static ssize_t adb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int ret; struct adbdev_state *state = file->private_data; struct adb_request *req; wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current); unsigned long flags; if (count < 2) return -EINVAL; if (count > sizeof(req->reply)) count = sizeof(req->reply); ret = verify_area(VERIFY_WRITE, buf, count); if (ret) return ret; req = NULL; spin_lock_irqsave(&state->lock, flags); add_wait_queue(&state->wait_queue, &wait); current->state = TASK_INTERRUPTIBLE; for (;;) { req = state->completed; if (req != NULL) state->completed = req->next; else if (atomic_read(&state->n_pending) == 0) ret = -EIO; if (req != NULL || ret != 0) break; if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; break; } if (signal_pending(current)) { ret = -ERESTARTSYS; break; } spin_unlock_irqrestore(&state->lock, flags); schedule(); spin_lock_irqsave(&state->lock, flags); } current->state = TASK_RUNNING; remove_wait_queue(&state->wait_queue, &wait); spin_unlock_irqrestore(&state->lock, flags); if (ret) return ret; ret = req->reply_len; if (ret > count) ret = count; if (ret > 0 && copy_to_user(buf, req->reply, ret)) ret = -EFAULT; kfree(req); return ret; }
static ssize_t adb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int ret = 0; struct adbdev_state *state = file->private_data; struct adb_request *req; wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current); unsigned long flags; if (count < 2) return -EINVAL; if (count > sizeof(req->reply)) count = sizeof(req->reply); if (!access_ok(VERIFY_WRITE, buf, count)) return -EFAULT; req = NULL; spin_lock_ir