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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: Vaibhav Agarwal <vaibhav.agarwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Vaibhav Agarwal 2016-05-04 16:29:19 +05:30 committed by Greg Kroah-Hartman
parent 7557d0481b
commit 84e0e38744
1 changed files with 15 additions and 22 deletions
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37
drivers/staging/greybus/audio_manager.c
View File

@ -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);
}