[lttng-modules.git] / lib / ringbuffer / ring_buffer_vfs.c

/*
 * ring_buffer_vfs.c
 *
 * Ring Buffer VFS file operations.
 *
 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/compat.h>

#include "../../wrapper/ringbuffer/backend.h"
#include "../../wrapper/ringbuffer/frontend.h"
#include "../../wrapper/ringbuffer/vfs.h"
#include "../../wrapper/poll.h"

static int put_ulong(unsigned long val, unsigned long arg)
{
	return put_user(val, (unsigned long __user *)arg);
}

#ifdef CONFIG_COMPAT
static int compat_put_ulong(compat_ulong_t val, unsigned long arg)
{
	return put_user(val, (compat_ulong_t __user *)compat_ptr(arg));
}
#endif

/*
 * This is not used by anonymous file descriptors. This code is left
 * there if we ever want to implement an inode with open() operation.
 */
int lib_ring_buffer_open(struct inode *inode, struct file *file,
		struct lib_ring_buffer *buf)
{
	int ret;

	if (!buf)
		return -EINVAL;

	ret = lib_ring_buffer_open_read(buf);
	if (ret)
		return ret;

	ret = nonseekable_open(inode, file);
	if (ret)
		goto release_read;
	return 0;

release_read:
	lib_ring_buffer_release_read(buf);
	return ret;
}
EXPORT_SYMBOL_GPL(lib_ring_buffer_open);

/**
 *	vfs_lib_ring_buffer_open - ring buffer open file operation
 *	@inode: opened inode
 *	@file: opened file
 *
 *	Open implementation. Makes sure only one open instance of a buffer is
 *	done at a given moment.
 */
static
int vfs_lib_ring_buffer_open(struct inode *inode, struct file *file)
{
	struct lib_ring_buffer *buf = inode->i_private;

	file->private_data = buf;
	return lib_ring_buffer_open(inode, file, buf);
}

int lib_ring_buffer_release(struct inode *inode, struct file *file,
		struct lib_ring_buffer *buf)
{
	lib_ring_buffer_release_read(buf);

	return 0;
}
EXPORT_SYMBOL_GPL(lib_ring_buffer_release);

/**
 *	vfs_lib_ring_buffer_release - ring buffer release file operation
 *	@inode: opened inode
 *	@file: opened file
 *
 *	Release implementation.
 */
static
int vfs_lib_ring_buffer_release(struct inode *inode, struct file *file)
{
	struct lib_ring_buffer *buf = file->private_data;

	return lib_ring_buffer_release(inode, file, buf);
}

unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait,
		struct lib_ring_buffer *buf)
{
	unsigned int mask = 0;
	struct channel *chan = buf->backend.chan;
	const struct lib_ring_buffer_config *config = &chan->backend.config;
	int finalized, disabled;

	if (filp->f_mode & FMODE_READ) {
		poll_wait_set_exclusive(wait);
		poll_wait(filp, &buf->read_wait, wait);

		finalized = lib_ring_buffer_is_finalized(config, buf);
		disabled = lib_ring_buffer_channel_is_disabled(chan);

		/*
		 * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
		 * finalized load before offsets loads.
		 */
		WARN_ON(atomic_long_read(&buf->active_readers) != 1);
retry:
		if (disabled)
			return POLLERR;

		if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan)
		  - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan)
		  == 0) {
			if (finalized)
				return POLLHUP;
			else {
				/*
				 * The memory barriers
				 * __wait_event()/wake_up_interruptible() take
				 * care of "raw_spin_is_locked" memory ordering.
				 */
				if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock))
					goto retry;
				else
					return 0;
			}
		} else {
			if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf),
					 chan)
			  - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf),
					 chan)
			  >= chan->backend.buf_size)
				return POLLPRI | POLLRDBAND;
			else
				return POLLIN | POLLRDNORM;
		}
	}
	return mask;
}
EXPORT_SYMBOL_GPL(lib_ring_buffer_poll);

