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Date:	Wed, 05 May 2010 11:02:13 +0100
From:	Alan Cox <alan@...ux.intel.com>
To:	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
	arnd@...db.de
Subject: [PATCH 06/20] synclink: kill the big kernel lock

We don't need it while waiting and we can lock the ioctls using the port
mutex. While at it eliminate use of the hangup mutex and switch to the port
mutex.

Signed-off-by: Alan Cox <alan@...ux.intel.com>
---

 drivers/char/synclink.c    |   19 ++++++-----
 drivers/char/synclink_gt.c |   78 +++++++++++++++++++-------------------------
 drivers/char/synclinkmp.c  |   32 +++++++-----------
 3 files changed, 56 insertions(+), 73 deletions(-)


diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index 0658fc5..4de1246 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 @@ static int mgsl_get_stats(struct mgsl_struct * info, struct mgsl_icount __user *
 	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 @@ static int mgsl_get_params(struct mgsl_struct * info, MGSL_PARAMS __user *user_p
 		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 @@ static int mgsl_set_params(struct mgsl_struct * info, MGSL_PARAMS __user *new_pa
 		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 @@ static int mgsl_ioctl(struct tty_struct *tty, struct file * file,
 		    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 @@ static int mgsl_ioctl(struct tty_struct *tty, struct file * file,
 		    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 @@ static void mgsl_close(struct tty_struct *tty, struct file * filp)
 
 	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 @@ static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout)
 	 * 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 @@ static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout)
 				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 4561ce2..d0f81f5 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 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
 	 * 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 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
 		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 @@ static int ioctl(struct tty_struct *tty, struct file *file,
 		    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 @@ static int ioctl(struct tty_struct *tty, struct file *file,
 	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 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
 	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 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
 				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 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
 	}
 
 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 @@ static int write_room(struct tty_struct *tty)
 	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 @@ static int write_room(struct tty_struct *tty)
 		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 @@ static void tx_release(struct tty_struct *tty)
  *
  * 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 @@ static int do_ioctl(struct tty_struct *tty, struct file *file,
 	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 @@ static int get_stats(SLMP_INFO * info, struct mgsl_icount __user *user_icount)
 	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 @@ static int get_params(SLMP_INFO * info, MGSL_PARAMS __user *user_params)
 		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 @@ static int set_params(SLMP_INFO * info, MGSL_PARAMS __user *new_params)
 		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;
 }

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