[PATCH] TTY layer buffering revamp

The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real.  That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification].  It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found.  This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty.  This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers.  This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
call directly and unsafely into function pointers it provides.  This will all
break.  Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

 int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero).  At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative.  (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

 int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room.  Now returns 1 for success, 0
for failure.

 int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters.  Returns the number inserted.

 int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added.  Returns a buffer
pointer in strptr and the length available.  This allows for hardware that
needs to use functions like insl or mencpy_fromio.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 977a74e..d6fcd0a 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -80,7 +80,7 @@
 
 config COMPUTONE
 	tristate "Computone IntelliPort Plus serial support"
-	depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
+	depends on SERIAL_NONSTANDARD
 	---help---
 	  This driver supports the entire family of Intelliport II/Plus
 	  controllers with the exception of the MicroChannel controllers and
@@ -153,7 +153,7 @@
 
 config ESPSERIAL
 	tristate "Hayes ESP serial port support"
-	depends on SERIAL_NONSTANDARD && ISA && BROKEN_ON_SMP && ISA_DMA_API
+	depends on SERIAL_NONSTANDARD && ISA && ISA_DMA_API
 	help
 	  This is a driver which supports Hayes ESP serial ports.  Both single
 	  port cards and multiport cards are supported.  Make sure to read
@@ -166,7 +166,7 @@
 
 config MOXA_INTELLIO
 	tristate "Moxa Intellio support"
-	depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
+	depends on SERIAL_NONSTANDARD
 	help
 	  Say Y here if you have a Moxa Intellio multiport serial card.
 
diff --git a/drivers/char/amiserial.c b/drivers/char/amiserial.c
index 10c81ec..869518e 100644
--- a/drivers/char/amiserial.c
+++ b/drivers/char/amiserial.c
@@ -265,8 +265,9 @@
         int status;
 	int serdatr;
 	struct tty_struct *tty = info->tty;
-	unsigned char ch;
+	unsigned char ch, flag;
 	struct	async_icount *icount;
+	int oe = 0;
 
 	icount = &info->state->icount;
 
@@ -282,15 +283,12 @@
 	    status |= UART_LSR_OE;
 
 	ch = serdatr & 0xff;
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-	  goto ignore_char;
-	*tty->flip.char_buf_ptr = ch;
 	icount->rx++;
 
 #ifdef SERIAL_DEBUG_INTR
 	printk("DR%02x:%02x...", ch, status);
 #endif
-	*tty->flip.flag_buf_ptr = 0;
+	flag = TTY_NORMAL;
 
 	/*
 	 * We don't handle parity or frame errors - but I have left
@@ -319,7 +317,7 @@
 	   * should be ignored.
 	   */
 	  if (status & info->ignore_status_mask)
-	    goto ignore_char;
+	    goto out;
 
 	  status &= info->read_status_mask;
 
@@ -327,33 +325,28 @@
 #ifdef SERIAL_DEBUG_INTR
 	    printk("handling break....");
 #endif
-	    *tty->flip.flag_buf_ptr = TTY_BREAK;
+	    flag = TTY_BREAK;
 	    if (info->flags & ASYNC_SAK)
 	      do_SAK(tty);
 	  } else if (status & UART_LSR_PE)
-	    *tty->flip.flag_buf_ptr = TTY_PARITY;
+	    flag = TTY_PARITY;
 	  else if (status & UART_LSR_FE)
-	    *tty->flip.flag_buf_ptr = TTY_FRAME;
+	    flag = TTY_FRAME;
 	  if (status & UART_LSR_OE) {
 	    /*
 	     * Overrun is special, since it's
 	     * reported immediately, and doesn't
 	     * affect the current character
 	     */
-	    if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-	      tty->flip.count++;
-	      tty->flip.flag_buf_ptr++;
-	      tty->flip.char_buf_ptr++;
-	      *tty->flip.flag_buf_ptr = TTY_OVERRUN;
-	    }
+	     oe = 1;
 	  }
 	}
-	tty->flip.flag_buf_ptr++;
-	tty->flip.char_buf_ptr++;
-	tty->flip.count++;
- ignore_char:
-
+	tty_insert_flip_char(tty, ch, flag);
+	if (oe == 1)
+		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	tty_flip_buffer_push(tty);
+out:
+	return;
 }
 
 static _INLINE_ void transmit_chars(struct async_struct *info)
diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c
index c8e7dae..39c61a7 100644
--- a/drivers/char/cyclades.c
+++ b/drivers/char/cyclades.c
@@ -641,6 +641,7 @@
 #include <linux/timer.h>
 #include <linux/interrupt.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/serial.h>
 #include <linux/major.h>
 #include <linux/string.h>
@@ -1086,7 +1087,7 @@
   int had_work;
   int mdm_change;
   int mdm_status;
-
+  int len;
     if((cinfo = (struct cyclades_card *)dev_id) == 0){
 #ifdef CY_DEBUG_INTERRUPTS
 	printk("cyy_interrupt: spurious interrupt %d\n\r", irq);
@@ -1163,63 +1164,43 @@
 				info->icount.rx++;
                                 continue;
                             }
-                            if (tty->flip.count < TTY_FLIPBUF_SIZE){
-                                tty->flip.count++;
+                            if (tty_buffer_request_room(tty, 1)) {
                                 if (data & info->read_status_mask){
                                     if(data & CyBREAK){
-                                        *tty->flip.flag_buf_ptr++ =
-	    						    TTY_BREAK;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_BREAK);
 					info->icount.rx++;
                                         if (info->flags & ASYNC_SAK){
                                             do_SAK(tty);
                                         }
                                     }else if(data & CyFRAME){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_FRAME;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_FRAME);
 					info->icount.rx++;
 					info->idle_stats.frame_errs++;
                                     }else if(data & CyPARITY){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_PARITY;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+					/* Pieces of seven... */
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_PARITY);
 					info->icount.rx++;
 					info->idle_stats.parity_errs++;
                                     }else if(data & CyOVERRUN){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_OVERRUN;
-                                        *tty->flip.char_buf_ptr++ = 0;
+                                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 					info->icount.rx++;
                                         /* If the flip buffer itself is
                                            overflowing, we still lose
                                            the next incoming character.
                                          */
-                                        if(tty->flip.count
-					           < TTY_FLIPBUF_SIZE){
-                                            tty->flip.count++;
-                                            *tty->flip.flag_buf_ptr++ =
-							     TTY_NORMAL;
-                                           *tty->flip.char_buf_ptr++ =
-					    cy_readb(base_addr+(CyRDSR<<index));
-					    info->icount.rx++;
-                                        }
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_FRAME);
+				        info->icount.rx++;
 					info->idle_stats.overruns++;
                                     /* These two conditions may imply */
                                     /* a normal read should be done. */
                                     /* }else if(data & CyTIMEOUT){ */
                                     /* }else if(data & CySPECHAR){ */
-                                    }else{
-                                        *tty->flip.flag_buf_ptr++ = 0;
-                                        *tty->flip.char_buf_ptr++ = 0;
-					info->icount.rx++;
+                                    }else {
+					tty_insert_flip_char(tty, 0, TTY_NORMAL);
+				        info->icount.rx++;
                                     }
                                 }else{
-                                    *tty->flip.flag_buf_ptr++ = 0;
-                                    *tty->flip.char_buf_ptr++ = 0;
+				    tty_insert_flip_char(tty, 0, TTY_NORMAL);
 				    info->icount.rx++;
                                 }
                             }else{
@@ -1240,14 +1221,10 @@
                                info->mon.char_max = char_count;
                             info->mon.char_last = char_count;
 #endif
-                            while(char_count--){
-                                if (tty->flip.count >= TTY_FLIPBUF_SIZE){
-                                        break;
-                                }
-                                tty->flip.count++;
+			    len = tty_buffer_request_room(tty, char_count);
+                            while(len--){
                                 data = cy_readb(base_addr+(CyRDSR<<index));
-                                *tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-                                *tty->flip.char_buf_ptr++ = data;
+				tty_insert_flip_char(tty, data, TTY_NORMAL);
 				info->idle_stats.recv_bytes++;
 				info->icount.rx++;
 #ifdef CY_16Y_HACK
@@ -1256,7 +1233,7 @@
                             }
                              info->idle_stats.recv_idle = jiffies;
                         }
-                        schedule_delayed_work(&tty->flip.work, 1);
+                        schedule_delayed_work(&tty->buf.work, 1);
                     }
                     /* end of service */
                     cy_writeb(base_addr+(CyRIR<<index), (save_xir & 0x3f));
@@ -1551,6 +1528,7 @@
   struct cyclades_card *cinfo = &cy_card[info->card];
   struct tty_struct *tty = info->tty;
   volatile int char_count;
+  int len;
 #ifdef BLOCKMOVE
   int small_count;
 #else
@@ -1606,18 +1584,11 @@
 		tty->flip.count += small_count;
 	    }
 #else
-	    while(char_count--){
-		if (tty->flip.count >= N_TTY_BUF_SIZE - tty->read_cnt)
-                    break;
-
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-		    break;
-
+	    len = tty_buffer_request_room(tty, char_count);
+	    while(len--){
 		data = cy_readb(cinfo->base_addr + rx_bufaddr + new_rx_get);
 		new_rx_get = (new_rx_get + 1) & (rx_bufsize - 1);
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-		*tty->flip.char_buf_ptr++ = data;
+		tty_insert_flip_char(tty, data, TTY_NORMAL);
 		info->idle_stats.recv_bytes++;
 		info->icount.rx++;
 	    }
@@ -1635,7 +1606,7 @@
 	    }
 #endif
 	    info->idle_stats.recv_idle = jiffies;
-	    schedule_delayed_work(&tty->flip.work, 1);
+	    schedule_delayed_work(&tty->buf.work, 1);
 	}
 	/* Update rx_get */
 	cy_writel(&buf_ctrl->rx_get, new_rx_get);
@@ -1763,23 +1734,17 @@
 
 	switch(cmd) {
 	    case C_CM_PR_ERROR:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_PARITY);
 		info->icount.rx++;
 		special_count++;
 		break;
 	    case C_CM_FR_ERROR:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_FRAME);
 		info->icount.rx++;
 		special_count++;
 		break;
 	    case C_CM_RXBRK:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_BREAK);
 		info->icount.rx++;
 		special_count++;
 		break;
@@ -1844,7 +1809,7 @@
 	if(delta_count)
 	    cy_sched_event(info, Cy_EVENT_DELTA_WAKEUP);
 	if(special_count)
-	    schedule_delayed_work(&tty->flip.work, 1);
+	    schedule_delayed_work(&tty->buf.work, 1);
     }
 }
 
diff --git a/drivers/char/epca.c b/drivers/char/epca.c
index 407708a..765c5c1 100644
--- a/drivers/char/epca.c
+++ b/drivers/char/epca.c
@@ -1786,9 +1786,7 @@
 		if (tty)  { /* Begin if valid tty */
 			if (event & BREAK_IND)  { /* Begin if BREAK_IND */
 				/* A break has been indicated */
-				tty->flip.count++;
-				*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-				*tty->flip.char_buf_ptr++ = 0;
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
 				tty_schedule_flip(tty); 
 			} else if (event & LOWTX_IND)  { /* Begin LOWTX_IND */
 				if (ch->statusflags & LOWWAIT) 
@@ -2124,7 +2122,6 @@
 	int dataToRead, wrapgap, bytesAvailable;
 	unsigned int tail, head;
 	unsigned int wrapmask;
-	int rc;
 
