diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index 0658fc5..2b03d4d 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -81,7 +81,6 @@
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/delay.h>
 #include <linux/netdevice.h>
 #include <linux/vmalloc.h>
@@ -2436,7 +2435,9 @@
 	if (!user_icount) {
 		memset(&info->icount, 0, sizeof(info->icount));
 	} else {
+		mutex_lock(&info->port.mutex);
 		COPY_TO_USER(err, user_icount, &info->icount, sizeof(struct mgsl_icount));
+		mutex_unlock(&info->port.mutex);
 		if (err)
 			return -EFAULT;
 	}
@@ -2461,7 +2462,9 @@
 		printk("%s(%d):mgsl_get_params(%s)\n",
 			 __FILE__,__LINE__, info->device_name);
 			
+	mutex_lock(&info->port.mutex);
 	COPY_TO_USER(err,user_params, &info->params, sizeof(MGSL_PARAMS));
+	mutex_unlock(&info->port.mutex);
 	if (err) {
 		if ( debug_level >= DEBUG_LEVEL_INFO )
 			printk( "%s(%d):mgsl_get_params(%s) user buffer copy failed\n",
@@ -2501,11 +2504,13 @@
 		return -EFAULT;
 	}
 	
+	mutex_lock(&info->port.mutex);
 	spin_lock_irqsave(&info->irq_spinlock,flags);
 	memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
 	spin_unlock_irqrestore(&info->irq_spinlock,flags);
 	
  	mgsl_change_params(info);
+	mutex_unlock(&info->port.mutex);
 	
 	return 0;
 	
@@ -2935,7 +2940,6 @@
 		    unsigned int cmd, unsigned long arg)
 {
 	struct mgsl_struct * info = tty->driver_data;
-	int ret;
 	
 	if (debug_level >= DEBUG_LEVEL_INFO)
 		printk("%s(%d):mgsl_ioctl %s cmd=%08X\n", __FILE__,__LINE__,
@@ -2950,10 +2954,7 @@
 		    return -EIO;
 	}
 
-	lock_kernel();
-	ret = mgsl_ioctl_common(info, cmd, arg);
-	unlock_kernel();
-	return ret;
+	return mgsl_ioctl_common(info, cmd, arg);
 }
 
 static int mgsl_ioctl_common(struct mgsl_struct *info, unsigned int cmd, unsigned long arg)
@@ -3109,12 +3110,14 @@
 
 	if (tty_port_close_start(&info->port, tty, filp) == 0)			 
 		goto cleanup;
-			
+
+	mutex_lock(&info->port.mutex);
  	if (info->port.flags & ASYNC_INITIALIZED)
  		mgsl_wait_until_sent(tty, info->timeout);
 	mgsl_flush_buffer(tty);
 	tty_ldisc_flush(tty);
 	shutdown(info);
+	mutex_unlock(&info->port.mutex);
 
 	tty_port_close_end(&info->port, tty);	
 	info->port.tty = NULL;
@@ -3162,7 +3165,6 @@
 	 * Note: use tight timings here to satisfy the NIST-PCTS.
 	 */ 
 
-	lock_kernel();
 	if ( info->params.data_rate ) {
 	       	char_time = info->timeout/(32 * 5);
 		if (!char_time)
@@ -3192,7 +3194,6 @@
 				break;
 		}
 	}
-	unlock_kernel();
       
 exit:
 	if (debug_level >= DEBUG_LEVEL_INFO)
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 334cf5c..3c7ac6a 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -40,8 +40,8 @@
 #define DBGBH(fmt) if (debug_level >= DEBUG_LEVEL_BH) printk fmt
 #define DBGISR(fmt) if (debug_level >= DEBUG_LEVEL_ISR) printk fmt
 #define DBGDATA(info, buf, size, label) if (debug_level >= DEBUG_LEVEL_DATA) trace_block((info), (buf), (size), (label))
-//#define DBGTBUF(info) dump_tbufs(info)
-//#define DBGRBUF(info) dump_rbufs(info)
+/*#define DBGTBUF(info) dump_tbufs(info)*/
+/*#define DBGRBUF(info) dump_rbufs(info)*/
 