/**
 *	vfs_lib_ring_buffer_poll - ring buffer poll file operation
 *	@filp: the file
 *	@wait: poll table
 *
 *	Poll implementation.
 */
static
unsigned int vfs_lib_ring_buffer_poll(struct file *filp, poll_table *wait)
{
	struct lib_ring_buffer *buf = filp->private_data;

	return lib_ring_buffer_poll(filp, wait, buf);
}

long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg, struct lib_ring_buffer *buf)
{
	struct channel *chan = buf->backend.chan;
	const struct lib_ring_buffer_config *config = &chan->backend.config;

	if (lib_ring_buffer_channel_is_disabled(chan))
		return -EIO;

	switch (cmd) {
	case RING_BUFFER_SNAPSHOT:
		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
					    &buf->prod_snapshot);
	case RING_BUFFER_SNAPSHOT_GET_CONSUMED:
		return put_ulong(buf->cons_snapshot, arg);
	case RING_BUFFER_SNAPSHOT_GET_PRODUCED:
		return put_ulong(buf->prod_snapshot, arg);
	case RING_BUFFER_GET_SUBBUF:
	{
		unsigned long uconsume;
		long ret;

		ret = get_user(uconsume, (unsigned long __user *) arg);
		if (ret)
			return ret; /* will return -EFAULT */
		ret = lib_ring_buffer_get_subbuf(buf, uconsume);
		if (!ret) {
			/* Set file position to zero at each successful "get" */
			filp->f_pos = 0;
		}
		return ret;
	}
	case RING_BUFFER_PUT_SUBBUF:
		lib_ring_buffer_put_subbuf(buf);
		return 0;

	case RING_BUFFER_GET_NEXT_SUBBUF:
	{
		long ret;

		ret = lib_ring_buffer_get_next_subbuf(buf);
		if (!ret) {
			/* Set file position to zero at each successful "get" */
			filp->f_pos = 0;
		}
		return ret;
	}
	case RING_BUFFER_PUT_NEXT_SUBBUF:
		lib_ring_buffer_put_next_subbuf(buf);
		return 0;
	case RING_BUFFER_GET_SUBBUF_SIZE:
		return put_ulong(lib_ring_buffer_get_read_data_size(config, buf),
				 arg);
	case RING_BUFFER_GET_PADDED_SUBBUF_SIZE:
	{
		unsigned long size;

		size = lib_ring_buffer_get_read_data_size(config, buf);
		size = PAGE_ALIGN(size);
		return put_ulong(size, arg);
	}
	case RING_BUFFER_GET_MAX_SUBBUF_SIZE:
		return put_ulong(chan->backend.subbuf_size, arg);
	case RING_BUFFER_GET_MMAP_LEN:
	{
		unsigned long mmap_buf_len;

		if (config->output != RING_BUFFER_MMAP)
			return -EINVAL;
		mmap_buf_len = chan->backend.buf_size;
		if (chan->backend.extra_reader_sb)
			mmap_buf_len += chan->backend.subbuf_size;
		if (mmap_buf_len > INT_MAX)
			return -EFBIG;
		return put_ulong(mmap_buf_len, arg);
	}
	case RING_BUFFER_GET_MMAP_READ_OFFSET:
	{
		unsigned long sb_bindex;

		if (config->output != RING_BUFFER_MMAP)
			return -EINVAL;
		sb_bindex = subbuffer_id_get_index(config,
						   buf->backend.buf_rsb.id);
		return put_ulong(buf->backend.array[sb_bindex]->mmap_offset,
				 arg);
	}
	case RING_BUFFER_FLUSH:
		lib_ring_buffer_switch_remote(buf);
		return 0;
	default:
		return -ENOIOCTLCMD;
	}
}
EXPORT_SYMBOL_GPL(lib_ring_buffer_ioctl);

