Le 20/03/2025 à 19:52, Jim Cromie a écrit :
struct _ddebug_info already has almost all dyndbg's info for a module,
so finish the encapsulation.  This puts the datum closer to where its
needed, improving the chance that we can obsolete the _ddebug.modame
field with a desc_modname(dp) accessor fn.

In static ddebug_add_module(&_ddebug_info_cursor..), force the
cursor-model by dropping the modname arg, and setting it explicitly
into the cursor before the 3 calls to it.

struct ddebug_table only uses .mod_name when applying >control
changes, and it has a _ddebug_info member anyway, so it keeps access
to the field, just with a different offset.

Signed-off-by: Jim Cromie <jim.cro...@gmail.com>

Reviewed-by: Louis Chauvet <louis.chau...@bootlin.com>

---
  include/linux/dynamic_debug.h |  1 +
  lib/dynamic_debug.c           | 41 ++++++++++++++++++-----------------
  2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 03a83a83b621..8043966a0fd6 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -198,6 +198,7 @@ struct _ddebug_class_users {
  } __packed;
struct _ddebug_info {
+       const char *mod_name;
        struct _ddebug_descs descs;
        struct _ddebug_class_maps maps;
        struct _ddebug_class_users users;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 3c9fb8324ad6..cd3eec5bb81c 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -49,7 +49,6 @@ extern struct _ddebug_class_user 
__stop___dyndbg_class_users[];
struct ddebug_table {
        struct list_head link;
-       const char *mod_name;
        struct _ddebug_info info;
  };
@@ -166,7 +165,7 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
  #define vpr_dt_info(dt_p, msg_p, ...) ({                              \
        struct ddebug_table const *_dt = dt_p;                          \
        v2pr_info(msg_p " module:%s nd:%d nc:%d nu:%d\n", ##__VA_ARGS__, \
-                 _dt->mod_name, _dt->info.descs.len, _dt->info.maps.len, \
+                 _dt->info.mod_name, _dt->info.descs.len, _dt->info.maps.len, \
                  _dt->info.users.len);                                      \
        })
@@ -215,7 +214,7 @@ static int ddebug_change(const struct ddebug_query *query, struct flag_settings /* match against the module name */
                if (query->module &&
-                   !match_wildcard(query->module, dt->mod_name))
+                   !match_wildcard(query->module, dt->info.mod_name))
                        continue;
if (query->class_string) {
@@ -283,7 +282,7 @@ static int ddebug_change(const struct ddebug_query *query, 
struct flag_settings
  #endif
                        v4pr_info("changed %s:%d [%s]%s %s => %s\n",
                                  trim_prefix(dp->filename), dp->lineno,
-                                 dt->mod_name, dp->function,
+                                 dt->info.mod_name, dp->function,
                                  ddebug_describe_flags(dp->flags, &fbuf),
                                  ddebug_describe_flags(newflags, &nbuf));
                        dp->flags = newflags;
@@ -1123,7 +1122,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
seq_printf(m, "%s:%u [%s]%s =%s \"",
                   trim_prefix(dp->filename), dp->lineno,
-                  iter->table->mod_name, dp->function,
+                  iter->table->info.mod_name, dp->function,
                   ddebug_describe_flags(dp->flags, &flags));
        seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
        seq_putc(m, '"');
@@ -1283,7 +1282,7 @@ static void ddebug_apply_class_users(const struct 
ddebug_table *dt)
  #define dd_mark_vector_subrange(_i, _dst, _sp, _box, _vec) ({ \
        int nc = 0;                                                     \
        for_subvec(_i, _sp, _box, _vec) {                               \
-               if (!strcmp((_sp)->mod_name, (_dst)->mod_name)) { \
+               if (!strcmp((_sp)->mod_name, (_dst)->info.mod_name)) {    \
                        if (!nc++)                                      \
                                (_dst)->info._vec.start = (_sp);     \
                } else {                                                \
@@ -1314,7 +1313,7 @@ ddebug_class_range_overlap(struct _ddebug_class_map *cm,
   * Allocate a new ddebug_table for the given module
   * and add it to the global list.
   */
-static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
+static int ddebug_add_module(struct _ddebug_info *di)
  {
        struct ddebug_table *dt;
        struct _ddebug_class_map *cm;
@@ -1325,20 +1324,19 @@ static int ddebug_add_module(struct _ddebug_info *di, 
const char *modname)
        if (!di->descs.len)
                return 0;
- v3pr_info("add-module: %s %d sites\n", modname, di->descs.len);
+       v3pr_info("add-module: %s %d sites\n", di->mod_name, di->descs.len);
dt = kzalloc(sizeof(*dt), GFP_KERNEL);
        if (dt == NULL) {
-               pr_err("error adding module: %s\n", modname);
+               pr_err("error adding module: %s\n", di->mod_name);
                return -ENOMEM;
        }
        /*
-        * 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.
+        * For built-in modules, name (as supplied in di by its
+        * callers) 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 = modname;
        dt->info = *di;
INIT_LIST_HEAD(&dt->link);
@@ -1368,10 +1366,10 @@ static int ddebug_add_module(struct _ddebug_info *di, 
const char *modname)
        if (dt->info.users.len)
                ddebug_apply_class_users(dt);
- vpr_info("%3u debug prints in module %s\n", di->descs.len, modname);
+       vpr_info("%3u debug prints in module %s\n", di->descs.len, 
di->mod_name);
        return 0;
  cleanup:
-       WARN_ONCE("dyndbg multi-classmap conflict in %s\n", modname);
+       WARN_ONCE("dyndbg multi-classmap conflict in %s\n", di->mod_name);
        kfree(dt);
        return -EINVAL;
@@ -1436,7 +1434,7 @@ static int ddebug_remove_module(const char *mod_name) mutex_lock(&ddebug_lock);
        list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
-               if (dt->mod_name == mod_name) {
+               if (dt->info.mod_name == mod_name) {
                        ddebug_table_free(dt);
                        ret = 0;
                        break;
@@ -1456,7 +1454,8 @@ static int ddebug_module_notify(struct notifier_block 
*self, unsigned long val,
switch (val) {
        case MODULE_STATE_COMING:
-               ret = ddebug_add_module(&mod->dyndbg_info, mod->name);
+               mod->dyndbg_info.mod_name = mod->name;
+               ret = ddebug_add_module(&mod->dyndbg_info);
                if (ret)
                        WARN(1, "Failed to allocate memory: dyndbg may not work 
properly.\n");
                break;
@@ -1556,7 +1555,8 @@ static int __init dynamic_debug_init(void)
                        mod_ct++;
                        di.descs.len = mod_sites;
                        di.descs.start = iter_mod_start;
-                       ret = ddebug_add_module(&di, modname);
+                       di.mod_name = modname;
+                       ret = ddebug_add_module(&di);
                        if (ret)
                                goto out_err;
@@ -1567,7 +1567,8 @@ static int __init dynamic_debug_init(void)
        }
        di.descs.len = mod_sites;
        di.descs.start = iter_mod_start;
-       ret = ddebug_add_module(&di, modname);
+       di.mod_name = modname;
+       ret = ddebug_add_module(&di);
        if (ret)
                goto out_err;

--
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com


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