 	/* ---------------------------------------------------------------
 		This routine is called by doint when a receive data event 
@@ -2162,16 +2159,15 @@
 		return;
 	}
 
-	if (tty->flip.count == TTY_FLIPBUF_SIZE) 
+	if (tty_buffer_request_room(tty, bytesAvailable + 1) == 0)
 		return;
 
 	if (readb(&bc->orun)) {
 		writeb(0, &bc->orun);
 		printk(KERN_WARNING "epca; overrun! DigiBoard device %s\n",tty->name);
+		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	}
 	rxwinon(ch);
-	rptr = tty->flip.char_buf_ptr;
-	rc = tty->flip.count;
 	while (bytesAvailable > 0)  { /* Begin while there is data on the card */
 		wrapgap = (head >= tail) ? head - tail : ch->rxbufsize - tail;
 		/* ---------------------------------------------------------------
@@ -2183,8 +2179,7 @@
 		/* --------------------------------------------------------------
 		   Make sure we don't overflow the buffer
 		----------------------------------------------------------------- */
-		if ((rc + dataToRead) > TTY_FLIPBUF_SIZE)
-			dataToRead = TTY_FLIPBUF_SIZE - rc;
+		dataToRead = tty_prepare_flip_string(tty, &rptr, dataToRead);
 		if (dataToRead == 0)
 			break;
 		/* ---------------------------------------------------------------
@@ -2192,13 +2187,9 @@
 			for translation if necessary.
 		------------------------------------------------------------------ */
 		memcpy_fromio(rptr, ch->rxptr + tail, dataToRead);
-		rc   += dataToRead;
-		rptr += dataToRead;
 		tail = (tail + dataToRead) & wrapmask;
 		bytesAvailable -= dataToRead;
 	} /* End while there is data on the card */
-	tty->flip.count = rc;
-	tty->flip.char_buf_ptr = rptr;
 	globalwinon(ch);
 	writew(tail, &bc->rout);
 	/* Must be called with global data */
diff --git a/drivers/char/esp.c b/drivers/char/esp.c
index 9f53d2fc..e469f64 100644
--- a/drivers/char/esp.c
+++ b/drivers/char/esp.c
@@ -345,26 +345,22 @@
 
 	for (i = 0; i < num_bytes; i++) {
 		if (!(err_buf->data[i] & status_mask)) {
-			*(tty->flip.char_buf_ptr++) = pio_buf->data[i];
+			int flag = 0;
 
 			if (err_buf->data[i] & 0x04) {
-				*(tty->flip.flag_buf_ptr++) = TTY_BREAK;
-
+				flag = TTY_BREAK;
 				if (info->flags & ASYNC_SAK)
 					do_SAK(tty);
 			}
 			else if (err_buf->data[i] & 0x02)
-				*(tty->flip.flag_buf_ptr++) = TTY_FRAME;
+				flag = TTY_FRAME;
 			else if (err_buf->data[i] & 0x01)
-				*(tty->flip.flag_buf_ptr++) = TTY_PARITY;
-			else
-				*(tty->flip.flag_buf_ptr++) = 0;
-		
-			tty->flip.count++;
+				flag = TTY_PARITY;
+			tty_insert_flip_char(tty, pio_buf->data[i], flag);
 		}
 	}
 
-	schedule_delayed_work(&tty->flip.work, 1);
+	schedule_delayed_work(&tty->buf.work, 1);
 
 	info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
 	release_pio_buffer(pio_buf);
@@ -397,7 +393,6 @@
 	int num_bytes;
 	unsigned long flags;
 	
-	
 	flags=claim_dma_lock();
 	disable_dma(dma);
 	clear_dma_ff(dma);
@@ -408,38 +403,31 @@
 	
 	info->icount.rx += num_bytes;
 
-	memcpy(tty->flip.char_buf_ptr, dma_buffer, num_bytes);
-	tty->flip.char_buf_ptr += num_bytes;
-	tty->flip.count += num_bytes;
-	memset(tty->flip.flag_buf_ptr, 0, num_bytes);
-	tty->flip.flag_buf_ptr += num_bytes;
-
 	if (num_bytes > 0) {
-		tty->flip.flag_buf_ptr--;
+		tty_insert_flip_string(tty, dma_buffer, num_bytes - 1);
 
 		status &= (0x1c & info->read_status_mask);
-
-		if (status & info->ignore_status_mask) {
-			tty->flip.count--;
-			tty->flip.char_buf_ptr--;
-			tty->flip.flag_buf_ptr--;
-		} else if (status & 0x10) {
-			*tty->flip.flag_buf_ptr = TTY_BREAK;
-			(info->icount.brk)++;
-			if (info->flags & ASYNC_SAK)
-				do_SAK(tty);
-		} else if (status & 0x08) {
-			*tty->flip.flag_buf_ptr = TTY_FRAME;
-			(info->icount.frame)++;
-		}
-		else if (status & 0x04) {
-			*tty->flip.flag_buf_ptr = TTY_PARITY;
-			(info->icount.parity)++;
-		}
-
-		tty->flip.flag_buf_ptr++;
 		
-		schedule_delayed_work(&tty->flip.work, 1);
+		/* Is the status significant or do we throw the last byte ? */
+		if (!(status & info->ignore_status_mask)) {
+			int statflag = 0;
+
+			if (status & 0x10) {
+				statflag = TTY_BREAK;
+				(info->icount.brk)++;
+				if (info->flags & ASYNC_SAK)
+					do_SAK(tty);
+			} else if (status & 0x08) {
+				statflag = TTY_FRAME;
+				(info->icount.frame)++;
+			}
+			else if (status & 0x04) {
+				statflag = TTY_PARITY;
+				(info->icount.parity)++;
+			}
+			tty_insert_flip_char(tty, dma_buffer[num_bytes - 1], statflag);
+		}
+		schedule_delayed_work(&tty->buf.work, 1);
 	}
 
 	if (dma_bytes != num_bytes) {
@@ -693,8 +681,7 @@
 		num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
 		num_bytes |= serial_in(info, UART_ESI_STAT2);
 
-		if (num_bytes > (TTY_FLIPBUF_SIZE - info->tty->flip.count))
-		  num_bytes = TTY_FLIPBUF_SIZE - info->tty->flip.count;
+		num_bytes = tty_buffer_request_room(info->tty, num_bytes);
 
 		if (num_bytes) {
 			if (dma_bytes ||
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index f921776..1994a92 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -597,9 +597,7 @@
 
 	/* Read data if any */
 	for (;;) {
-		int count = N_INBUF;
-		if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
-			count = TTY_FLIPBUF_SIZE - tty->flip.count;
+		int count = tty_buffer_request_room(tty, N_INBUF);
 
 		/* If flip is full, just reschedule a later read */
 		if (count == 0) {
@@ -635,7 +633,7 @@
 			tty_insert_flip_char(tty, buf[i], 0);
 		}
 
-		if (tty->flip.count)
+		if (count)
 			tty_schedule_flip(tty);
 
 		/*
diff --git a/drivers/char/hvcs.c b/drivers/char/hvcs.c
index 53dc77c..831eb4e 100644
--- a/drivers/char/hvcs.c
+++ b/drivers/char/hvcs.c
@@ -456,12 +456,11 @@
 	/* remove the read masks */
 	hvcsd->todo_mask &= ~(HVCS_READ_MASK);
 
-	if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) {
+	if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
 		got = hvc_get_chars(unit_address,
 				&buf[0],
 				HVCS_BUFF_LEN);
-		for (i=0;got && i<got;i++)
-			tty_insert_flip_char(tty, buf[i], TTY_NORMAL);
+		tty_insert_flip_string(tty, buf, got);
 	}
 
 	/* Give the TTY time to process the data we just sent. */
@@ -469,10 +468,9 @@
 		hvcsd->todo_mask |= HVCS_QUICK_READ;
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
-	if (tty->flip.count) {
-		/* This is synch because tty->low_latency == 1 */
+	/* This is synch because tty->low_latency == 1 */
+	if(got)
 		tty_flip_buffer_push(tty);
-	}
 
 	if (!got) {
 		/* Do this _after_ the flip_buffer_push */
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 1bbf507..86033be 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -115,6 +115,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/termios.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
@@ -773,6 +774,7 @@
 	unsigned short base, header, word_count, count;
 	unsigned char channel;
 	short byte_count;
+	unsigned char *rp;
 	
 	card = (struct isi_board *) dev_id;
 