/**
 *	vfs_lib_ring_buffer_ioctl - control ring buffer reader synchronization
 *
 *	@filp: the file
 *	@cmd: the command
 *	@arg: command arg
 *
 *	This ioctl implements commands necessary for producer/consumer
 *	and flight recorder reader interaction :
 *	RING_BUFFER_GET_NEXT_SUBBUF
 *		Get the next sub-buffer that can be read. It never blocks.
 *	RING_BUFFER_PUT_NEXT_SUBBUF
 *		Release the currently read sub-buffer.
 *	RING_BUFFER_GET_SUBBUF_SIZE
 *		returns the size of the current sub-buffer.
 *	RING_BUFFER_GET_MAX_SUBBUF_SIZE
 *		returns the maximum size for sub-buffers.
 *	RING_BUFFER_GET_NUM_SUBBUF
 *		returns the number of reader-visible sub-buffers in the per cpu
 *              channel (for mmap).
 *      RING_BUFFER_GET_MMAP_READ_OFFSET
 *              returns the offset of the subbuffer belonging to the reader.
 *              Should only be used for mmap clients.
 */
static
long vfs_lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct lib_ring_buffer *buf = filp->private_data;

	return lib_ring_buffer_ioctl(filp, cmd, arg, buf);
}

#ifdef CONFIG_COMPAT
long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg, struct lib_ring_buffer *buf)
{
	struct channel *chan = buf->backend.chan;
	const struct lib_ring_buffer_config *config = &chan->backend.config;

	if (lib_ring_buffer_channel_is_disabled(chan))
		return -EIO;

	switch (cmd) {
	case RING_BUFFER_COMPAT_SNAPSHOT:
		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
						&buf->prod_snapshot);
	case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED:
		return compat_put_ulong(buf->cons_snapshot, arg);
	case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED:
		return compat_put_ulong(buf->prod_snapshot, arg);
	case RING_BUFFER_COMPAT_GET_SUBBUF:
	{
		__u32 uconsume;
		unsigned long consume;
		long ret;

		ret = get_user(uconsume, (__u32 __user *) arg);
		if (ret)
			return ret; /* will return -EFAULT */
		consume = buf->cons_snapshot;
		consume &= ~0xFFFFFFFFL;
		consume |= uconsume;
		ret = lib_ring_buffer_get_subbuf(buf, consume);
		if (!ret) {
			/* Set file position to zero at each successful "get" */
			filp->f_pos = 0;
		}
		return ret;
	}
	case RING_BUFFER_COMPAT_PUT_SUBBUF:
		lib_ring_buffer_put_subbuf(buf);
		return 0;

	case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF:
	{
		long ret;

		ret = lib_ring_buffer_get_next_subbuf(buf);
		if (!ret) {
			/* Set file position to zero at each successful "get" */
			filp->f_pos = 0;
		}
		return ret;
	}
	case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF:
		lib_ring_buffer_put_next_subbuf(buf);
		return 0;
	case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE:
	{
		unsigned long data_size;

		data_size = lib_ring_buffer_get_read_data_size(config, buf);
		if (data_size > UINT_MAX)
			return -EFBIG;
		return compat_put_ulong(data_size, arg);
	}
	case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE:
	{
		unsigned long size;

		size = lib_ring_buffer_get_read_data_size(config, buf);
		size = PAGE_ALIGN(size);
		if (size > UINT_MAX)
			return -EFBIG;
		return compat_put_ulong(size, arg);
	}
	case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE:
		if (chan->backend.subbuf_size > UINT_MAX)
			return -EFBIG;
		return compat_put_ulong(chan->backend.subbuf_size, arg);
	case RING_BUFFER_COMPAT_GET_MMAP_LEN:
	{
		unsigned long mmap_buf_len;

		if (config->output != RING_BUFFER_MMAP)
			return -EINVAL;
		mmap_buf_len = chan->backend.buf_size;
		if (chan->backend.extra_reader_sb)
			mmap_buf_len += chan->backend.subbuf_size;
		if (mmap_buf_len > UINT_MAX)
			return -EFBIG;
		return compat_put_ulong(mmap_buf_len, arg);
	}
	case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET:
	{
		unsigned long sb_bindex, read_offset;

