Merge branch 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/gregkh/tty-2.6 * 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: serial: mfd: adjust the baud rate setting TTY: open/hangup race fixup TTY: don't allow reopen when ldisc is changing NET: wan/x25, fix ldisc->open retval TTY: ldisc, fix open flag handling serial8250: Mark console as CON_ANYTIME
cbmeeks · Dec 2, 2010 · eed5ee1 · eed5ee1
2 parents 435a5ae + a5880a9
commit eed5ee1
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Showing 6 changed files with 24 additions and 20 deletions.
diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c
@@ -577,7 +577,7 @@ static int x25_asy_open_tty(struct tty_struct *tty)
 	if (err)
 		return err;
 	/* Done.  We have linked the TTY line to a channel. */
-	return sl->dev->base_addr;
+	return 0;
 }
 
 

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
@@ -2872,7 +2872,7 @@ static struct console serial8250_console = {
 	.device		= uart_console_device,
 	.setup		= serial8250_console_setup,
 	.early_setup	= serial8250_console_early_setup,
-	.flags		= CON_PRINTBUFFER,
+	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
 	.index		= -1,
 	.data		= &serial8250_reg,
 };

diff --git a/drivers/serial/mfd.c b/drivers/serial/mfd.c
@@ -900,8 +900,7 @@ serial_hsu_set_termios(struct uart_port *port, struct ktermios *termios,
 	unsigned char cval, fcr = 0;
 	unsigned long flags;
 	unsigned int baud, quot;
-	u32 mul = 0x3600;
-	u32 ps = 0x10;
+	u32 ps, mul;
 
 	switch (termios->c_cflag & CSIZE) {
 	case CS5:
@@ -943,31 +942,24 @@ serial_hsu_set_termios(struct uart_port *port, struct ktermios *termios,
 	baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
 
 	quot = 1;
+	ps = 0x10;
+	mul = 0x3600;
 	switch (baud) {
 	case 3500000:
 		mul = 0x3345;
 		ps = 0xC;
 		break;
-	case 3000000:
-		mul = 0x2EE0;
-		break;
-	case 2500000:
-		mul = 0x2710;
-		break;
-	case 2000000:
-		mul = 0x1F40;
-		break;
 	case 1843200:
 		mul = 0x2400;
 		break;
+	case 3000000:
+	case 2500000:
+	case 2000000:
 	case 1500000:
-		mul = 0x1770;
-		break;
 	case 1000000:
-		mul = 0xFA0;
-		break;
 	case 500000:
-		mul = 0x7D0;
+		/* mul/ps/quot = 0x9C4/0x10/0x1 will make a 500000 bps */
+		mul = baud / 500000 * 0x9C4;
 		break;
 	default:
 		/* Use uart_get_divisor to get quot for other baud rates */

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
@@ -559,6 +559,9 @@ void __tty_hangup(struct tty_struct *tty)
 
 	tty_lock();
 
+	/* some functions below drop BTM, so we need this bit */
+	set_bit(TTY_HUPPING, &tty->flags);
+
 	/* inuse_filps is protected by the single tty lock,
 	   this really needs to change if we want to flush the
 	   workqueue with the lock held */
@@ -578,6 +581,10 @@ void __tty_hangup(struct tty_struct *tty)
 	}
 	spin_unlock(&tty_files_lock);
 
+	/*
+	 * it drops BTM and thus races with reopen
+	 * we protect the race by TTY_HUPPING
+	 */
 	tty_ldisc_hangup(tty);
 
 	read_lock(&tasklist_lock);
@@ -615,7 +622,6 @@ void __tty_hangup(struct tty_struct *tty)
 	tty->session = NULL;
 	tty->pgrp = NULL;
 	tty->ctrl_status = 0;
-	set_bit(TTY_HUPPED, &tty->flags);
 	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 
 	/* Account for the p->signal references we killed */
@@ -641,6 +647,7 @@ void __tty_hangup(struct tty_struct *tty)
 	 * can't yet guarantee all that.
 	 */
 	set_bit(TTY_HUPPED, &tty->flags);
+	clear_bit(TTY_HUPPING, &tty->flags);
 	tty_ldisc_enable(tty);
 
 	tty_unlock();
@@ -1310,7 +1317,9 @@ static int tty_reopen(struct tty_struct *tty)
 {
 	struct tty_driver *driver = tty->driver;
 
-	if (test_bit(TTY_CLOSING, &tty->flags))
+	if (test_bit(TTY_CLOSING, &tty->flags) ||
+			test_bit(TTY_HUPPING, &tty->flags) ||
+			test_bit(TTY_LDISC_CHANGING, &tty->flags))
 		return -EIO;
 
 	if (driver->type == TTY_DRIVER_TYPE_PTY &&

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
@@ -454,6 +454,8 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
                 /* BTM here locks versus a hangup event */
 		WARN_ON(!tty_locked());
 		ret = ld->ops->open(tty);
+		if (ret)
+			clear_bit(TTY_LDISC_OPEN, &tty->flags);
 		return ret;
 	}
 	return 0;

diff --git a/include/linux/tty.h b/include/linux/tty.h
@@ -366,6 +366,7 @@ struct tty_file_private {
 #define TTY_HUPPED 		18	/* Post driver->hangup() */
 #define TTY_FLUSHING		19	/* Flushing to ldisc in progress */
 #define TTY_FLUSHPENDING	20	/* Queued buffer flush pending */
+#define TTY_HUPPING 		21	/* ->hangup() in progress */
 
 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))