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/*
* linux/include/linux/relay.h
*
* Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
* Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
*
* CONFIG_RELAY definitions and declarations
*/
#ifndef _LINUX_RELAY_H
#define _LINUX_RELAY_H
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/bug.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/kref.h>
#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE)
#define RELAYFS_CHANNEL_VERSION 7
struct rchan_buf
{
void *start;
void *data;
size_t offset;
size_t subbufs_produced;
size_t subbufs_consumed;
struct rchan *chan;
wait_queue_head_t read_wait;
struct timer_list timer;
struct dentry *dentry;
struct kref kref;
struct page **page_array;
unsigned int page_count;
unsigned int finalized;
size_t *padding;
size_t prev_padding;
size_t bytes_consumed;
size_t early_bytes;
unsigned int cpu;
} ____cacheline_aligned;
struct rchan
{
u32 version;
size_t subbuf_size;
size_t n_subbufs;
size_t alloc_size;
struct rchan_callbacks *cb;
struct kref kref;
void *private_data;
size_t last_toobig;
struct rchan_buf *buf[NR_CPUS];
int is_global;
struct list_head list;
struct dentry *parent;
int has_base_filename;
char base_filename[NAME_MAX];
};
struct rchan_callbacks
{
int (*subbuf_start) (struct rchan_buf *buf,
void *subbuf,
void *prev_subbuf,
size_t prev_padding);
void (*buf_mapped)(struct rchan_buf *buf,
struct file *filp);
void (*buf_unmapped)(struct rchan_buf *buf,
struct file *filp);
struct dentry *(*create_buf_file)(const char *filename,
struct dentry *parent,
umode_t mode,
struct rchan_buf *buf,
int *is_global);
int (*remove_buf_file)(struct dentry *dentry);
};
struct rchan *relay_open(const char *base_filename,
struct dentry *parent,
size_t subbuf_size,
size_t n_subbufs,
struct rchan_callbacks *cb,
void *private_data);
extern int relay_late_setup_files(struct rchan *chan,
const char *base_filename,
struct dentry *parent);
extern void relay_close(struct rchan *chan);
extern void relay_flush(struct rchan *chan);
extern void relay_subbufs_consumed(struct rchan *chan,
unsigned int cpu,
size_t consumed);
extern void relay_reset(struct rchan *chan);
extern int relay_buf_full(struct rchan_buf *buf);
extern size_t relay_switch_subbuf(struct rchan_buf *buf,
size_t length);
/**
* relay_write - write data into the channel
* @chan: relay channel
* @data: data to be written
* @length: number of bytes to write
*
* Writes data into the current cpu's channel buffer.
*
* Protects the buffer by disabling interrupts. Use this
* if you might be logging from interrupt context. Try
* __relay_write() if you know you won't be logging from
* interrupt context.
*/
static inline void relay_write(struct rchan *chan,
const void *data,
size_t length)
{
unsigned long flags;
struct rchan_buf *buf;
local_irq_save(flags);
buf = chan->buf[smp_processor_id()];
if (unlikely(buf->offset + length > chan->subbuf_size))
length = relay_switch_subbuf(buf, length);
memcpy(buf->data + buf->offset, data, length);
buf->offset += length;
local_irq_restore(flags);
}
/**
* __relay_write - write data into the channel
* @chan: relay channel
* @data: data to be written
* @length: number of bytes to write
*
* Writes data into the current cpu's channel buffer.
*
* Protects the buffer by disabling preemption. Use
* relay_write() if you might be logging from interrupt
* context.
*/
static inline void __relay_write(struct rchan *chan,
const void *data,
size_t length)
{
struct rchan_buf *buf;
buf = chan->buf[get_cpu()];
if (unlikely(buf->offset + length > buf->chan->subbuf_size))
length = relay_switch_subbuf(buf, length);
memcpy(buf->data + buf->offset, data, length);
buf->offset += length;
put_cpu();
}
static inline void *relay_reserve(struct rchan *chan, size_t length)
{
void *reserved;
struct rchan_buf *buf = chan->buf[smp_processor_id()];
if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
length = relay_switch_subbuf(buf, length);
if (!length)
return NULL;
}
reserved = buf->data + buf->offset;
buf->offset += length;
return reserved;
}
static inline void subbuf_start_reserve(struct rchan_buf *buf,
size_t length)
{
BUG_ON(length >= buf->chan->subbuf_size - 1);
buf->offset = length;
}
extern const struct file_operations relay_file_operations;
#endif
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