		if (config->output != RING_BUFFER_MMAP)
			return -EINVAL;
		sb_bindex = subbuffer_id_get_index(config,
						   buf->backend.buf_rsb.id);
		read_offset = buf->backend.array[sb_bindex]->mmap_offset;
		if (read_offset > UINT_MAX)
			return -EINVAL;
		return compat_put_ulong(read_offset, arg);
	}
	case RING_BUFFER_COMPAT_FLUSH:
		lib_ring_buffer_switch_remote(buf);
		return 0;
	default:
		return -ENOIOCTLCMD;
	}
}
EXPORT_SYMBOL_GPL(lib_ring_buffer_compat_ioctl);

static
long vfs_lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
				  unsigned long arg)
{
	struct lib_ring_buffer *buf = filp->private_data;

	return lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
}
#endif

const struct file_operations lib_ring_buffer_file_operations = {
	.owner = THIS_MODULE,
	.open = vfs_lib_ring_buffer_open,
	.release = vfs_lib_ring_buffer_release,
	.poll = vfs_lib_ring_buffer_poll,
	.splice_read = vfs_lib_ring_buffer_splice_read,
	.mmap = vfs_lib_ring_buffer_mmap,
	.unlocked_ioctl = vfs_lib_ring_buffer_ioctl,
	.llseek = vfs_lib_ring_buffer_no_llseek,
#ifdef CONFIG_COMPAT
	.compat_ioctl = vfs_lib_ring_buffer_compat_ioctl,
#endif
};
EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Ring Buffer Library VFS");
Commit	Line	Data
f3bc08c5 MD	1	/*
	2	* ring_buffer_vfs.c
	3	*
f3bc08c5 MD	4	* Ring Buffer VFS file operations.
f3bc08c5 MD	5	*
886d51a3 MD	6	* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
f3bc08c5 MD	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/fs.h>
	25	#include <linux/compat.h>
	26
	27	#include "../../wrapper/ringbuffer/backend.h"
	28	#include "../../wrapper/ringbuffer/frontend.h"
	29	#include "../../wrapper/ringbuffer/vfs.h"
	30	#include "../../wrapper/poll.h"
	31
	32	static int put_ulong(unsigned long val, unsigned long arg)
	33	{
	34	return put_user(val, (unsigned long __user *)arg);
	35	}
	36
	37	#ifdef CONFIG_COMPAT
	38	static int compat_put_ulong(compat_ulong_t val, unsigned long arg)
	39	{
	40	return put_user(val, (compat_ulong_t __user *)compat_ptr(arg));
	41	}
	42	#endif
	43
b3b8072b MD	44	/*
	45	* This is not used by anonymous file descriptors. This code is left
	46	* there if we ever want to implement an inode with open() operation.
	47	*/
d83004aa JD	48	int lib_ring_buffer_open(struct inode inode, struct file file,
d83004aa JD	49	struct lib_ring_buffer *buf)
f3bc08c5	50	{
f3bc08c5 MD	51	int ret;
f3bc08c5 MD	52
733ce41d MD	53	if (!buf)
	54	return -EINVAL;
	55
f3bc08c5 MD	56	ret = lib_ring_buffer_open_read(buf);
	57	if (ret)
	58	return ret;
	59
f3bc08c5 MD	60	ret = nonseekable_open(inode, file);
	61	if (ret)
	62	goto release_read;
	63	return 0;
	64
	65	release_read:
	66	lib_ring_buffer_release_read(buf);
	67	return ret;
	68	}
d83004aa	69	EXPORT_SYMBOL_GPL(lib_ring_buffer_open);
f3bc08c5 MD	70
f3bc08c5 MD	71	/**
d83004aa	72	* vfs_lib_ring_buffer_open - ring buffer open file operation
f3bc08c5 MD	73	* @inode: opened inode
	74	* @file: opened file
	75	*
d83004aa JD	76	* Open implementation. Makes sure only one open instance of a buffer is
d83004aa JD	77	* done at a given moment.
f3bc08c5	78	*/
