+++ /dev/null
-/*
- * linux/include/linux/relayfs_fs.h
- *
- * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
- * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
- *
- * RelayFS definitions and declarations
- */
-
-#ifndef _LINUX_RELAYFS_FS_H
-#define _LINUX_RELAYFS_FS_H
-
-#include <linux/config.h>
-#include <linux/types.h>
-#include <linux/sched.h>
-#include <linux/wait.h>
-#include <linux/list.h>
-#include <linux/fs.h>
-#include <linux/poll.h>
-#include <linux/kref.h>
-
-/*
- * Tracks changes to rchan/rchan_buf structs
- */
-#define RELAYFS_CHANNEL_VERSION 6
-
-/*
- * Per-cpu relay channel buffer
- */
-struct rchan_buf
-{
- void *start; /* start of channel buffer */
- void *data; /* start of current sub-buffer */
- size_t offset; /* current offset into sub-buffer */
- size_t subbufs_produced; /* count of sub-buffers produced */
- size_t subbufs_consumed; /* count of sub-buffers consumed */
- struct rchan *chan; /* associated channel */
- wait_queue_head_t read_wait; /* reader wait queue */
- struct work_struct wake_readers; /* reader wake-up work struct */
- struct dentry *dentry; /* channel file dentry */
- struct kref kref; /* channel buffer refcount */
- struct page **page_array; /* array of current buffer pages */
- unsigned int page_count; /* number of current buffer pages */
- unsigned int finalized; /* buffer has been finalized */
- size_t *padding; /* padding counts per sub-buffer */
- size_t prev_padding; /* temporary variable */
- size_t bytes_consumed; /* bytes consumed in cur read subbuf */
- unsigned int cpu; /* this buf's cpu */
-} ____cacheline_aligned;
-
-/*
- * Relay channel data structure
- */
-struct rchan
-{
- u32 version; /* the version of this struct */
- size_t subbuf_size; /* sub-buffer size */
- size_t n_subbufs; /* number of sub-buffers per buffer */
- size_t alloc_size; /* total buffer size allocated */
- struct rchan_callbacks *cb; /* client callbacks */
- struct kref kref; /* channel refcount */
- void *private_data; /* for user-defined data */
- size_t last_toobig; /* tried to log event > subbuf size */
- struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
-};
-
-/*
- * Relay channel client callbacks
- */
-struct rchan_callbacks
-{
- /*
- * subbuf_start - called on buffer-switch to a new sub-buffer
- * @buf: the channel buffer containing the new sub-buffer
- * @subbuf: the start of the new sub-buffer
- * @prev_subbuf: the start of the previous sub-buffer
- * @prev_padding: unused space at the end of previous sub-buffer
- *
- * The client should return 1 to continue logging, 0 to stop
- * logging.
- *
- * NOTE: subbuf_start will also be invoked when the buffer is
- * created, so that the first sub-buffer can be initialized
- * if necessary. In this case, prev_subbuf will be NULL.
- *
- * NOTE: the client can reserve bytes at the beginning of the new
- * sub-buffer by calling subbuf_start_reserve() in this callback.
- */
- int (*subbuf_start) (struct rchan_buf *buf,
- void *subbuf,
- void *prev_subbuf,
- size_t prev_padding);
-
- /*
- * buf_mapped - relayfs buffer mmap notification
- * @buf: the channel buffer
- * @filp: relayfs file pointer
- *
- * Called when a relayfs file is successfully mmapped
- */
- void (*buf_mapped)(struct rchan_buf *buf,
- struct file *filp);
-
- /*
- * buf_unmapped - relayfs buffer unmap notification
- * @buf: the channel buffer
- * @filp: relayfs file pointer
- *
- * Called when a relayfs file is successfully unmapped
- */
- void (*buf_unmapped)(struct rchan_buf *buf,
- struct file *filp);
- /*
- * create_buf_file - create file to represent a relayfs channel buffer
- * @filename: the name of the file to create
- * @parent: the parent of the file to create
- * @mode: the mode of the file to create
- * @buf: the channel buffer
- * @is_global: outparam - set non-zero if the buffer should be global
- *
- * Called during relay_open(), once for each per-cpu buffer,
- * to allow the client to create a file to be used to
- * represent the corresponding channel buffer. If the file is
- * created outside of relayfs, the parent must also exist in
- * that filesystem.
- *
- * The callback should return the dentry of the file created
- * to represent the relay buffer.
- *
- * Setting the is_global outparam to a non-zero value will
- * cause relay_open() to create a single global buffer rather
- * than the default set of per-cpu buffers.
- *
- * See Documentation/filesystems/relayfs.txt for more info.
- */
- struct dentry *(*create_buf_file)(const char *filename,
- struct dentry *parent,
- int mode,
- struct rchan_buf *buf,
- int *is_global);
-
- /*
- * remove_buf_file - remove file representing a relayfs channel buffer
- * @dentry: the dentry of the file to remove
- *
- * Called during relay_close(), once for each per-cpu buffer,
- * to allow the client to remove a file used to represent a
- * channel buffer.
- *
- * The callback should return 0 if successful, negative if not.
- */
- int (*remove_buf_file)(struct dentry *dentry);
-};
-
-/*
- * relayfs kernel API, fs/relayfs/relay.c
- */
-
-struct rchan *relay_open(const char *base_filename,
- struct dentry *parent,
- size_t subbuf_size,
- size_t n_subbufs,
- struct rchan_callbacks *cb);
-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);
-extern struct dentry *relayfs_create_dir(const char *name,
- struct dentry *parent);
-extern int relayfs_remove_dir(struct dentry *dentry);
-extern struct dentry *relayfs_create_file(const char *name,
- struct dentry *parent,
- int mode,
- struct file_operations *fops,
- void *data);
-extern int relayfs_remove_file(struct dentry *dentry);
-
-/**
- * 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();
-}
-
-/**
- * relay_reserve - reserve slot in channel buffer
- * @chan: relay channel
- * @length: number of bytes to reserve
- *
- * Returns pointer to reserved slot, NULL if full.
- *
- * Reserves a slot in the current cpu's channel buffer.
- * Does not protect the buffer at all - caller must provide
- * appropriate synchronization.
- */
-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;
-}
-
-/**
- * subbuf_start_reserve - reserve bytes at the start of a sub-buffer
- * @buf: relay channel buffer
- * @length: number of bytes to reserve
- *
- * Helper function used to reserve bytes at the beginning of
- * a sub-buffer in the subbuf_start() callback.
- */
-static inline void subbuf_start_reserve(struct rchan_buf *buf,
- size_t length)
-{
- BUG_ON(length >= buf->chan->subbuf_size - 1);
- buf->offset = length;
-}
-
-/*
- * exported relay file operations, fs/relayfs/inode.c
- */
-extern struct file_operations relay_file_operations;
-
-#endif /* _LINUX_RELAYFS_FS_H */
-
projects / linux-2.6 / commitdiff