Merge branch 'quilt/ttydev'

13 files changed, 1408 insertions, 375 deletions

diff --git a/Documentation/filesystems/devpts.txt b/Documentation/filesystems/devpts.txt
new file mode 100644
index 000000000000..68dffd87f9b7
--- /dev/null
+++ b/Documentation/filesystems/devpts.txt
@@ -0,0 +1,132 @@
+
+To support containers, we now allow multiple instances of devpts filesystem,
+such that indices of ptys allocated in one instance are independent of indices
+allocated in other instances of devpts.
+
+To preserve backward compatibility, this support for multiple instances is
+enabled only if:
+
+	- CONFIG_DEVPTS_MULTIPLE_INSTANCES=y, and
+	- '-o newinstance' mount option is specified while mounting devpts
+
+IOW, devpts now supports both single-instance and multi-instance semantics.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=n, there is no change in behavior and
+this referred to as the "legacy" mode. In this mode, the new mount options
+(-o newinstance and -o ptmxmode) will be ignored with a 'bogus option' message
+on console.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and devpts is mounted without the
+'newinstance' option (as in current start-up scripts) the new mount binds
+to the initial kernel mount of devpts. This mode is referred to as the
+'single-instance' mode and the current, single-instance semantics are
+preserved, i.e PTYs are common across the system.
+
+The only difference between this single-instance mode and the legacy mode
+is the presence of new, '/dev/pts/ptmx' node with permissions 0000, which
+can safely be ignored.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and 'newinstance' option is specified,
+the mount is considered to be in the multi-instance mode and a new instance
+of the devpts fs is created. Any ptys created in this instance are independent
+of ptys in other instances of devpts. Like in the single-instance mode, the
+/dev/pts/ptmx node is present. To effectively use the multi-instance mode,
+open of /dev/ptmx must be a redirected to '/dev/pts/ptmx' using a symlink or
+bind-mount.
+
+Eg: A container startup script could do the following:
+
+	$ chmod 0666 /dev/pts/ptmx
+	$ rm /dev/ptmx
+	$ ln -s pts/ptmx /dev/ptmx
+	$ ns_exec -cm /bin/bash
+
+	# We are now in new container
+
+	$ umount /dev/pts
+	$ mount -t devpts -o newinstance lxcpts /dev/pts
+	$ sshd -p 1234
+
+where 'ns_exec -cm /bin/bash' calls clone() with CLONE_NEWNS flag and execs
+/bin/bash in the child process.  A pty created by the sshd is not visible in
+the original mount of /dev/pts.
+
+User-space changes
+------------------
+
+In multi-instance mode (i.e '-o newinstance' mount option is specified at least
+once), following user-space issues should be noted.
+
+1. If -o newinstance mount option is never used, /dev/pts/ptmx can be ignored
+   and no change is needed to system-startup scripts.
+
+2. To effectively use multi-instance mode (i.e -o newinstance is specified)
+   administrators or startup scripts should "redirect" open of /dev/ptmx to
+   /dev/pts/ptmx using either a bind mount or symlink.
+
+	$ mount -t devpts -o newinstance devpts /dev/pts
+
+   followed by either
+
+	$ rm /dev/ptmx
+	$ ln -s pts/ptmx /dev/ptmx
+	$ chmod 666 /dev/pts/ptmx
+   or
+	$ mount -o bind /dev/pts/ptmx /dev/ptmx
+
+3. The '/dev/ptmx -> pts/ptmx' symlink is the preferred method since it
+   enables better error-reporting and treats both single-instance and
+   multi-instance mounts similarly.
+
+   But this method requires that system-startup scripts set the mode of
+   /dev/pts/ptmx correctly (default mode is 0000). The scripts can set the
+   mode by, either
+
+   	- adding ptmxmode mount option to devpts entry in /etc/fstab, or
+	- using 'chmod 0666 /dev/pts/ptmx'
+
+4. If multi-instance mode mount is needed for containers, but the system
+   startup scripts have not yet been updated, container-startup scripts
+   should bind mount /dev/ptmx to /dev/pts/ptmx to avoid breaking single-
+   instance mounts.
+
+   Or, in general, container-startup scripts should use:
+
+	mount -t devpts -o newinstance -o ptmxmode=0666 devpts /dev/pts
+	if [ ! -L /dev/ptmx ]; then
+		mount -o bind /dev/pts/ptmx /dev/ptmx
+	fi
+
+   When all devpts mounts are multi-instance, /dev/ptmx can permanently be
+   a symlink to pts/ptmx and the bind mount can be ignored.
+
+5. A multi-instance mount that is not accompanied by the /dev/ptmx to
+   /dev/pts/ptmx redirection would result in an unusable/unreachable pty.
+
+	mount -t devpts -o newinstance lxcpts /dev/pts
+
+   immediately followed by:
+
+	open("/dev/ptmx")
+
+    would create a pty, say /dev/pts/7, in the initial kernel mount.
+    But /dev/pts/7 would be invisible in the new mount.
+
+6. The permissions for /dev/pts/ptmx node should be specified when mounting
+   /dev/pts, using the '-o ptmxmode=%o' mount option (default is 0000).
+
+	mount -t devpts -o newinstance -o ptmxmode=0644 devpts /dev/pts
+
+   The permissions can be later be changed as usual with 'chmod'.
+
+	chmod 666 /dev/pts/ptmx
+
+7. A mount of devpts without the 'newinstance' option results in binding to
+   initial kernel mount.  This behavior while preserving legacy semantics,
+   does not provide strict isolation in a container environment. i.e by
+   mounting devpts without the 'newinstance' option, a container could
+   get visibility into the 'host' or root container's devpts.
+   
+   To workaround this and have strict isolation, all mounts of devpts,
+   including the mount in the root container, should use the newinstance
+   option.
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 755adf745dad..99197213c7b1 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -443,6 +443,17 @@ config UNIX98_PTYS
 	  All modern Linux systems use the Unix98 ptys.  Say Y unless
 	  you're on an embedded system and want to conserve memory.
 
+config DEVPTS_MULTIPLE_INSTANCES
+	bool "Support multiple instances of devpts"
+	depends on UNIX98_PTYS
+	default n
+	---help---
+	  Enable support for multiple instances of devpts filesystem.
+	  If you want to have isolated PTY namespaces (eg: in containers),
+	  say Y here.  Otherwise, say N. If enabled, each mount of devpts
+	  filesystem with the '-o newinstance' option will create an
+	  independent PTY namespace.
+
 config LEGACY_PTYS
 	bool "Legacy (BSD) PTY support"
 	default y
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 5b819b12675a..65f88ef7dbce 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -529,7 +529,7 @@ static void hvc_set_winsz(struct work_struct *work)
 	tty = tty_kref_get(hp->tty);
 	spin_unlock_irqrestore(&hp->lock, hvc_flags);
 
-	tty_do_resize(tty, tty, &ws);
+	tty_do_resize(tty, &ws);
 	tty_kref_put(tty);
 }
 
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index efbfe9612658..3922a084205e 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -47,8 +47,8 @@
 #include <linux/bitops.h>
 #include <linux/audit.h>
 #include <linux/file.h>
+#include <linux/uaccess.h>
 
-#include <asm/uaccess.h>
 #include <asm/system.h>
 
 /* number of characters left in xmit buffer before select has we have room */
@@ -62,6 +62,17 @@
 #define TTY_THRESHOLD_THROTTLE		128 /* now based on remaining room */
 #define TTY_THRESHOLD_UNTHROTTLE 	128
 
+/*
+ * Special byte codes used in the echo buffer to represent operations
+ * or special handling of characters.  Bytes in the echo buffer that
+ * are not part of such special blocks are treated as normal character
+ * codes.
+ */
+#define ECHO_OP_START 0xff
+#define ECHO_OP_MOVE_BACK_COL 0x80
+#define ECHO_OP_SET_CANON_COL 0x81
+#define ECHO_OP_ERASE_TAB 0x82
+
 static inline unsigned char *alloc_buf(void)
 {
 	gfp_t prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
@@ -169,6 +180,7 @@ static void check_unthrottle(struct tty_struct *tty)
  *
  *	Locking: tty_read_lock for read fields.
  */
+
 static void reset_buffer_flags(struct tty_struct *tty)
 {
 	unsigned long flags;
@@ -176,6 +188,11 @@ static void reset_buffer_flags(struct tty_struct *tty)
 	spin_lock_irqsave(&tty->read_lock, flags);
 	tty->read_head = tty->read_tail = tty->read_cnt = 0;
 	spin_unlock_irqrestore(&tty->read_lock, flags);
+
+	mutex_lock(&tty->echo_lock);
+	tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0;
+	mutex_unlock(&tty->echo_lock);
+
 	tty->canon_head = tty->canon_data = tty->erasing = 0;
 	memset(&tty->read_flags, 0, sizeof tty->read_flags);
 	n_tty_set_room(tty);
@@ -266,89 +283,118 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
 }
 
 /**
- *	opost			-	output post processor
+ *	do_output_char			-	output one character
  *	@c: character (or partial unicode symbol)
  *	@tty: terminal device
+ *	@space: space available in tty driver write buffer
  *
- *	Perform OPOST processing.  Returns -1 when the output device is
- *	full and the character must be retried. Note that Linux currently
- *	ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't
- *	relevant in the world today. If you ever need them, add them here.
+ *	This is a helper function that handles one output character
+ *	(including special characters like TAB, CR, LF, etc.),
+ *	putting the results in the tty driver's write buffer.
+ *
+ *	Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
+ *	and NLDLY.  They simply aren't relevant in the world today.
+ *	If you ever need them, add them here.
+ *
+ *	Returns the number of bytes of buffer space used or -1 if
+ *	no space left.
  *
- *	Called from both the receive and transmit sides and can be called
- *	re-entrantly. Relies on lock_kernel() for tty->column state.
+ *	Locking: should be called under the output_lock to protect
+ *		 the column state and space left in the buffer
  */
 
-static int opost(unsigned char c, struct tty_struct *tty)
+static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
 {
-	int	space, spaces;
+	int	spaces;
 
-	space = tty_write_room(tty);
 	if (!space)
 		return -1;
 