d83004aa JD	79	static
d83004aa JD	80	int vfs_lib_ring_buffer_open(struct inode inode, struct file file)
f3bc08c5	81	{
d83004aa JD	82	struct lib_ring_buffer *buf = inode->i_private;
	83
	84	file->private_data = buf;
	85	return lib_ring_buffer_open(inode, file, buf);
	86	}
f3bc08c5	87
d83004aa JD	88	int lib_ring_buffer_release(struct inode inode, struct file file,
	89	struct lib_ring_buffer *buf)
	90	{
f3bc08c5 MD	91	lib_ring_buffer_release_read(buf);
	92
	93	return 0;
	94	}
d83004aa	95	EXPORT_SYMBOL_GPL(lib_ring_buffer_release);
f3bc08c5 MD	96
f3bc08c5 MD	97	/**
d83004aa JD	98	* vfs_lib_ring_buffer_release - ring buffer release file operation
	99	* @inode: opened inode
	100	* @file: opened file
f3bc08c5	101	*
d83004aa	102	* Release implementation.
f3bc08c5	103	*/
d83004aa JD	104	static
	105	int vfs_lib_ring_buffer_release(struct inode inode, struct file file)
	106	{
	107	struct lib_ring_buffer *buf = file->private_data;
	108
	109	return lib_ring_buffer_release(inode, file, buf);
	110	}
	111
	112	unsigned int lib_ring_buffer_poll(struct file filp, poll_table wait,
	113	struct lib_ring_buffer *buf)
f3bc08c5 MD	114	{
f3bc08c5 MD	115	unsigned int mask = 0;
f3bc08c5	116	struct channel *chan = buf->backend.chan;
5a8fd222	117	const struct lib_ring_buffer_config *config = &chan->backend.config;
254ec7bc	118	int finalized, disabled;
f3bc08c5 MD	119
f3bc08c5 MD	120	if (filp->f_mode & FMODE_READ) {
a33e44a6	121	poll_wait_set_exclusive(wait);
f3bc08c5 MD	122	poll_wait(filp, &buf->read_wait, wait);
	123
	124	finalized = lib_ring_buffer_is_finalized(config, buf);
254ec7bc MD	125	disabled = lib_ring_buffer_channel_is_disabled(chan);
254ec7bc MD	126
f3bc08c5 MD	127	/*
	128	* lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
	129	* finalized load before offsets loads.
	130	*/
	131	WARN_ON(atomic_long_read(&buf->active_readers) != 1);
	132	retry:
254ec7bc MD	133	if (disabled)
	134	return POLLERR;
	135
f3bc08c5 MD	136	if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan)
	137	- subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan)
	138	== 0) {
	139	if (finalized)
	140	return POLLHUP;
	141	else {
	142	/*
	143	* The memory barriers
	144	* __wait_event()/wake_up_interruptible() take
	145	* care of "raw_spin_is_locked" memory ordering.
	146	*/
	147	if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock))
	148	goto retry;
	149	else
	150	return 0;
	151	}
	152	} else {
	153	if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf),
	154	chan)
	155	- subbuf_trunc(lib_ring_buffer_get_consumed(config, buf),
	156	chan)
	157	>= chan->backend.buf_size)
	158	return POLLPRI \| POLLRDBAND;
	159	else
	160	return POLLIN \| POLLRDNORM;
	161	}
	162	}
	163	return mask;
	164	}
d83004aa	165	EXPORT_SYMBOL_GPL(lib_ring_buffer_poll);
f3bc08c5 MD	166
f3bc08c5 MD	167	/**
d83004aa	168	* vfs_lib_ring_buffer_poll - ring buffer poll file operation
f3bc08c5	169	* @filp: the file
d83004aa	170	* @wait: poll table
f3bc08c5	171	*
d83004aa	172	* Poll implementation.
f3bc08c5	173	*/
d83004aa JD	174	static
d83004aa JD	175	unsigned int vfs_lib_ring_buffer_poll(struct file filp, poll_table wait)
