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tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions 

Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that
are used by seq_buf_path(). This makes the code similar to the
seq_file: seq_path() function, and will help to be able to consolidate
the functions between seq_file and trace_seq.

Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org
Link: http://lkml.kernel.org/r/20141114011412.977571447@goodmis.org

Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2014-10-29 17:30:50 -04:00 committed by Steven Rostedt
parent 8cd709ae76
commit 01cb06a4c2
2 changed files with 44 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
include/linux/seq_buf.h
View File

@ -70,6 +70,47 @@ static inline unsigned int seq_buf_used(struct seq_buf *s)
return min(s->len, s->size);
}
/**
* seq_buf_get_buf - get buffer to write arbitrary data to
* @s: the seq_buf handle
* @bufp: the beginning of the buffer is stored here
*
* Return the number of bytes available in the buffer, or zero if
* there's no space.
*/
static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
{
WARN_ON(s->len > s->size + 1);
if (s->len < s->size) {
*bufp = s->buffer + s->len;
return s->size - s->len;
}
*bufp = NULL;
return 0;
}
/**
* seq_buf_commit - commit data to the buffer
* @s: the seq_buf handle
* @num: the number of bytes to commit
*
* Commit @num bytes of data written to a buffer previously acquired
* by seq_buf_get. To signal an error condition, or that the data
* didn't fit in the available space, pass a negative @num value.
*/
static inline void seq_buf_commit(struct seq_buf *s, int num)
{
if (num < 0) {
seq_buf_set_overflow(s);
} else {
/* num must be negative on overflow */
BUG_ON(s->len + num > s->size);
s->len += num;
}
}
extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)

7
kernel/trace/seq_buf.c
View File

@ -293,8 +293,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
*/
int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
char *buf = s->buffer + s->len;
size_t size = seq_buf_buffer_left(s);
char *buf;
size_t size = seq_buf_get_buf(s, &buf);
int res = -1;
WARN_ON(s->size == 0);
@ -307,8 +307,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
res = end - buf;
}
}
if (res > 0)
s->len += res;
seq_buf_commit(s, res);
return res;
}