linux-kernel - [PATCH 16/25] dynamic_debug: require 'a' flag to explicitly mark pending queries

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Date:	Mon, 25 Jul 2011 15:42:41 -0600
From:	Jim Cromie <jim.cromie@...il.com>
To:	jbaron@...hat.com
Cc:	bvanassche@....org, joe@...ches.com, gregkh@...e.de,
	linux-kernel@...r.kernel.org, gnb@...h.org,
	Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH 16/25] dynamic_debug: require 'a' flag to explicitly mark pending queries

Require that user mark pending queries explicitly, otherwise warn
that they do not apply.  Note that pending rules are still applied
by default, and are only added to pending-list if they do not apply,
and bear the flag.

Add queries_match() to test newly submitted pending query against
those already on the pending list, and either update the flags
or add the new query

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
 lib/dynamic_debug.c |   42 ++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0c25ba0..05773c8 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -91,6 +91,7 @@ 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_APPEND, 'a' },
 };
 
 /* format a string into buf[] which describes the _ddebug's flags */
@@ -458,13 +459,50 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 	return 0;
 }
 
-/* copy query off stack, save flags & mask, and store in pending-list */
+static bool queries_match(struct ddebug_query *q1, struct ddebug_query *q2)
+{
+	if (!q1->module ^ !q2->module ||
+		!q1->filename ^ !q2->filename ||
+		!q1->function ^ !q2->function ||
+		!q1->format ^ !q2->format)
+		return false;  /* a match-spec set/unset state differs */
+
+	if (q1->last_lineno != q2->last_lineno ||
+		q1->first_lineno != q2->first_lineno)
+		return false;
+
+	if ((q1->module && strcmp(q1->module, q2->module)) ||
+		(q1->filename && strcmp(q1->filename, q2->filename)) ||
+		(q1->function && strcmp(q1->function, q2->function)) ||
+		(q1->format && strcmp(q1->format, q2->format)))
+		return false;
+
+	return true;
+}
+
+/* copy query off stack, save flags & mask, and store or update in
+   pending-list.  Called with ddebug_lock held.
+ */
 static int ddebug_save_pending(struct ddebug_query *query,
 				unsigned int flags, unsigned int mask)
 {
-	struct pending_query *pq;
+	struct pending_query *pq, *pqnext;
 	char *qstr;
 
+	list_for_each_entry_safe(pq, pqnext, &pending_queries, link) {
+		if (queries_match(query, &pq->query)) {
+			/* query already in list, update flags */
+			if (pq->flags != flags)
+				pq->flags = flags;
+			if (pq->mask != mask)
+				pq->mask = mask;
+			qstr = show_pending_query(pq);
+			pr_debug("already pending, updated it: %s\n", qstr);
+			kfree(qstr);
+			return 0;
+		}
+	}
+
 	qstr = show_ddebug_query(query);
 	pr_debug("add to pending: %s\n", qstr);
 	kfree(qstr);
-- 
1.7.4.1

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