f3bc08c5 MD	176	{
f3bc08c5 MD	177	struct lib_ring_buffer *buf = filp->private_data;
d83004aa JD	178
	179	return lib_ring_buffer_poll(filp, wait, buf);
	180	}
	181
	182	long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
	183	unsigned long arg, struct lib_ring_buffer *buf)
	184	{
f3bc08c5	185	struct channel *chan = buf->backend.chan;
5a8fd222	186	const struct lib_ring_buffer_config *config = &chan->backend.config;
f3bc08c5	187
254ec7bc MD	188	if (lib_ring_buffer_channel_is_disabled(chan))
	189	return -EIO;
	190
f3bc08c5 MD	191	switch (cmd) {
	192	case RING_BUFFER_SNAPSHOT:
	193	return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
	194	&buf->prod_snapshot);
	195	case RING_BUFFER_SNAPSHOT_GET_CONSUMED:
	196	return put_ulong(buf->cons_snapshot, arg);
	197	case RING_BUFFER_SNAPSHOT_GET_PRODUCED:
	198	return put_ulong(buf->prod_snapshot, arg);
	199	case RING_BUFFER_GET_SUBBUF:
	200	{
	201	unsigned long uconsume;
	202	long ret;
	203
	204	ret = get_user(uconsume, (unsigned long __user *) arg);
	205	if (ret)
	206	return ret; /* will return -EFAULT */
	207	ret = lib_ring_buffer_get_subbuf(buf, uconsume);
	208	if (!ret) {
	209	/* Set file position to zero at each successful "get" */
	210	filp->f_pos = 0;
	211	}
	212	return ret;
	213	}
	214	case RING_BUFFER_PUT_SUBBUF:
	215	lib_ring_buffer_put_subbuf(buf);
	216	return 0;
	217
	218	case RING_BUFFER_GET_NEXT_SUBBUF:
	219	{
	220	long ret;
	221
	222	ret = lib_ring_buffer_get_next_subbuf(buf);
	223	if (!ret) {
	224	/* Set file position to zero at each successful "get" */
	225	filp->f_pos = 0;
	226	}
	227	return ret;
	228	}
	229	case RING_BUFFER_PUT_NEXT_SUBBUF:
	230	lib_ring_buffer_put_next_subbuf(buf);
	231	return 0;
	232	case RING_BUFFER_GET_SUBBUF_SIZE:
	233	return put_ulong(lib_ring_buffer_get_read_data_size(config, buf),
	234	arg);
	235	case RING_BUFFER_GET_PADDED_SUBBUF_SIZE:
	236	{
	237	unsigned long size;
	238
	239	size = lib_ring_buffer_get_read_data_size(config, buf);
	240	size = PAGE_ALIGN(size);
	241	return put_ulong(size, arg);
	242	}
	243	case RING_BUFFER_GET_MAX_SUBBUF_SIZE:
	244	return put_ulong(chan->backend.subbuf_size, arg);
	245	case RING_BUFFER_GET_MMAP_LEN:
	246	{
	247	unsigned long mmap_buf_len;
	248
	249	if (config->output != RING_BUFFER_MMAP)
	250	return -EINVAL;
	251	mmap_buf_len = chan->backend.buf_size;
	252	if (chan->backend.extra_reader_sb)
	253	mmap_buf_len += chan->backend.subbuf_size;
	254	if (mmap_buf_len > INT_MAX)
255	return -EFBIG;
256	return put_ulong(mmap_buf_len, arg);
257	}
258	case RING_BUFFER_GET_MMAP_READ_OFFSET:
259	{
260	unsigned long sb_bindex;
261
262	if (config->output != RING_BUFFER_MMAP)
263	return -EINVAL;
264	sb_bindex = subbuffer_id_get_index(config,
265	buf->backend.buf_rsb.id);
266	return put_ulong(buf->backend.array[sb_bindex]->mmap_offset,
267	arg);
268	}
5c055266	269	case RING_BUFFER_FLUSH:
5e391252	270	lib_ring_buffer_switch_remote(buf);
5c055266	271	return 0;
f3bc08c5 MD	272	default:
	273	return -ENOIOCTLCMD;
	274	}
	275	}
d83004aa JD	276	EXPORT_SYMBOL_GPL(lib_ring_buffer_ioctl);
	277
	278	/**