-	lock_kernel();
-	if (O_OPOST(tty)) {
-		switch (c) {
-		case '\n':
-			if (O_ONLRET(tty))
-				tty->column = 0;
-			if (O_ONLCR(tty)) {
-				if (space < 2) {
-					unlock_kernel();
-					return -1;
-				}
-				tty_put_char(tty, '\r');
-				tty->column = 0;
-			}
-			tty->canon_column = tty->column;
-			break;
-		case '\r':
-			if (O_ONOCR(tty) && tty->column == 0) {
-				unlock_kernel();
-				return 0;
-			}
-			if (O_OCRNL(tty)) {
-				c = '\n';
-				if (O_ONLRET(tty))
-					tty->canon_column = tty->column = 0;
-				break;
-			}
+	switch (c) {
+	case '\n':
+		if (O_ONLRET(tty))
+			tty->column = 0;
+		if (O_ONLCR(tty)) {
+			if (space < 2)
+				return -1;
 			tty->canon_column = tty->column = 0;
+			tty_put_char(tty, '\r');
+			tty_put_char(tty, c);
+			return 2;
+		}
+		tty->canon_column = tty->column;
+		break;
+	case '\r':
+		if (O_ONOCR(tty) && tty->column == 0)
+			return 0;
+		if (O_OCRNL(tty)) {
+			c = '\n';
+			if (O_ONLRET(tty))
+				tty->canon_column = tty->column = 0;
 			break;
-		case '\t':
-			spaces = 8 - (tty->column & 7);
-			if (O_TABDLY(tty) == XTABS) {
-				if (space < spaces) {
-					unlock_kernel();
-					return -1;
-				}
-				tty->column += spaces;
-				tty->ops->write(tty, "        ", spaces);
-				unlock_kernel();
-				return 0;
-			}
+		}
+		tty->canon_column = tty->column = 0;
+		break;
+	case '\t':
+		spaces = 8 - (tty->column & 7);
+		if (O_TABDLY(tty) == XTABS) {
+			if (space < spaces)
+				return -1;
 			tty->column += spaces;
-			break;
-		case '\b':
-			if (tty->column > 0)
-				tty->column--;
-			break;
-		default:
+			tty->ops->write(tty, "        ", spaces);
+			return spaces;
+		}
+		tty->column += spaces;
+		break;
+	case '\b':
+		if (tty->column > 0)
+			tty->column--;
+		break;
+	default:
+		if (!iscntrl(c)) {
 			if (O_OLCUC(tty))
 				c = toupper(c);
-			if (!iscntrl(c) && !is_continuation(c, tty))
+			if (!is_continuation(c, tty))
 				tty->column++;
-			break;
 		}
+		break;
 	}
+
 	tty_put_char(tty, c);
-	unlock_kernel();
-	return 0;
+	return 1;
 }
 
 /**
- *	opost_block		-	block postprocess
+ *	process_output			-	output post processor
+ *	@c: character (or partial unicode symbol)
+ *	@tty: terminal device
+ *
+ *	Perform OPOST processing.  Returns -1 when the output device is
+ *	full and the character must be retried.
+ *
+ *	Locking: output_lock to protect column state and space left
+ *		 (also, this is called from n_tty_write under the
+ *		  tty layer write lock)
+ */
+
+static int process_output(unsigned char c, struct tty_struct *tty)
+{
+	int	space, retval;
+
+	mutex_lock(&tty->output_lock);
+
+	space = tty_write_room(tty);
+	retval = do_output_char(c, tty, space);
+
+	mutex_unlock(&tty->output_lock);
+	if (retval < 0)
+		return -1;
+	else
+		return 0;
+}
+
+/**
+ *	process_output_block		-	block post processor
  *	@tty: terminal device
  *	@inbuf: user buffer
  *	@nr: number of bytes
@@ -358,26 +404,32 @@ static int opost(unsigned char c, struct tty_struct *tty)
  *	the simple cases normally found and helps to generate blocks of
  *	symbols for the console driver and thus improve performance.
  *
- *	Called from n_tty_write under the tty layer write lock. Relies
- *	on lock_kernel for the tty->column state.
+ *	Locking: output_lock to protect column state and space left
+ *		 (also, this is called from n_tty_write under the
+ *		  tty layer write lock)
  */
 
-static ssize_t opost_block(struct tty_struct *tty,
-		       const unsigned char *buf, unsigned int nr)
+static ssize_t process_output_block(struct tty_struct *tty,
+				    const unsigned char *buf, unsigned int nr)
 {
 	int	space;
 	int 	i;
 	const unsigned char *cp;
 
+	mutex_lock(&tty->output_lock);
+
 	space = tty_write_room(tty);
-	if (!space)
+	if (!space) {
+		mutex_unlock(&tty->output_lock);
 		return 0;
+	}
 	if (nr > space)
 		nr = space;
 
-	lock_kernel();
 	for (i = 0, cp = buf; i < nr; i++, cp++) {
-		switch (*cp) {
+		unsigned char c = *cp;
+
+		switch (c) {
 		case '\n':
 			if (O_ONLRET(tty))
 				tty->column = 0;
@@ -399,54 +451,403 @@ static ssize_t opost_block(struct tty_struct *tty,
 				tty->column--;
 			break;
 		default:
-			if (O_OLCUC(tty))
-				goto break_out;
-			if (!iscntrl(*cp))
-				tty->column++;
+			if (!iscntrl(c)) {
+				if (O_OLCUC(tty))
+					goto break_out;
+				if (!is_continuation(c, tty))
+					tty->column++;
+			}
 			break;
 		}
 	}
 break_out:
-	if (tty->ops->flush_chars)
-		tty->ops->flush_chars(tty);
 	i = tty->ops->write(tty, buf, i);
-	unlock_kernel();
+
+	mutex_unlock(&tty->output_lock);
 	return i;
 }
 
+/**
+ *	process_echoes	-	write pending echo characters
+ *	@tty: terminal device
+ *
+ *	Write previously buffered echo (and other ldisc-generated)
+ *	characters to the tty.
+ *
+ *	Characters generated by the ldisc (including echoes) need to
+ *	be buffered because the driver's write buffer can fill during
+ *	heavy program output.  Echoing straight to the driver will
+ *	often fail under these conditions, causing lost characters and
+ *	resulting mismatches of ldisc state information.
+ *
+ *	Since the ldisc state must represent the characters actually sent
+ *	to the driver at the time of the write, operations like certain
+ *	changes in column state are also saved in the buffer and executed
+ *	here.
+ *
+ *	A circular fifo buffer is used so that the most recent characters
+ *	are prioritized.  Also, when control characters are echoed with a
+ *	prefixed "^", the pair is treated atomically and thus not separated.
+ *
+ *	Locking: output_lock to protect column state and space left,
+ *		 echo_lock to protect the echo buffer
+ */
+
+static void process_echoes(struct tty_struct *tty)
+{
+	int	space, nr;
+	unsigned char c;
+	unsigned char *cp, *buf_end;
+
+	if (!tty->echo_cnt)
+		return;
+
+	mutex_lock(&tty->output_lock);
+	mutex_lock(&tty->echo_lock);
+
+	space = tty_write_room(tty);
+
+	buf_end = tty->echo_buf + N_TTY_BUF_SIZE;
+	cp = tty->echo_buf + tty->echo_pos;
+	nr = tty->echo_cnt;
+	while (nr > 0) {
+		c = *cp;
+		if (c == ECHO_OP_START) {
+			unsigned char op;
+			unsigned char *opp;
+			int no_space_left = 0;
+
+			/*
+			 * If the buffer byte is the start of a multi-byte
+			 * operation, get the next byte, which is either the
+			 * op code or a control character value.
+			 */
+			opp = cp + 1;
+			if (opp == buf_end)
+				opp -= N_TTY_BUF_SIZE;
+			op = *opp;
+
+			switch (op) {
+				unsigned int num_chars, num_bs;
+
+			case ECHO_OP_ERASE_TAB:
+				if (++opp == buf_end)
+					opp -= N_TTY_BUF_SIZE;
+				num_chars = *opp;
+
+				/*
+				 * Determine how many columns to go back
+				 * in order to erase the tab.
+				 * This depends on the number of columns
+				 * used by other characters within the tab
+				 * area.  If this (modulo 8) count is from
+				 * the start of input rather than from a
+				 * previous tab, we offset by canon column.
+				 * Otherwise, tab spacing is normal.
+				 */
+				if (!(num_chars & 0x80))
+					num_chars += tty->canon_column;
+				num_bs = 8 - (num_chars & 7);
+
+				if (num_bs > space) {
+					no_space_left = 1;
+					break;
+				}
+				space -= num_bs;
+				while (num_bs--) {
+					tty_put_char(tty, '\b');
+					if (tty->column > 0)
+						tty->column--;
+				}
+				cp += 3;
+				nr -= 3;
+				break;
+
+			case ECHO_OP_SET_CANON_COL:
+				tty->canon_column = tty->column;
+				cp += 2;
+				nr -= 2;
+				break;
+
+			case ECHO_OP_MOVE_BACK_COL:
+				if (tty->column > 0)
+					tty->column--;
+				cp += 2;
+				nr -= 2;
+				break;
+
+			case ECHO_OP_START:
+				/* This is an escaped echo op start code */
+				if (!space) {
+					no_space_left = 1;
+					break;
+				}
+				tty_put_char(tty, ECHO_OP_START);
+				tty->column++;
+				space--;
+				cp += 2;
+				nr -= 2;
+				break;
+
+			default:
+				if (iscntrl(op)) {
+					if (L_ECHOCTL(tty)) {
+						/*
+						 * Ensure there is enough space
+						 * for the whole ctrl pair.
+						 */
+						if (space < 2) {
+							no_space_left = 1;
+							break;
+						}
+						tty_put_char(tty, '^');
+						tty_put_char(tty, op ^ 0100);
+						tty->column += 2;
+						space -= 2;
+					} else {
+						if (!space) {
+							no_space_left = 1;
+							break;
+						}
+						tty_put_char(tty, op);
+						space--;
+					}
+				}
+				/*
+				 * If above falls through, this was an
+				 * undefined op.
+				 */
+				cp += 2;
+				nr -= 2;
+			}
+
+			if (no_space_left)
+				break;
+		} else {
+			int retval;
+
+			retval = do_output_char(c, tty, space);
+			if (retval < 0)
+				break;
+			space -= retval;
+			cp += 1;
+			nr -= 1;
+		}
+
+		/* When end of circular buffer reached, wrap around */
+		if (cp >= buf_end)
+			cp -= N_TTY_BUF_SIZE;
+	}
+
+	if (nr == 0) {
+		tty->echo_pos = 0;
+		tty->echo_cnt = 0;
+		tty->echo_overrun = 0;
+	} else {
+		int num_processed = tty->echo_cnt - nr;
+		tty->echo_pos += num_processed;
+		tty->echo_pos &= N_TTY_BUF_SIZE - 1;
+		tty->echo_cnt = nr;
+		if (num_processed > 0)
+			tty->echo_overrun = 0;
+	}
+
+	mutex_unlock(&tty->echo_lock);
+	mutex_unlock(&tty->output_lock);
+
+	if (tty->ops->flush_chars)
+		tty->ops->flush_chars(tty);
+}
+
+/**
+ *	add_echo_byte	-	add a byte to the echo buffer
+ *	@c: unicode byte to echo
+ *	@tty: terminal device
+ *
+ *	Add a character or operation byte to the echo buffer.
+ *
+ *	Should be called under the echo lock to protect the echo buffer.
+ */
+
+static void add_echo_byte(unsigned char c, struct tty_struct *tty)
+{
+	int	new_byte_pos;
+
+	if (tty->echo_cnt == N_TTY_BUF_SIZE) {
+		/* Circular buffer is already at capacity */
+		new_byte_pos = tty->echo_pos;
+
+		/*
+		 * Since the buffer start position needs to be advanced,
+		 * be sure to step by a whole operation byte group.
+		 */
+		if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) {
+			if (tty->echo_buf[(tty->echo_pos + 1) &
+					  (N_TTY_BUF_SIZE - 1)] ==
+						ECHO_OP_ERASE_TAB) {
+				tty->echo_pos += 3;
+				tty->echo_cnt -= 2;
+			} else {
+				tty->echo_pos += 2;
+				tty->echo_cnt -= 1;
+			}
+		} else {
+			tty->echo_pos++;
+		}
+		tty->echo_pos &= N_TTY_BUF_SIZE - 1;
+
+		tty->echo_overrun = 1;
+	} else {
+		new_byte_pos = tty->echo_pos + tty->echo_cnt;
+		new_byte_pos &= N_TTY_BUF_SIZE - 1;
+		tty->echo_cnt++;
+	}
+
+	tty->echo_buf[new_byte_pos] = c;
+}
+
+/**
+ *	echo_move_back_col	-	add operation to move back a column
+ *	@tty: terminal device
+ *
+ *	Add an operation to the echo buffer to move back one column.
+ *
+ *	Locking: echo_lock to protect the echo buffer
+ */
+
+static void echo_move_back_col(struct tty_struct *tty)
+{
+	mutex_lock(&tty->echo_lock);
+
+	add_echo_byte(ECHO_OP_START, tty);
+	add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty);
+
+	mutex_unlock(&tty->echo_lock);
+}
+
+/**
+ *	echo_set_canon_col	-	add operation to set the canon column
+ *	@tty: terminal device
+ *
+ *	Add an operation to the echo buffer to set the canon column
+ *	to the current column.
+ *
+ *	Locking: echo_lock to protect the echo buffer
+ */
+
+static void echo_set_canon_col(struct tty_struct *tty)
+{
+	mutex_lock(&tty->echo_lock);
+
+	add_echo_byte(ECHO_OP_START, tty);
+	add_echo_byte(ECHO_OP_SET_CANON_COL, tty);
+
+	mutex_unlock(&tty->echo_lock);
+}
+
+/**
+ *	echo_erase_tab	-	add operation to erase a tab
+ *	@num_chars: number of character columns already used
+ *	@after_tab: true if num_chars starts after a previous tab
+ *	@tty: terminal device
+ *
+ *	Add an operation to the echo buffer to erase a tab.
+ *
+ *	Called by the eraser function, which knows how many character
+ *	columns have been used since either a previous tab or the start
+ *	of input.  This information will be used later, along with
+ *	canon column (if applicable), to go back the correct number
+ *	of columns.
+ *
+ *	Locking: echo_lock to protect the echo buffer
+ */
+
+static void echo_erase_tab(unsigned int num_chars, int after_tab,
+			   struct tty_struct *tty)
+{
+	mutex_lock(&tty->echo_lock);
+
+	add_echo_byte(ECHO_OP_START, tty);
+	add_echo_byte(ECHO_OP_ERASE_TAB, tty);
+
+	/* We only need to know this modulo 8 (tab spacing) */
+	num_chars &= 7;
+
+	/* Set the high bit as a flag if num_chars is after a previous tab */
+	if (after_tab)
+		num_chars |= 0x80;
+
+	add_echo_byte(num_chars, tty);
+
+	mutex_unlock(&tty->echo_lock);
+}
+
+/**
+ *	echo_char_raw	-	echo a character raw
+ *	@c: unicode byte to echo
+ *	@tty: terminal device
+ *
+ *	Echo user input back onto the screen. This must be called only when
+ *	L_ECHO(tty) is true. Called from the driver receive_buf path.
+ *
+ *	This variant does not treat control characters specially.
+ *
+ *	Locking: echo_lock to protect the echo buffer
+ */
+
+static void echo_char_raw(unsigned char c, struct tty_struct *tty)
+{
+	mutex_lock(&tty->echo_lock);
+
+	if (c == ECHO_OP_START) {
+		add_echo_byte(ECHO_OP_START, tty);
+		add_echo_byte(ECHO_OP_START, tty);
+	} else {
+		add_echo_byte(c, tty);
+	}
+
+	mutex_unlock(&tty->echo_lock);
+}
 
