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linux-next/include/linux/trace_seq.h
Steven Rostedt (Red Hat) 7b039cb4c5 tracing: Add trace_seq_buffer_ptr() helper function
There's several locations in the kernel that open code the calculation
of the next location in the trace_seq buffer. This is usually done with

  p->buffer + p->len

Instead of having this open coded, supply a helper function in the
header to do it for them. This function is called trace_seq_buffer_ptr().

Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:39 -04:00

118 lines
2.9 KiB
C

#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H
#include <linux/fs.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];
unsigned int len;
unsigned int readpos;
int full;
};
static inline void
trace_seq_init(struct trace_seq *s)
{
s->len = 0;
s->readpos = 0;
s->full = 0;
}
/**
* 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 + s->len;
}
/*
* Currently only defined when tracing is enabled.
*/
#ifdef CONFIG_TRACING
extern __printf(2, 3)
int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
extern int
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 int trace_seq_puts(struct trace_seq *s, const char *str);
extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
extern int 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 int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits);
#else /* CONFIG_TRACING */
static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
return 0;
}
static inline int
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
return 0;
}
static inline int
trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
return 0;
}
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 int trace_seq_puts(struct trace_seq *s, const char *str)
{
return 0;
}
static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
return 0;
}
static inline int
trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
return 0;
}
static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
return 0;
}
static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
{
return 0;
}
#endif /* CONFIG_TRACING */
#endif /* _LINUX_TRACE_SEQ_H */