Sometimes, device drivers are bound into each other via try_module_get(), making such references invisible when looking at /proc/modules or lsmod.
Add a function to allow setting up module references for such cases, and call it when try_module_get() is used. Reviewed-by: Dan Williams <[email protected]> Signed-off-by: Mauro Carvalho Chehab <[email protected]> --- See [PATCH v3 0/2] at: https://lore.kernel.org/all/[email protected]/ include/linux/module.h | 4 +++- kernel/module/main.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 34 insertions(+), 3 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index 46d4d5f2516e..836851baaad4 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -620,7 +620,9 @@ extern void __module_get(struct module *module); /* This is the Right Way to get a module: if it fails, it's being removed, * so pretend it's not there. */ -extern bool try_module_get(struct module *module); +extern bool __try_module_get(struct module *module, struct module *this); + +#define try_module_get(mod) __try_module_get(mod, THIS_MODULE) extern void module_put(struct module *module); diff --git a/kernel/module/main.c b/kernel/module/main.c index 05a42d8fcd7a..d63ebf52392b 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -631,6 +631,33 @@ static int ref_module(struct module *a, struct module *b) return 0; } +static int ref_module_dependency(struct module *mod, struct module *this) +{ + int ret; + + if (!this || !this->name) + return -EINVAL; + + if (mod == this) + return 0; + + mutex_lock(&module_mutex); + + ret = ref_module(this, mod); + +#ifdef CONFIG_MODULE_UNLOAD + if (ret) + goto ret; + + ret = sysfs_create_link(mod->holders_dir, + &this->mkobj.kobj, this->name); +#endif + +ret: + mutex_unlock(&module_mutex); + return ret; +} + /* Clear the unload stuff of the module. */ static void module_unload_free(struct module *mod) { @@ -841,7 +868,7 @@ void __module_get(struct module *module) } EXPORT_SYMBOL(__module_get); -bool try_module_get(struct module *module) +bool __try_module_get(struct module *module, struct module *this) { bool ret = true; @@ -856,9 +883,11 @@ bool try_module_get(struct module *module) preempt_enable(); } + if (ret) + ref_module_dependency(module, this); return ret; } -EXPORT_SYMBOL(try_module_get); +EXPORT_SYMBOL(__try_module_get); void module_put(struct module *module) { -- 2.35.1