 /**
- *	echo_char	-	echo characters
+ *	echo_char	-	echo a character
  *	@c: unicode byte to echo
  *	@tty: terminal device
  *
  *	Echo user input back onto the screen. This must be called only when
  *	L_ECHO(tty) is true. Called from the driver receive_buf path.
  *
- *	Relies on BKL for tty column locking
+ *	This variant tags control characters to be possibly echoed as
+ *	as "^X" (where X is the letter representing the control char).
+ *
+ *	Locking: echo_lock to protect the echo buffer
  */
 
 static void echo_char(unsigned char c, struct tty_struct *tty)
 {
-	if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
-		tty_put_char(tty, '^');
-		tty_put_char(tty, c ^ 0100);
-		tty->column += 2;
-	} else
-		opost(c, tty);
+	mutex_lock(&tty->echo_lock);
+
+	if (c == ECHO_OP_START) {
+		add_echo_byte(ECHO_OP_START, tty);
+		add_echo_byte(ECHO_OP_START, tty);
+	} else {
+		if (iscntrl(c) && c != '\t')
+			add_echo_byte(ECHO_OP_START, tty);
+		add_echo_byte(c, tty);
+	}
+
+	mutex_unlock(&tty->echo_lock);
 }
 
 /**
- *	finsh_erasing		-	complete erase
+ *	finish_erasing		-	complete erase
  *	@tty: tty doing the erase
- *
- *	Relies on BKL for tty column locking
  */
+
 static inline void finish_erasing(struct tty_struct *tty)
 {
 	if (tty->erasing) {
-		tty_put_char(tty, '/');
-		tty->column++;
+		echo_char_raw('/', tty);
 		tty->erasing = 0;
 	}
 }
@@ -460,7 +861,7 @@ static inline void finish_erasing(struct tty_struct *tty)
  *	present in the stream from the driver layer. Handles the complexities
  *	of UTF-8 multibyte symbols.
  *
- *	Locking: read_lock for tty buffers, BKL for column/erasing state
+ *	Locking: read_lock for tty buffers
  */
 
 static void eraser(unsigned char c, struct tty_struct *tty)
@@ -471,7 +872,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
 
 	/* FIXME: locking needed ? */
 	if (tty->read_head == tty->canon_head) {
-		/* opost('\a', tty); */		/* what do you think? */
+		/* process_output('\a', tty); */ /* what do you think? */
 		return;
 	}
 	if (c == ERASE_CHAR(tty))
@@ -497,7 +898,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
 			echo_char(KILL_CHAR(tty), tty);
 			/* Add a newline if ECHOK is on and ECHOKE is off. */
 			if (L_ECHOK(tty))
-				opost('\n', tty);
+				echo_char_raw('\n', tty);
 			return;
 		}
 		kill_type = KILL;
@@ -533,67 +934,61 @@ static void eraser(unsigned char c, struct tty_struct *tty)
 		if (L_ECHO(tty)) {
 			if (L_ECHOPRT(tty)) {
 				if (!tty->erasing) {
-					tty_put_char(tty, '\\');
-					tty->column++;
+					echo_char_raw('\\', tty);
 					tty->erasing = 1;
 				}
 				/* if cnt > 1, output a multi-byte character */
 				echo_char(c, tty);
 				while (--cnt > 0) {
 					head = (head+1) & (N_TTY_BUF_SIZE-1);
-					tty_put_char(tty, tty->read_buf[head]);
+					echo_char_raw(tty->read_buf[head], tty);
+					echo_move_back_col(tty);
 				}
 			} else if (kill_type == ERASE && !L_ECHOE(tty)) {
 				echo_char(ERASE_CHAR(tty), tty);
 			} else if (c == '\t') {
-				unsigned int col = tty->canon_column;
-				unsigned long tail = tty->canon_head;
-
-				/* Find the column of the last char. */
-				while (tail != tty->read_head) {
+				unsigned int num_chars = 0;
+				int after_tab = 0;
+				unsigned long tail = tty->read_head;
+
+				/*
+				 * Count the columns used for characters
+				 * since the start of input or after a
+				 * previous tab.
+				 * This info is used to go back the correct
+				 * number of columns.
+				 */
+				while (tail != tty->canon_head) {
+					tail = (tail-1) & (N_TTY_BUF_SIZE-1);
 					c = tty->read_buf[tail];
-					if (c == '\t')
-						col = (col | 7) + 1;
-					else if (iscntrl(c)) {
+					if (c == '\t') {
+						after_tab = 1;
+						break;
+					} else if (iscntrl(c)) {
 						if (L_ECHOCTL(tty))
-							col += 2;
-					} else if (!is_continuation(c, tty))
-						col++;
-					tail = (tail+1) & (N_TTY_BUF_SIZE-1);
-				}
-
-				/* should never happen */
-				if (tty->column > 0x80000000)
-					tty->column = 0;
-
-				/* Now backup to that column. */
-				while (tty->column > col) {
-					/* Can't use opost here. */
-					tty_put_char(tty, '\b');
-					if (tty->column > 0)
-						tty->column--;
+							num_chars += 2;
+					} else if (!is_continuation(c, tty)) {
+						num_chars++;
+					}
 				}
+				echo_erase_tab(num_chars, after_tab, tty);
 			} else {
 				if (iscntrl(c) && L_ECHOCTL(tty)) {
-					tty_put_char(tty, '\b');
-					tty_put_char(tty, ' ');
-					tty_put_char(tty, '\b');
-					if (tty->column > 0)
-						tty->column--;
+					echo_char_raw('\b', tty);
+					echo_char_raw(' ', tty);
+					echo_char_raw('\b', tty);
 				}
 				if (!iscntrl(c) || L_ECHOCTL(tty)) {
-					tty_put_char(tty, '\b');
-					tty_put_char(tty, ' ');
-					tty_put_char(tty, '\b');
-					if (tty->column > 0)
-						tty->column--;
+					echo_char_raw('\b', tty);
+					echo_char_raw(' ', tty);
+					echo_char_raw('\b', tty);
 				}
 			}
 		}
 		if (kill_type == ERASE)
 			break;
 	}
-	if (tty->read_head == tty->canon_head)
+	if (tty->read_head == tty->canon_head && L_ECHO(tty))
 		finish_erasing(tty);
 }
 