@@ -903,14 +905,10 @@
 				break;
 				
 			case 1:	/* Received Break !!!	 */
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					break;
-				*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-				*tty->flip.char_buf_ptr++ = 0;
-				tty->flip.count++;
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
 				if (port->flags & ASYNC_SAK)
 					do_SAK(tty);
-				schedule_delayed_work(&tty->flip.work, 1);
+				tty_flip_buffer_push(tty);
 				break;
 				
 			case 2:	/* Statistics		 */
@@ -923,23 +921,19 @@
 		}	 
 	}
 	else {				/* Data   Packet */
-		count = min_t(unsigned short, byte_count, (TTY_FLIPBUF_SIZE - tty->flip.count));
+
+		count = tty_prepare_flip_string(tty, &rp, byte_count & ~1);
 #ifdef ISICOM_DEBUG
 		printk(KERN_DEBUG "ISICOM: Intr: Can rx %d of %d bytes.\n", 
 					count, byte_count);
 #endif			
 		word_count = count >> 1;
-		insw(base, tty->flip.char_buf_ptr, word_count);
-		tty->flip.char_buf_ptr += (word_count << 1);		
+		insw(base, rp, word_count);
 		byte_count -= (word_count << 1);
 		if (count & 0x0001) {
-			*tty->flip.char_buf_ptr++ = (char)(inw(base) & 0xff);
+			tty_insert_flip_char(tty,  inw(base) & 0xff, TTY_NORMAL);
 			byte_count -= 2;
 		}	
-		memset(tty->flip.flag_buf_ptr, 0, count);
-		tty->flip.flag_buf_ptr += count;
-		tty->flip.count += count;
-		
 		if (byte_count > 0) {
 			printk(KERN_DEBUG "ISICOM: Intr(0x%x:%d): Flip buffer overflow! dropping bytes...\n",
 					base, channel+1);
@@ -948,7 +942,7 @@
 				byte_count -= 2;
 			}
 		}
-		schedule_delayed_work(&tty->flip.work, 1);
+		tty_flip_buffer_push(tty);
 	}
 	if (card->isa == YES)
 		ClearInterrupt(base);
diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index 24435f8..28c5a31 100644
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -2711,17 +2711,13 @@
 		stlen = size - tail;
 	}
 
-	len = MIN(len, (TTY_FLIPBUF_SIZE - tty->flip.count));
+	len = tty_buffer_request_room(tty, len);
+	/* FIXME : iomap ? */
 	shbuf = (volatile char *) EBRDGETMEMPTR(brdp, portp->rxoffset);
 
 	while (len > 0) {
 		stlen = MIN(len, stlen);
-		memcpy(tty->flip.char_buf_ptr, (char *) (shbuf + tail), stlen);
-		memset(tty->flip.flag_buf_ptr, 0, stlen);
-		tty->flip.char_buf_ptr += stlen;
-		tty->flip.flag_buf_ptr += stlen;
-		tty->flip.count += stlen;
-
+		tty_insert_flip_string(tty, (char *)(shbuf + tail), stlen);
 		len -= stlen;
 		tail += stlen;
 		if (tail >= size) {
@@ -2906,16 +2902,12 @@
 
 		if ((nt.data & DT_RXBREAK) && (portp->rxmarkmsk & BRKINT)) {
 			if (tty != (struct tty_struct *) NULL) {
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					tty->flip.count++;
-					*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-					*tty->flip.char_buf_ptr++ = 0;
-					if (portp->flags & ASYNC_SAK) {
-						do_SAK(tty);
-						EBRDENABLE(brdp);
-					}
-					tty_schedule_flip(tty);
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
+				if (portp->flags & ASYNC_SAK) {
+					do_SAK(tty);
+					EBRDENABLE(brdp);
 				}
+				tty_schedule_flip(tty);
 			}
 		}
 
@@ -4940,7 +4932,7 @@
 	if (portp->tty != (struct tty_struct *) NULL) {
 		if (portp->tty->driver_data == portp) {
 			stli_comstats.ttystate = portp->tty->flags;
-			stli_comstats.rxbuffered = portp->tty->flip.count;
+			stli_comstats.rxbuffered = -1 /*portp->tty->flip.count*/;
 			if (portp->tty->termios != (struct termios *) NULL) {
 				stli_comstats.cflags = portp->tty->termios->c_cflag;
 				stli_comstats.iflags = portp->tty->termios->c_iflag;
diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index 46a3a8c..5e3ef55 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -269,7 +269,7 @@
 static int MoxaPortDCDON(int);
 static void MoxaPortFlushData(int, int);
 static int MoxaPortWriteData(int, unsigned char *, int);
-static int MoxaPortReadData(int, unsigned char *, int);
+static int MoxaPortReadData(int, struct tty_struct *tty);
 static int MoxaPortTxQueue(int);
 static int MoxaPortRxQueue(int);
 static int MoxaPortTxFree(int);
@@ -301,6 +301,8 @@
 	.tiocmset = moxa_tiocmset,
 };
 
+static spinlock_t moxa_lock = SPIN_LOCK_UNLOCKED;
+
 #ifdef CONFIG_PCI
 static int moxa_get_PCI_conf(struct pci_dev *p, int board_type, moxa_board_conf * board)
 {
@@ -645,10 +647,10 @@
 	if (ch == NULL)
 		return (0);
 	port = ch->port;
-	save_flags(flags);
-	cli();
+
+	spin_lock_irqsave(&moxa_lock, flags);
 	len = MoxaPortWriteData(port, (unsigned char *) buf, count);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 
 	/*********************************************
 	if ( !(ch->statusflags & LOWWAIT) &&
@@ -723,11 +725,10 @@
 	if (ch == NULL)
 		return;
 	port = ch->port;
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	moxaXmitBuff[0] = c;
 	MoxaPortWriteData(port, moxaXmitBuff, 1);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 	/************************************************
 	if ( !(ch->statusflags & LOWWAIT) && (MoxaPortTxFree(port) <= 100) )
 	*************************************************/
@@ -1030,12 +1031,12 @@
 	printk("block_til_ready before block: ttys%d, count = %d\n",
 	       ch->line, ch->count);
 #endif
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	if (!tty_hung_up_p(filp))
 		ch->count--;
-	restore_flags(flags);
 	ch->blocked_open++;
+	spin_unlock_irqrestore(&moxa_lock, flags);
+
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (tty_hung_up_p(filp) ||
@@ -1062,17 +1063,21 @@
 	}
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&ch->open_wait, &wait);
+
+	spin_lock_irqsave(&moxa_lock, flags);
 	if (!tty_hung_up_p(filp))
 		ch->count++;
 	ch->blocked_open--;
+	spin_unlock_irqrestore(&moxa_lock, flags);
 #ifdef SERIAL_DEBUG_OPEN
 	printk("block_til_ready after blocking: ttys%d, count = %d\n",
 	       ch->line, ch->count);
 #endif
 	if (retval)
 		return (retval);
+	/* FIXME: review to see if we need to use set_bit on these */
 	ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
-	return (0);
+	return 0;
 }
 
 static void setup_empty_event(struct tty_struct *tty)
@@ -1080,15 +1085,14 @@
 	struct moxa_str *ch = tty->driver_data;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	ch->statusflags |= EMPTYWAIT;
 	moxaEmptyTimer_on[ch->port] = 0;
 	del_timer(&moxaEmptyTimer[ch->port]);
 	moxaEmptyTimer[ch->port].expires = jiffies + HZ;
 	moxaEmptyTimer_on[ch->port] = 1;
 	add_timer(&moxaEmptyTimer[ch->port]);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 }
 
 static void check_xmit_empty(unsigned long data)
@@ -1135,8 +1139,6 @@
 {
 	struct tty_struct *tp;
 	struct termios *ts;
-	int i, count, rc, space;
-	unsigned char *charptr, *flagptr;
 	unsigned long flags;
 
 	ts = NULL;
@@ -1150,24 +1152,10 @@
 		MoxaPortFlushData(ch->port, 0);
 		return;
 	}
-	space = TTY_FLIPBUF_SIZE - tp->flip.count;
-	if (space <= 0)
-		return;
-	charptr = tp->flip.char_buf_ptr;
-	flagptr = tp->flip.flag_buf_ptr;
-	rc = tp->flip.count;
-	save_flags(flags);
-	cli();
-	count = MoxaPortReadData(ch->port, charptr, space);
-	restore_flags(flags);
-	for (i = 0; i < count; i++)
-		*flagptr++ = 0;
-	charptr += count;
-	rc += count;
-	tp->flip.count = rc;
-	tp->flip.char_buf_ptr = charptr;
-	tp->flip.flag_buf_ptr = flagptr;
-	tty_schedule_flip(ch->tty);
+	spin_lock_irqsave(&moxa_lock, flags);
+	MoxaPortReadData(ch->port, tp);
+	spin_unlock_irqrestore(&moxa_lock, flags);
+	tty_schedule_flip(tp);
 }
 
 #define Magic_code	0x404
@@ -1774,7 +1762,7 @@
  *	14. MoxaPortDCDON(int port);					     *
  *	15. MoxaPortFlushData(int port, int mode);	                     *
  *	16. MoxaPortWriteData(int port, unsigned char * buffer, int length); *
- *	17. MoxaPortReadData(int port, unsigned char * buffer, int length);  *
+ *	17. MoxaPortReadData(int port, struct tty_struct *tty); 	     *
  *	18. MoxaPortTxBufSize(int port);				     *
  *	19. MoxaPortRxBufSize(int port);				     *
  *	20. MoxaPortTxQueue(int port);					     *
@@ -2003,10 +1991,9 @@
  *
  *      Function 21:    Read data.
  *      Syntax:
- *      int  MoxaPortReadData(int port, unsigned char * buffer, int length);
+ *      int  MoxaPortReadData(int port, struct tty_struct *tty);
  *           int port           : port number (0 - 127)
- *           unsigned char * buffer     : pointer to read data buffer.
- *           int length         : read data buffer length
+ *	     struct tty_struct *tty : tty for data
  *
  *           return:    0 - length      : real read data length
  *
@@ -2504,7 +2491,7 @@
 	return (total);
 }
 
-int MoxaPortReadData(int port, unsigned char * buffer, int space)
+int MoxaPortReadData(int port, struct tty_struct *tty)
 {
 	register ushort head, pageofs;
 	int i, count, cnt, len, total, remain;
@@ -2522,9 +2509,9 @@
 	count = (tail >= head) ? (tail - head)
 	    : (tail - head + rx_mask + 1);
 	if (count == 0)
-		return (0);
+		return 0;
 
-	total = (space > count) ? count : space;
+	total = count;
 	remain = count - total;
 	moxaLog.rxcnt[port] += total;
 	count = total;
@@ -2539,7 +2526,7 @@
 			len = (count > len) ? len : count;
 			ofs = baseAddr + DynPage_addr + bufhead + head;
 			for (i = 0; i < len; i++)
-				*buffer++ = readb(ofs + i);
+				tty_insert_flip_char(tty, readb(ofs + i), TTY_NORMAL);
 			head = (head + len) & rx_mask;
 			count -= len;
 		}
@@ -2556,7 +2543,7 @@
 			writew(pageno, baseAddr + Control_reg);
 			ofs = baseAddr + DynPage_addr + pageofs;
 			for (i = 0; i < cnt; i++)
-				*buffer++ = readb(ofs + i);
+				tty_insert_flip_char(tty, readb(ofs + i), TTY_NORMAL);
 			if (count == 0) {
 				writew((head + len) & rx_mask, ofsAddr + RXrptr);
 				break;
diff --git a/drivers/char/mxser.c b/drivers/char/mxser.c
index 51bb2a3..ea725a9 100644
--- a/drivers/char/mxser.c
+++ b/drivers/char/mxser.c
@@ -1982,7 +1982,7 @@
 
 	spin_lock_irqsave(&info->slock, flags);
 
