On 2021/11/18 11:36, wangyangbo wrote: > @@ -2170,11 +2170,11 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd, > { > switch (cmd) { > case LOOP_CTL_ADD: > - return loop_add(parm); > + return loop_add(MINOR(parm)); Better to return -EINVAL or something if out of minor range? > case LOOP_CTL_REMOVE: > - return loop_control_remove(parm); > + return loop_control_remove(MINOR(parm)); This is bad, for this change makes if (idx < 0) { pr_warn("deleting an unspecified loop device is not supported.\n"); return -EINVAL; } dead code by masking the argument to 0-1048575 range. > case LOOP_CTL_GET_FREE: > - return loop_control_get_free(parm); > + return loop_control_get_free(MINOR(parm)); This is pointless, for the passed argument is not used. By the way, didn't someone already propose removal of this argument? > default: > return -ENOSYS; > } >