@@ -712,6 +1107,7 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty,
 static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 {
 	unsigned long flags;
+	int parmrk;
 
 	if (tty->raw) {
 		put_tty_queue(c, tty);
@@ -721,18 +1117,21 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 	if (I_ISTRIP(tty))
 		c &= 0x7f;
 	if (I_IUCLC(tty) && L_IEXTEN(tty))
-		c=tolower(c);
+		c = tolower(c);
 
 	if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
-	    ((I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty)) ||
-	     c == INTR_CHAR(tty) || c == QUIT_CHAR(tty) || c == SUSP_CHAR(tty)))
+	    I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
+	    c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
 		start_tty(tty);
+		process_echoes(tty);
+	}
 
 	if (tty->closing) {
 		if (I_IXON(tty)) {
-			if (c == START_CHAR(tty))
+			if (c == START_CHAR(tty)) {
 				start_tty(tty);
-			else if (c == STOP_CHAR(tty))
+				process_echoes(tty);
+			} else if (c == STOP_CHAR(tty))
 				stop_tty(tty);
 		}
 		return;
@@ -745,19 +1144,23 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 	 * up.
 	 */
 	if (!test_bit(c, tty->process_char_map) || tty->lnext) {
-		finish_erasing(tty);
 		tty->lnext = 0;
+		parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
+		if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
+			/* beep if no space */
+			if (L_ECHO(tty))
+				process_output('\a', tty);
+			return;
+		}
 		if (L_ECHO(tty)) {
-			if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
-				tty_put_char(tty, '\a'); /* beep if no space */
-				return;
-			}
+			finish_erasing(tty);
 			/* Record the column of first canon char. */
 			if (tty->canon_head == tty->read_head)
-				tty->canon_column = tty->column;
+				echo_set_canon_col(tty);
 			echo_char(c, tty);
+			process_echoes(tty);
 		}
-		if (I_PARMRK(tty) && c == (unsigned char) '\377')
+		if (parmrk)
 			put_tty_queue(c, tty);
 		put_tty_queue(c, tty);
 		return;
@@ -766,6 +1169,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 	if (I_IXON(tty)) {
 		if (c == START_CHAR(tty)) {
 			start_tty(tty);
+			process_echoes(tty);
 			return;
 		}
 		if (c == STOP_CHAR(tty)) {
@@ -786,7 +1190,6 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 		if (c == SUSP_CHAR(tty)) {
 send_signal:
 			/*
-			 * Echo character, and then send the signal.
 			 * Note that we do not use isig() here because we want
 			 * the order to be:
 			 * 1) flush, 2) echo, 3) signal
@@ -795,8 +1198,12 @@ send_signal:
 				n_tty_flush_buffer(tty);
 				tty_driver_flush_buffer(tty);
 			}
-			if (L_ECHO(tty))
+			if (I_IXON(tty))
+				start_tty(tty);
+			if (L_ECHO(tty)) {
 				echo_char(c, tty);
+				process_echoes(tty);
+			}
 			if (tty->pgrp)
 				kill_pgrp(tty->pgrp, signal, 1);
 			return;
@@ -815,6 +1222,7 @@ send_signal:
 		if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
 		    (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
 			eraser(c, tty);
+			process_echoes(tty);
 			return;
 		}
 		if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
@@ -822,8 +1230,9 @@ send_signal:
 			if (L_ECHO(tty)) {
 				finish_erasing(tty);
 				if (L_ECHOCTL(tty)) {
-					tty_put_char(tty, '^');
-					tty_put_char(tty, '\b');
+					echo_char_raw('^', tty);
+					echo_char_raw('\b', tty);
+					process_echoes(tty);
 				}
 			}
 			return;
@@ -834,22 +1243,29 @@ send_signal:
 
 			finish_erasing(tty);
 			echo_char(c, tty);
-			opost('\n', tty);
+			echo_char_raw('\n', tty);
 			while (tail != tty->read_head) {
 				echo_char(tty->read_buf[tail], tty);
 				tail = (tail+1) & (N_TTY_BUF_SIZE-1);
 			}
+			process_echoes(tty);
 			return;
 		}
 		if (c == '\n') {
+			if (tty->read_cnt >= N_TTY_BUF_SIZE) {
+				if (L_ECHO(tty))
+					process_output('\a', tty);
+				return;
+			}
 			if (L_ECHO(tty) || L_ECHONL(tty)) {
-				if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
-					tty_put_char(tty, '\a');
-				opost('\n', tty);
+				echo_char_raw('\n', tty);
+				process_echoes(tty);
 			}
 			goto handle_newline;
 		}
 		if (c == EOF_CHAR(tty)) {
+			if (tty->read_cnt >= N_TTY_BUF_SIZE)
+				return;
 			if (tty->canon_head != tty->read_head)
 				set_bit(TTY_PUSH, &tty->flags);
 			c = __DISABLED_CHAR;
@@ -857,22 +1273,28 @@ send_signal:
 		}
 		if ((c == EOL_CHAR(tty)) ||
 		    (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
+			parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
+				 ? 1 : 0;
+			if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
+				if (L_ECHO(tty))
+					process_output('\a', tty);
+				return;
+			}
 			/*
 			 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
 			 */
 			if (L_ECHO(tty)) {
-				if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
-					tty_put_char(tty, '\a');
 				/* Record the column of first canon char. */
 				if (tty->canon_head == tty->read_head)
-					tty->canon_column = tty->column;
+					echo_set_canon_col(tty);
 				echo_char(c, tty);
+				process_echoes(tty);
 			}
 			/*
 			 * XXX does PARMRK doubling happen for
 			 * EOL_CHAR and EOL2_CHAR?
 			 */
-			if (I_PARMRK(tty) && c == (unsigned char) '\377')
+			if (parmrk)
 				put_tty_queue(c, tty);
 
 handle_newline:
@@ -889,23 +1311,27 @@ handle_newline:
 		}
 	}
 
-	finish_erasing(tty);
+	parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
+	if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
+		/* beep if no space */
+		if (L_ECHO(tty))
+			process_output('\a', tty);
+		return;
+	}
 	if (L_ECHO(tty)) {
-		if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
-			tty_put_char(tty, '\a'); /* beep if no space */
-			return;
-		}
+		finish_erasing(tty);
 		if (c == '\n')
-			opost('\n', tty);
+			echo_char_raw('\n', tty);
 		else {
 			/* Record the column of first canon char. */
 			if (tty->canon_head == tty->read_head)
-				tty->canon_column = tty->column;
+				echo_set_canon_col(tty);
 			echo_char(c, tty);
 		}
+		process_echoes(tty);
 	}
 
-	if (I_PARMRK(tty) && c == (unsigned char) '\377')
+	if (parmrk)
 		put_tty_queue(c, tty);
 
 	put_tty_queue(c, tty);
@@ -923,6 +1349,9 @@ handle_newline:
 
 static void n_tty_write_wakeup(struct tty_struct *tty)
 {
+	/* Write out any echoed characters that are still pending */
+	process_echoes(tty);
+
 	if (tty->fasync) {
 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 		kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
@@ -1134,6 +1563,10 @@ static void n_tty_close(struct tty_struct *tty)
 		free_buf(tty->read_buf);
 		tty->read_buf = NULL;
 	}
+	if (tty->echo_buf) {
+		free_buf(tty->echo_buf);
+		tty->echo_buf = NULL;
+	}
 }
 
 /**
@@ -1151,13 +1584,19 @@ static int n_tty_open(struct tty_struct *tty)
 	if (!tty)
 		return -EINVAL;
 
-	/* This one is ugly. Currently a malloc failure here can panic */
+	/* These are ugly. Currently a malloc failure here can panic */
 	if (!tty->read_buf) {
 		tty->read_buf = alloc_buf();
 		if (!tty->read_buf)
 			return -ENOMEM;
 	}
+	if (!tty->echo_buf) {
+		tty->echo_buf = alloc_buf();
+		if (!tty->echo_buf)
+			return -ENOMEM;
+	}
 	memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
+	memset(tty->echo_buf, 0, N_TTY_BUF_SIZE);
 	reset_buffer_flags(tty);
 	tty->column = 0;
 	n_tty_set_termios(tty, NULL);
@@ -1487,16 +1926,23 @@ do_it_again:
  *	@buf: userspace buffer pointer
  *	@nr: size of I/O
  *
- *	Write function of the terminal device. This is serialized with
+ *	Write function of the terminal device.  This is serialized with
  *	respect to other write callers but not to termios changes, reads
- *	and other such events. We must be careful with N_TTY as the receive
- *	code will echo characters, thus calling driver write methods.
+ *	and other such events.  Since the receive code will echo characters,
+ *	thus calling driver write methods, the output_lock is used in
+ *	the output processing functions called here as well as in the
+ *	echo processing function to protect the column state and space
+ *	left in the buffer.
  *
  *	This code must be sure never to sleep through a hangup.
+ *
+ *	Locking: output_lock to protect column state and space left
+ *		 (note that the process_output*() functions take this
+ *		  lock themselves)
  */
 
 static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
-			  const unsigned char *buf, size_t nr)
+			   const unsigned char *buf, size_t nr)
 {
 	const unsigned char *b = buf;
 	DECLARE_WAITQUEUE(wait, current);
@@ -1510,6 +1956,9 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 			return retval;
 	}
 
+	/* Write out any echoed characters that are still pending */
+	process_echoes(tty);
+
 	add_wait_queue(&tty->write_wait, &wait);
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
@@ -1523,7 +1972,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 		}
 		if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
 			while (nr > 0) {
-				ssize_t num = opost_block(tty, b, nr);
+				ssize_t num = process_output_block(tty, b, nr);
 				if (num < 0) {
 					if (num == -EAGAIN)
 						break;
@@ -1535,7 +1984,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 				if (nr == 0)
 					break;
 				c = *b;
-				if (opost(c, tty) < 0)
+				if (process_output(c, tty) < 0)
 					break;
 				b++; nr--;
 			}
@@ -1663,4 +2112,3 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = {
 	.receive_buf     = n_tty_receive_buf,
 	.write_wakeup    = n_tty_write_wakeup
 };
-
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 6d4582712b1f..b5daaaa9007e 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -230,6 +230,55 @@ static void pty_set_termios(struct tty_struct *tty,
 	tty->termios->c_cflag |= (CS8 | CREAD);
 }
 
+/**
+ *	pty_do_resize		-	resize event
+ *	@tty: tty being resized
+ *	@real_tty: real tty (not the same as tty if using a pty/tty pair)
+ *	@rows: rows (character)
+ *	@cols: cols (character)
+ *
+ *	Update the termios variables and send the neccessary signals to
+ *	peform a terminal resize correctly
+ */
+
+int pty_resize(struct tty_struct *tty,  struct winsize *ws)
+{
+	struct pid *pgrp, *rpgrp;
+	unsigned long flags;
+	struct tty_struct *pty = tty->link;
+
+	/* For a PTY we need to lock the tty side */
+	mutex_lock(&tty->termios_mutex);
+	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
+		goto done;
+
+	/* Get the PID values and reference them so we can
+	   avoid holding the tty ctrl lock while sending signals.
+	   We need to lock these individually however. */
+
+	spin_lock_irqsave(&tty->ctrl_lock, flags);
+	pgrp = get_pid(tty->pgrp);
+	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+	spin_lock_irqsave(&pty->ctrl_lock, flags);
+	rpgrp = get_pid(pty->pgrp);
+	spin_unlock_irqrestore(&pty->ctrl_lock, flags);
+
+	if (pgrp)
+		kill_pgrp(pgrp, SIGWINCH, 1);
+	if (rpgrp != pgrp && rpgrp)
+		kill_pgrp(rpgrp, SIGWINCH, 1);
+
+	put_pid(pgrp);
+	put_pid(rpgrp);
+
+	tty->winsize = *ws;
+	pty->winsize = *ws;	/* Never used so will go away soon */
+done:
+	mutex_unlock(&tty->termios_mutex);
+	return 0;
+}
+
 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	struct tty_struct *o_tty;
@@ -290,6 +339,7 @@ static const struct tty_operations pty_ops = {
 	.chars_in_buffer = pty_chars_in_buffer,
 	.unthrottle = pty_unthrottle,
 	.set_termios = pty_set_termios,
+	.resize = pty_resize
 };
 
