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Commit 84e0e387 authored by Vaibhav Agarwal's avatar Vaibhav Agarwal Committed by Greg Kroah-Hartman
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greybus: audio:gb_manager: Use proper locking around kobject_xxx 



read/write_lock_irqsave mechanism was used to protect modules
list & kobject_xxx() in gb_audio_manager. Since kobject_xxx calls
can sleep spin_lock variants can't be used there. So use rw_sem
for protecting modules_list.

Signed-off-by: default avatarVaibhav Agarwal <vaibhav.agarwal@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 7557d048

drivers/staging/greybus/audio_manager.c

+15 −22
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
static struct kset *manager_kset;



static LIST_HEAD(modules_list);

static DEFINE_RWLOCK(modules_lock);

static DECLARE_RWSEM(modules_rwsem);

static DEFINE_IDA(module_id);



/* helpers */
@@ -42,7 +42,6 @@ static struct gb_audio_manager_module *gb_audio_manager_get_locked(int id) 
int gb_audio_manager_add(struct gb_audio_manager_module_descriptor *desc)

{

	struct gb_audio_manager_module *module;

	unsigned long flags;

	int id;

	int err;
@@ -55,9 +54,9 @@ int gb_audio_manager_add(struct gb_audio_manager_module_descriptor *desc) 
	}



	/* Add it to the list */

	write_lock_irqsave(&modules_lock, flags);

	down_write(&modules_rwsem);

	list_add_tail(&module->list, &modules_list);

	write_unlock_irqrestore(&modules_lock, flags);

	up_write(&modules_rwsem);



	return module->id;

}
@@ -66,20 +65,18 @@ EXPORT_SYMBOL_GPL(gb_audio_manager_add); 
int gb_audio_manager_remove(int id)

{

	struct gb_audio_manager_module *module;

	unsigned long flags;



	write_lock_irqsave(&modules_lock, flags);

	down_write(&modules_rwsem);



	module = gb_audio_manager_get_locked(id);

	if (!module) {

		write_unlock_irqrestore(&modules_lock, flags);

		up_write(&modules_rwsem);

		return -EINVAL;

	}



	ida_simple_remove(&module_id, module->id);

	list_del(&module->list);

	kobject_put(&module->kobj);

	write_unlock_irqrestore(&modules_lock, flags);

	up_write(&modules_rwsem);

	ida_simple_remove(&module_id, module->id);

	return 0;

}

EXPORT_SYMBOL_GPL(gb_audio_manager_remove);
@@ -88,9 +85,8 @@ void gb_audio_manager_remove_all(void) 
{

	struct gb_audio_manager_module *module, *next;

	int is_empty = 1;

	unsigned long flags;



	write_lock_irqsave(&modules_lock, flags);

	down_write(&modules_rwsem);



	list_for_each_entry_safe(module, next, &modules_list, list) {

		list_del(&module->list);
@@ -99,7 +95,7 @@ void gb_audio_manager_remove_all(void) 


	is_empty = list_empty(&modules_list);



	write_unlock_irqrestore(&modules_lock, flags);

	up_write(&modules_rwsem);



	if (!is_empty)

		pr_warn("Not all nodes were deleted\n");
@@ -109,12 +105,11 @@ EXPORT_SYMBOL_GPL(gb_audio_manager_remove_all); 
struct gb_audio_manager_module *gb_audio_manager_get_module(int id)

{

	struct gb_audio_manager_module *module;

	unsigned long flags;



	read_lock_irqsave(&modules_lock, flags);

	down_read(&modules_rwsem);

	module = gb_audio_manager_get_locked(id);

	kobject_get(&module->kobj);

	read_unlock_irqrestore(&modules_lock, flags);

	up_read(&modules_rwsem);

	return module;

}

EXPORT_SYMBOL_GPL(gb_audio_manager_get_module);
@@ -128,11 +123,10 @@ EXPORT_SYMBOL_GPL(gb_audio_manager_put_module); 
int gb_audio_manager_dump_module(int id)

{

	struct gb_audio_manager_module *module;

	unsigned long flags;



	read_lock_irqsave(&modules_lock, flags);

	down_read(&modules_rwsem);

	module = gb_audio_manager_get_locked(id);

	read_unlock_irqrestore(&modules_lock, flags);

	up_read(&modules_rwsem);



	if (!module)

		return -EINVAL;
@@ -146,14 +140,13 @@ void gb_audio_manager_dump_all(void) 
{

	struct gb_audio_manager_module *module;

	int count = 0;

	unsigned long flags;



	read_lock_irqsave(&modules_lock, flags);

	down_read(&modules_rwsem);

	list_for_each_entry(module, &modules_list, list) {

		gb_audio_manager_module_dump(module);

		count++;

	}

	read_unlock_irqrestore(&modules_lock, flags);

	up_read(&modules_rwsem);



	pr_info("Number of connected modules: %d\n", count);

}