Merge branch 'bkl-removal' of git://git.lwn.net/linux-2.6

* 'bkl-removal' of git://git.lwn.net/linux-2.6: (146 commits)
  IB/umad: BKL is not needed for ib_umad_open()
  IB/uverbs: BKL is not needed for ib_uverbs_open()
  bf561-coreb: BKL unneeded for open()
  Call fasync() functions without the BKL
  snd/PCM: fasync BKL pushdown
  ipmi: fasync BKL pushdown
  ecryptfs: fasync BKL pushdown
  Bluetooth VHCI: fasync BKL pushdown
  tty_io: fasync BKL pushdown
  tun: fasync BKL pushdown
  i2o: fasync BKL pushdown
  mpt: fasync BKL pushdown
  Remove BKL from remote_llseek v2
  Make FAT users happier by not deadlocking
  x86-mce: BKL pushdown
  vmwatchdog: BKL pushdown
  vmcp: BKL pushdown
  via-pmu: BKL pushdown
  uml-random: BKL pushdown
  uml-mmapper: BKL pushdown
  ...

38 files changed, 214 insertions, 75 deletions

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index e6cb1ab..a96f319 100644
--- a/drivers/char/agp/frontend.c
+++ b/drivers/char/agp/frontend.c
@@ -39,6 +39,7 @@
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include "agp.h"
@@ -677,6 +678,7 @@ static int agp_open(struct inode *inode, struct file *file)
 	struct agp_client *client;
 	int rc = -ENXIO;
 
+	lock_kernel();
 	mutex_lock(&(agp_fe.agp_mutex));
 
 	if (minor != AGPGART_MINOR)
@@ -703,12 +705,14 @@ static int agp_open(struct inode *inode, struct file *file)
 	agp_insert_file_private(priv);
 	DBG("private=%p, client=%p", priv, client);
 	mutex_unlock(&(agp_fe.agp_mutex));
+	unlock_kernel();
 	return 0;
 
 err_out_nomem:
 	rc = -ENOMEM;
 err_out:
 	mutex_unlock(&(agp_fe.agp_mutex));
+	unlock_kernel();
 	return rc;
 }
 
diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c
index cdd876d..da8a165 100644
--- a/drivers/char/apm-emulation.c
+++ b/drivers/char/apm-emulation.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/miscdevice.h>
@@ -416,6 +417,7 @@ static int apm_open(struct inode * inode, struct file * filp)
 {
 	struct apm_user *as;
 
+	lock_kernel();
 	as = kzalloc(sizeof(*as), GFP_KERNEL);
 	if (as) {
 		/*
@@ -435,6 +437,7 @@ static int apm_open(struct inode * inode, struct file * filp)
 
 		filp->private_data = as;
 	}
+	unlock_kernel();
 
 	return as ? 0 : -ENOMEM;
 }
diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c
index b6f2639..d8cff90 100644
--- a/drivers/char/briq_panel.c
+++ b/drivers/char/briq_panel.c
@@ -6,6 +6,7 @@
 
 #include <linux/module.h>
 
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
@@ -67,11 +68,15 @@ static void set_led(char state)
 
 static int briq_panel_open(struct inode *ino, struct file *filep)
 {
-	/* enforce single access */
-	if (vfd_is_open)
+	lock_kernel();
+	/* enforce single access, vfd_is_open is protected by BKL */
+	if (vfd_is_open) {
+		unlock_kernel();
 		return -EBUSY;
+	}
 	vfd_is_open = 1;
 
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/drivers/char/cs5535_gpio.c b/drivers/char/cs5535_gpio.c
index c0a4a0b..04ba906 100644
--- a/drivers/char/cs5535_gpio.c
+++ b/drivers/char/cs5535_gpio.c
@@ -17,6 +17,7 @@
 #include <linux/cdev.h>
 #include <linux/ioport.h>
 #include <linux/pci.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
@@ -157,6 +158,7 @@ static int cs5535_gpio_open(struct inode *inode, struct file *file)
 {
 	u32 m = iminor(inode);
 
