TTY: crisv10, remove unused tmp_buf

This used to be a helper buffer for generic_serial. generic_serial is
gone, tmp_buf shall be removed.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Mikael Starvik <starvik@axis.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/crisv10.c

@@ -952,19 +952,6 @@ static const struct control_pins e100_modem_pins[NR_PORTS] =
 /* Input */
 #define E100_DSR_GET(info) ((*e100_modem_pins[(info)->line].dsr_port) & e100_modem_pins[(info)->line].dsr_mask)
 
-
-/*
- * tmp_buf is used as a temporary buffer by serial_write.  We need to
- * lock it in case the memcpy_fromfs blocks while swapping in a page,
- * and some other program tries to do a serial write at the same time.
- * Since the lock will only come under contention when the system is
- * swapping and available memory is low, it makes sense to share one
- * buffer across all the serial ports, since it significantly saves
- * memory if large numbers of serial ports are open.
- */
-static unsigned char *tmp_buf;
-static DEFINE_MUTEX(tmp_buf_mutex);
-
 /* Calculate the chartime depending on baudrate, numbor of bits etc. */
 static void update_char_time(struct e100_serial * info)
 {
@@ -3150,7 +3137,7 @@ static int rs_raw_write(struct tty_struct *tty,
 
 	/* first some sanity checks */
 
-	if (!tty || !info->xmit.buf || !tmp_buf)
+	if (!tty || !info->xmit.buf)
 		return 0;
 
 #ifdef SERIAL_DEBUG_DATA
@@ -4106,7 +4093,6 @@ rs_open(struct tty_struct *tty, struct file * filp)
 {
 	struct e100_serial	*info;
 	int 			retval;
-	unsigned long           page;
 	int                     allocated_resources = 0;
 
 	info = rs_table + tty->index;
@@ -4124,17 +4110,6 @@ rs_open(struct tty_struct *tty, struct file * filp)
 
 	tty->low_latency = !!(info->flags & ASYNC_LOW_LATENCY);
 
-	if (!tmp_buf) {
-		page = get_zeroed_page(GFP_KERNEL);
-		if (!page) {
-			return -ENOMEM;
-		}
-		if (tmp_buf)
-			free_page(page);
-		else
-			tmp_buf = (unsigned char *) page;
-	}
-
 	/*
 	 * If the port is in the middle of closing, bail out now
 	 */