diff options
| -rw-r--r-- | drivers/misc/ntsync.c | 53 | ||||
| -rw-r--r-- | include/uapi/linux/ntsync.h | 1 |
2 files changed, 54 insertions, 0 deletions
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index a2826dbff2f4..33e26240d9e7 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -396,6 +396,57 @@ static int ntsync_sem_release(struct ntsync_obj *sem, void __user *argp) return ret; } +/* + * Actually change the mutex state, returning -EPERM if not the owner. + */ +static int unlock_mutex_state(struct ntsync_obj *mutex, + const struct ntsync_mutex_args *args) +{ + ntsync_assert_held(mutex); + + if (mutex->u.mutex.owner != args->owner) + return -EPERM; + + if (!--mutex->u.mutex.count) + mutex->u.mutex.owner = 0; + return 0; +} + +static int ntsync_mutex_unlock(struct ntsync_obj *mutex, void __user *argp) +{ + struct ntsync_mutex_args __user *user_args = argp; + struct ntsync_device *dev = mutex->dev; + struct ntsync_mutex_args args; + __u32 prev_count; + bool all; + int ret; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + if (!args.owner) + return -EINVAL; + + if (mutex->type != NTSYNC_TYPE_MUTEX) + return -EINVAL; + + all = ntsync_lock_obj(dev, mutex); + + prev_count = mutex->u.mutex.count; + ret = unlock_mutex_state(mutex, &args); + if (!ret) { + if (all) + try_wake_all_obj(dev, mutex); + try_wake_any_mutex(mutex); + } + + ntsync_unlock_obj(dev, mutex, all); + + if (!ret && put_user(prev_count, &user_args->count)) + ret = -EFAULT; + + return ret; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj = file->private_data; @@ -415,6 +466,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, switch (cmd) { case NTSYNC_IOC_SEM_RELEASE: return ntsync_sem_release(obj, argp); + case NTSYNC_IOC_MUTEX_UNLOCK: + return ntsync_mutex_unlock(obj, argp); default: return -ENOIOCTLCMD; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index bb7fb94f5856..9186304b253c 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -40,5 +40,6 @@ struct ntsync_wait_args { #define NTSYNC_IOC_CREATE_MUTEX _IOW ('N', 0x84, struct ntsync_mutex_args) #define NTSYNC_IOC_SEM_RELEASE _IOWR('N', 0x81, __u32) +#define NTSYNC_IOC_MUTEX_UNLOCK _IOWR('N', 0x85, struct ntsync_mutex_args) #endif |