Merge tag 'tty-5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are 2 tty and serial fixes for 5.0-rc2 that resolve some reported
  issues.

  The first is a simple serial driver fix for a regression that showed
  up in 5.0-rc1. The second one resolves a number of reported issues
  with the recent tty locking fixes that went into 5.0-rc1. Lots of
  people have tested the second one and say it resolves their issues.

  Both have been in linux-next with no reported issues"

* tag 'tty-5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: Don't hold ldisc lock in tty_reopen() if ldisc present
  serial: lantiq: Do not swap register read/writes

drivers/tty/serial/lantiq.c

@@ -114,9 +114,9 @@ struct ltq_uart_port {
 
 static inline void asc_update_bits(u32 clear, u32 set, void __iomem *reg)
 {
-	u32 tmp = readl(reg);
+	u32 tmp = __raw_readl(reg);
 
-	writel((tmp & ~clear) | set, reg);
+	__raw_writel((tmp & ~clear) | set, reg);
 }
 
 static inline struct
@@ -144,7 +144,7 @@ lqasc_start_tx(struct uart_port *port)
 static void
 lqasc_stop_rx(struct uart_port *port)
 {
-	writel(ASCWHBSTATE_CLRREN, port->membase + LTQ_ASC_WHBSTATE);
+	__raw_writel(ASCWHBSTATE_CLRREN, port->membase + LTQ_ASC_WHBSTATE);
 }
 
 static int
@@ -153,11 +153,12 @@ lqasc_rx_chars(struct uart_port *port)
 	struct tty_port *tport = &port->state->port;
 	unsigned int ch = 0, rsr = 0, fifocnt;
 
-	fifocnt = readl(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
+	fifocnt = __raw_readl(port->membase + LTQ_ASC_FSTAT) &
+		  ASCFSTAT_RXFFLMASK;
 	while (fifocnt--) {
 		u8 flag = TTY_NORMAL;
 		ch = readb(port->membase + LTQ_ASC_RBUF);
-		rsr = (readl(port->membase + LTQ_ASC_STATE)
+		rsr = (__raw_readl(port->membase + LTQ_ASC_STATE)
 			& ASCSTATE_ANY) | UART_DUMMY_UER_RX;
 		tty_flip_buffer_push(tport);
 		port->icount.rx++;
@@ -217,7 +218,7 @@ lqasc_tx_chars(struct uart_port *port)
 		return;
 	}
 
-	while (((readl(port->membase + LTQ_ASC_FSTAT) &
+	while (((__raw_readl(port->membase + LTQ_ASC_FSTAT) &
 		ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF) != 0) {
 		if (port->x_char) {
 			writeb(port->x_char, port->membase + LTQ_ASC_TBUF);
@@ -245,7 +246,7 @@ lqasc_tx_int(int irq, void *_port)
 	unsigned long flags;
 	struct uart_port *port = (struct uart_port *)_port;
 	spin_lock_irqsave(&ltq_asc_lock, flags);
-	writel(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
+	__raw_writel(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
 	lqasc_start_tx(port);
 	return IRQ_HANDLED;
@@ -270,7 +271,7 @@ lqasc_rx_int(int irq, void *_port)
 	unsigned long flags;
 	struct uart_port *port = (struct uart_port *)_port;
 	spin_lock_irqsave(&ltq_asc_lock, flags);
-	writel(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
+	__raw_writel(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
 	lqasc_rx_chars(port);
 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
 	return IRQ_HANDLED;
@@ -280,7 +281,8 @@ static unsigned int
 lqasc_tx_empty(struct uart_port *port)
 {
 	int status;
-	status = readl(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
+	status = __raw_readl(port->membase + LTQ_ASC_FSTAT) &
+		 ASCFSTAT_TXFFLMASK;
 	return status ? 0 : TIOCSER_TEMT;
 }
 
@@ -313,12 +315,12 @@ lqasc_startup(struct uart_port *port)
 	asc_update_bits(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
 		port->membase + LTQ_ASC_CLC);
 
-	writel(0, port->membase + LTQ_ASC_PISEL);
-	writel(
+	__raw_writel(0, port->membase + LTQ_ASC_PISEL);
+	__raw_writel(
 		((TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) |
 		ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
 		port->membase + LTQ_ASC_TXFCON);
-	writel(
+	__raw_writel(
 		((RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK)
 		| ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
 		port->membase + LTQ_ASC_RXFCON);
@@ -350,7 +352,7 @@ lqasc_startup(struct uart_port *port)
 		goto err2;
 	}
 
-	writel(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
+	__raw_writel(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
 		port->membase + LTQ_ASC_IRNREN);
 	return 0;
 
@@ -369,7 +371,7 @@ lqasc_shutdown(struct uart_port *port)
 	free_irq(ltq_port->rx_irq, port);
 	free_irq(ltq_port->err_irq, port);
 
-	writel(0, port->membase + LTQ_ASC_CON);
+	__raw_writel(0, port->membase + LTQ_ASC_CON);
 	asc_update_bits(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
 		port->membase + LTQ_ASC_RXFCON);
 	asc_update_bits(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
@@ -461,13 +463,13 @@ lqasc_set_termios(struct uart_port *port,
 	asc_update_bits(ASCCON_BRS, 0, port->membase + LTQ_ASC_CON);
 
 	/* now we can write the new baudrate into the register */
-	writel(divisor, port->membase + LTQ_ASC_BG);
+	__raw_writel(divisor, port->membase + LTQ_ASC_BG);
 
 	/* turn the baudrate generator back on */
 	asc_update_bits(0, ASCCON_R, port->membase + LTQ_ASC_CON);
 
 	/* enable rx */
-	writel(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
+	__raw_writel(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
 
 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
 
@@ -578,7 +580,7 @@ lqasc_console_putchar(struct uart_port *port, int ch)
 		return;
 
 	do {
-		fifofree = (readl(port->membase + LTQ_ASC_FSTAT)
+		fifofree = (__raw_readl(port->membase + LTQ_ASC_FSTAT)
 			& ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF;
 	} while (fifofree == 0);
 	writeb(ch, port->membase + LTQ_ASC_TBUF);

drivers/tty/tty_io.c

@@ -1256,7 +1256,8 @@ static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *
 static int tty_reopen(struct tty_struct *tty)
 {
 	struct tty_driver *driver = tty->driver;
-	int retval;
+	struct tty_ldisc *ld;
+	int retval = 0;
 
 	if (driver->type == TTY_DRIVER_TYPE_PTY &&
 	    driver->subtype == PTY_TYPE_MASTER)
@@ -1268,13 +1269,18 @@ static int tty_reopen(struct tty_struct *tty)
 	if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
 		return -EBUSY;
 
-	retval = tty_ldisc_lock(tty, 5 * HZ);
-	if (retval)
-		return retval;
+	ld = tty_ldisc_ref_wait(tty);
+	if (ld) {
+		tty_ldisc_deref(ld);
+	} else {
+		retval = tty_ldisc_lock(tty, 5 * HZ);
+		if (retval)
+			return retval;
 
-	if (!tty->ldisc)
-		retval = tty_ldisc_reinit(tty, tty->termios.c_line);
-	tty_ldisc_unlock(tty);
+		if (!tty->ldisc)
+			retval = tty_ldisc_reinit(tty, tty->termios.c_line);
+		tty_ldisc_unlock(tty);
+	}
 
 	if (retval == 0)
 		tty->count++;