-	recv_room = tty->ldisc.receive_room(tty);
+	recv_room = tty->receive_room;
 	if ((recv_room == 0) && (!info->ldisc_stop_rx)) {
 		//mxser_throttle(tty);
 		mxser_stoprx(tty);
diff --git a/drivers/char/n_hdlc.c b/drivers/char/n_hdlc.c
index a133a62..70f487d 100644
--- a/drivers/char/n_hdlc.c
+++ b/drivers/char/n_hdlc.c
@@ -212,7 +212,6 @@
 	.ioctl		= n_hdlc_tty_ioctl,
 	.poll		= n_hdlc_tty_poll,
 	.receive_buf	= n_hdlc_tty_receive,
-	.receive_room	= n_hdlc_tty_room,
 	.write_wakeup	= n_hdlc_tty_wakeup,
 };
 
@@ -337,6 +336,7 @@
 		
 	tty->disc_data = n_hdlc;
 	n_hdlc->tty    = tty;
+	tty->receive_room = 65536;
 	
 #if defined(TTY_NO_WRITE_SPLIT)
 	/* change tty_io write() to not split large writes into 8K chunks */
@@ -478,22 +478,6 @@
 }	/* end of n_hdlc_tty_wakeup() */
 
 /**
- * n_hdlc_tty_room - Return the amount of space left in the receiver's buffer
- * @tty	- pointer to associated tty instance data
- *
- * Callback function from tty driver. Return the amount of space left in the
- * receiver's buffer to decide if remote transmitter is to be throttled.
- */
-static int n_hdlc_tty_room(struct tty_struct *tty)
-{
-	if (debuglevel >= DEBUG_LEVEL_INFO)	
-		printk("%s(%d)n_hdlc_tty_room() called\n",__FILE__,__LINE__);
-	/* always return a larger number to prevent */
-	/* throttling of remote transmitter. */
-	return 65536;
-}	/* end of n_hdlc_tty_root() */
-
-/**
  * n_hdlc_tty_receive - Called by tty driver when receive data is available
  * @tty	- pointer to tty instance data
  * @data - pointer to received data
diff --git a/drivers/char/n_r3964.c b/drivers/char/n_r3964.c
index 853c98c..c48de09 100644
--- a/drivers/char/n_r3964.c
+++ b/drivers/char/n_r3964.c
@@ -147,7 +147,6 @@
 		      struct poll_table_struct  *wait);
 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
                               char *fp, int count);
-static int  r3964_receive_room(struct tty_struct *tty);
 
 static struct tty_ldisc tty_ldisc_N_R3964 = {
 	.owner	 = THIS_MODULE,
@@ -161,7 +160,6 @@
 	.set_termios = r3964_set_termios,
 	.poll	= r3964_poll,            
 	.receive_buf = r3964_receive_buf,
-	.receive_room = r3964_receive_room,
 };
 
 
@@ -1119,6 +1117,7 @@
    pInfo->nRetry = 0;
    
    tty->disc_data = pInfo;
+   tty->receive_room = 65536;
 
    init_timer(&pInfo->tmr);
    pInfo->tmr.data = (unsigned long)pInfo;
@@ -1405,12 +1404,5 @@
     }
 }
 
-static int r3964_receive_room(struct tty_struct *tty)
-{
-   TRACE_L("receive_room");
-   return -1;
-}
-
-
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_LDISC(N_R3964);
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index c556f4d..ccad7ae 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -78,7 +78,32 @@
 		free_page((unsigned long) buf);
 }
 
-static inline void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
+/**
+ *	n_tty_set__room	-	receive space
+ *	@tty: terminal
+ *
+ *	Called by the driver to find out how much data it is
+ *	permitted to feed to the line discipline without any being lost
+ *	and thus to manage flow control. Not serialized. Answers for the
+ *	"instant".
+ */
+
+static void n_tty_set_room(struct tty_struct *tty)
+{
+	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+
+	/*
+	 * If we are doing input canonicalization, and there are no
+	 * pending newlines, let characters through without limit, so
+	 * that erase characters will be handled.  Other excess
+	 * characters will be beeped.
+	 */
+	if (left <= 0)
+		left = tty->icanon && !tty->canon_data;
+	tty->receive_room = left;
+}
+
+static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
 {
 	if (tty->read_cnt < N_TTY_BUF_SIZE) {
 		tty->read_buf[tty->read_head] = c;
@@ -87,7 +112,7 @@
 	}
 }
 
-static inline void put_tty_queue(unsigned char c, struct tty_struct *tty)
+static void put_tty_queue(unsigned char c, struct tty_struct *tty)
 {
 	unsigned long flags;
 	/*
@@ -136,6 +161,7 @@
 	spin_unlock_irqrestore(&tty->read_lock, flags);
 	tty->canon_head = tty->canon_data = tty->erasing = 0;
 	memset(&tty->read_flags, 0, sizeof tty->read_flags);
+	n_tty_set_room(tty);
 	check_unthrottle(tty);
 }
 
@@ -838,30 +864,6 @@
 	put_tty_queue(c, tty);
 }	
 
-/**
- *	n_tty_receive_room	-	receive space
- *	@tty: terminal
- *
- *	Called by the driver to find out how much data it is
- *	permitted to feed to the line discipline without any being lost
- *	and thus to manage flow control. Not serialized. Answers for the
- *	"instant".
- */
- 
-static int n_tty_receive_room(struct tty_struct *tty)
-{
-	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
-
-	/*
-	 * If we are doing input canonicalization, and there are no
-	 * pending newlines, let characters through without limit, so
-	 * that erase characters will be handled.  Other excess
-	 * characters will be beeped.
-	 */
-	if (left <= 0)
-		left = tty->icanon && !tty->canon_data;
-	return left;
-}
 
 /**
  *	n_tty_write_wakeup	-	asynchronous I/O notifier
@@ -953,6 +955,8 @@
 			tty->driver->flush_chars(tty);
 	}
 
+	n_tty_set_room(tty);
+
 	if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
 		kill_fasync(&tty->fasync, SIGIO, POLL_IN);
 		if (waitqueue_active(&tty->read_wait))
@@ -964,7 +968,7 @@
 	 * mode.  We don't want to throttle the driver if we're in
 	 * canonical mode and don't have a newline yet!
 	 */
-	if (n_tty_receive_room(tty) < TTY_THRESHOLD_THROTTLE) {
+	if (tty->receive_room < TTY_THRESHOLD_THROTTLE) {
 		/* check TTY_THROTTLED first so it indicates our state */
 		if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
 		    tty->driver->throttle)
@@ -999,6 +1003,7 @@
 	if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
 		tty->raw = 1;
 		tty->real_raw = 1;
+		n_tty_set_room(tty);
 		return;
 	}
 	if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
@@ -1051,6 +1056,7 @@
 		else
 			tty->real_raw = 0;
 	}
+	n_tty_set_room(tty);
 }
 
 /**
@@ -1130,7 +1136,7 @@
  *
  */
  
-static inline int copy_from_read_buf(struct tty_struct *tty,
+static int copy_from_read_buf(struct tty_struct *tty,
 				      unsigned char __user **b,
 				      size_t *nr)
 
@@ -1308,6 +1314,7 @@
 				retval = -ERESTARTSYS;
 				break;
 			}
+			n_tty_set_room(tty);
 			clear_bit(TTY_DONT_FLIP, &tty->flags);
 			timeout = schedule_timeout(timeout);
 			set_bit(TTY_DONT_FLIP, &tty->flags);
@@ -1401,6 +1408,8 @@
 	} else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
 		 goto do_it_again;
 
+	n_tty_set_room(tty);
+
 	return retval;
 }
 
@@ -1553,7 +1562,6 @@
 	normal_poll,		/* poll */
 	NULL,			/* hangup */
 	n_tty_receive_buf,	/* receive_buf */
-	n_tty_receive_room,	/* receive_room */
 	n_tty_write_wakeup	/* write_wakeup */
 };
 
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index 9fb10c9..8a8ca32 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -1007,8 +1007,9 @@
 
 static void rx_ready_async(MGSLPC_INFO *info, int tcd)
 {
-	unsigned char data, status;
+	unsigned char data, status, flag;
 	int fifo_count;
+	int work = 0;
  	struct tty_struct *tty = info->tty;
  	struct mgsl_icount *icount = &info->icount;
 
@@ -1023,20 +1024,16 @@
 			fifo_count = 32;
 	} else
 		fifo_count = 32;
-	
+
+	tty_buffer_request_room(tty, fifo_count);
 	/* Flush received async data to receive data buffer. */ 
 	while (fifo_count) {
 		data   = read_reg(info, CHA + RXFIFO);
 		status = read_reg(info, CHA + RXFIFO);
 		fifo_count -= 2;
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			break;
-			
-		*tty->flip.char_buf_ptr = data;
 		icount->rx++;
-		
-		*tty->flip.flag_buf_ptr = 0;
+		flag = TTY_NORMAL;
 
 		// if no frameing/crc error then save data
 		// BIT7:parity error
@@ -1055,26 +1052,23 @@
 			status &= info->read_status_mask;
 
 			if (status & BIT7)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (status & BIT6)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
-		
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
+		work += tty_insert_flip_char(tty, data, flag);
 	}
 	issue_command(info, CHA, CMD_RXFIFO);
 
 	if (debug_level >= DEBUG_LEVEL_ISR) {
-		printk("%s(%d):rx_ready_async count=%d\n",
-			__FILE__,__LINE__,tty->flip.count);
+		printk("%s(%d):rx_ready_async",
+			__FILE__,__LINE__);
 		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,icount->rx,icount->brk,
 			icount->parity,icount->frame,icount->overrun);
 	}
 			
-	if (tty->flip.count)
+	if (work)
 		tty_flip_buffer_push(tty);
 }
 
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 49f3997..9b5a2c0 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -111,7 +111,7 @@
 	if (!to || tty->stopped)
 		return 0;
 
-	c = to->ldisc.receive_room(to);
+	c = to->receive_room;
 	if (c > count)
 		c = count;
 	to->ldisc.receive_buf(to, buf, NULL, c);
@@ -126,7 +126,7 @@
 	if (!to || tty->stopped)
 		return 0;
 
