> I was actually wrong, flush_to_ldisc does handle reentrancy. > It can only have one caller to disc->receive_buf() at a time. So > long chains of recursion don't seem to be possible, even if called > from IRQ context. disc->receive_buf is single threaded but if it then sends characters back in the same context (eg flow control) you get re-entry in the driver. > And studying the way ppp does writing, it can bypass the tty_write() > call and directly call the drivers. So that bypasses the transmit > locking problems I saw. tty_write() is the layer above the ldisc. tty_write() feeds a line discipline from (usually) user space. Line disciplines write direct to the tty. > > This is going to require some more thought. But I believe it can be > done with adding a poll routine to the tty_operations structure What status do you need to poll ? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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