 
 #include <linux/module.h>
@@ -62,7 +62,6 @@
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/netdevice.h>
 #include <linux/vmalloc.h>
 #include <linux/init.h>
@@ -901,8 +900,6 @@
 	 * Note: use tight timings here to satisfy the NIST-PCTS.
 	 */
 
-	lock_kernel();
-
 	if (info->params.data_rate) {
 	       	char_time = info->timeout/(32 * 5);
 		if (!char_time)
@@ -920,8 +917,6 @@
 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
 			break;
 	}
-	unlock_kernel();
-
 exit:
 	DBGINFO(("%s wait_until_sent exit\n", info->device_name));
 }
@@ -1041,8 +1036,37 @@
 		    return -EIO;
 	}
 
-	lock_kernel();
-
+	switch (cmd) {
+	case MGSL_IOCWAITEVENT:
+		return wait_mgsl_event(info, argp);
+	case TIOCMIWAIT:
+		return modem_input_wait(info,(int)arg);
+	case TIOCGICOUNT:
+		spin_lock_irqsave(&info->lock,flags);
+		cnow = info->icount;
+		spin_unlock_irqrestore(&info->lock,flags);
+		p_cuser = argp;
+		if (put_user(cnow.cts, &p_cuser->cts) ||
+		    put_user(cnow.dsr, &p_cuser->dsr) ||
+		    put_user(cnow.rng, &p_cuser->rng) ||
+		    put_user(cnow.dcd, &p_cuser->dcd) ||
+		    put_user(cnow.rx, &p_cuser->rx) ||
+		    put_user(cnow.tx, &p_cuser->tx) ||
+		    put_user(cnow.frame, &p_cuser->frame) ||
+		    put_user(cnow.overrun, &p_cuser->overrun) ||
+		    put_user(cnow.parity, &p_cuser->parity) ||
+		    put_user(cnow.brk, &p_cuser->brk) ||
+		    put_user(cnow.buf_overrun, &p_cuser->buf_overrun))
+			return -EFAULT;
+		return 0;
+	case MGSL_IOCSGPIO:
+		return set_gpio(info, argp);
+	case MGSL_IOCGGPIO:
+		return get_gpio(info, argp);
+	case MGSL_IOCWAITGPIO:
+		return wait_gpio(info, argp);
+	}
+	mutex_lock(&info->port.mutex);
 	switch (cmd) {
 	case MGSL_IOCGPARAMS:
 		ret = get_params(info, argp);
@@ -1068,50 +1092,16 @@
 	case MGSL_IOCGSTATS:
 		ret = get_stats(info, argp);
 		break;
-	case MGSL_IOCWAITEVENT:
-		ret = wait_mgsl_event(info, argp);
-		break;
-	case TIOCMIWAIT:
-		ret = modem_input_wait(info,(int)arg);
-		break;
 	case MGSL_IOCGIF:
 		ret = get_interface(info, argp);
 		break;
 	case MGSL_IOCSIF:
 		ret = set_interface(info,(int)arg);
 		break;
-	case MGSL_IOCSGPIO:
-		ret = set_gpio(info, argp);
-		break;
-	case MGSL_IOCGGPIO:
-		ret = get_gpio(info, argp);
-		break;
-	case MGSL_IOCWAITGPIO:
-		ret = wait_gpio(info, argp);
-		break;
-	case TIOCGICOUNT:
-		spin_lock_irqsave(&info->lock,flags);
-		cnow = info->icount;
-		spin_unlock_irqrestore(&info->lock,flags);
-		p_cuser = argp;
-		if (put_user(cnow.cts, &p_cuser->cts) ||
-		    put_user(cnow.dsr, &p_cuser->dsr) ||
-		    put_user(cnow.rng, &p_cuser->rng) ||
-		    put_user(cnow.dcd, &p_cuser->dcd) ||
-		    put_user(cnow.rx, &p_cuser->rx) ||
-		    put_user(cnow.tx, &p_cuser->tx) ||
-		    put_user(cnow.frame, &p_cuser->frame) ||
-		    put_user(cnow.overrun, &p_cuser->overrun) ||
-		    put_user(cnow.parity, &p_cuser->parity) ||
-		    put_user(cnow.brk, &p_cuser->brk) ||
-		    put_user(cnow.buf_overrun, &p_cuser->buf_overrun))
-			ret = -EFAULT;
-		ret = 0;
-		break;
 	default:
 		ret = -ENOIOCTLCMD;
 	}
-	unlock_kernel();
+	mutex_unlock(&info->port.mutex);
 	return ret;
 }
 
diff --git a/drivers/char/synclinkmp.c b/drivers/char/synclinkmp.c
index 2b18adc..8da976b 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -52,7 +52,6 @@
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/netdevice.h>
 #include <linux/vmalloc.h>
 #include <linux/init.h>
@@ -1062,9 +1061,7 @@
 	if (sanity_check(info, tty->name, "wait_until_sent"))
 		return;
 