+	cycle_kernel_lock();
 	/* the mask says which pins are usable by this driver */
 	if ((mask & (1 << m)) == 0)
 		return -EINVAL;
diff --git a/drivers/char/ds1286.c b/drivers/char/ds1286.c
index ea35ab2..fb584938 100644
--- a/drivers/char/ds1286.c
+++ b/drivers/char/ds1286.c
@@ -27,6 +27,7 @@
  * option) any later version.
  */
 #include <linux/ds1286.h>
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
@@ -252,6 +253,7 @@ static int ds1286_ioctl(struct inode *inode, struct file *file,
 
 static int ds1286_open(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	spin_lock_irq(&ds1286_lock);
 
 	if (ds1286_status & RTC_IS_OPEN)
@@ -260,10 +262,12 @@ static int ds1286_open(struct inode *inode, struct file *file)
 	ds1286_status |= RTC_IS_OPEN;
 
 	spin_unlock_irq(&ds1286_lock);
+	unlock_kernel();
 	return 0;
 
 out_busy:
 	spin_lock_irq(&ds1286_lock);
+	unlock_kernel();
 	return -EBUSY;
 }
 
diff --git a/drivers/char/ds1620.c b/drivers/char/ds1620.c
index 334ad5b..34275c6 100644
--- a/drivers/char/ds1620.c
+++ b/drivers/char/ds1620.c
@@ -8,6 +8,7 @@
 #include <linux/proc_fs.h>
 #include <linux/capability.h>
 #include <linux/init.h>
+#include <linux/smp_lock.h>
 
 #include <asm/hardware.h>
 #include <asm/mach-types.h>
@@ -208,6 +209,12 @@ static void ds1620_read_state(struct therm *therm)
 	therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
 }
 
+static int ds1620_open(struct inode *inode, struct file *file)
+{
+	cycle_kernel_lock();
+	return nonseekable_open(inode, file);
+}
+
 static ssize_t
 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 {
@@ -336,7 +343,7 @@ static struct proc_dir_entry *proc_therm_ds1620;
 
 static const struct file_operations ds1620_fops = {
 	.owner		= THIS_MODULE,
-	.open		= nonseekable_open,
+	.open		= ds1620_open,
 	.read		= ds1620_read,
 	.ioctl		= ds1620_ioctl,
 };
diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index a69c652..7bf7485 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -33,6 +33,7 @@
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/device.h>
+#include <linux/smp_lock.h>
 
 #include <asm/atarihw.h>
 #include <asm/traps.h>
@@ -436,13 +437,17 @@ static unsigned int dsp56k_poll(struct file *file, poll_table *wait)
 static int dsp56k_open(struct inode *inode, struct file *file)
 {
 	int dev = iminor(inode) & 0x0f;
+	int ret = 0;
 
+	lock_kernel();
 	switch(dev)
 	{
 	case DSP56K_DEV_56001:
 
-		if (test_and_set_bit(0, &dsp56k.in_use))
-			return -EBUSY;
+		if (test_and_set_bit(0, &dsp56k.in_use)) {
+			ret = -EBUSY;
+			goto out;
+		}
 
 		dsp56k.timeout = TIMEOUT;
 		dsp56k.maxio = MAXIO;
@@ -458,10 +463,11 @@ static int dsp56k_open(struct inode *inode, struct file *file)
 		break;
 
 	default:
-		return -ENODEV;
+		ret = -ENODEV;
 	}
-
-	return 0;
+out:
+	unlock_kernel();
+	return ret;
 }
 
 static int dsp56k_release(struct inode *inode, struct file *file)
diff --git a/drivers/char/dtlk.c b/drivers/char/dtlk.c
index abde6dd..6b900b2 100644
--- a/drivers/char/dtlk.c
+++ b/drivers/char/dtlk.c
@@ -56,6 +56,7 @@
 #include <linux/errno.h>	/* for -EBUSY */
 #include <linux/ioport.h>	/* for request_region */
 #include <linux/delay.h>	/* for loops_per_jiffy */
+#include <linux/smp_lock.h>	/* cycle_kernel_lock() */
 #include <asm/io.h>		/* for inb_p, outb_p, inb, outb, etc. */
 #include <asm/uaccess.h>	/* for get_user, etc. */
 #include <linux/wait.h>		/* for wait_queue */
@@ -288,10 +289,12 @@ static int dtlk_ioctl(struct inode *inode,
 	}
 }
 
+/* Note that nobody ever sets dtlk_busy... */
 static int dtlk_open(struct inode *inode, struct file *file)
 {
 	TRACE_TEXT("(dtlk_open");
 
