Fix tty_drain() and, thus, TIOCDRAIN of the current tty(4) incarnation
to actually wait until the TX FIFOs of UARTs have be drained before returning. This is done by bringing the equivalent of the TS_BUSY flag found in the previous implementation back in an ABI-preserving way. Reported and tested by: Patrick Powell Most likely, drivers for USB-serial-adapters likewise incorporating TX FIFOs as well as other terminal devices that buffer output in some form should also provide implementations of tsw_busy. MFC after: 3 days
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parent
eb2ad8724b
commit
9750d9e5b6
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=294362
@ -355,6 +355,18 @@ uart_tty_free(void *arg)
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*/
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}
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static bool
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uart_tty_busy(struct tty *tp)
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{
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struct uart_softc *sc;
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sc = tty_softc(tp);
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if (sc == NULL || sc->sc_leaving)
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return (FALSE);
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return (sc->sc_txbusy);
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}
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static struct ttydevsw uart_tty_class = {
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.tsw_flags = TF_INITLOCK|TF_CALLOUT,
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.tsw_open = uart_tty_open,
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@ -365,6 +377,7 @@ static struct ttydevsw uart_tty_class = {
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.tsw_param = uart_tty_param,
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.tsw_modem = uart_tty_modem,
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.tsw_free = uart_tty_free,
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.tsw_busy = uart_tty_busy,
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};
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int
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@ -132,11 +132,11 @@ tty_drain(struct tty *tp, int leaving)
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/* buffer is inaccessible */
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return (0);
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while (ttyoutq_bytesused(&tp->t_outq) > 0) {
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while (ttyoutq_bytesused(&tp->t_outq) > 0 || ttydevsw_busy(tp)) {
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ttydevsw_outwakeup(tp);
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/* Could be handled synchronously. */
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bytesused = ttyoutq_bytesused(&tp->t_outq);
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if (bytesused == 0)
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if (bytesused == 0 && !ttydevsw_busy(tp))
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return (0);
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/* Wait for data to be drained. */
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@ -955,6 +955,13 @@ ttydevsw_deffree(void *softc)
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panic("Terminal device freed without a free-handler");
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}
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static bool
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ttydevsw_defbusy(struct tty *tp __unused)
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{
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return (FALSE);
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}
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/*
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* TTY allocation and deallocation. TTY devices can be deallocated when
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* the driver doesn't use it anymore, when the TTY isn't a session's
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@ -989,6 +996,7 @@ tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
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PATCH_FUNC(mmap);
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PATCH_FUNC(pktnotify);
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PATCH_FUNC(free);
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PATCH_FUNC(busy);
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#undef PATCH_FUNC
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tp = malloc(sizeof(struct tty), M_TTY, M_WAITOK|M_ZERO);
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@ -54,6 +54,7 @@ typedef int tsw_mmap_t(struct tty *tp, vm_ooffset_t offset,
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vm_paddr_t * paddr, int nprot, vm_memattr_t *memattr);
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typedef void tsw_pktnotify_t(struct tty *tp, char event);
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typedef void tsw_free_t(void *softc);
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typedef bool tsw_busy_t(struct tty *tp);
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struct ttydevsw {
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unsigned int tsw_flags; /* Default TTY flags. */
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@ -74,7 +75,9 @@ struct ttydevsw {
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tsw_free_t *tsw_free; /* Destructor. */
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void *tsw_spare[4]; /* For future use. */
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tsw_busy_t *tsw_busy; /* Draining output. */
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void *tsw_spare[3]; /* For future use. */
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};
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static __inline int
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@ -181,4 +184,13 @@ ttydevsw_free(struct tty *tp)
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tp->t_devsw->tsw_free(tty_softc(tp));
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}
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static __inline bool
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ttydevsw_busy(struct tty *tp)
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{
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MPASS(tty_gone(tp));
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return (tp->t_devsw->tsw_busy(tp));
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}
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#endif /* !_SYS_TTYDEVSW_H_ */
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