Zitat von Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>:
On Tue, Jul 24, 2018 at 11:05:29AM +0200, Guido Kiener wrote:+struct usbtmc_ctrlrequest { + struct usbtmc_request req; + __u64 data; /* pointer to user space */ +} __attribute__ ((packed));Hint, this structure could just be: struct usbtmc_ctrlreqest { struct usbtmc_request req; __u8 data[0]; } __attribute__((__aligned__(8))); No more pointer mess anymore, right?
Yes. But we prefer copy by reference and not by value. Especially for the next USBTMC_IOCTL_WRITE/READ function, we want to copy many bytes (MB and GB) by reference. I had a lengthy discussion with many developers, and we prefer pointer mess before we loose any microsecond. Regards, Guido -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
