#ifndef _LINUX_TRACE_SEQ_H
  #define _LINUX_TRACE_SEQ_H

  #include <linux/seq_buf.h>

  #include <asm/page.h>

  /*
   * Trace sequences are used to allow a function to call several other functions

   * to create a string of data to use (up to a max of PAGE_SIZE).

   */
  
  struct trace_seq {
  	unsigned char		buffer[PAGE_SIZE];

  	struct seq_buf		seq;

  	int			full;

  };
  
  static inline void
  trace_seq_init(struct trace_seq *s)
  {

  	seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);

  	s->full = 0;

  }

  /**

   * trace_seq_used - amount of actual data written to buffer
   * @s: trace sequence descriptor
   *
   * Returns the amount of data written to the buffer.
   *
   * IMPORTANT!
   *
   * Use this instead of @s->seq.len if you need to pass the amount
   * of data from the buffer to another buffer (userspace, or what not).
   * The @s->seq.len on overflow is bigger than the buffer size and
   * using it can cause access to undefined memory.
   */
  static inline int trace_seq_used(struct trace_seq *s)
  {
  	return seq_buf_used(&s->seq);
  }
  
  /**

   * trace_seq_buffer_ptr - return pointer to next location in buffer
   * @s: trace sequence descriptor
   *
   * Returns the pointer to the buffer where the next write to
   * the buffer will happen. This is useful to save the location
   * that is about to be written to and then return the result
   * of that write.
   */
  static inline unsigned char *
  trace_seq_buffer_ptr(struct trace_seq *s)
  {

  	return s->buffer + seq_buf_used(&s->seq);

  }

  /**
   * trace_seq_has_overflowed - return true if the trace_seq took too much
   * @s: trace sequence descriptor
   *
   * Returns true if too much data was added to the trace_seq and it is
   * now full and will not take anymore.
   */
  static inline bool trace_seq_has_overflowed(struct trace_seq *s)
  {

  	return s->full || seq_buf_has_overflowed(&s->seq);

  }

  /*
   * Currently only defined when tracing is enabled.
   */
  #ifdef CONFIG_TRACING

  extern __printf(2, 3)

  void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);

  extern __printf(2, 0)

  void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
  extern void

  trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);

  extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);

  extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
  			     int cnt);

  extern void trace_seq_puts(struct trace_seq *s, const char *str);
  extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
  extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
  extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,

  				unsigned int len);

  extern int trace_seq_path(struct trace_seq *s, const struct path *path);

  extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,

  			     int nmaskbits);

  #else /* CONFIG_TRACING */

  static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)

  {

  }

  static inline void

  trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
  {

  }

  static inline void

  trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
  		  int nmaskbits)
  {

  }

  static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)

  {

  	return 0;

  }

  static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
  				    int cnt)

  {
  	return 0;
  }

  static inline void trace_seq_puts(struct trace_seq *s, const char *str)

  {

  }

  static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)

  {

  }

  static inline void

  trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)

  {

  }

  static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,

  				       unsigned int len)

  {

  }

  static inline int trace_seq_path(struct trace_seq *s, const struct path *path)

  {
  	return 0;
  }
  #endif /* CONFIG_TRACING */
  
  #endif /* _LINUX_TRACE_SEQ_H */