+	cycle_kernel_lock();
 	nonseekable_open(inode, file);
 	switch (iminor(inode)) {
 	case DTLK_MINOR:
diff --git a/drivers/char/efirtc.c b/drivers/char/efirtc.c
index 49233f5..d57ca3e 100644
--- a/drivers/char/efirtc.c
+++ b/drivers/char/efirtc.c
@@ -28,6 +28,7 @@
  */
 
 
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
@@ -272,6 +273,7 @@ efi_rtc_open(struct inode *inode, struct file *file)
 	 * We do accept multiple open files at the same time as we
 	 * synchronize on the per call operation.
 	 */
+	cycle_kernel_lock();
 	return 0;
 }
 
diff --git a/drivers/char/genrtc.c b/drivers/char/genrtc.c
index 69f0a29..aac0985 100644
--- a/drivers/char/genrtc.c
+++ b/drivers/char/genrtc.c
@@ -51,6 +51,7 @@
 #include <linux/init.h>
 #include <linux/poll.h>
 #include <linux/proc_fs.h>
+#include <linux/smp_lock.h>
 #include <linux/workqueue.h>
 
 #include <asm/uaccess.h>
@@ -338,12 +339,16 @@ static int gen_rtc_ioctl(struct inode *inode, struct file *file,
 
 static int gen_rtc_open(struct inode *inode, struct file *file)
 {
-	if (gen_rtc_status & RTC_IS_OPEN)
+	lock_kernel();
+	if (gen_rtc_status & RTC_IS_OPEN) {
+		unlock_kernel();
 		return -EBUSY;
+	}
 
 	gen_rtc_status |= RTC_IS_OPEN;
 	gen_rtc_irq_data = 0;
 	irq_active = 0;
+	unlock_kernel();
 
 	return 0;
 }
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index e7fb0bc..fb0a85a 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -14,6 +14,7 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/major.h>
@@ -193,6 +194,7 @@ static int hpet_open(struct inode *inode, struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		return -EINVAL;
 
+	lock_kernel();
 	spin_lock_irq(&hpet_lock);
 
 	for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
@@ -207,6 +209,7 @@ static int hpet_open(struct inode *inode, struct file *file)
 
 	if (!devp) {
 		spin_unlock_irq(&hpet_lock);
+		unlock_kernel();
 		return -EBUSY;
 	}
 
@@ -214,6 +217,7 @@ static int hpet_open(struct inode *inode, struct file *file)
 	devp->hd_irqdata = 0;
 	devp->hd_flags |= HPET_OPEN;
 	spin_unlock_irq(&hpet_lock);
+	unlock_kernel();
 
 	return 0;
 }
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 662d60e..e5d583c 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -37,6 +37,7 @@
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
+#include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/miscdevice.h>
 #include <linux/delay.h>
@@ -86,6 +87,7 @@ static int rng_dev_open(struct inode *inode, struct file *filp)
 		return -EINVAL;
 	if (filp->f_mode & FMODE_WRITE)
 		return -EINVAL;
+	cycle_kernel_lock();
 	return 0;
 }
 
diff --git a/drivers/char/ip2/ip2main.c b/drivers/char/ip2/ip2main.c
index c12cf8f..61b6fe4 100644
--- a/drivers/char/ip2/ip2main.c
+++ b/drivers/char/ip2/ip2main.c
@@ -98,6 +98,7 @@
 #include <linux/major.h>
 #include <linux/wait.h>
 #include <linux/device.h>
+#include <linux/smp_lock.h>
 
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
@@ -2908,42 +2909,11 @@ ip2_ipl_ioctl ( struct inode *pInode, struct file *pFile, UINT cmd, ULONG arg )
 static int
 ip2_ipl_open( struct inode *pInode, struct file *pFile )
 {
-	unsigned int iplminor = iminor(pInode);
-	i2eBordStrPtr pB;
-	i2ChanStrPtr  pCh;
 
