[PATCH 19/25] dynamic_debug: add flags filtering to flags spec

Jim Cromie
2011-07-25T21:43:55Z

Change definition of flags spec to [pmflta_]*[-+=][pmflta_]*
The flags preceding the op are optional filter-flags; if provided,
they add an additional constraint to call-site matching done
by ddebug_change; call-sites which do not have all specified flags
are skipped (additional flags are allowed).

This allows query/rules like "p+t" to turn on TID logging for all
currently enabled call-sites, while leaving the others alone.
This will also allow filtering on pending rules (with 'a' flag),
which will support removal of pending rules.

Also allow 0 flags byte, so that active rules can be completely
reset by writing "p=" or "p=_".

Patch factors flag-scanning into ddebug_parse_flag_settings(),
and uses it for both filter-flags and new flags, and adds pr_err()
where useful.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
lib/dynamic_debug.c | 81 ++++++++++++++++++++++++++++++++-------------------
1 files changed, 51 insertions(+), 30 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 37f9748..275cf30 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -180,7 +180,8 @@ static bool query_matches_callsite(struct _ddebug *dp,
* were matched. Called with ddebug_lock held.
*/
static int ddebug_change(const struct ddebug_query *query,
- unsigned int flags, unsigned int mask)
+ unsigned int flags, unsigned int mask,
+ unsigned int filter)
{
int i;
struct ddebug_table *dt;
@@ -202,6 +203,9 @@ static int ddebug_change(const struct ddebug_query *query,
if (!query_matches_callsite(dp, query))
continue;

+ if (filter && (dp->flags & filter) != filter)
+ continue;
+
nfound++;

newflags = (dp->flags & mask) | flags;
@@ -402,28 +406,9 @@ static int ddebug_parse_query(char *words[], int nwords,
return 0;
}

-/*
- * Parse `str' as a flags specification, format [-+=][p]+.
- * Sets up *maskp and *flagsp to be used when changing the
- * flags fields of matched _ddebug's. Returns 0 on success
- * or <0 on error.
- */
-static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
- unsigned int *maskp)
+static int ddebug_parse_flag_settings(const char *str)
{
- unsigned flags = 0;
- int op = '=', i;
-
- switch (*str) {
- case '+':
- case '-':
- case '=':
- op = *str++;
- break;
- default:
- return -EINVAL;
- }
- pr_debug("op='%c'\n", op);
+ int i, flags = 0;

for ( ; *str ; ++str) {
for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
@@ -432,12 +417,46 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
break;
}
}
- if (i < 0)
+ if (i < 0 && *str) {
+ pr_err("unknown flag: %c\n", *str);
return -EINVAL;
+ }
}
- if (flags == 0)
+ return flags;
+}
+
+/*
+ * Parse `str' as a flags filter and specification, with format
+ * [ptlmfa]*[-+=][ptlmfa]+. Sets up *maskp, *flagsp and *filterp to
+ * be used when changing the flags fields of matched _ddebug's.
+ * Returns 0 on success or <0 on error.
+ */
+static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
+ unsigned int *maskp, unsigned int *filterp)
+{
+ int flags, filter;
+ int op = '=';
+ char *s = strpbrk(str, "+-=");
+
+ if (!s) {
+ pr_err("flags spec missing op, expecting [+-=]\n");
return -EINVAL;
- pr_debug("flags=0x%x\n", flags);
+ } else {
+ op = *s;
+ *s++ = '\0';
+ }
+ filter = ddebug_parse_flag_settings(str);
+ if (filter < 0) {
+ pr_err("flags_filter=0x%x\n", filter);
+ return -EINVAL;
+ }
+ *filterp = filter;
+
+ flags = ddebug_parse_flag_settings(s);
+ if (flags < 0) {
+ pr_err("flags=0x%x\n", flags);
+ return -EINVAL;
+ }

/* calculate final *flagsp, *maskp according to mask and op */
switch (op) {
@@ -454,7 +473,9 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
*flagsp = 0;
break;
}
- pr_debug("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+ pr_debug("filter=0x%x op='%c' flags=0x%x *flagsp=0x%x *maskp=0x%x\n",
+ filter, op, flags, *flagsp, *maskp);
+
return 0;
}

@@ -539,7 +560,7 @@ static int ddebug_save_pending(struct ddebug_query *query,

static int ddebug_exec_query(char *query_string)
{
- unsigned int flags = 0, mask = 0;
+ unsigned int flags = 0, mask = 0, filter = 0;
struct ddebug_query query;
#define MAXWORDS 9
int nwords;
@@ -551,12 +572,12 @@ static int ddebug_exec_query(char *query_string)
return -EINVAL;
if (ddebug_parse_query(words, nwords-1, &query))
return -EINVAL;
- if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
+ if (ddebug_parse_flags(words[nwords-1], &flags, &mask, &filter))
return -EINVAL;

/* actually go and implement the change */
mutex_lock(&ddebug_lock);
- nfound = ddebug_change(&query, flags, mask);
+ nfound = ddebug_change(&query, flags, mask, filter);
qstr = show_ddebug_query(&query);
pr_debug("nfound %d on %s\n", nfound, qstr);
if (!nfound) {
@@ -917,7 +938,7 @@ static void apply_pending_queries(struct ddebug_table *dt)
char *qstr;

list_for_each_entry_safe(pq, pqnext, &pending_queries, link) {
- nfound = ddebug_change(&pq->query, pq->flags, pq->mask);
+ nfound = ddebug_change(&pq->query, pq->flags, pq->mask, 0);
qstr = show_pending_query(pq);
pr_debug("%s: %s\n", (nfound) ? "applied" : "no-match", qstr);
kfree(qstr);
--
1.7.4.1