> On Tuesday, 6. November 2001 10:57, Duncan Sands wrote: > > That's not the end of the world, but it is ugly > > (extra locks, global data, all that) and wouldn't be necessary if probe/ > > ioctl/disconnect worked like open/read-write/close. > > Can you explain to me how open/read-write/close are > protected against races? One Task writing and another one > closing the device?
Yes, this was unclear. I was refering to earlier in the message (or an earlier message) in which I pointed out that having open and close methods allows you to keep a usage count of how many people have opened your device. On a disconnect, you can check if the device is open; if it not open, then you can free memory etc; otherwise you can mark that a disconnect occured, and when the last close occurs, the close method can free memory etc. This was in contrast with the ioctl you can specify in struct usb_driver: since there are no open/close methods, you can't keep a count in this way and that is a pain (see previous discussion for why it is a pain). How you were to deduce this discussion from the above lines, I don't know! You were right to jump on these lines. All the best, Duncan. _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