 #ifdef IP2DEBUG_IPL
 	printk (KERN_DEBUG "IP2IPL: open\n" );
 #endif
-
-	switch(iplminor) {
-	// These are the IPL devices
-	case 0:
-	case 4:
-	case 8:
-	case 12:
-		break;
-
-	// These are the status devices
-	case 1:
-	case 5:
-	case 9:
-	case 13:
-		break;
-
-	// These are the debug devices
-	case 2:
-	case 6:
-	case 10:
-	case 14:
-		pB = i2BoardPtrTable[iplminor / 4];
-		pCh = (i2ChanStrPtr) pB->i2eChannelPtr;
-		break;
-
-	// This is the trace device
-	case 3:
-		break;
-	}
+	cycle_kernel_lock();
 	return 0;
 }
 
diff --git a/drivers/char/ip27-rtc.c b/drivers/char/ip27-rtc.c
index 86e6538..ec9d044 100644
--- a/drivers/char/ip27-rtc.c
+++ b/drivers/char/ip27-rtc.c
@@ -27,6 +27,7 @@
 #include <linux/bcd.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/ioport.h>
@@ -163,15 +164,18 @@ static long rtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 static int rtc_open(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	spin_lock_irq(&rtc_lock);
 
 	if (rtc_status & RTC_IS_OPEN) {
 		spin_unlock_irq(&rtc_lock);
+		unlock_kernel();
 		return -EBUSY;
 	}
 
 	rtc_status |= RTC_IS_OPEN;
 	spin_unlock_irq(&rtc_lock);
+	unlock_kernel();
 
 	return 0;
 }
diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index 0246a2b8..c11a404 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -43,6 +43,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/compat.h>
+#include <linux/smp_lock.h>
 
 struct ipmi_file_private
 {
@@ -100,7 +101,9 @@ static int ipmi_fasync(int fd, struct file *file, int on)
 	struct ipmi_file_private *priv = file->private_data;
 	int                      result;
 
+	lock_kernel(); /* could race against open() otherwise */
 	result = fasync_helper(fd, file, on, &priv->fasync_queue);
+	unlock_kernel();
 
 	return (result);
 }
@@ -121,6 +124,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
 	if (!priv)
 		return -ENOMEM;
 
+	lock_kernel();
 	priv->file = file;
 
 	rv = ipmi_create_user(if_num,
@@ -129,7 +133,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
 			      &(priv->user));
 	if (rv) {
 		kfree(priv);
-		return rv;
+		goto out;
 	}
 
 	file->private_data = priv;
@@ -144,7 +148,9 @@ static int ipmi_open(struct inode *inode, struct file *file)
 	priv->default_retries = -1;
 	priv->default_retry_time_ms = 0;
 
-	return 0;
+out:
+	unlock_kernel();
+	return rv;
 }
 
 static int ipmi_release(struct inode *inode, struct file *file)
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 0e6df28..235fab0 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -35,6 +35,7 @@
 #include <linux/moduleparam.h>
 #include <linux/ipmi.h>
 #include <linux/ipmi_smi.h>
+#include <linux/smp_lock.h>
 #include <linux/watchdog.h>
 #include <linux/miscdevice.h>
 #include <linux/init.h>
@@ -818,6 +819,8 @@ static int ipmi_open(struct inode *ino, struct file *filep)
 		if (test_and_set_bit(0, &ipmi_wdog_open))
 			return -EBUSY;
 
+		cycle_kernel_lock();
+
 		/*
 		 * Don't start the timer now, let it start on the
 		 * first heartbeat.
diff --git a/drivers/char/lcd.c b/drivers/char/lcd.c
index 4fe9206..1c29b20 100644
--- a/drivers/char/lcd.c
+++ b/drivers/char/lcd.c
@@ -20,6 +20,7 @@
 #include <linux/mc146818rtc.h>
 #include <linux/netdevice.h>
 #include <linux/sched.h>
+#include <linux/smp_lock.h>
 #include <linux/delay.h>
 
 #include <asm/io.h>
@@ -414,6 +415,8 @@ static int lcd_ioctl(struct inode *inode, struct file *file,
 
 static int lcd_open(struct inode *inode, struct file *file)
 {
+	cycle_kernel_lock();
+
 	if (!lcd_present)
 		return -ENXIO;
 	else
diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 60ac642..71abb4c 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -126,6 +126,7 @@
 #include <linux/device.h>
 #include <linux/wait.h>
 #include <linux/jiffies.h>
+#include <linux/smp_lock.h>
 