-	return to->ldisc.receive_room(to);
+	return to->receive_room;
 }
 
 /*
diff --git a/drivers/char/rio/riointr.c b/drivers/char/rio/riointr.c
index e42e7b5..ddda9c1 100644
--- a/drivers/char/rio/riointr.c
+++ b/drivers/char/rio/riointr.c
@@ -38,6 +38,7 @@
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <asm/io.h>
 #include <asm/system.h>
 #include <asm/string.h>
@@ -560,6 +561,7 @@
   struct PKT *PacketP;
   register uint	DataCnt;
   uchar *	ptr;
+  unsigned char *buf;
   int copied =0;
 
   static int intCount, RxIntCnt;
@@ -657,8 +659,7 @@
 	  ** and available space.
 	  */
 			
-	  transCount = min_t(unsigned int, PacketP->len & PKT_LEN_MASK,
-			   TTY_FLIPBUF_SIZE - TtyP->flip.count);
+	  transCount = tty_buffer_request_room(TtyP, PacketP->len & PKT_LEN_MASK);
 	  rio_dprintk (RIO_DEBUG_REC,  "port %d: Copy %d bytes\n", 
 				      PortP->PortNum, transCount);
 	  /*
@@ -678,9 +679,8 @@
 #endif
 	  ptr = (uchar *) PacketP->data + PortP->RxDataStart;
 
-	  rio_memcpy_fromio (TtyP->flip.char_buf_ptr, ptr, transCount);
-	  memset(TtyP->flip.flag_buf_ptr, TTY_NORMAL, transCount);
-
+	  tty_prepare_flip_string(TtyP, &buf, transCount);
+	  rio_memcpy_fromio (buf, ptr, transCount);
 #ifdef STATS
 	  /*
 	  ** keep a count for statistical purposes
@@ -690,9 +690,6 @@
 	  PortP->RxDataStart	+= transCount;
 	  PacketP->len		-= transCount;
 	  copied += transCount;
-	  TtyP->flip.count += transCount;
-	  TtyP->flip.char_buf_ptr += transCount;
-	  TtyP->flip.flag_buf_ptr += transCount;
 
 
 #ifdef ___DEBUG_IT___
diff --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c
index 5dae325..050e70e 100644
--- a/drivers/char/riscom8.c
+++ b/drivers/char/riscom8.c
@@ -46,6 +46,7 @@
 #include <linux/major.h>
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/tty_flip.h>
 
 #include <asm/uaccess.h>
 
@@ -354,28 +355,17 @@
 	struct riscom_port *port;
 	struct tty_struct *tty;
 	unsigned char status;
-	unsigned char ch;
+	unsigned char ch, flag;
 	
 	if (!(port = rc_get_port(bp, "Receive")))
 		return;
 
 	tty = port->tty;
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)  {
-		printk(KERN_WARNING "rc%d: port %d: Working around flip "
-				    "buffer overflow.\n",
-		       board_No(bp), port_No(port));
-		return;
-	}
 	
 #ifdef RC_REPORT_OVERRUN	
 	status = rc_in(bp, CD180_RCSR);
-	if (status & RCSR_OE)  {
+	if (status & RCSR_OE)
 		port->overrun++;
-#if 0		
-		printk(KERN_ERR "rc%d: port %d: Overrun. Total %ld overruns\n", 
-		       board_No(bp), port_No(port), port->overrun);
-#endif		
-	}
 	status &= port->mark_mask;
 #else	
 	status = rc_in(bp, CD180_RCSR) & port->mark_mask;
@@ -393,25 +383,24 @@
 	} else if (status & RCSR_BREAK)  {
 		printk(KERN_INFO "rc%d: port %d: Handling break...\n",
 		       board_No(bp), port_No(port));
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+		flag = TTY_BREAK;
 		if (port->flags & ASYNC_SAK)
 			do_SAK(tty);
 		
 	} else if (status & RCSR_PE) 
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+		flag = TTY_PARITY;
 	
 	else if (status & RCSR_FE) 
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+		flag = TTY_FRAME;
 	
         else if (status & RCSR_OE)
-		*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+		flag = TTY_OVERRUN;
 	
 	else
-		*tty->flip.flag_buf_ptr++ = 0;
+		flag = TTY_NORMAL;
 	
-	*tty->flip.char_buf_ptr++ = ch;
-	tty->flip.count++;
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_insert_flip_char(tty, ch, flag);
+	tty_flip_buffer_push(tty);
 }
 
 static inline void rc_receive(struct riscom_board const * bp)
@@ -432,17 +421,15 @@
 #endif	
 	
 	while (count--)  {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)  {
+		if (tty_buffer_request_room(tty, 1) == 0)  {
 			printk(KERN_WARNING "rc%d: port %d: Working around "
 					    "flip buffer overflow.\n",
 			       board_No(bp), port_No(port));
 			break;
 		}
-		*tty->flip.char_buf_ptr++ = rc_in(bp, CD180_RDR);
-		*tty->flip.flag_buf_ptr++ = 0;
-		tty->flip.count++;
+		tty_insert_flip_char(tty, rc_in(bp, CD180_RDR), TTY_NORMAL);
 	}
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_flip_buffer_push(tty);
 }
 
 static inline void rc_transmit(struct riscom_board const * bp)
diff --git a/drivers/char/rocket.c b/drivers/char/rocket.c
index d3bc731..0949dce 100644
--- a/drivers/char/rocket.c
+++ b/drivers/char/rocket.c
@@ -325,19 +325,16 @@
 {
 	unsigned int CharNStat;
 	int ToRecv, wRecv, space = 0, count;
-	unsigned char *cbuf;
-	char *fbuf;
+	unsigned char *cbuf, *chead;
+	char *fbuf, *fhead;
 	struct tty_ldisc *ld;
 
 	ld = tty_ldisc_ref(tty);
 
 	ToRecv = sGetRxCnt(cp);
-	if (ld)
-		space = ld->receive_room(tty);
+	space = tty->receive_room;
 	if (space > 2 * TTY_FLIPBUF_SIZE)
 		space = 2 * TTY_FLIPBUF_SIZE;
-	cbuf = tty->flip.char_buf;
-	fbuf = tty->flip.flag_buf;
 	count = 0;
 #ifdef ROCKET_DEBUG_INTR
 	printk(KERN_INFO "rp_do_receive(%d, %d)...", ToRecv, space);
@@ -350,9 +347,13 @@
 	if (ToRecv > space)
 		ToRecv = space;
 
+	ToRecv = tty_prepare_flip_string_flags(tty, &chead, &fhead, ToRecv);
 	if (ToRecv <= 0)
 		goto done;
 
+	cbuf = chead;
+	fbuf = fhead;
+
 	/*
 	 * if status indicates there are errored characters in the
 	 * FIFO, then enter status mode (a word in FIFO holds
@@ -399,7 +400,7 @@
 			else if (CharNStat & STMRCVROVRH)
 				*fbuf++ = TTY_OVERRUN;
 			else
-				*fbuf++ = 0;
+				*fbuf++ = TTY_NORMAL;
 			*cbuf++ = CharNStat & 0xff;
 			count++;
 			ToRecv--;
@@ -426,13 +427,13 @@
 			sInStrW(sGetTxRxDataIO(cp), (unsigned short *) cbuf, wRecv);
 		if (ToRecv & 1)
 			cbuf[ToRecv - 1] = sInB(sGetTxRxDataIO(cp));
-		memset(fbuf, 0, ToRecv);
+		memset(fbuf, TTY_NORMAL, ToRecv);
 		cbuf += ToRecv;
 		fbuf += ToRecv;
 		count += ToRecv;
 	}
 	/*  Push the data up to the tty layer */
-	ld->receive_buf(tty, tty->flip.char_buf, tty->flip.flag_buf, count);
+	ld->receive_buf(tty, cbuf, fbuf, count);
 done:
 	tty_ldisc_deref(ld);
 }
diff --git a/drivers/char/selection.c b/drivers/char/selection.c
index 5b187c8..71093a9 100644
--- a/drivers/char/selection.c
+++ b/drivers/char/selection.c
@@ -275,7 +275,8 @@
 int paste_selection(struct tty_struct *tty)
 {
 	struct vc_data *vc = (struct vc_data *)tty->driver_data;
-	int	pasted = 0, count;
+	int	pasted = 0;
+	unsigned int count;
 	struct  tty_ldisc *ld;
 	DECLARE_WAITQUEUE(wait, current);
 
@@ -293,7 +294,7 @@
 			continue;
 		}
 		count = sel_buffer_lth - pasted;
-		count = min(count, tty->ldisc.receive_room(tty));
+		count = min(count, tty->receive_room);
 		tty->ldisc.receive_buf(tty, sel_buffer + pasted, NULL, count);
 		pasted += count;
 	}
diff --git a/drivers/char/ser_a2232.c b/drivers/char/ser_a2232.c
index dda30e4..80a5b84 100644
--- a/drivers/char/ser_a2232.c
+++ b/drivers/char/ser_a2232.c
@@ -194,11 +194,6 @@
 */
 	struct tty_struct *tty = port->gs.tty;
 
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-		return;
-
-	tty->flip.count++;
-
 #if 0
 	switch(err) {
 	case TTY_BREAK:
@@ -212,8 +207,7 @@
 	}
 #endif
 
