD	39	long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
d83004aa JD	40	unsigned long arg, struct lib_ring_buffer *buf);
f3bc08c5 MD	41	#ifdef CONFIG_COMPAT
f3bc08c5 MD	42	long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
d83004aa	43	unsigned long arg, struct lib_ring_buffer *buf);
f3bc08c5 MD	44	#endif
f3bc08c5 MD	45
d83004aa JD	46	ssize_t vfs_lib_ring_buffer_file_splice_read(struct file in, loff_t ppos,
	47	struct pipe_inode_info *pipe, size_t len, unsigned int flags);
	48	loff_t vfs_lib_ring_buffer_no_llseek(struct file *file, loff_t offset,
	49	int origin);
	50	int vfs_lib_ring_buffer_mmap(struct file filp, struct vm_area_struct vma);
	51	ssize_t vfs_lib_ring_buffer_splice_read(struct file in, loff_t ppos,
	52	struct pipe_inode_info *pipe, size_t len,
	53	unsigned int flags);
	54
f3bc08c5 MD	55	/*
	56	* Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and
	57	* consume sub-buffers sequentially.
	58	*
	59	* Reading sub-buffers without consuming them can be performed with:
	60	*
	61	* RING_BUFFER_SNAPSHOT
	62	* RING_BUFFER_SNAPSHOT_GET_CONSUMED
	63	* RING_BUFFER_SNAPSHOT_GET_PRODUCED
	64	*
	65	* to get the offset range to consume, and then by passing each sub-buffer
	66	* offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it
	67	* with RING_BUFFER_PUT_SUBBUF.
	68	*
	69	* Note that the "snapshot" API can be used to read the sub-buffer in reverse
	70	* order, which is useful for flight recorder snapshots.
	71	*/
	72
	73	/* Get a snapshot of the current ring buffer producer and consumer positions */
	74	#define RING_BUFFER_SNAPSHOT _IO(0xF6, 0x00)
	75	/* Get the consumer position (iteration start) */
	76	#define RING_BUFFER_SNAPSHOT_GET_CONSUMED _IOR(0xF6, 0x01, unsigned long)
76447e2f JD	77	/* Get the producer position (iteration end) */
	78	#define RING_BUFFER_SNAPSHOT_GET_PRODUCED _IOR(0xF6, 0x02, unsigned long)
	79	/* Get exclusive read access to the specified sub-buffer position */
	80	#define RING_BUFFER_GET_SUBBUF _IOW(0xF6, 0x03, unsigned long)
	81	/* Release exclusive sub-buffer access */
	82	#define RING_BUFFER_PUT_SUBBUF _IO(0xF6, 0x04)
	83
	84	/* Get exclusive read access to the next sub-buffer that can be read. */
	85	#define RING_BUFFER_GET_NEXT_SUBBUF _IO(0xF6, 0x05)
	86	/* Release exclusive sub-buffer access, move consumer forward. */
	87	#define RING_BUFFER_PUT_NEXT_SUBBUF _IO(0xF6, 0x06)
	88	/* returns the size of the current sub-buffer, without padding (for mmap). */
	89	#define RING_BUFFER_GET_SUBBUF_SIZE _IOR(0xF6, 0x07, unsigned long)
	90	/* returns the size of the current sub-buffer, with padding (for splice). */
	91	#define RING_BUFFER_GET_PADDED_SUBBUF_SIZE _IOR(0xF6, 0x08, unsigned long)
	92	/* returns the maximum size for sub-buffers. */
	93	#define RING_BUFFER_GET_MAX_SUBBUF_SIZE _IOR(0xF6, 0x09, unsigned long)
	94	/* returns the length to mmap. */
	95	#define RING_BUFFER_GET_MMAP_LEN _IOR(0xF6, 0x0A, unsigned long)
	96	/* returns the offset of the subbuffer belonging to the mmap reader. */
	97	#define RING_BUFFER_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, unsigned long)
c6f05468	98	/* Flush the current sub-buffer, if non-empty. */
76447e2f	99	#define RING_BUFFER_FLUSH _IO(0xF6, 0x0C)
9616f0bf JD	100	/* Get the current version of the metadata cache (after a get_next). */
9616f0bf JD	101	#define RING_BUFFER_GET_METADATA_VERSION _IOR(0xF6, 0x0D, uint64_t)
4dce5a48 JG	102	/*
	103	* Get a snapshot of the current ring buffer producer and consumer positions,
	104	* regardless of whether or not the two positions are contained within the same
	105	* sub-buffer.