 /* Traditional BSD devices */
@@ -319,6 +369,7 @@ static const struct tty_operations pty_ops_bsd = {
 	.unthrottle = pty_unthrottle,
 	.set_termios = pty_set_termios,
 	.ioctl = pty_bsd_ioctl,
+	.resize = pty_resize
 };
 
 static void __init legacy_pty_init(void)
@@ -561,7 +612,8 @@ static const struct tty_operations ptm_unix98_ops = {
 	.unthrottle = pty_unthrottle,
 	.set_termios = pty_set_termios,
 	.ioctl = pty_unix98_ioctl,
-	.shutdown = pty_unix98_shutdown
+	.shutdown = pty_unix98_shutdown,
+	.resize = pty_resize
 };
 
 static const struct tty_operations pty_unix98_ops = {
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 59f472143f08..966be866d5f7 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1111,9 +1111,7 @@ void tty_write_message(struct tty_struct *tty, char *msg)
  *		Locks the line discipline as required
  *		Writes to the tty driver are serialized by the atomic_write_lock
  *	and are then processed in chunks to the device. The line discipline
- *	write method will not be involked in parallel for each device
- *		The line discipline write method is called under the big
- *	kernel lock for historical reasons. New code should not rely on this.
+ *	write method will not be invoked in parallel for each device.
  */
 
 static ssize_t tty_write(struct file *file, const char __user *buf,
@@ -1213,7 +1211,7 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
  *	be held until the 'fast-open' is also done. Will change once we
  *	have refcounting in the driver and per driver locking
  */
-struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
+static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
 		struct inode *inode, int idx)
 {
 	struct tty_struct *tty;
@@ -2046,7 +2044,6 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
 /**
  *	tty_do_resize		-	resize event
  *	@tty: tty being resized
- *	@real_tty: real tty (not the same as tty if using a pty/tty pair)
  *	@rows: rows (character)
  *	@cols: cols (character)
  *
@@ -2054,41 +2051,34 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
  *	peform a terminal resize correctly
  */
 
-int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
-					struct winsize *ws)
+int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
 {
-	struct pid *pgrp, *rpgrp;
+	struct pid *pgrp;
 	unsigned long flags;
 
-	/* For a PTY we need to lock the tty side */
-	mutex_lock(&real_tty->termios_mutex);
-	if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
+	/* Lock the tty */
+	mutex_lock(&tty->termios_mutex);
+	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 		goto done;
 	/* Get the PID values and reference them so we can
 	   avoid holding the tty ctrl lock while sending signals */
 	spin_lock_irqsave(&tty->ctrl_lock, flags);
 	pgrp = get_pid(tty->pgrp);
-	rpgrp = get_pid(real_tty->pgrp);
 	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 
 	if (pgrp)
 		kill_pgrp(pgrp, SIGWINCH, 1);
-	if (rpgrp != pgrp && rpgrp)
-		kill_pgrp(rpgrp, SIGWINCH, 1);
-
 	put_pid(pgrp);
-	put_pid(rpgrp);
 
 	tty->winsize = *ws;
-	real_tty->winsize = *ws;
 done:
-	mutex_unlock(&real_tty->termios_mutex);
+	mutex_unlock(&tty->termios_mutex);
 	return 0;
 }
 
 /**
  *	tiocswinsz		-	implement window size set ioctl
- *	@tty; tty
+ *	@tty; tty side of tty
  *	@arg: user buffer for result
  *
  *	Copies the user idea of the window size to the kernel. Traditionally
@@ -2101,17 +2091,16 @@ done:
  *	then calls into the default method.
  */
 
-static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
-	struct winsize __user *arg)
+static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
 {
 	struct winsize tmp_ws;
 	if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
 		return -EFAULT;
 
 	if (tty->ops->resize)
-		return tty->ops->resize(tty, real_tty, &tmp_ws);
+		return tty->ops->resize(tty, &tmp_ws);
 	else
-		return tty_do_resize(tty, real_tty, &tmp_ws);
+		return tty_do_resize(tty, &tmp_ws);
 }
 
 /**
@@ -2536,7 +2525,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case TIOCGWINSZ:
 		return tiocgwinsz(real_tty, p);
 	case TIOCSWINSZ:
-		return tiocswinsz(tty, real_tty, p);
+		return tiocswinsz(real_tty, p);
 	case TIOCCONS:
 		return real_tty != tty ? -EINVAL : tioccons(file);
 	case FIONBIO:
@@ -2781,6 +2770,8 @@ void initialize_tty_struct(struct tty_struct *tty,
 	INIT_WORK(&tty->hangup_work, do_tty_hangup);
 	mutex_init(&tty->atomic_read_lock);
 	mutex_init(&tty->atomic_write_lock);
+	mutex_init(&tty->output_lock);
+	mutex_init(&tty->echo_lock);
 	spin_lock_init(&tty->read_lock);
 	spin_lock_init(&tty->ctrl_lock);
 	INIT_LIST_HEAD(&tty->tty_files);
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index a5af6072e2b3..808a1de2adea 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -819,8 +819,8 @@ static inline int resize_screen(struct vc_data *vc, int width, int height,
  *	ctrl_lock of the tty IFF a tty is passed.
  */
 
-static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
-		struct vc_data *vc, unsigned int cols, unsigned int lines)
+static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
+				unsigned int cols, unsigned int lines)
 {
 	unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
 	unsigned int old_cols, old_rows, old_row_size, old_screen_size;
@@ -932,7 +932,7 @@ static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
 		ws.ws_row = vc->vc_rows;
 		ws.ws_col = vc->vc_cols;
 		ws.ws_ypixel = vc->vc_scan_lines;
-		tty_do_resize(tty, real_tty, &ws);
+		tty_do_resize(tty, &ws);
 	}
 
 	if (CON_IS_VISIBLE(vc))
@@ -954,13 +954,12 @@ static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
 
 int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
 {
-	return vc_do_resize(vc->vc_tty, vc->vc_tty, vc, cols, rows);
+	return vc_do_resize(vc->vc_tty, vc, cols, rows);
 }
 
 /**
  *	vt_resize		-	resize a VT
  *	@tty: tty to resize
- *	@real_tty: tty if a pty/tty pair
  *	@ws: winsize attributes
  *
  *	Resize a virtual terminal. This is called by the tty layer as we
@@ -971,14 +970,13 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
  *	termios_mutex and the tty ctrl_lock in that order.
  */
 
-int vt_resize(struct tty_struct *tty, struct tty_struct *real_tty,
-	struct winsize *ws)
+int vt_resize(struct tty_struct *tty, struct winsize *ws)
 {
 	struct vc_data *vc = tty->driver_data;
 	int ret;
 
 	acquire_console_sem();
-	ret = vc_do_resize(tty, real_tty, vc, ws->ws_col, ws->ws_row);
+	ret = vc_do_resize(tty, vc, ws->ws_col, ws->ws_row);
 	release_console_sem();
 	return ret;
 }
@@ -2679,7 +2677,7 @@ static int con_write_room(struct tty_struct *tty)
 {
 	if (tty->stopped)
 		return 0;
-	return 4096;		/* No limit, really; we're not buffering */
+	return 32768;		/* No limit, really; we're not buffering */
 }
 
 static int con_chars_in_buffer(struct tty_struct *tty)
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 569f0e2476c6..318d69dce8e1 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -22,7 +22,8 @@
 #include <linux/tty_flip.h>
 #include <linux/serial_core.h>
 
-#ifdef CONFIG_KGDB_UART
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
 #include <linux/kgdb.h>
 #include <asm/irq_regs.h>
 #endif
@@ -45,6 +46,16 @@
 static struct bfin_serial_port bfin_serial_ports[BFIN_UART_NR_PORTS];
 static int nr_active_ports = ARRAY_SIZE(bfin_serial_resource);
 
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+
+# ifndef CONFIG_SERIAL_BFIN_PIO
+#  error KGDB only support UART in PIO mode.
+# endif
+
+static int kgdboc_port_line;
+static int kgdboc_break_enabled;
+#endif
 /*
  * Setup for console. Argument comes from the menuconfig
  */
@@ -62,13 +73,17 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
 
 static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
 
+static void bfin_serial_reset_irda(struct uart_port *port);
+
 /*
  * interrupts are disabled on entry
  */
 static void bfin_serial_stop_tx(struct uart_port *port)
 {
 	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+#ifdef CONFIG_SERIAL_BFIN_DMA
 	struct circ_buf *xmit = &uart->port.info->xmit;
+#endif
 
 	while (!(UART_GET_LSR(uart) & TEMT))
 		cpu_relax();
@@ -94,6 +109,14 @@ static void bfin_serial_stop_tx(struct uart_port *port)
 static void bfin_serial_start_tx(struct uart_port *port)
 {
 	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+	struct tty_struct *tty = uart->port.info->port.tty;
+
+	/*
+	 * To avoid losting RX interrupt, we reset IR function
+	 * before sending data.
+	 */
+	if (tty->termios->c_line == N_IRDA)
+		bfin_serial_reset_irda(port);
 
 #ifdef CONFIG_SERIAL_BFIN_DMA
 	if (uart->tx_done)
@@ -110,9 +133,7 @@ static void bfin_serial_start_tx(struct uart_port *port)
 static void bfin_serial_stop_rx(struct uart_port *port)
 {
 	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
-#ifdef CONFIG_KGDB_UART
-	if (uart->port.line != CONFIG_KGDB_UART_PORT)
-#endif
+
 	UART_CLEAR_IER(uart, ERBFI);
 }
 
@@ -123,49 +144,6 @@ static void bfin_serial_enable_ms(struct uart_port *port)
 {
 }
 
-#ifdef CONFIG_KGDB_UART
-static int kgdb_entry_state;
-
-void kgdb_put_debug_char(int chr)
-{
-	struct bfin_serial_port *uart;
-
-	if (CONFIG_KGDB_UART_PORT < 0
-		|| CONFIG_KGDB_UART_PORT >= BFIN_UART_NR_PORTS)
-		uart = &bfin_serial_ports[0];
-	else
-		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
-
-	while (!(UART_GET_LSR(uart) & THRE)) {
-		SSYNC();
-	}
-
-	UART_CLEAR_DLAB(uart);
-	UART_PUT_CHAR(uart, (unsigned char)chr);
-	SSYNC();
-}
-
-int kgdb_get_debug_char(void)
-{
-	struct bfin_serial_port *uart;
-	unsigned char chr;
-
-	if (CONFIG_KGDB_UART_PORT < 0
-		|| CONFIG_KGDB_UART_PORT >= BFIN_UART_NR_PORTS)
-		uart = &bfin_serial_ports[0];
-	else
-		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
-
-	while(!(UART_GET_LSR(uart) & DR)) {
-		SSYNC();
-	}
-	UART_CLEAR_DLAB(uart);
-	chr = UART_GET_CHAR(uart);
-	SSYNC();
-
-	return chr;
-}
-#endif
 
 #if ANOMALY_05000363 && defined(CONFIG_SERIAL_BFIN_PIO)
 # define UART_GET_ANOMALY_THRESHOLD(uart)    ((uart)->anomaly_threshold)
@@ -178,7 +156,7 @@ int kgdb_get_debug_char(void)
 #ifdef CONFIG_SERIAL_BFIN_PIO
 static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 {
-	struct tty_struct *tty = uart->port.info->port.tty;
+	struct tty_struct *tty = NULL;
 	unsigned int status, ch, flg;
 	static struct timeval anomaly_start = { .tv_sec = 0 };
 
@@ -188,27 +166,18 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
  	ch = UART_GET_CHAR(uart);
  	uart->port.icount.rx++;
 