-	*tty->flip.flag_buf_ptr++ = err;
-	*tty->flip.char_buf_ptr++ = ch;
+	tty_insert_flip_char(tty, ch, err);
 	tty_flip_buffer_push(tty);
 }
 
diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
index a580748..f36342a 100644
--- a/drivers/char/serial167.c
+++ b/drivers/char/serial167.c
@@ -422,45 +422,35 @@
 	    base_addr[CyREOIR] = rfoc ? 0 : CyNOTRANS;
 	    return IRQ_HANDLED;
 	}
-	if (tty->flip.count < TTY_FLIPBUF_SIZE){
-	    tty->flip.count++;
+	if (tty_buffer_request_room(tty, 1) != 0){
 	    if (err & info->read_status_mask){
 		if(err & CyBREAK){
-		    *tty->flip.flag_buf_ptr++ = TTY_BREAK;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_BREAK);
 		    if (info->flags & ASYNC_SAK){
 			do_SAK(tty);
 		    }
 		}else if(err & CyFRAME){
-		    *tty->flip.flag_buf_ptr++ = TTY_FRAME;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_FRAME);
 		}else if(err & CyPARITY){
-		    *tty->flip.flag_buf_ptr++ = TTY_PARITY;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_PARITY);
 		}else if(err & CyOVERRUN){
-		    *tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
-		    *tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		    /*
 		       If the flip buffer itself is
 		       overflowing, we still loose
 		       the next incoming character.
 		     */
-		    if(tty->flip.count < TTY_FLIPBUF_SIZE){
-			tty->flip.count++;
-			*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-			*tty->flip.char_buf_ptr++ = data;
-		    }
+		    tty_insert_flip_char(tty, data, TTY_NORMAL);
+		}
 		/* These two conditions may imply */
 		/* a normal read should be done. */
 		/* else if(data & CyTIMEOUT) */
 		/* else if(data & CySPECHAR) */
 		}else{
-		    *tty->flip.flag_buf_ptr++ = 0;
-		    *tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, 0, TTY_NORMAL);
 		}
 	    }else{
-		*tty->flip.flag_buf_ptr++ = 0;
-		*tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, data, TTY_NORMAL);
 	    }
 	}else{
 	    /* there was a software buffer overrun
@@ -692,12 +682,7 @@
 #endif
 	while(char_count--){
 	    data = base_addr[CyRDR];
-	    if (tty->flip.count >= TTY_FLIPBUF_SIZE){
-		continue;
-	    }
-	    tty->flip.count++;
-	    *tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-	    *tty->flip.char_buf_ptr++ = data;
+	    tty_insert_flip_char(tty, data, TTY_NORMAL);
 #ifdef CYCLOM_16Y_HACK
 	    udelay(10L);
 #endif
diff --git a/drivers/char/specialix.c b/drivers/char/specialix.c
index 0bbfce4..0a574bd 100644
--- a/drivers/char/specialix.c
+++ b/drivers/char/specialix.c
@@ -85,6 +85,7 @@
 #include <linux/interrupt.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/mm.h>
 #include <linux/serial.h>
 #include <linux/fcntl.h>
@@ -665,7 +666,7 @@
 	struct specialix_port *port;
 	struct tty_struct *tty;
 	unsigned char status;
-	unsigned char ch;
+	unsigned char ch, flag;
 
 	func_enter();
 
@@ -676,8 +677,6 @@
 		return;
 	}
 	tty = port->tty;
-	dprintk (SX_DEBUG_RX, "port: %p count: %d BUFF_SIZE: %d\n",
-		 port,  tty->flip.count, TTY_FLIPBUF_SIZE);
 
 	status = sx_in(bp, CD186x_RCSR);
 
@@ -691,7 +690,7 @@
 
 	/* This flip buffer check needs to be below the reading of the
 	   status register to reset the chip's IRQ.... */
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+	if (tty_buffer_request_room(tty, 1) == 0) {
 		dprintk(SX_DEBUG_FIFO, "sx%d: port %d: Working around flip buffer overflow.\n",
 		       board_No(bp), port_No(port));
 		func_exit();
@@ -712,26 +711,24 @@
 	} else if (status & RCSR_BREAK) {
 		dprintk(SX_DEBUG_RX, "sx%d: port %d: Handling break...\n",
 		       board_No(bp), port_No(port));
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+		flag = TTY_BREAK;
 		if (port->flags & ASYNC_SAK)
 			do_SAK(tty);
 
 	} else if (status & RCSR_PE)
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+		flag = TTY_PARITY;
 
 	else if (status & RCSR_FE)
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+		flag = TTY_FRAME;
 
 	else if (status & RCSR_OE)
-		*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+		flag = TTY_OVERRUN;
 
 	else
-		*tty->flip.flag_buf_ptr++ = 0;
+		flag = TTY_NORMAL;
 
-	*tty->flip.char_buf_ptr++ = ch;
-	tty->flip.count++;
-	schedule_delayed_work(&tty->flip.work, 1);
-
+	if(tty_insert_flip_char(tty, ch, flag))
+		tty_flip_buffer_push(tty);
 	func_exit();
 }
 
@@ -755,18 +752,11 @@
 	dprintk (SX_DEBUG_RX, "port: %p: count: %d\n", port, count);
 	port->hits[count > 8 ? 9 : count]++;
 
-	while (count--) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			printk(KERN_INFO "sx%d: port %d: Working around flip buffer overflow.\n",
-			       board_No(bp), port_No(port));
-			break;
-		}
-		*tty->flip.char_buf_ptr++ = sx_in(bp, CD186x_RDR);
-		*tty->flip.flag_buf_ptr++ = 0;
-		tty->flip.count++;
-	}
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_buffer_request_room(tty, count);
 
+	while (count--)
+		tty_insert_flip_char(tty, sx_in(bp, CD186x_RDR), TTY_NORMAL);
+	tty_flip_buffer_push(tty);
 	func_exit();
 }
 
diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index acef2ab..0e20780 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -2901,7 +2901,8 @@
 	if (portp->tty != (struct tty_struct *) NULL) {
 		if (portp->tty->driver_data == portp) {
 			portp->stats.ttystate = portp->tty->flags;
-			portp->stats.rxbuffered = portp->tty->flip.count;
+			/* No longer available as a statistic */
+			portp->stats.rxbuffered = 1; /*portp->tty->flip.count; */
 			if (portp->tty->termios != (struct termios *) NULL) {
 				portp->stats.cflags = portp->tty->termios->c_cflag;
 				portp->stats.iflags = portp->tty->termios->c_iflag;
@@ -4045,9 +4046,7 @@
 	if ((ioack & ACK_TYPMASK) == ACK_TYPRXGOOD) {
 		outb((RDCR + portp->uartaddr), ioaddr);
 		len = inb(ioaddr + EREG_DATA);
-		if ((tty == (struct tty_struct *) NULL) ||
-		    (tty->flip.char_buf_ptr == (char *) NULL) ||
-		    ((buflen = TTY_FLIPBUF_SIZE - tty->flip.count) == 0)) {
+		if (tty == NULL || (buflen = tty_buffer_request_room(tty, len)) == 0) {
 			len = MIN(len, sizeof(stl_unwanted));
 			outb((RDSR + portp->uartaddr), ioaddr);
 			insb((ioaddr + EREG_DATA), &stl_unwanted[0], len);
@@ -4056,12 +4055,10 @@
 		} else {
 			len = MIN(len, buflen);
 			if (len > 0) {
+				unsigned char *ptr;
 				outb((RDSR + portp->uartaddr), ioaddr);
-				insb((ioaddr + EREG_DATA), tty->flip.char_buf_ptr, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.flag_buf_ptr += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.count += len;
+				tty_prepare_flip_string(tty, &ptr, len);
+				insb((ioaddr + EREG_DATA), ptr, len);
 				tty_schedule_flip(tty);
 				portp->stats.rxtotal += len;
 			}
@@ -4085,8 +4082,7 @@
 				portp->stats.txxoff++;
 			goto stl_rxalldone;
 		}
-		if ((tty != (struct tty_struct *) NULL) &&
-		    ((portp->rxignoremsk & status) == 0)) {
+		if (tty != NULL && (portp->rxignoremsk & status) == 0) {
 			if (portp->rxmarkmsk & status) {
 				if (status & ST_BREAK) {
 					status = TTY_BREAK;
@@ -4106,14 +4102,8 @@
 			} else {
 				status = 0;
 			}
-			if (tty->flip.char_buf_ptr != (char *) NULL) {
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					*tty->flip.flag_buf_ptr++ = status;
-					*tty->flip.char_buf_ptr++ = ch;
-					tty->flip.count++;
-				}
-				tty_schedule_flip(tty);
-			}
+			tty_insert_flip_char(tty, ch, status);
+			tty_schedule_flip(tty);
 		}
 	} else {
 		printk("STALLION: bad RX interrupt ack value=%x\n", ioack);
@@ -5012,9 +5002,7 @@
 	len = inb(ioaddr + XP_DATA) + 1;
 
 	if ((iack & IVR_TYPEMASK) == IVR_RXDATA) {
-		if ((tty == (struct tty_struct *) NULL) ||
-		    (tty->flip.char_buf_ptr == (char *) NULL) ||
-		    ((buflen = TTY_FLIPBUF_SIZE - tty->flip.count) == 0)) {
+		if (tty == NULL || (buflen = tty_buffer_request_room(tty, len)) == 0) {
 			len = MIN(len, sizeof(stl_unwanted));
 			outb(GRXFIFO, (ioaddr + XP_ADDR));
 			insb((ioaddr + XP_DATA), &stl_unwanted[0], len);
@@ -5023,12 +5011,10 @@
 		} else {
 			len = MIN(len, buflen);
 			if (len > 0) {
+				unsigned char *ptr;
 				outb(GRXFIFO, (ioaddr + XP_ADDR));
-				insb((ioaddr + XP_DATA), tty->flip.char_buf_ptr, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.flag_buf_ptr += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.count += len;
+				tty_prepare_flip_string(tty, &ptr, len);
+				insb((ioaddr + XP_DATA), ptr, len);
 				tty_schedule_flip(tty);
 				portp->stats.rxtotal += len;
 			}
@@ -5096,14 +5082,8 @@
 			status = 0;
 		}
 
-		if (tty->flip.char_buf_ptr != (char *) NULL) {
-			if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-				*tty->flip.flag_buf_ptr++ = status;
-				*tty->flip.char_buf_ptr++ = ch;
-				tty->flip.count++;
-			}
-			tty_schedule_flip(tty);
-		}
+		tty_insert_flip_char(tty, ch, status);
+		tty_schedule_flip(tty);
 
 		if (status == 0)
 			portp->stats.rxtotal++;
diff --git a/drivers/char/sx.c b/drivers/char/sx.c
index 564f317..64bf89c 100644
--- a/drivers/char/sx.c
+++ b/drivers/char/sx.c
@@ -1085,6 +1085,7 @@
 	int rx_op;
 	struct tty_struct *tty;
 	int copied=0;
+	unsigned char *rp;
 
 	func_enter2 ();
 	tty = port->gs.tty;
@@ -1095,8 +1096,8 @@
 		sx_dprintk (SX_DEBUG_RECEIVE, "rxop=%d, c = %d.\n", rx_op, c); 
 
 		/* Don't copy more bytes than there is room for in the buffer */
-		if (tty->flip.count + c > TTY_FLIPBUF_SIZE) 
-			c = TTY_FLIPBUF_SIZE - tty->flip.count;
+
+		c = tty_prepare_flip_string(tty, &rp, c);
 
 		sx_dprintk (SX_DEBUG_RECEIVE, "c = %d.\n", c); 
 
