[PATCH 09/25] dynamic_debug: describe_flags with '=[pmflt_]*'

From: jim . cromie
Date: Wed Nov 30 2011 - 15:01:19 EST


From: Jim Cromie <jim.cromie@xxxxxxxxx>

Change describe_flags() to emit '=[pmflt_]+' for current callsite
flags, or just '=_' when they're disabled. Having '=' in output
allows a more selective grep expression; in contrast '-' may appear
in filenames, line-ranges, and format-strings. '=' also has better
mnemonics, saying; "the current setting is equal to <flags>".

This allows grep "=_" <dbgfs>/dynamic_debug/control to see disabled
callsites while avoiding the many occurrences of " = " seen in format
strings.

Enlarge flagsbufs to handle additional flag char, and alter
ddebug_parse_flags() to allow flags=0, so that user can turn off all
debug flags via:

~# echo =_ > <dbgfs>/dynamic_debug/control

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
include/linux/dynamic_debug.h | 3 ++-
lib/dynamic_debug.c | 21 ++++++++++-----------
2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 29ea09a..fc39640 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -21,7 +21,8 @@ struct _ddebug {
* The bits here are changed dynamically when the user
* writes commands to <debugfs>/dynamic_debug/control
*/
-#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
+#define _DPRINTK_FLAGS_NONE 0
+#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
#define _DPRINTK_FLAGS_INCL_MODNAME (1<<1)
#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 6904fdc..6a170c3 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -75,6 +75,7 @@ static struct { unsigned flag:8; char opt_char; } opt_array[] = {
{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
{ _DPRINTK_FLAGS_INCL_TID, 't' },
+ { _DPRINTK_FLAGS_NONE, '_' },
};

/* format a string into buf[] which describes the _ddebug's flags */
@@ -84,12 +85,12 @@ static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
char *p = buf;
int i;

- BUG_ON(maxlen < 4);
+ BUG_ON(maxlen < 6);
for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
if (dp->flags & opt_array[i].flag)
*p++ = opt_array[i].opt_char;
if (p == buf)
- *p++ = '-';
+ *p++ = '_';
*p = '\0';

return buf;
@@ -108,7 +109,7 @@ static void ddebug_change(const struct ddebug_query *query,
struct ddebug_table *dt;
unsigned int newflags;
unsigned int nfound = 0;
- char flagbuf[8];
+ char flagbuf[10];

/* search for matching ddebugs */
mutex_lock(&ddebug_lock);
@@ -152,7 +153,7 @@ static void ddebug_change(const struct ddebug_query *query,
continue;
dp->flags = newflags;
if (verbose)
- pr_info("changed %s:%d [%s]%s %s\n",
+ pr_info("changed %s:%d [%s]%s =%s\n",
dp->filename, dp->lineno,
dt->mod_name, dp->function,
ddebug_describe_flags(dp, flagbuf,
@@ -370,8 +371,6 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
if (i < 0)
return -EINVAL;
}
- if (flags == 0)
- return -EINVAL;
if (verbose)
pr_info("flags=0x%x\n", flags);

@@ -666,7 +665,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
{
struct ddebug_iter *iter = m->private;
struct _ddebug *dp = p;
- char flagsbuf[8];
+ char flagsbuf[10];

if (verbose)
pr_info("called m=%p p=%p\n", m, p);
@@ -677,10 +676,10 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
return 0;
}

- seq_printf(m, "%s:%u [%s]%s %s \"",
- dp->filename, dp->lineno,
- iter->table->mod_name, dp->function,
- ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
+ seq_printf(m, "%s:%u [%s]%s =%s \"",
+ dp->filename, dp->lineno,
+ iter->table->mod_name, dp->function,
+ ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
seq_escape(m, dp->format, "\t\r\n\"");
seq_puts(m, "\"\n");

--
1.7.7.3

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