From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
To: Jessica Yu <jeyu@kernel.org>, <rusty@rustcorp.com.au>,
<kay.sievers@vrfy.org>, <clabbe.montjoie@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, <wangxiaogang3@huawei.com>,
<zhoukang7@huawei.com>, Mingfangsen <mingfangsen@huawei.com>
Subject: [PATCH v3] module: add link_flag pram in ref_module func to decide whether add usage link
Date: Sat, 20 Jul 2019 22:40:30 +0800 [thread overview]
Message-ID: <48019b31-3a74-1821-8ad3-72c9ef1219ba@huawei.com> (raw)
Users can call ref_module func in their modules to construct
relationships with other modules. However, the holders
'/sys/module/<mod-name>/holders' of the target module donot include
the users` module. So lsmod command misses detailed info of 'Used by'.
When load module, the process is given as follows,
load_module()
-> mod_sysfs_setup()
-> add_usage_links
-> do_init_module
-> mod->init()
add_usage_links func creates holders of target modules linking to
this module. If ref_module is called in mod->init() func, the usage
links cannot be added.
Consider that add_module_usage and add usage_link may separate, the
link_flag pram is added in ref_module func to decide whether add usage
link after add_module_usage. If link_flag is true, it means usage link
of a to b's holder_dir should be created immediately after add_module_usage.
V2->V3:
- add link_flag pram in ref_module func to decide whether add usage link
V1->V2:
- remove incorrect Fixes tag
- fix error handling of sysfs_create_link as suggested by Jessica Yu
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Suggested-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Kang Zhou <zhoukang7@huawei.com>
---
include/linux/module.h | 2 +-
kernel/module.c | 27 ++++++++++++++++++++-------
2 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 188998d3dca9..9ec04b9e93e8 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -632,7 +632,7 @@ static inline void __module_get(struct module *module)
#define symbol_put_addr(p) do { } while (0)
#endif /* CONFIG_MODULE_UNLOAD */
-int ref_module(struct module *a, struct module *b);
+int ref_module(struct module *a, struct module *b, bool link_flag);
/* This is a #define so the string doesn't get put in every .o file */
#define module_name(mod) \
diff --git a/kernel/module.c b/kernel/module.c
index 80c7c09584cf..00e4862a8ef7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -837,25 +837,26 @@ static int already_uses(struct module *a, struct module *b)
* 'b' can walk the list to see who sourced them), and of 'a'
* targets (so 'a' can see what modules it targets).
*/
-static int add_module_usage(struct module *a, struct module *b)
+static struct module_use *add_module_usage(struct module *a, struct module *b)
{
struct module_use *use;
pr_debug("Allocating new usage for %s.\n", a->name);
use = kmalloc(sizeof(*use), GFP_ATOMIC);
if (!use)
- return -ENOMEM;
+ return NULL;
use->source = a;
use->target = b;
list_add(&use->source_list, &b->source_list);
list_add(&use->target_list, &a->target_list);
- return 0;
+ return use;
}
/* Module a uses b: caller needs module_mutex() */
-int ref_module(struct module *a, struct module *b)
+int ref_module(struct module *a, struct module *b, bool link_flag)
{
+ struct module_use *use;
int err;
if (b == NULL || already_uses(a, b))
@@ -866,9 +867,21 @@ int ref_module(struct module *a, struct module *b)
if (err)
return err;
- err = add_module_usage(a, b);
+ use = add_module_usage(a, b);
+ if (!use) {
+ module_put(b);
+ return -ENOMEM;
+ }
+
+ if (!link_flag)
+ return 0;
+
+ err = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
if (err) {
module_put(b);
+ list_del(&use->source_list);
+ list_del(&use->target_list);
+ kfree(use);
return err;
}
return 0;
@@ -1152,7 +1165,7 @@ static inline void module_unload_free(struct module *mod)
{
}
-int ref_module(struct module *a, struct module *b)
+int ref_module(struct module *a, struct module *b, bool link_flag)
{
return strong_try_module_get(b);
}
@@ -1407,7 +1420,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
goto getname;
}
- err = ref_module(mod, owner);
+ err = ref_module(mod, owner, false);
if (err) {
sym = ERR_PTR(err);
goto getname;
--
2.19.1
next reply other threads:[~2019-07-20 14:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-20 14:40 Zhiqiang Liu [this message]
2019-09-11 3:16 ` [PATCH v3] module: add link_flag pram in ref_module func to decide whether add usage link Zhiqiang Liu
2019-09-11 20:03 ` Jessica Yu
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