@@ -1111,14 +1112,8 @@
 		sx_dprintk (SX_DEBUG_RECEIVE , "Copying over %d chars. First is %d at %lx\n", c, 
 		            read_sx_byte (port->board, CHAN_OFFSET(port,hi_rxbuf) + rx_op),
 		            CHAN_OFFSET(port, hi_rxbuf)); 
-		memcpy_fromio (tty->flip.char_buf_ptr, 
+		memcpy_fromio (rp,
 		               port->board->base + CHAN_OFFSET(port,hi_rxbuf) + rx_op, c);
-		memset(tty->flip.flag_buf_ptr, TTY_NORMAL, c);
-
-		/* Update the kernel buffer end */
-		tty->flip.count += c;
-		tty->flip.char_buf_ptr += c;
-		tty->flip.flag_buf_ptr += c;
 
 		/* This one last. ( Not essential.)
 		   It allows the card to start putting more data into the buffer! 
diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index 789572f..9f1b466 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -1467,6 +1467,7 @@
 {
 	int Fifocount;
 	u16 status;
+	int work = 0;
 	unsigned char DataByte;
  	struct tty_struct *tty = info->tty;
  	struct	mgsl_icount *icount = &info->icount;
@@ -1487,6 +1488,8 @@
 	/* flush the receive FIFO */
 
 	while( (Fifocount = (usc_InReg(info,RICR) >> 8)) ) {
+		int flag;
+
 		/* read one byte from RxFIFO */
 		outw( (inw(info->io_base + CCAR) & 0x0780) | (RDR+LSBONLY),
 		      info->io_base + CCAR );
@@ -1498,13 +1501,9 @@
 				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) )
 			usc_UnlatchRxstatusBits(info,RXSTATUS_ALL);
 		
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			continue;
-			
-		*tty->flip.char_buf_ptr = DataByte;
 		icount->rx++;
 		
-		*tty->flip.flag_buf_ptr = 0;
+		flag = 0;
 		if ( status & (RXSTATUS_FRAMING_ERROR + RXSTATUS_PARITY_ERROR +
 				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) ) {
 			printk("rxerr=%04X\n",status);					
@@ -1530,41 +1529,31 @@
 			status &= info->read_status_mask;
 		
 			if (status & RXSTATUS_BREAK_RECEIVED) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 				if (info->flags & ASYNC_SAK)
 					do_SAK(tty);
 			} else if (status & RXSTATUS_PARITY_ERROR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (status & RXSTATUS_FRAMING_ERROR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
-			if (status & RXSTATUS_OVERRUN) {
-				/* Overrun is special, since it's
-				 * reported immediately, and doesn't
-				 * affect the current character
-				 */
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					tty->flip.count++;
-					tty->flip.flag_buf_ptr++;
-					tty->flip.char_buf_ptr++;
-					*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-				}
-			}
+				flag = TTY_FRAME;
 		}	/* end of if (error) */
-		
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
+		tty_insert_flip_char(tty, DataByte, flag);
+		if (status & RXSTATUS_OVERRUN) {
+			/* Overrun is special, since it's
+			 * reported immediately, and doesn't
+			 * affect the current character
+			 */
+			work += tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+		}
 	}
 
 	if ( debug_level >= DEBUG_LEVEL_ISR ) {
-		printk("%s(%d):mgsl_isr_receive_data flip count=%d\n",
-			__FILE__,__LINE__,tty->flip.count);
 		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,icount->rx,icount->brk,
 			icount->parity,icount->frame,icount->overrun);
 	}
 			
-	if ( tty->flip.count )
+	if(work)
 		tty_flip_buffer_push(tty);
 }
 
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 41759cd..79c81de 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -1749,6 +1749,9 @@
 	unsigned char status;
 	struct slgt_desc *bufs = info->rbufs;
 	int i, count;
+	int chars = 0;
+	int stat;
+	unsigned char ch;
 
 	start = end = info->rbuf_current;
 
@@ -1760,16 +1763,15 @@
 		DBGDATA(info, p, count, "rx");
 
 		for(i=0 ; i < count; i+=2, p+=2) {
-			if (tty) {
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					tty_flip_buffer_push(tty);
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					break;
-				*tty->flip.char_buf_ptr = *p;
-				*tty->flip.flag_buf_ptr = 0;
+			if (tty && chars) {
+				tty_flip_buffer_push(tty);
+				chars = 0;
 			}
+			ch = *p;
 			icount->rx++;
 
+			stat = 0;
+
 			if ((status = *(p+1) & (BIT9 + BIT8))) {
 				if (status & BIT9)
 					icount->parity++;
@@ -1778,17 +1780,14 @@
 				/* discard char if tty control flags say so */
 				if (status & info->ignore_status_mask)
 					continue;
-				if (tty) {
-					if (status & BIT9)
-						*tty->flip.flag_buf_ptr = TTY_PARITY;
-					else if (status & BIT8)
-						*tty->flip.flag_buf_ptr = TTY_FRAME;
-				}
+				if (status & BIT9)
+					stat = TTY_PARITY;
+				else if (status & BIT8)
+					stat = TTY_FRAME;
 			}
 			if (tty) {
-				tty->flip.flag_buf_ptr++;
-				tty->flip.char_buf_ptr++;
-				tty->flip.count++;
+				tty_insert_flip_char(tty, ch, stat);
+				chars++;
 			}
 		}
 
@@ -1811,7 +1810,7 @@
 			break;
 	}
 
-	if (tty && tty->flip.count)
+	if (tty && chars)
 		tty_flip_buffer_push(tty);
 }
 
@@ -2029,7 +2028,7 @@
 			if (info->tty) {
 				if (!(status & info->ignore_status_mask)) {
 					if (info->read_status_mask & MASK_BREAK) {
-						*info->tty->flip.flag_buf_ptr = TTY_BREAK;
+						tty_insert_flip_char(info->tty, 0, TTY_BREAK);
 						if (info->flags & ASYNC_SAK)
 							do_SAK(info->tty);
 					}
diff --git a/drivers/char/synclinkmp.c b/drivers/char/synclinkmp.c
index a9467e7..960adb2 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -2196,7 +2196,7 @@
 			if ( tty ) {
 				if (!(status & info->ignore_status_mask1)) {
 					if (info->read_status_mask1 & BRKD) {
-						*tty->flip.flag_buf_ptr = TTY_BREAK;
+						tty_insert_flip_char(tty, 0, TTY_BREAK);
 						if (info->flags & ASYNC_SAK)
 							do_SAK(tty);
 					}
@@ -2240,16 +2240,10 @@
 
 	while((status = read_reg(info,CST0)) & BIT0)
 	{
+		int flag = 0;
+		int over = 0;
 		DataByte = read_reg(info,TRB);
 
-		if ( tty ) {
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				continue;
-
-			*tty->flip.char_buf_ptr = DataByte;
-			*tty->flip.flag_buf_ptr = 0;
-		}
-
 		icount->rx++;
 
 		if ( status & (PE + FRME + OVRN) ) {
@@ -2272,42 +2266,34 @@
 
 			if ( tty ) {
 				if (status & PE)
-					*tty->flip.flag_buf_ptr = TTY_PARITY;
+					flag = TTY_PARITY;
 				else if (status & FRME)
-					*tty->flip.flag_buf_ptr = TTY_FRAME;
+					flag = TTY_FRAME;
 				if (status & OVRN) {
 					/* Overrun is special, since it's
 					 * reported immediately, and doesn't
 					 * affect the current character
 					 */
-					if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-						tty->flip.count++;
-						tty->flip.flag_buf_ptr++;
-						tty->flip.char_buf_ptr++;
-						*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-					}
+					over = 1;
 				}
 			}
 		}	/* end of if (error) */
 
 		if ( tty ) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+			tty_insert_flip_char(tty, DataByte, flag);
+			if (over)
+				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		}
 	}
 
 	if ( debug_level >= DEBUG_LEVEL_ISR ) {
-		printk("%s(%d):%s isr_rxrdy() flip count=%d\n",
-			__FILE__,__LINE__,info->device_name,
-			tty ? tty->flip.count : 0);
 		printk("%s(%d):%s rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,info->device_name,
 			icount->rx,icount->brk,icount->parity,
 			icount->frame,icount->overrun);
 	}
 
-	if ( tty && tty->flip.count )
+	if ( tty )
 		tty_flip_buffer_push(tty);
 }
 
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 4b1eef5..1eda82b 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -166,9 +166,12 @@
 	return tty;
 }
 
+static void tty_buffer_free_all(struct tty_struct *);
+
 static inline void free_tty_struct(struct tty_struct *tty)
 {
 	kfree(tty->write_buf);
+	tty_buffer_free_all(tty);
 	kfree(tty);
 }
 