	279	* vfs_lib_ring_buffer_ioctl - control ring buffer reader synchronization
	280	*
	281	* @filp: the file
	282	* @cmd: the command
	283	* @arg: command arg
	284	*
	285	* This ioctl implements commands necessary for producer/consumer
	286	* and flight recorder reader interaction :
	287	* RING_BUFFER_GET_NEXT_SUBBUF
	288	* Get the next sub-buffer that can be read. It never blocks.
	289	* RING_BUFFER_PUT_NEXT_SUBBUF
	290	* Release the currently read sub-buffer.
	291	* RING_BUFFER_GET_SUBBUF_SIZE
	292	* returns the size of the current sub-buffer.
	293	* RING_BUFFER_GET_MAX_SUBBUF_SIZE
	294	* returns the maximum size for sub-buffers.
	295	* RING_BUFFER_GET_NUM_SUBBUF
	296	* returns the number of reader-visible sub-buffers in the per cpu
	297	* channel (for mmap).
	298	* RING_BUFFER_GET_MMAP_READ_OFFSET
	299	* returns the offset of the subbuffer belonging to the reader.
	300	* Should only be used for mmap clients.
	301	*/
	302	static
	303	long vfs_lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	304	{
	305	struct lib_ring_buffer *buf = filp->private_data;
	306
	307	return lib_ring_buffer_ioctl(filp, cmd, arg, buf);
	308	}
f3bc08c5 MD	309
	310	#ifdef CONFIG_COMPAT
	311	long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
d83004aa	312	unsigned long arg, struct lib_ring_buffer *buf)
f3bc08c5	313	{
f3bc08c5	314	struct channel *chan = buf->backend.chan;
5a8fd222	315	const struct lib_ring_buffer_config *config = &chan->backend.config;
254ec7bc MD	316
	317	if (lib_ring_buffer_channel_is_disabled(chan))
	318	return -EIO;
f3bc08c5 MD	319
f3bc08c5 MD	320	switch (cmd) {
216f7feb	321	case RING_BUFFER_COMPAT_SNAPSHOT:
f3bc08c5 MD	322	return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
f3bc08c5 MD	323	&buf->prod_snapshot);
216f7feb	324	case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED:
f3bc08c5	325	return compat_put_ulong(buf->cons_snapshot, arg);
216f7feb	326	case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED:
f3bc08c5	327	return compat_put_ulong(buf->prod_snapshot, arg);
216f7feb	328	case RING_BUFFER_COMPAT_GET_SUBBUF:
f3bc08c5 MD	329	{
	330	__u32 uconsume;
	331	unsigned long consume;
	332	long ret;
	333
	334	ret = get_user(uconsume, (__u32 __user *) arg);
	335	if (ret)
	336	return ret; /* will return -EFAULT */
	337	consume = buf->cons_snapshot;
	338	consume &= ~0xFFFFFFFFL;
	339	consume \|= uconsume;
	340	ret = lib_ring_buffer_get_subbuf(buf, consume);
	341	if (!ret) {
	342	/* Set file position to zero at each successful "get" */
	343	filp->f_pos = 0;
	344	}
	345	return ret;
	346	}
216f7feb	347	case RING_BUFFER_COMPAT_PUT_SUBBUF:
f3bc08c5 MD	348	lib_ring_buffer_put_subbuf(buf);
	349	return 0;
	350
216f7feb	351	case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF:
f3bc08c5 MD	352	{
	353	long ret;
	354
	355	ret = lib_ring_buffer_get_next_subbuf(buf);
	356	if (!ret) {
	357	/* Set file position to zero at each successful "get" */
	358	filp->f_pos = 0;
	359	}
	360	return ret;
	361	}
216f7feb	362	case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF:
f3bc08c5 MD	363	lib_ring_buffer_put_next_subbuf(buf);