-#ifdef CONFIG_KGDB_UART
-	if (uart->port.line == CONFIG_KGDB_UART_PORT) {
-		struct pt_regs *regs = get_irq_regs();
-		if (uart->port.cons->index == CONFIG_KGDB_UART_PORT && ch == 0x1) { /* Ctrl + A */
-			kgdb_breakkey_pressed(regs);
-			return;
-		} else if (kgdb_entry_state == 0 && ch == '$') {/* connection from KGDB */
-			kgdb_entry_state = 1;
-		} else if (kgdb_entry_state == 1 && ch == 'q') {
-			kgdb_entry_state = 0;
-			kgdb_breakkey_pressed(regs);
-			return;
-		} else if (ch == 0x3) {/* Ctrl + C */
-			kgdb_entry_state = 0;
-			kgdb_breakkey_pressed(regs);
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+	if (kgdb_connected && kgdboc_port_line == uart->port.line)
+		if (ch == 0x3) {/* Ctrl + C */
+			kgdb_breakpoint();
 			return;
-		} else {
-			kgdb_entry_state = 0;
 		}
-	}
+
+	if (!uart->port.info || !uart->port.info->tty)
+		return;
 #endif
+	tty = uart->port.info->tty;
 
 	if (ANOMALY_05000363) {
 		/* The BF533 (and BF561) family of processors have a nice anomaly
@@ -250,6 +219,7 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 			return;
 
  known_good_char:
+			status &= ~BI;
 			anomaly_start.tv_sec = 0;
 		}
 	}
@@ -445,7 +415,9 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
 
 void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
 {
-	int x_pos, pos;
+	int x_pos, pos, flags;
+
+	spin_lock_irqsave(&uart->port.lock, flags);
 
 	uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel);
 	x_pos = get_dma_curr_xcount(uart->rx_dma_channel);
@@ -463,6 +435,8 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
 		uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
 	}
 
+	spin_unlock_irqrestore(&uart->port.lock, flags);
+
 	mod_timer(&(uart->rx_dma_timer), jiffies + DMA_RX_FLUSH_JIFFIES);
 }
 
@@ -497,10 +471,9 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id)
 	spin_lock(&uart->port.lock);
 	irqstat = get_dma_curr_irqstat(uart->rx_dma_channel);
 	clear_dma_irqstat(uart->rx_dma_channel);
+	bfin_serial_dma_rx_chars(uart);
 	spin_unlock(&uart->port.lock);
 
-	mod_timer(&(uart->rx_dma_timer), jiffies);
-
 	return IRQ_HANDLED;
 }
 #endif
@@ -630,16 +603,16 @@ static int bfin_serial_startup(struct uart_port *port)
 	uart->rx_dma_timer.expires = jiffies + DMA_RX_FLUSH_JIFFIES;
 	add_timer(&(uart->rx_dma_timer));
 #else
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+	if (kgdboc_port_line == uart->port.line && kgdboc_break_enabled)
+		kgdboc_break_enabled = 0;
+	else {
+# endif
 	if (request_irq(uart->port.irq, bfin_serial_rx_int, IRQF_DISABLED,
 	     "BFIN_UART_RX", uart)) {
-# ifdef	CONFIG_KGDB_UART
-		if (uart->port.line != CONFIG_KGDB_UART_PORT) {
-# endif
 		printk(KERN_NOTICE "Unable to attach BlackFin UART RX interrupt\n");
 		return -EBUSY;
-# ifdef	CONFIG_KGDB_UART
-		}
-# endif
 	}
 
 	if (request_irq
@@ -685,6 +658,10 @@ static int bfin_serial_startup(struct uart_port *port)
 		}
 	}
 # endif
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+	}
+# endif
 #endif
 	UART_SET_IER(uart, ERBFI);
 	return 0;
@@ -716,9 +693,6 @@ static void bfin_serial_shutdown(struct uart_port *port)
 		break;
 	};
 #endif
-#ifdef	CONFIG_KGDB_UART
-	if (uart->port.line != CONFIG_KGDB_UART_PORT)
-#endif
 	free_irq(uart->port.irq, uart);
 	free_irq(uart->port.irq+1, uart);
 #endif
@@ -887,6 +861,65 @@ static void bfin_serial_set_ldisc(struct uart_port *port)
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static void bfin_serial_poll_put_char(struct uart_port *port, unsigned char chr)
+{
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+
+	while (!(UART_GET_LSR(uart) & THRE))
+		cpu_relax();
+
+	UART_CLEAR_DLAB(uart);
+	UART_PUT_CHAR(uart, (unsigned char)chr);
+}
+
+static int bfin_serial_poll_get_char(struct uart_port *port)
+{
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+	unsigned char chr;
+
+	while (!(UART_GET_LSR(uart) & DR))
+		cpu_relax();
+
+	UART_CLEAR_DLAB(uart);
+	chr = UART_GET_CHAR(uart);
+
+	return chr;
+}
+#endif
+
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+static void bfin_kgdboc_port_shutdown(struct uart_port *port)
+{
+	if (kgdboc_break_enabled) {
+		kgdboc_break_enabled = 0;
+		bfin_serial_shutdown(port);
+	}
+}
+
+static int bfin_kgdboc_port_startup(struct uart_port *port)
+{
+	kgdboc_port_line = port->line;
+	kgdboc_break_enabled = !bfin_serial_startup(port);
+	return 0;
+}
+#endif
+
+static void bfin_serial_reset_irda(struct uart_port *port)
+{
+	int line = port->line;
+	unsigned short val;
+
+	val = UART_GET_GCTL(&bfin_serial_ports[line]);
+	val &= ~(IREN | RPOLC);
+	UART_PUT_GCTL(&bfin_serial_ports[line], val);
+	SSYNC();
+	val |= (IREN | RPOLC);
+	UART_PUT_GCTL(&bfin_serial_ports[line], val);
+	SSYNC();
+}
+
 static struct uart_ops bfin_serial_pops = {
 	.tx_empty	= bfin_serial_tx_empty,
 	.set_mctrl	= bfin_serial_set_mctrl,
@@ -905,6 +938,15 @@ static struct uart_ops bfin_serial_pops = {
 	.request_port	= bfin_serial_request_port,
 	.config_port	= bfin_serial_config_port,
 	.verify_port	= bfin_serial_verify_port,
+#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+	defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
+	.kgdboc_port_startup	= bfin_kgdboc_port_startup,
+	.kgdboc_port_shutdown	= bfin_kgdboc_port_shutdown,
+#endif
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_put_char	= bfin_serial_poll_put_char,
+	.poll_get_char	= bfin_serial_poll_get_char,
+#endif
 };
 
 static void __init bfin_serial_init_ports(void)
@@ -950,7 +992,7 @@ static void __init bfin_serial_init_ports(void)
 
 }
 
-#ifdef CONFIG_SERIAL_BFIN_CONSOLE
+#if defined(CONFIG_SERIAL_BFIN_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
 /*
  * If the port was already initialised (eg, by a boot loader),
  * try to determine the current setup.
@@ -994,24 +1036,20 @@ bfin_serial_console_get_options(struct bfin_serial_port *uart, int *baud,
 	}
 	pr_debug("%s:baud = %d, parity = %c, bits= %d\n", __func__, *baud, *parity, *bits);
 }
-#endif
 
-#if defined(CONFIG_SERIAL_BFIN_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
 static struct uart_driver bfin_serial_reg;
 
 static int __init
 bfin_serial_console_setup(struct console *co, char *options)
 {
 	struct bfin_serial_port *uart;
-# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	int baud = 57600;
 	int bits = 8;
 	int parity = 'n';
-#  ifdef CONFIG_SERIAL_BFIN_CTSRTS
+# ifdef CONFIG_SERIAL_BFIN_CTSRTS
 	int flow = 'r';
-#  else
+# else
 	int flow = 'n';
-#  endif
 # endif
 
 	/*
@@ -1023,16 +1061,12 @@ bfin_serial_console_setup(struct console *co, char *options)
 		co->index = 0;
 	uart = &bfin_serial_ports[co->index];
 
-# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else
 		bfin_serial_console_get_options(uart, &baud, &parity, &bits);
 
 	return uart_set_options(&uart->port, co, baud, parity, bits, flow);
-# else
-	return 0;
-# endif
 }
 #endif /* defined (CONFIG_SERIAL_BFIN_CONSOLE) ||
 				 defined (CONFIG_EARLY_PRINTK) */
@@ -1076,10 +1110,7 @@ static int __init bfin_serial_rs_console_init(void)
 {
 	bfin_serial_init_ports();
 	register_console(&bfin_serial_console);
-#ifdef CONFIG_KGDB_UART
-	kgdb_entry_state = 0;
-	init_kgdb_uart();
-#endif
+
 	return 0;
 }
 console_initcall(bfin_serial_rs_console_init);
@@ -1144,7 +1175,7 @@ struct console __init *bfin_earlyserial_init(unsigned int port,
 	return &bfin_early_serial_console;
 }
 
-#endif /* CONFIG_SERIAL_BFIN_CONSOLE */
+#endif /* CONFIG_EARLY_PRINTK */
 
 static struct uart_driver bfin_serial_reg = {
 	.owner			= THIS_MODULE,
@@ -1235,10 +1266,6 @@ static struct platform_driver bfin_serial_driver = {
 static int __init bfin_serial_init(void)
 {
 	int ret;
-#ifdef CONFIG_KGDB_UART
-	struct bfin_serial_port *uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
-	struct ktermios t;
-#endif
 
 	pr_info("Serial: Blackfin serial driver\n");
 
@@ -1252,21 +1279,6 @@ static int __init bfin_serial_init(void)
 			uart_unregister_driver(&bfin_serial_reg);
 		}
 	}
-#ifdef CONFIG_KGDB_UART
-	if (uart->port.cons->index != CONFIG_KGDB_UART_PORT) {
-		request_irq(uart->port.irq, bfin_serial_rx_int,
-			IRQF_DISABLED, "BFIN_UART_RX", uart);
-		pr_info("Request irq for kgdb uart port\n");
-		UART_SET_IER(uart, ERBFI);
-		SSYNC();
-		t.c_cflag = CS8|B57600;
-		t.c_iflag = 0;
-		t.c_oflag = 0;
-		t.c_lflag = ICANON;
-		t.c_line = CONFIG_KGDB_UART_PORT;
-		bfin_serial_set_termios(&uart->port, &t, &t);
-	}
-#endif
 	return ret;
 }
 
@@ -1276,6 +1288,7 @@ static void __exit bfin_serial_exit(void)
 	uart_unregister_driver(&bfin_serial_reg);
 }
 
+
 module_init(bfin_serial_init);
 module_exit(bfin_serial_exit);
 
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 0f2b67244af6..d9bf9a5c20ec 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -442,7 +442,7 @@ static void sierra_indat_callback(struct urb *urb)
 		    " endpoint %02x.", __func__, status, endpoint);
 	} else {
 		if (urb->actual_length) {
-		tty = tty_port_tty_get(&port->port);
+			tty = tty_port_tty_get(&port->port);
 			tty_buffer_request_room(tty, urb->actual_length);
 			tty_insert_flip_string(tty, data, urb->actual_length);
 			tty_flip_buffer_push(tty);
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 794b5ffe4397..aafa684a900f 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -269,15 +269,19 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 		return;
 	}
 
