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serial: core: Privatize tty->hw_stopped
tty->hw_stopped is not used by the tty core and is thread-unsafe; hw_stopped is a member of a bitfield whose fields are updated non-atomically and no lock is suitable for serializing updates. Replace serial core usage of tty->hw_stopped with uport->hw_stopped. Use int storage which works around Alpha EV4/5 non-atomic byte storage, since uart_port uses different locks to protect certain fields within the structure. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
317c136020
commit
d01f4d181c
3 changed files with 22 additions and 23 deletions
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@ -108,22 +108,22 @@ static void bfin_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
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static irqreturn_t bfin_serial_mctrl_cts_int(int irq, void *dev_id)
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{
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struct bfin_serial_port *uart = dev_id;
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unsigned int status = bfin_serial_get_mctrl(&uart->port);
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struct uart_port *uport = &uart->port;
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unsigned int status = bfin_serial_get_mctrl(uport);
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#ifdef CONFIG_SERIAL_BFIN_HARD_CTSRTS
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struct tty_struct *tty = uart->port.state->port.tty;
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UART_CLEAR_SCTS(uart);
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if (tty->hw_stopped) {
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if (uport->hw_stopped) {
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if (status) {
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tty->hw_stopped = 0;
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uart_write_wakeup(&uart->port);
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uport->hw_stopped = 0;
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uart_write_wakeup(uport);
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}
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} else {
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if (!status)
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tty->hw_stopped = 1;
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uport->hw_stopped = 1;
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}
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#endif
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uart_handle_cts_change(&uart->port, status & TIOCM_CTS);
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uart_handle_cts_change(uport, status & TIOCM_CTS);
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return IRQ_HANDLED;
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}
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@ -95,7 +95,7 @@ static void __uart_start(struct tty_struct *tty)
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struct uart_state *state = tty->driver_data;
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struct uart_port *port = state->uart_port;
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if (!tty->stopped && !tty->hw_stopped)
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if (!uart_tx_stopped(port))
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port->ops->start_tx(port);
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}
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@ -181,10 +181,11 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
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}
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spin_lock_irq(&uport->lock);
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if (uart_cts_enabled(uport)) {
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if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
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tty->hw_stopped = 1;
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}
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if (uart_cts_enabled(uport) &&
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!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
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uport->hw_stopped = 1;
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else
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uport->hw_stopped = 0;
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spin_unlock_irq(&uport->lock);
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}
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@ -949,7 +950,7 @@ static int uart_get_lsr_info(struct tty_struct *tty,
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*/
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if (uport->x_char ||
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((uart_circ_chars_pending(&state->xmit) > 0) &&
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!tty->stopped && !tty->hw_stopped))
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!uart_tx_stopped(uport)))
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result &= ~TIOCSER_TEMT;
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return put_user(result, value);
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@ -1295,7 +1296,7 @@ static void uart_set_termios(struct tty_struct *tty,
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/*
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* If the port is doing h/w assisted flow control, do nothing.
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* We assume that tty->hw_stopped has never been set.
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* We assume that port->hw_stopped has never been set.
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*/
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if (uport->flags & UPF_HARD_FLOW)
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return;
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@ -1303,7 +1304,7 @@ static void uart_set_termios(struct tty_struct *tty,
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/* Handle turning off CRTSCTS */
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if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
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spin_lock_irqsave(&uport->lock, flags);
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tty->hw_stopped = 0;
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uport->hw_stopped = 0;
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__uart_start(tty);
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spin_unlock_irqrestore(&uport->lock, flags);
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}
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@ -1311,7 +1312,7 @@ static void uart_set_termios(struct tty_struct *tty,
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else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
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spin_lock_irqsave(&uport->lock, flags);
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if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) {
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tty->hw_stopped = 1;
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uport->hw_stopped = 1;
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uport->ops->stop_tx(uport);
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}
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spin_unlock_irqrestore(&uport->lock, flags);
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@ -2788,23 +2789,20 @@ EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
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*/
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void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
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{
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struct tty_port *port = &uport->state->port;
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struct tty_struct *tty = port->tty;
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lockdep_assert_held_once(&uport->lock);
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uport->icount.cts++;
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if (uart_cts_enabled(uport)) {
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if (tty->hw_stopped) {
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if (uport->hw_stopped) {
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if (status) {
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tty->hw_stopped = 0;
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uport->hw_stopped = 0;
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uport->ops->start_tx(uport);
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uart_write_wakeup(uport);
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}
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} else {
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if (!status) {
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tty->hw_stopped = 1;
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uport->hw_stopped = 1;
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uport->ops->stop_tx(uport);
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}
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}
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@ -197,6 +197,7 @@ struct uart_port {
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#define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
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#define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
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int hw_stopped; /* sw-assisted CTS flow state */
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unsigned int mctrl; /* current modem ctrl settings */
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unsigned int timeout; /* character-based timeout */
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unsigned int type; /* port type */
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@ -357,7 +358,7 @@ int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
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static inline int uart_tx_stopped(struct uart_port *port)
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{
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struct tty_struct *tty = port->state->port.tty;
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if(tty->stopped || tty->hw_stopped)
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if (tty->stopped || port->hw_stopped)
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return 1;
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return 0;
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}
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