Scsi - Index of

426 /* store the actual length of the data transferred */
427 if (act_len)
428 *act_len = us->current_urb->actual_length;
429 return interpret_urb_result(us, pipe, length, result,
430 us->current_urb->actual_length);
431 }
一路走来的同志们不会对这里这个usb_fill_bulk_urb()完全陌生.我们的确是第一次见这个函数,但是
此前我们有见过usb_fill_control_urb(),除此之外还有一个叫做usb_fill_int_urb()的函数,不用说,这几
个函数是差不多的,只不过她们分别对应usb 传输模式中的bulk,control,interrupt.唯一一处和
usb_fill_control_urb 不同的便是bulk 传输不需要有一个setup_packet.具体来
看,usb_fill_bulk_urb()定义于include/linux/usb.h:
845 /**
846 * usb_fill_bulk_urb - macro to help initialize a bulk urb
847 * @urb: pointer to the urb to initialize.
848 * @dev: pointer to the struct usb_device for this urb.
849 * @pipe: the endpoint pipe
850 * @transfer_buffer: pointer to the transfer buffer
851 * @buffer_length: length of the transfer buffer
852 * @complete: pointer to the usb_complete_t function
155
853 * @context: what to set the urb context to.
854 *
855 * Initializes a bulk urb with the proper information needed to submit it
856 * to a device.
857 */
858 static inline void usb_fill_bulk_urb (struct urb *urb,
859 struct usb_device *dev,
860 unsigned int pipe,
861 void *transfer_buffer,
862 int buffer_length,
863 usb_complete_t complete,
864 void *context)
865 {
866 spin_lock_init(&urb->lock);
867 urb->dev = dev;
868 urb->pipe = pipe;
869 urb->transfer_buffer = transfer_buffer;
870 urb->transfer_buffer_length = buffer_length;
871 urb->complete = complete;
872 urb->context = context;
873 }
看过了那个usb_fill_control_urb 之后看这个函数应该是很简单的了.结合上面调用这个函数的代码,可
知,urb->complete 被赋值为usb_stor_blocking_completion,不用说,这个函数之后肯定会被调用.正
如上次控制传输中所讲的那样.