linux-kernel - [RFC PATCH v2 15/19] dyndbg: add ddebug_site

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Date:   Fri, 25 Dec 2020 13:19:40 -0700
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, gregkh@...uxfoundation.org,
        linux-kernel@...r.kernel.org
Cc:     Jim Cromie <jim.cromie@...il.com>
Subject: [RFC PATCH v2 15/19] dyndbg: add ddebug_site_get/put api with pass-thru impl

Now that site info is optional, abstract it so we can manage it more
flexibly later.  Change all site users to use ddebug_site_get(p)
instead, which just returns ->site.  ddebug_site_put is called to
balance gets, it currently does nothing.

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
 lib/dynamic_debug.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8ad9be28f38e..25f49515c235 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -144,6 +144,14 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 		 query->first_lineno, query->last_lineno);
 }
 
+static struct _ddebug_callsite *ddebug_site_get(struct _ddebug *dp)
+{
+	return dp->site;
+}
+static inline void ddebug_site_put(struct _ddebug *dp)
+{
+}
+
 static int ddebug_match_site(const struct ddebug_query *query,
 			     const struct _ddebug *dp,
 			     const struct _ddebug_callsite *dc)
@@ -242,13 +250,13 @@ static int ddebug_change(const struct ddebug_query *query,
 			struct _ddebug_callsite *dc = dp->site;
 
 			if (!ddebug_match_site(query, dp, dc))
-				continue;
+				goto skipsite;
 
 			nfound++;
 
 			newflags = (dp->flags & modifiers->mask) | modifiers->flags;
 			if (newflags == dp->flags)
-				continue;
+				goto skipsite;
 
 			ddebug_alter_site(dp, modifiers);
 
@@ -264,6 +272,9 @@ static int ddebug_change(const struct ddebug_query *query,
 					  dt->mod_name, dp->lineno,
 					  ddebug_describe_flags(dp->flags, &fbuf),
 					  dp->format);
+
+		skipsite:
+			ddebug_site_put(dp);
 		}
 	}
 	mutex_unlock(&ddebug_lock);
@@ -633,11 +644,11 @@ static int remaining(int wrote)
 	return 0;
 }
 
-static char *__dynamic_emit_prefix(const struct _ddebug *dp, char *buf)
+static char *__dynamic_emit_prefix(struct _ddebug *dp, char *buf)
 {
 	int pos_after_tid;
 	int pos = 0;
-	const struct _ddebug_callsite *desc = dp->site;
+	const struct _ddebug_callsite *desc;
 
 	*buf = '\0';
 
@@ -653,6 +664,7 @@ static char *__dynamic_emit_prefix(const struct _ddebug *dp, char *buf)
 	if (!(dp->flags & _DPRINTK_FLAGS_INCL_ANYSITE))
 		return buf;
 
+	desc = ddebug_site_get(dp);
 	if (desc) {
 		if (dp->flags & _DPRINTK_FLAGS_INCL_MODNAME)
 			pos += snprintf(buf + pos, remaining(pos), "%s:",
@@ -670,6 +682,8 @@ static char *__dynamic_emit_prefix(const struct _ddebug *dp, char *buf)
 	if (pos >= PREFIX_SIZE)
 		buf[PREFIX_SIZE - 1] = '\0';
 
+	ddebug_site_put(dp);
+
 	return buf;
 }
 
@@ -952,7 +966,8 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		return 0;
 	}
 
-	dc = dp->site;
+	dc = ddebug_site_get(dp);
+
 	if (dc) {
 		seq_printf(m, "%s:%u [%s]%s =%s \"",
 			   trim_prefix(dc->filename), dp->lineno,
@@ -968,6 +983,8 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		seq_puts(m, "\"\n");
 	}
 
+	ddebug_site_put(dp);
+
 	return 0;
 }
 
-- 
2.29.2