@@ -231,6 +234,201 @@
 }
 
 /*
+ * Tty buffer allocation management
+ */
+
+static void tty_buffer_free_all(struct tty_struct *tty)
+{
+	struct tty_buffer *thead;
+	while((thead = tty->buf.head) != NULL) {
+		tty->buf.head = thead->next;
+		kfree(thead);
+	}
+	while((thead = tty->buf.free) != NULL) {
+		tty->buf.free = thead->next;
+		kfree(thead);
+	}
+	tty->buf.tail = NULL;
+}
+
+static void tty_buffer_init(struct tty_struct *tty)
+{
+	tty->buf.head = NULL;
+	tty->buf.tail = NULL;
+	tty->buf.free = NULL;
+}
+
+static struct tty_buffer *tty_buffer_alloc(size_t size)
+{
+	struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+	if(p == NULL)
+		return NULL;
+	p->used = 0;
+	p->size = size;
+	p->next = NULL;
+	p->char_buf_ptr = (char *)(p->data);
+	p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
+/* 	printk("Flip create %p\n", p); */
+	return p;
+}
+
+/* Must be called with the tty_read lock held. This needs to acquire strategy
+   code to decide if we should kfree or relink a given expired buffer */
+
+static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
+{
+	/* Dumb strategy for now - should keep some stats */
+/* 	printk("Flip dispose %p\n", b); */
+	if(b->size >= 512)
+		kfree(b);
+	else {
+		b->next = tty->buf.free;
+		tty->buf.free = b;
+	}
+}
+
+static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
+{
+	struct tty_buffer **tbh = &tty->buf.free;
+	while((*tbh) != NULL) {
+		struct tty_buffer *t = *tbh;
+		if(t->size >= size) {
+			*tbh = t->next;
+			t->next = NULL;
+			t->used = 0;
+			/* DEBUG ONLY */
+			memset(t->data, '*', size);
+/* 			printk("Flip recycle %p\n", t); */
+			return t;
+		}
+		tbh = &((*tbh)->next);
+	}
+	/* Round the buffer size out */
+	size = (size + 0xFF) & ~ 0xFF;
+	return tty_buffer_alloc(size);
+	/* Should possibly check if this fails for the largest buffer we
+	   have queued and recycle that ? */
+}
+
+int tty_buffer_request_room(struct tty_struct *tty, size_t size)
+{
+	struct tty_buffer *b = tty->buf.head, *n;
+	int left = 0;
+
+	/* OPTIMISATION: We could keep a per tty "zero" sized buffer to
+	   remove this conditional if its worth it. This would be invisible
+	   to the callers */
+	if(b != NULL)
+		left = b->size - b->used;
+	if(left >= size)
+		return size;
+	/* This is the slow path - looking for new buffers to use */
+	n = tty_buffer_find(tty, size);
+	if(n == NULL)
+		return left;
+	n->next = b;
+	if(b != NULL)
+		b->next = n;
+	else
+		tty->buf.head = n;
+	tty->buf.tail = n;
+	return size;
+}
+
+EXPORT_SYMBOL_GPL(tty_buffer_request_room);
+
+int tty_insert_flip_string(struct tty_struct *tty, unsigned char *chars, size_t size)
+{
+	int copied = 0;
+	do {
+		int space = tty_buffer_request_room(tty, size - copied);
+		struct tty_buffer *tb = tty->buf.tail;
+		/* If there is no space then tb may be NULL */
+		if(unlikely(space == 0))
+			break;
+		memcpy(tb->char_buf_ptr + tb->used, chars, space);
+		memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
+		tb->used += space;
+		copied += space;
+		chars += space;
+/* 		printk("Flip insert %d.\n", space); */
+	}
+	/* There is a small chance that we need to split the data over
+	   several buffers. If this is the case we must loop */
+	while (unlikely(size > copied));
+	return copied;
+}
+
+EXPORT_SYMBOL_GPL(tty_insert_flip_string);
+
+int tty_insert_flip_string_flags(struct tty_struct *tty, unsigned char *chars, char *flags, size_t size)
+{
+	int copied = 0;
+	do {
+		int space = tty_buffer_request_room(tty, size - copied);
+		struct tty_buffer *tb = tty->buf.tail;
+		/* If there is no space then tb may be NULL */
+		if(unlikely(space == 0))
+			break;
+		memcpy(tb->char_buf_ptr + tb->used, chars, space);
+		memcpy(tb->flag_buf_ptr + tb->used, flags, space);
+		tb->used += space;
+		copied += space;
+		chars += space;
+		flags += space;
+	}
+	/* There is a small chance that we need to split the data over
+	   several buffers. If this is the case we must loop */
+	while (unlikely(size > copied));
+	return copied;
+}
+
+EXPORT_SYMBOL_GPL(tty_insert_flip_string_flags);
+
+
+/*
+ *	Prepare a block of space in the buffer for data. Returns the length
+ *	available and buffer pointer to the space which is now allocated and
+ *	accounted for as ready for normal characters. This is used for drivers
+ *	that need their own block copy routines into the buffer. There is no
+ *	guarantee the buffer is a DMA target!
+ */
+
+int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size)
+{
+	int space = tty_buffer_request_room(tty, size);
+	struct tty_buffer *tb = tty->buf.tail;
+	*chars = tb->char_buf_ptr + tb->used;
+	memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
+	tb->used += space;
+	return space;
+}
+
+EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
+
+/*
+ *	Prepare a block of space in the buffer for data. Returns the length
+ *	available and buffer pointer to the space which is now allocated and
+ *	accounted for as ready for characters. This is used for drivers
+ *	that need their own block copy routines into the buffer. There is no
+ *	guarantee the buffer is a DMA target!
+ */
+
+int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size)
+{
+	int space = tty_buffer_request_room(tty, size);
+	struct tty_buffer *tb = tty->buf.tail;
+	*chars = tb->char_buf_ptr + tb->used;
+	*flags = tb->flag_buf_ptr + tb->used;
+	tb->used += space;
+	return space;
+}
+
+EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
+
+
+
+/*
  *	This is probably overkill for real world processors but
  *	they are not on hot paths so a little discipline won't do 
  *	any harm.
@@ -492,6 +690,17 @@
 	if (ld == NULL)
 		return -EINVAL;
 
+	/*
+	 *	No more input please, we are switching. The new ldisc
+	 *	will update this value in the ldisc open function
+	 */
+
+	tty->receive_room = 0;
+
+	/*
+	 *	Problem: What do we do if this blocks ?
+	 */
+
 	tty_wait_until_sent(tty, 0);
 
 	if (tty->ldisc.num == ldisc) {
@@ -560,9 +769,9 @@
 	 *	we say so later on.
 	 */
 
-	work = cancel_delayed_work(&tty->flip.work);
+	work = cancel_delayed_work(&tty->buf.work);
 	/*
-	 * Wait for ->hangup_work and ->flip.work handlers to terminate
+	 * Wait for ->hangup_work and ->buf.work handlers to terminate
 	 */
 	 
 	flush_scheduled_work();
@@ -616,7 +825,7 @@
 	/* Restart it in case no characters kick it off. Safe if
 	   already running */
 	if (work)
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 	return retval;
 }
 
@@ -1721,10 +1930,10 @@
 	 */
 	clear_bit(TTY_LDISC, &tty->flags);
 	clear_bit(TTY_DONT_FLIP, &tty->flags);
-	cancel_delayed_work(&tty->flip.work);
+	cancel_delayed_work(&tty->buf.work);
 
 	/*
-	 * Wait for ->hangup_work and ->flip.work handlers to terminate
+	 * Wait for ->hangup_work and ->buf.work handlers to terminate
 	 */
 	 
 	flush_scheduled_work();
@@ -2518,17 +2727,15 @@
 
 /*
  * This routine is called out of the software interrupt to flush data
- * from the flip buffer to the line discipline. 
+ * from the buffer chain to the line discipline.
  */
  
 static void flush_to_ldisc(void *private_)
 {
 	struct tty_struct *tty = (struct tty_struct *) private_;
-	unsigned char	*cp;
-	char		*fp;
-	int		count;
 	unsigned long 	flags;
 	struct tty_ldisc *disc;
+	struct tty_buffer *tbuf;
 
 	disc = tty_ldisc_ref(tty);
 	if (disc == NULL)	/*  !TTY_LDISC */
@@ -2538,28 +2745,22 @@
 		/*
 		 * Do it after the next timer tick:
 		 */
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 		goto out;
 	}
 	spin_lock_irqsave(&tty->read_lock, flags);
-	if (tty->flip.buf_num) {
-		cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
-		fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
-		tty->flip.buf_num = 0;
-		tty->flip.char_buf_ptr = tty->flip.char_buf;
-		tty->flip.flag_buf_ptr = tty->flip.flag_buf;
-	} else {
-		cp = tty->flip.char_buf;
-		fp = tty->flip.flag_buf;
-		tty->flip.buf_num = 1;
-		tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
-		tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
+	while((tbuf = tty->buf.head) != NULL) {
+		tty->buf.head = tbuf->next;
+		spin_unlock_irqrestore(&tty->read_lock, flags);
+		/* printk("Process buffer %p for %d\n", tbuf, tbuf->used); */
+		disc->receive_buf(tty, tbuf->char_buf_ptr,
+				       tbuf->flag_buf_ptr,
+				       tbuf->used);
+		spin_lock_irqsave(&tty->read_lock, flags);
+		tty_buffer_free(tty, tbuf);
 	}
-	count = tty->flip.count;
-	tty->flip.count = 0;
+	tty->buf.tail = NULL;
 	spin_unlock_irqrestore(&tty->read_lock, flags);
-
-	disc->receive_buf(tty, cp, fp, count);
 out:
 	tty_ldisc_deref(disc);
 }
@@ -2654,11 +2855,12 @@
 	if (tty->low_latency)
 		flush_to_ldisc((void *) tty);
 	else
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 }
 
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
+
 /*
  * This subroutine initializes a tty structure.
  */
@@ -2669,10 +2871,10 @@
 	tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
 	tty->pgrp = -1;
 	tty->overrun_time = jiffies;
-	tty->flip.char_buf_ptr = tty->flip.char_buf;
-	tty->flip.flag_buf_ptr = tty->flip.flag_buf;
-	INIT_WORK(&tty->flip.work, flush_to_ldisc, tty);
-	init_MUTEX(&tty->flip.pty_sem);
+	tty->buf.head = tty->buf.tail = NULL;
+	tty_buffer_init(tty);
+	INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
+	init_MUTEX(&tty->buf.pty_sem);
 	init_MUTEX(&tty->termios_sem);
 	init_waitqueue_head(&tty->write_wait);
 	init_waitqueue_head(&tty->read_wait);
diff --git a/drivers/char/viocons.c b/drivers/char/viocons.c
index 4d75c26..cb82ebf 100644
--- a/drivers/char/viocons.c
+++ b/drivers/char/viocons.c
@@ -993,11 +993,10 @@
 		 * Don't attempt to copy more data into the buffer than we
 		 * have room for because it would fail without indication.
 		 */
-		if ((tty->flip.count + 1) > TTY_FLIPBUF_SIZE) {
+		if(tty_insert_flip_char(tty, cevent->data[index], TTY_NORMAL) == 0) {
 			printk(VIOCONS_KERN_WARN "input buffer overflow!\n");
 			break;
 		}
-		tty_insert_flip_char(tty, cevent->data[index], TTY_NORMAL);
 	}
 
 	/* if cevent->len == 0 then no data was added to the buffer and flip.count == 0 */
diff --git a/drivers/char/vme_scc.c b/drivers/char/vme_scc.c
index 33e71e2..d932528 100644
--- a/drivers/char/vme_scc.c
+++ b/drivers/char/vme_scc.c
@@ -434,13 +434,7 @@
 		SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);
 		return IRQ_HANDLED;
 	}
-	if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = 0;
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
-	}
+	tty_insert_flip_char(tty, ch, 0);
 
 	/* Check if another character is already ready; in that case, the
 	 * spcond_int() function must be used, because this character may have an
@@ -487,13 +481,7 @@
 		else
 			err = 0;
 
-		if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-			*tty->flip.char_buf_ptr = ch;
-			*tty->flip.flag_buf_ptr = err;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		tty_insert_flip_char(tty, ch, err);
 
 		/* ++TeSche: *All* errors have to be cleared manually,
 		 * else the condition persists for the next chars