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Subject[PATCH v3 08/23] dynamic_debug: don't duplicate modname in ddebug_add_module
Date
For built-in modules, we're already reusing the passed-in string via
kstrdup_const(). But for actual modules (i.e. when we're called from
dynamic_debug_setup in module.c), the passed-in string (which points
at the name[] array inside struct module) is also
guaranteed to live at least as long as the struct ddebug_table, since
free_module() calls ddebug_remove_module().

Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
lib/dynamic_debug.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c7c96bc7654a..2155e0e23530 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -847,17 +847,17 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *name)
{
struct ddebug_table *dt;
- const char *new_name;

dt = kzalloc(sizeof(*dt), GFP_KERNEL);
if (dt == NULL)
return -ENOMEM;
- new_name = kstrdup_const(name, GFP_KERNEL);
- if (new_name == NULL) {
- kfree(dt);
- return -ENOMEM;
- }
- dt->mod_name = new_name;
+ /*
+ * For built-in modules, name lives in .rodata and is
+ * immortal. For loaded modules, name points at the name[]
+ * member of struct module, which lives at least as long as
+ * this struct ddebug_table.
+ */
+ dt->mod_name = name;
dt->num_ddebugs = n;
dt->ddebugs = tab;

@@ -913,7 +913,6 @@ int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *module)
static void ddebug_table_free(struct ddebug_table *dt)
{
list_del_init(&dt->link);
- kfree_const(dt->mod_name);
kfree(dt);
}

--
2.19.1.6.gbde171bbf5
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