-	lock_kernel();
-
-	if (!(info->port.flags & ASYNC_INITIALIZED))
+	if (!test_bit(ASYNCB_INITIALIZED, &info->port.flags))
 		goto exit;
 
 	orig_jiffies = jiffies;
@@ -1094,8 +1091,10 @@
 				break;
 		}
 	} else {
-		//TODO: determine if there is something similar to USC16C32
-		// 	TXSTATUS_ALL_SENT status
+		/*
+		 * TODO: determine if there is something similar to USC16C32
+		 * 	 TXSTATUS_ALL_SENT status
+		 */
 		while ( info->tx_active && info->tx_enabled) {
 			msleep_interruptible(jiffies_to_msecs(char_time));
 			if (signal_pending(current))
@@ -1106,7 +1105,6 @@
 	}
 
 exit:
-	unlock_kernel();
 	if (debug_level >= DEBUG_LEVEL_INFO)
 		printk("%s(%d):%s wait_until_sent() exit\n",
 			 __FILE__,__LINE__, info->device_name );
@@ -1122,7 +1120,6 @@
 	if (sanity_check(info, tty->name, "write_room"))
 		return 0;
 
-	lock_kernel();
 	if (info->params.mode == MGSL_MODE_HDLC) {
 		ret = (info->tx_active) ? 0 : HDLC_MAX_FRAME_SIZE;
 	} else {
@@ -1130,7 +1127,6 @@
 		if (ret < 0)
 			ret = 0;
 	}
-	unlock_kernel();
 
 	if (debug_level >= DEBUG_LEVEL_INFO)
 		printk("%s(%d):%s write_room()=%d\n",
@@ -1251,7 +1247,7 @@
  *
  * Return Value:	0 if success, otherwise error code
  */
-static int do_ioctl(struct tty_struct *tty, struct file *file,
+static int ioctl(struct tty_struct *tty, struct file *file,
 		 unsigned int cmd, unsigned long arg)
 {
 	SLMP_INFO *info = tty->driver_data;
@@ -1341,16 +1337,6 @@
 	return 0;
 }
 
-static int ioctl(struct tty_struct *tty, struct file *file,
-		 unsigned int cmd, unsigned long arg)
-{
-	int ret;
-	lock_kernel();
-	ret = do_ioctl(tty, file, cmd, arg);
-	unlock_kernel();
-	return ret;
-}
-
 /*
  * /proc fs routines....
  */
@@ -2883,7 +2869,9 @@
 	if (!user_icount) {
 		memset(&info->icount, 0, sizeof(info->icount));
 	} else {
+		mutex_lock(&info->port.mutex);
 		COPY_TO_USER(err, user_icount, &info->icount, sizeof(struct mgsl_icount));
+		mutex_unlock(&info->port.mutex);
 		if (err)
 			return -EFAULT;
 	}
@@ -2898,7 +2886,9 @@
 		printk("%s(%d):%s get_params()\n",
 			 __FILE__,__LINE__, info->device_name);
 
+	mutex_lock(&info->port.mutex);
 	COPY_TO_USER(err,user_params, &info->params, sizeof(MGSL_PARAMS));
+	mutex_unlock(&info->port.mutex);
 	if (err) {
 		if ( debug_level >= DEBUG_LEVEL_INFO )
 			printk( "%s(%d):%s get_params() user buffer copy failed\n",
@@ -2926,11 +2916,13 @@
 		return -EFAULT;
 	}
 
+	mutex_lock(&info->port.mutex);
 	spin_lock_irqsave(&info->lock,flags);
 	memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
 	spin_unlock_irqrestore(&info->lock,flags);
 
  	change_params(info);
+	mutex_unlock(&info->port.mutex);
 
 	return 0;
 }