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Subject[PATCH 19/26] dynamic_debug: add flags filtering to flags spec
Date
From: Jim Cromie <jim.cromie@gmail.com>

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 also allows rules like "a-a" to select pending queries and
remove them from the list.

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 | 85 +++++++++++++++++++++++++++++++--------------------
1 files changed, 52 insertions(+), 33 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 29dbf69..3c9244d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -191,7 +191,8 @@ 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;
@@ -213,6 +214,9 @@ 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;
@@ -406,29 +410,9 @@ 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;
- }
- if (verbose)
- pr_info("op='%c'\n", op);
+ int i, flags = 0;

for ( ; *str ; ++str) {
for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
@@ -437,13 +421,46 @@ 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
+ * [pmflta_]*[-+=][pmflta_]+. 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;
- if (verbose)
- pr_info("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) {
@@ -461,7 +478,9 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
break;
}
if (verbose)
- pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+ pr_info("filter=0x%x op='%c' flags=0x%x *flagsp=0x%x *maskp=0x%x\n",
+ filter, op, flags, *flagsp, *maskp);
+
return 0;
}

@@ -563,7 +582,7 @@ 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;
@@ -575,14 +594,14 @@ 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 */
- nfound = ddebug_change(&query, flags, mask);
+ nfound = ddebug_change(&query, flags, mask, filter);
vpr_info_dq((&query), (nfound) ? "applied" : "no-match");

- if (flags & _DPRINTK_FLAGS_APPEND)
+ if (flags & _DPRINTK_FLAGS_APPEND || filter & _DPRINTK_FLAGS_APPEND)
rc = ddebug_save_pending(&query, flags, mask);

return rc;
@@ -950,7 +969,7 @@ static void apply_pending_queries(struct ddebug_table *dt)
int nfound;

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);
vpr_info_pq(pq, (nfound) ?
"applied pending" : "no-match on pending");
}
--
1.7.4.4


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