static int ioctl_queue_iso()

in core-cdev.c [1067:1165]

• 77 lines of code
• 25 McCabe index (conditional complexity)

static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
{
	struct fw_cdev_queue_iso *a = &arg->queue_iso;
	struct fw_cdev_iso_packet __user *p, *end, *next;
	struct fw_iso_context *ctx = client->iso_context;
	unsigned long payload, buffer_end, transmit_header_bytes = 0;
	u32 control;
	int count;
	struct {
		struct fw_iso_packet packet;
		u8 header[256];
	} u;

	if (ctx == NULL || a->handle != 0)
		return -EINVAL;

	/*
	 * If the user passes a non-NULL data pointer, has mmap()'ed
	 * the iso buffer, and the pointer points inside the buffer,
	 * we setup the payload pointers accordingly.  Otherwise we
	 * set them both to 0, which will still let packets with
	 * payload_length == 0 through.  In other words, if no packets
	 * use the indirect payload, the iso buffer need not be mapped
	 * and the a->data pointer is ignored.
	 */
	payload = (unsigned long)a->data - client->vm_start;
	buffer_end = client->buffer.page_count << PAGE_SHIFT;
	if (a->data == 0 || client->buffer.pages == NULL ||
	    payload >= buffer_end) {
		payload = 0;
		buffer_end = 0;
	}

	if (ctx->type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL && payload & 3)
		return -EINVAL;

	p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);

	end = (void __user *)p + a->size;
	count = 0;
	while (p < end) {
		if (get_user(control, &p->control))
			return -EFAULT;
		u.packet.payload_length = GET_PAYLOAD_LENGTH(control);
		u.packet.interrupt = GET_INTERRUPT(control);
		u.packet.skip = GET_SKIP(control);
		u.packet.tag = GET_TAG(control);
		u.packet.sy = GET_SY(control);
		u.packet.header_length = GET_HEADER_LENGTH(control);

		switch (ctx->type) {
		case FW_ISO_CONTEXT_TRANSMIT:
			if (u.packet.header_length & 3)
				return -EINVAL;
			transmit_header_bytes = u.packet.header_length;
			break;

		case FW_ISO_CONTEXT_RECEIVE:
			if (u.packet.header_length == 0 ||
			    u.packet.header_length % ctx->header_size != 0)
				return -EINVAL;
			break;

		case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
			if (u.packet.payload_length == 0 ||
			    u.packet.payload_length & 3)
				return -EINVAL;
			break;
		}

		next = (struct fw_cdev_iso_packet __user *)
			&p->header[transmit_header_bytes / 4];
		if (next > end)
			return -EINVAL;
		if (copy_from_user
		    (u.packet.header, p->header, transmit_header_bytes))
			return -EFAULT;
		if (u.packet.skip && ctx->type == FW_ISO_CONTEXT_TRANSMIT &&
		    u.packet.header_length + u.packet.payload_length > 0)
			return -EINVAL;
		if (payload + u.packet.payload_length > buffer_end)
			return -EINVAL;

		if (fw_iso_context_queue(ctx, &u.packet,
					 &client->buffer, payload))
			break;

		p = next;
		payload += u.packet.payload_length;
		count++;
	}
	fw_iso_context_queue_flush(ctx);

	a->size    -= uptr_to_u64(p) - a->packets;
	a->packets  = uptr_to_u64(p);
	a->data     = client->vm_start + payload;

	return count;
}