-	--port->port.count;
-	if (port->port.count == 0)
+	if (port->port.count == 1)
 		/* only call the device specific close if this
-		 * port is being closed by the last owner */
+		 * port is being closed by the last owner. Ensure we do
+		 * this before we drop the port count. The call is protected
+		 * by the port mutex
+		 */
 		port->serial->type->close(tty, port, filp);
 
-	if (port->port.count == (port->console? 1 : 0)) {
+	if (port->port.count == (port->console ? 2 : 1)) {
 		struct tty_struct *tty = tty_port_tty_get(&port->port);
 		if (tty) {
+			/* We must do this before we drop the port count to
+			   zero. */
 			if (tty->driver_data)
 				tty->driver_data = NULL;
 			tty_port_tty_set(&port->port, NULL);
@@ -285,13 +289,14 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 		}
 	}
 
-	if (port->port.count == 0) {
+	if (port->port.count == 1) {
 		mutex_lock(&port->serial->disc_mutex);
 		if (!port->serial->disconnected)
 			usb_autopm_put_interface(port->serial->interface);
 		mutex_unlock(&port->serial->disc_mutex);
 		module_put(port->serial->type->driver.owner);
 	}
+	--port->port.count;
 
 	mutex_unlock(&port->mutex);
 	usb_serial_put(port->serial);
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 4a714f6c1bed..500648544033 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -27,25 +27,32 @@
 #define DEVPTS_SUPER_MAGIC 0x1cd1
 
 #define DEVPTS_DEFAULT_MODE 0600
+/*
+ * ptmx is a new node in /dev/pts and will be unused in legacy (single-
+ * instance) mode. To prevent surprises in user space, set permissions of
+ * ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful
+ * permissions.
+ */
+#define DEVPTS_DEFAULT_PTMX_MODE 0000
 #define PTMX_MINOR	2
 
 extern int pty_limit;			/* Config limit on Unix98 ptys */
-static DEFINE_IDA(allocated_ptys);
 static DEFINE_MUTEX(allocated_ptys_lock);
 
 static struct vfsmount *devpts_mnt;
-static struct dentry *devpts_root;
 
-static struct {
+struct pts_mount_opts {
 	int setuid;
 	int setgid;
 	uid_t   uid;
 	gid_t   gid;
 	umode_t mode;
-} config = {.mode = DEVPTS_DEFAULT_MODE};
+	umode_t ptmxmode;
+	int newinstance;
+};
 
 enum {
-	Opt_uid, Opt_gid, Opt_mode,
+	Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance,
 	Opt_err
 };
 
@@ -53,18 +60,50 @@ static const match_table_t tokens = {
 	{Opt_uid, "uid=%u"},
 	{Opt_gid, "gid=%u"},
 	{Opt_mode, "mode=%o"},
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+	{Opt_ptmxmode, "ptmxmode=%o"},
+	{Opt_newinstance, "newinstance"},
+#endif
 	{Opt_err, NULL}
 };
 
-static int devpts_remount(struct super_block *sb, int *flags, char *data)
+struct pts_fs_info {
+	struct ida allocated_ptys;
+	struct pts_mount_opts mount_opts;
+	struct dentry *ptmx_dentry;
+};
+
+static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct super_block *pts_sb_from_inode(struct inode *inode)
+{
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+	if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
+		return inode->i_sb;
+#endif
+	return devpts_mnt->mnt_sb;
+}
+
+#define PARSE_MOUNT	0
+#define PARSE_REMOUNT	1
+
+static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 {
 	char *p;
 
-	config.setuid  = 0;
-	config.setgid  = 0;
-	config.uid     = 0;
-	config.gid     = 0;
-	config.mode    = DEVPTS_DEFAULT_MODE;
+	opts->setuid  = 0;
+	opts->setgid  = 0;
+	opts->uid     = 0;
+	opts->gid     = 0;
+	opts->mode    = DEVPTS_DEFAULT_MODE;
+	opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
+
+	/* newinstance makes sense only on initial mount */
+	if (op == PARSE_MOUNT)
+		opts->newinstance = 0;
 
 	while ((p = strsep(&data, ",")) != NULL) {
 		substring_t args[MAX_OPT_ARGS];
@@ -79,20 +118,32 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
 		case Opt_uid:
 			if (match_int(&args[0], &option))
 				return -EINVAL;
-			config.uid = option;
-			config.setuid = 1;
+			opts->uid = option;
+			opts->setuid = 1;
 			break;
 		case Opt_gid:
 			if (match_int(&args[0], &option))
 				return -EINVAL;
-			config.gid = option;
-			config.setgid = 1;
+			opts->gid = option;
+			opts->setgid = 1;
 			break;
 		case Opt_mode:
 			if (match_octal(&args[0], &option))
 				return -EINVAL;
-			config.mode = option & S_IALLUGO;
+			opts->mode = option & S_IALLUGO;
+			break;
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+		case Opt_ptmxmode:
+			if (match_octal(&args[0], &option))
+				return -EINVAL;
+			opts->ptmxmode = option & S_IALLUGO;
+			break;
+		case Opt_newinstance:
+			/* newinstance makes sense only on initial mount */
+			if (op == PARSE_MOUNT)
+				opts->newinstance = 1;
 			break;
+#endif
 		default:
 			printk(KERN_ERR "devpts: called with bogus options\n");
 			return -EINVAL;
@@ -102,13 +153,108 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
 	return 0;
 }
 
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+static int mknod_ptmx(struct super_block *sb)
+{
+	int mode;
+	int rc = -ENOMEM;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct dentry *root = sb->s_root;
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
+	struct pts_mount_opts *opts = &fsi->mount_opts;
+
+	mutex_lock(&root->d_inode->i_mutex);
+
+	/* If we have already created ptmx node, return */
+	if (fsi->ptmx_dentry) {
+		rc = 0;
+		goto out;
+	}
+
+	dentry = d_alloc_name(root, "ptmx");
+	if (!dentry) {
+		printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n");
+		goto out;
+	}
+
+	/*
+	 * Create a new 'ptmx' node in this mount of devpts.
+	 */
+	inode = new_inode(sb);
+	if (!inode) {
+		printk(KERN_ERR "Unable to alloc inode for ptmx node\n");
+		dput(dentry);
+		goto out;
+	}
+
+	inode->i_ino = 2;
+	inode->i_uid = inode->i_gid = 0;
+	inode->i_blocks = 0;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+
+	mode = S_IFCHR|opts->ptmxmode;
+	init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2));
+
+	d_add(dentry, inode);
+
+	fsi->ptmx_dentry = dentry;
+	rc = 0;
+
+	printk(KERN_DEBUG "Created ptmx node in devpts ino %lu\n",
+			inode->i_ino);
+out:
+	mutex_unlock(&root->d_inode->i_mutex);
+	return rc;
+}
+
+static void update_ptmx_mode(struct pts_fs_info *fsi)
+{
+	struct inode *inode;
+	if (fsi->ptmx_dentry) {
+		inode = fsi->ptmx_dentry->d_inode;
+		inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
+	}
+}
+#else
+static inline void update_ptmx_mode(struct pts_fs_info *fsi)
+{
+       return;
+}
+#endif
+
+static int devpts_remount(struct super_block *sb, int *flags, char *data)
+{
+	int err;
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
+	struct pts_mount_opts *opts = &fsi->mount_opts;
+
+	err = parse_mount_options(data, PARSE_REMOUNT, opts);
+
+	/*
+	 * parse_mount_options() restores options to default values
+	 * before parsing and may have changed ptmxmode. So, update the
+	 * mode in the inode too. Bogus options don't fail the remount,
+	 * so do this even on error return.
+	 */
+	update_ptmx_mode(fsi);
+
+	return err;
+}
+
 static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
 {
-	if (config.setuid)
-		seq_printf(seq, ",uid=%u", config.uid);
-	if (config.setgid)
-		seq_printf(seq, ",gid=%u", config.gid);
-	seq_printf(seq, ",mode=%03o", config.mode);
+	struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb);
+	struct pts_mount_opts *opts = &fsi->mount_opts;
+
+	if (opts->setuid)
+		seq_printf(seq, ",uid=%u", opts->uid);
+	if (opts->setgid)
+		seq_printf(seq, ",gid=%u", opts->gid);
+	seq_printf(seq, ",mode=%03o", opts->mode);
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+	seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode);
+#endif
 
 	return 0;
 }
@@ -119,10 +265,25 @@ static const struct super_operations devpts_sops = {
 	.show_options	= devpts_show_options,
 };
 
+static void *new_pts_fs_info(void)
+{
+	struct pts_fs_info *fsi;
+
+	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);
+	if (!fsi)
+		return NULL;
+
+	ida_init(&fsi->allocated_ptys);
+	fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
+	fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
+
+	return fsi;
+}
+
 static int
 devpts_fill_super(struct super_block *s, void *data, int silent)
 {
-	struct inode * inode;
+	struct inode *inode;
 
 	s->s_blocksize = 1024;
 	s->s_blocksize_bits = 10;
@@ -130,9 +291,13 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
 	s->s_op = &devpts_sops;
 	s->s_time_gran = 1;
 
+	s->s_fs_info = new_pts_fs_info();
+	if (!s->s_fs_info)
+		goto fail;
+
 	inode = new_inode(s);
 	if (!inode)
-		goto fail;
+		goto free_fsi;
 	inode->i_ino = 1;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 	inode->i_blocks = 0;
@@ -142,27 +307,226 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
 	inode->i_fop = &simple_dir_operations;
 	inode->i_nlink = 2;
 
-	devpts_root = s->s_root = d_alloc_root(inode);
+	s->s_root = d_alloc_root(inode);
 	if (s->s_root)
 		return 0;
-	
-	printk("devpts: get root dentry failed\n");
+
+	printk(KERN_ERR "devpts: get root dentry failed\n");
 	iput(inode);
+
+free_fsi:
+	kfree(s->s_fs_info);
 fail:
 	return -ENOMEM;
 }
 