	106	*/
	107	#define RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS _IO(0xF6, 0x0E)
c6f05468 MD	108	/* Flush the current sub-buffer, even if empty. */
c6f05468 MD	109	#define RING_BUFFER_FLUSH_EMPTY _IO(0xF6, 0x0F)
d1344afa JD	110	/*
	111	* Reset the position of what has been consumed from the metadata cache to 0
	112	* so it can be read again.
	113	*/
	114	#define RING_BUFFER_METADATA_CACHE_DUMP _IO(0xF6, 0x10)
c245d0d3 MD	115	/* Clear ring buffer content. */
c245d0d3 MD	116	#define RING_BUFFER_CLEAR _IO(0xF6, 0x11)
76447e2f JD	117
	118	#ifdef CONFIG_COMPAT
	119	/* Get a snapshot of the current ring buffer producer and consumer positions */
	120	#define RING_BUFFER_COMPAT_SNAPSHOT RING_BUFFER_SNAPSHOT
	121	/* Get the consumer position (iteration start) */
216f7feb JD	122	#define RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED \
216f7feb JD	123	_IOR(0xF6, 0x01, compat_ulong_t)
f3bc08c5	124	/* Get the producer position (iteration end) */
216f7feb JD	125	#define RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED \
216f7feb JD	126	_IOR(0xF6, 0x02, compat_ulong_t)
f3bc08c5	127	/* Get exclusive read access to the specified sub-buffer position */
216f7feb	128	#define RING_BUFFER_COMPAT_GET_SUBBUF _IOW(0xF6, 0x03, compat_ulong_t)
f3bc08c5	129	/* Release exclusive sub-buffer access */
216f7feb	130	#define RING_BUFFER_COMPAT_PUT_SUBBUF RING_BUFFER_PUT_SUBBUF
f3bc08c5 MD	131
f3bc08c5 MD	132	/* Get exclusive read access to the next sub-buffer that can be read. */
216f7feb	133	#define RING_BUFFER_COMPAT_GET_NEXT_SUBBUF RING_BUFFER_GET_NEXT_SUBBUF
f3bc08c5	134	/* Release exclusive sub-buffer access, move consumer forward. */
216f7feb	135	#define RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF RING_BUFFER_PUT_NEXT_SUBBUF
f3bc08c5	136	/* returns the size of the current sub-buffer, without padding (for mmap). */
216f7feb	137	#define RING_BUFFER_COMPAT_GET_SUBBUF_SIZE _IOR(0xF6, 0x07, compat_ulong_t)
f3bc08c5	138	/* returns the size of the current sub-buffer, with padding (for splice). */
216f7feb JD	139	#define RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE \
216f7feb JD	140	_IOR(0xF6, 0x08, compat_ulong_t)
f3bc08c5	141	/* returns the maximum size for sub-buffers. */
216f7feb	142	#define RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE _IOR(0xF6, 0x09, compat_ulong_t)
f3bc08c5	143	/* returns the length to mmap. */
216f7feb	144	#define RING_BUFFER_COMPAT_GET_MMAP_LEN _IOR(0xF6, 0x0A, compat_ulong_t)
f3bc08c5	145	/* returns the offset of the subbuffer belonging to the mmap reader. */
216f7feb	146	#define RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, compat_ulong_t)
c6f05468	147	/* Flush the current sub-buffer, if non-empty. */
216f7feb	148	#define RING_BUFFER_COMPAT_FLUSH RING_BUFFER_FLUSH
9616f0bf JD	149	/* Get the current version of the metadata cache (after a get_next). */
9616f0bf JD	150	#define RING_BUFFER_COMPAT_GET_METADATA_VERSION RING_BUFFER_GET_METADATA_VERSION
4dce5a48 JG	151	/*
	152	* Get a snapshot of the current ring buffer producer and consumer positions,
	153	* regardless of whether or not the two positions are contained within the same
	154	* sub-buffer.
	155	*/
	156	#define RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS \
	157	RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS
c6f05468 MD	158	/* Flush the current sub-buffer, even if empty. */
	159	#define RING_BUFFER_COMPAT_FLUSH_EMPTY \
	160	RING_BUFFER_FLUSH_EMPTY
c245d0d3 MD	161	/* Clear ring buffer content. */
	162	#define RING_BUFFER_COMPAT_CLEAR \
	163	RING_BUFFER_CLEAR
76447e2f	164	#endif /* CONFIG_COMPAT */
f3bc08c5	165
886d51a3	166	#endif /* _LIB_RING_BUFFER_VFS_H */