f3bc08c5 MD	364	return 0;
216f7feb	365	case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE:
f3bc08c5 MD	366	{
	367	unsigned long data_size;
	368
	369	data_size = lib_ring_buffer_get_read_data_size(config, buf);
	370	if (data_size > UINT_MAX)
	371	return -EFBIG;
4343ec8e	372	return compat_put_ulong(data_size, arg);
f3bc08c5	373	}
216f7feb	374	case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE:
f3bc08c5 MD	375	{
	376	unsigned long size;
	377
	378	size = lib_ring_buffer_get_read_data_size(config, buf);
	379	size = PAGE_ALIGN(size);
	380	if (size > UINT_MAX)
	381	return -EFBIG;
4343ec8e	382	return compat_put_ulong(size, arg);
f3bc08c5	383	}
216f7feb	384	case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE:
f3bc08c5 MD	385	if (chan->backend.subbuf_size > UINT_MAX)
f3bc08c5 MD	386	return -EFBIG;
4343ec8e	387	return compat_put_ulong(chan->backend.subbuf_size, arg);
216f7feb	388	case RING_BUFFER_COMPAT_GET_MMAP_LEN:
f3bc08c5 MD	389	{
	390	unsigned long mmap_buf_len;
	391
	392	if (config->output != RING_BUFFER_MMAP)
	393	return -EINVAL;
	394	mmap_buf_len = chan->backend.buf_size;
	395	if (chan->backend.extra_reader_sb)
	396	mmap_buf_len += chan->backend.subbuf_size;
	397	if (mmap_buf_len > UINT_MAX)
	398	return -EFBIG;
4343ec8e	399	return compat_put_ulong(mmap_buf_len, arg);
f3bc08c5	400	}
216f7feb	401	case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET:
f3bc08c5 MD	402	{
	403	unsigned long sb_bindex, read_offset;
	404
	405	if (config->output != RING_BUFFER_MMAP)
	406	return -EINVAL;
	407	sb_bindex = subbuffer_id_get_index(config,
	408	buf->backend.buf_rsb.id);
	409	read_offset = buf->backend.array[sb_bindex]->mmap_offset;
	410	if (read_offset > UINT_MAX)
	411	return -EINVAL;
4343ec8e	412	return compat_put_ulong(read_offset, arg);
f3bc08c5	413	}
216f7feb	414	case RING_BUFFER_COMPAT_FLUSH:
5e391252	415	lib_ring_buffer_switch_remote(buf);
5c055266	416	return 0;
f3bc08c5 MD	417	default:
	418	return -ENOIOCTLCMD;
	419	}
	420	}
d83004aa JD	421	EXPORT_SYMBOL_GPL(lib_ring_buffer_compat_ioctl);
	422
	423	static
	424	long vfs_lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
	425	unsigned long arg)
	426	{
	427	struct lib_ring_buffer *buf = filp->private_data;
	428
	429	return lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
	430	}
f3bc08c5 MD	431	#endif
	432
	433	const struct file_operations lib_ring_buffer_file_operations = {
a33c9927	434	.owner = THIS_MODULE,
d83004aa JD	435	.open = vfs_lib_ring_buffer_open,
	436	.release = vfs_lib_ring_buffer_release,
	437	.poll = vfs_lib_ring_buffer_poll,
	438	.splice_read = vfs_lib_ring_buffer_splice_read,
	439	.mmap = vfs_lib_ring_buffer_mmap,
	440	.unlocked_ioctl = vfs_lib_ring_buffer_ioctl,
	441	.llseek = vfs_lib_ring_buffer_no_llseek,
f3bc08c5	442	#ifdef CONFIG_COMPAT
d83004aa	443	.compat_ioctl = vfs_lib_ring_buffer_compat_ioctl,
f3bc08c5 MD	444	#endif
	445	};
	446	EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations);
	447
	448	MODULE_LICENSE("GPL and additional rights");
	449	MODULE_AUTHOR("Mathieu Desnoyers");
	450	MODULE_DESCRIPTION("Ring Buffer Library VFS");