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>

diff --git a/drivers/staging/greybus/audio_manager.c b/drivers/staging/greybus/audio_manager.c
index bc5be4907c81db09236c0df0e70f5cc0ce0c9bea..619bdee46ee5df9eb79e215b0c00c3ca2f367aad 100644 (file)
--- a/drivers/staging/greybus/audio_manager.c
+++ b/drivers/staging/greybus/audio_manager.c
@@ -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);
 }