+static int compare_init_pts_sb(struct super_block *s, void *p)
+{
+	if (devpts_mnt)
+		return devpts_mnt->mnt_sb == s;
+	return 0;
+}
+
+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+/*
+ * Safely parse the mount options in @data and update @opts.
+ *
+ * devpts ends up parsing options two times during mount, due to the
+ * two modes of operation it supports. The first parse occurs in
+ * devpts_get_sb() when determining the mode (single-instance or
+ * multi-instance mode). The second parse happens in devpts_remount()
+ * or new_pts_mount() depending on the mode.
+ *
+ * Parsing of options modifies the @data making subsequent parsing
+ * incorrect. So make a local copy of @data and parse it.
+ *
+ * Return: 0 On success, -errno on error
+ */
+static int safe_parse_mount_options(void *data, struct pts_mount_opts *opts)
+{
+	int rc;
+	void *datacp;
+
+	if (!data)
+		return 0;
+
+	/* Use kstrdup() ?  */
+	datacp = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!datacp)
+		return -ENOMEM;
+
+	memcpy(datacp, data, PAGE_SIZE);
+	rc = parse_mount_options((char *)datacp, PARSE_MOUNT, opts);
+	kfree(datacp);
+
+	return rc;
+}
+
+/*
+ * Mount a new (private) instance of devpts.  PTYs created in this
+ * instance are independent of the PTYs in other devpts instances.
+ */
+static int new_pts_mount(struct file_system_type *fs_type, int flags,
+		void *data, struct vfsmount *mnt)
+{
+	int err;
+	struct pts_fs_info *fsi;
+	struct pts_mount_opts *opts;
+
+	printk(KERN_NOTICE "devpts: newinstance mount\n");
+
+	err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt);
+	if (err)
+		return err;
+
+	fsi = DEVPTS_SB(mnt->mnt_sb);
+	opts = &fsi->mount_opts;
+
+	err = parse_mount_options(data, PARSE_MOUNT, opts);
+	if (err)
+		goto fail;
+
+	err = mknod_ptmx(mnt->mnt_sb);
+	if (err)
+		goto fail;
+
+	return 0;
+
+fail:
+	dput(mnt->mnt_sb->s_root);
+	deactivate_super(mnt->mnt_sb);
+	return err;
+}
+
+/*
+ * Check if 'newinstance' mount option was specified in @data.
+ *
+ * Return: -errno  	on error (eg: invalid mount options specified)
+ * 	 : 1 		if 'newinstance' mount option was specified
+ * 	 : 0 		if 'newinstance' mount option was NOT specified
+ */
+static int is_new_instance_mount(void *data)
+{
+	int rc;
+	struct pts_mount_opts opts;
+
+	if (!data)
+		return 0;
+
+	rc = safe_parse_mount_options(data, &opts);
+	if (!rc)
+		rc = opts.newinstance;
+
+	return rc;
+}
+
+/*
+ * get_init_pts_sb()
+ *
+ *     This interface is needed to support multiple namespace semantics in
+ *     devpts while preserving backward compatibility of the current 'single-
+ *     namespace' semantics. i.e all mounts of devpts without the 'newinstance'
+ *     mount option should bind to the initial kernel mount, like
+ *     get_sb_single().
+ *
+ *     Mounts with 'newinstance' option create a new private namespace.
+ *
+ *     But for single-mount semantics, devpts cannot use get_sb_single(),
+ *     because get_sb_single()/sget() find and use the super-block from
+ *     the most recent mount of devpts. But that recent mount may be a
+ *     'newinstance' mount and get_sb_single() would pick the newinstance
+ *     super-block instead of the initial super-block.
+ *
+ *     This interface is identical to get_sb_single() except that it
+ *     consistently selects the 'single-namespace' superblock even in the
+ *     presence of the private namespace (i.e 'newinstance') super-blocks.
+ */
+static int get_init_pts_sb(struct file_system_type *fs_type, int flags,
+		void *data, struct vfsmount *mnt)
+{
+	struct super_block *s;
+	int error;
+
+	s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);
+	if (IS_ERR(s))
+		return PTR_ERR(s);
+
+	if (!s->s_root) {
+		s->s_flags = flags;
+		error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
+		if (error) {
+			up_write(&s->s_umount);
+			deactivate_super(s);
+			return error;
+		}
+		s->s_flags |= MS_ACTIVE;
+	}
+	do_remount_sb(s, flags, data, 0);
+	return simple_set_mnt(mnt, s);
+}
+
+/*
+ * Mount or remount the initial kernel mount of devpts. This type of
+ * mount maintains the legacy, single-instance semantics, while the
+ * kernel still allows multiple-instances.
+ */
+static int init_pts_mount(struct file_system_type *fs_type, int flags,
+		void *data, struct vfsmount *mnt)
+{
+	int err;
+
+	err = get_init_pts_sb(fs_type, flags, data, mnt);
+	if (err)
+		return err;
+
+	err = mknod_ptmx(mnt->mnt_sb);
+	if (err) {
+		dput(mnt->mnt_sb->s_root);
+		deactivate_super(mnt->mnt_sb);
+	}
+
+	return err;
+}
+
 static int devpts_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
+	int new;
+
+	new = is_new_instance_mount(data);
+	if (new < 0)
+		return new;
+
+	if (new)
+		return new_pts_mount(fs_type, flags, data, mnt);
+
+	return init_pts_mount(fs_type, flags, data, mnt);
+}
+#else
+/*
+ * This supports only the legacy single-instance semantics (no
+ * multiple-instance semantics)
+ */
+static int devpts_get_sb(struct file_system_type *fs_type, int flags,
+		const char *dev_name, void *data, struct vfsmount *mnt)
+{
 	return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt);
 }
+#endif
+
+static void devpts_kill_sb(struct super_block *sb)
+{
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
+
+	kfree(fsi);
+	kill_litter_super(sb);
+}
 
 static struct file_system_type devpts_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "devpts",
 	.get_sb		= devpts_get_sb,
-	.kill_sb	= kill_anon_super,
+	.kill_sb	= devpts_kill_sb,
 };
 
 /*
@@ -172,16 +536,17 @@ static struct file_system_type devpts_fs_type = {
 
 int devpts_new_index(struct inode *ptmx_inode)
 {
+	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
 	int index;
 	int ida_ret;
 
 retry:
-	if (!ida_pre_get(&allocated_ptys, GFP_KERNEL)) {
+	if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
 		return -ENOMEM;
-	}
 
 	mutex_lock(&allocated_ptys_lock);
-	ida_ret = ida_get_new(&allocated_ptys, &index);
+	ida_ret = ida_get_new(&fsi->allocated_ptys, &index);
 	if (ida_ret < 0) {
 		mutex_unlock(&allocated_ptys_lock);
 		if (ida_ret == -EAGAIN)
@@ -190,7 +555,7 @@ retry:
 	}
 
 	if (index >= pty_limit) {
-		ida_remove(&allocated_ptys, index);
+		ida_remove(&fsi->allocated_ptys, index);
 		mutex_unlock(&allocated_ptys_lock);
 		return -EIO;
 	}
@@ -200,18 +565,26 @@ retry:
 
 void devpts_kill_index(struct inode *ptmx_inode, int idx)
 {
+	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
+
 	mutex_lock(&allocated_ptys_lock);
-	ida_remove(&allocated_ptys, idx);
+	ida_remove(&fsi->allocated_ptys, idx);
 	mutex_unlock(&allocated_ptys_lock);
 }
 
 int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
 {
-	int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
+	/* tty layer puts index from devpts_new_index() in here */
+	int number = tty->index;
 	struct tty_driver *driver = tty->driver;
 	dev_t device = MKDEV(driver->major, driver->minor_start+number);
 	struct dentry *dentry;
-	struct inode *inode = new_inode(devpts_mnt->mnt_sb);
+	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+	struct inode *inode = new_inode(sb);
+	struct dentry *root = sb->s_root;
+	struct pts_fs_info *fsi = DEVPTS_SB(sb);
+	struct pts_mount_opts *opts = &fsi->mount_opts;
 	char s[12];
 
 	/* We're supposed to be given the slave end of a pty */
@@ -221,25 +594,25 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
 	if (!inode)
 		return -ENOMEM;
 
-	inode->i_ino = number+2;
-	inode->i_uid = config.setuid ? config.uid : current->fsuid;
-	inode->i_gid = config.setgid ? config.gid : current->fsgid;
+	inode->i_ino = number+3;
+	inode->i_uid = opts->setuid ? opts->uid : current->fsuid;
+	inode->i_gid = opts->setgid ? opts->gid : current->fsgid;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-	init_special_inode(inode, S_IFCHR|config.mode, device);
+	init_special_inode(inode, S_IFCHR|opts->mode, device);
 	inode->i_private = tty;
 	tty->driver_data = inode;
 
 	sprintf(s, "%d", number);
 
-	mutex_lock(&devpts_root->d_inode->i_mutex);
+	mutex_lock(&root->d_inode->i_mutex);
 
-	dentry = d_alloc_name(devpts_root, s);
+	dentry = d_alloc_name(root, s);
 	if (!IS_ERR(dentry)) {
 		d_add(dentry, inode);
-		fsnotify_create(devpts_root->d_inode, dentry);
+		fsnotify_create(root->d_inode, dentry);
 	}
 
-	mutex_unlock(&devpts_root->d_inode->i_mutex);
+	mutex_unlock(&root->d_inode->i_mutex);
 
 	return 0;
 }
@@ -256,20 +629,27 @@ struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)
 void devpts_pty_kill(struct tty_struct *tty)
 {
 	struct inode *inode = tty->driver_data;
+	struct super_block *sb = pts_sb_from_inode(inode);
+	struct dentry *root = sb->s_root;
 	struct dentry *dentry;
 
 	BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
 
-	mutex_lock(&devpts_root->d_inode->i_mutex);
+	mutex_lock(&root->d_inode->i_mutex);
 
 	dentry = d_find_alias(inode);
-	if (dentry && !IS_ERR(dentry)) {
+	if (IS_ERR(dentry))
+		goto out;
+
+	if (dentry) {
 		inode->i_nlink--;
 		d_delete(dentry);
-		dput(dentry);
+		dput(dentry);	/* d_alloc_name() in devpts_pty_new() */
 	}
 
-	mutex_unlock(&devpts_root->d_inode->i_mutex);
+	dput(dentry);		/* d_find_alias above */
+out:
+	mutex_unlock(&root->d_inode->i_mutex);
 }
 
 static int __init init_devpts_fs(void)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 3b8121d4e36f..474f5d976379 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -253,6 +253,7 @@ struct tty_struct {
 	unsigned int column;
 	unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
 	unsigned char closing:1;
+	unsigned char echo_overrun:1;
 	unsigned short minimum_to_wake;
 	unsigned long overrun_time;
 	int num_overrun;
@@ -262,11 +263,16 @@ struct tty_struct {
 	int read_tail;
 	int read_cnt;
 	unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
+	unsigned char *echo_buf;
+	unsigned int echo_pos;
+	unsigned int echo_cnt;
 	int canon_data;
 	unsigned long canon_head;
 	unsigned int canon_column;
 	struct mutex atomic_read_lock;
 	struct mutex atomic_write_lock;
+	struct mutex output_lock;
+	struct mutex echo_lock;
 	unsigned char *write_buf;
 	int write_cnt;
 	spinlock_t read_lock;
@@ -354,8 +360,7 @@ extern int tty_write_room(struct tty_struct *tty);
 extern void tty_driver_flush_buffer(struct tty_struct *tty);
 extern void tty_throttle(struct tty_struct *tty);
 extern void tty_unthrottle(struct tty_struct *tty);
-extern int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
-						struct winsize *ws);
+extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 extern void tty_shutdown(struct tty_struct *tty);
 extern void tty_free_termios(struct tty_struct *tty);
 extern int is_current_pgrp_orphaned(void);
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 78416b901589..08e088334dba 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -196,8 +196,7 @@
  *	Optional: If not provided then the write method is called under
  *	the atomic write lock to keep it serialized with the ldisc.
  *
- * int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
- *				unsigned int rows, unsigned int cols);
+ * int (*resize)(struct tty_struct *tty, struct winsize *ws)
  *
  *	Called when a termios request is issued which changes the
  *	requested terminal geometry.
@@ -258,8 +257,7 @@ struct tty_operations {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
-	int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
-				struct winsize *ws);
+	int (*resize)(struct tty_struct *tty, struct winsize *ws);
 	int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 #ifdef CONFIG_CONSOLE_POLL
 	int (*poll_init)(struct tty_driver *driver, int line, char *options);