 #include <linux/parport.h>
 #undef LP_STATS
@@ -489,14 +490,21 @@ static ssize_t lp_read(struct file * file, char __user * buf,
 static int lp_open(struct inode * inode, struct file * file)
 {
 	unsigned int minor = iminor(inode);
+	int ret = 0;
 
-	if (minor >= LP_NO)
-		return -ENXIO;
-	if ((LP_F(minor) & LP_EXIST) == 0)
-		return -ENXIO;
-	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor)))
-		return -EBUSY;
-
+	lock_kernel();
+	if (minor >= LP_NO) {
+		ret = -ENXIO;
+		goto out;
+	}
+	if ((LP_F(minor) & LP_EXIST) == 0) {
+		ret = -ENXIO;
+		goto out;
+	}
+	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor))) {
+		ret = -EBUSY;
+		goto out;
+	}
 	/* If ABORTOPEN is set and the printer is offline or out of paper,
 	   we may still want to open it to perform ioctl()s.  Therefore we
 	   have commandeered O_NONBLOCK, even though it is being used in
@@ -510,21 +518,25 @@ static int lp_open(struct inode * inode, struct file * file)
 		if (status & LP_POUTPA) {
 			printk(KERN_INFO "lp%d out of paper\n", minor);
 			LP_F(minor) &= ~LP_BUSY;
-			return -ENOSPC;
+			ret = -ENOSPC;
+			goto out;
 		} else if (!(status & LP_PSELECD)) {
 			printk(KERN_INFO "lp%d off-line\n", minor);
 			LP_F(minor) &= ~LP_BUSY;
-			return -EIO;
+			ret = -EIO;
+			goto out;
 		} else if (!(status & LP_PERRORP)) {
 			printk(KERN_ERR "lp%d printer error\n", minor);
 			LP_F(minor) &= ~LP_BUSY;
-			return -EIO;
+			ret = -EIO;
+			goto out;
 		}
 	}
 	lp_table[minor].lp_buffer = kmalloc(LP_BUFFER_SIZE, GFP_KERNEL);
 	if (!lp_table[minor].lp_buffer) {
 		LP_F(minor) &= ~LP_BUSY;
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto out;
 	}
 	/* Determine if the peripheral supports ECP mode */
 	lp_claim_parport_or_block (&lp_table[minor]);
@@ -540,7 +552,9 @@ static int lp_open(struct inode * inode, struct file * file)
 	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
 	lp_release_parport (&lp_table[minor]);
 	lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
-	return 0;
+out:
+	unlock_kernel();
+	return ret;
 }
 
 static int lp_release(struct inode * inode, struct file * file)
diff --git a/drivers/char/mbcs.c b/drivers/char/mbcs.c
index f4716ad..acd8e9e 100644
--- a/drivers/char/mbcs.c
+++ b/drivers/char/mbcs.c
@@ -24,6 +24,7 @@
 #include <linux/mm.h>
 #include <linux/uio.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -382,15 +383,19 @@ static int mbcs_open(struct inode *ip, struct file *fp)
 	struct mbcs_soft *soft;
 	int minor;
 
+	lock_kernel();
 	minor = iminor(ip);
 
+	/* Nothing protects access to this list... */
 	list_for_each_entry(soft, &soft_list, list) {
 		if (soft->nasid == minor) {
 			fp->private_data = soft->cxdev;
+			unlock_kernel();
 			return 0;
 		}
 	}
 
+	unlock_kernel();
 	return -ENODEV;
 }
 
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 934ffaf..070e22e 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -26,6 +26,7 @@
 #include <linux/bootmem.h>
 #include <linux/splice.h>
 #include <linux/pfn.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -889,6 +890,9 @@ static const struct file_operations kmsg_fops = {
 
 static int memory_open(struct inode * inode, struct file * filp)
 {
+	int ret = 0;
+
+	lock_kernel();
 	switch (iminor(inode)) {
 		case 1:
 			filp->f_op = &mem_fops;
@@ -932,11 +936,13 @@ static int memory_open(struct inode * inode, struct file * filp)
 			break;
 #endif
 		default:
+			unlock_kernel();
 			return -ENXIO;
 	}
 	if (filp->f_op && filp->f_op->open)
-		return filp->f_op->open(inode,filp);
-	return 0;
+		ret = filp->f_op->open(inode,filp);
+	unlock_kernel();
+	return ret;
 }
 
 static const struct file_operations memory_fops = {
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index eaace0d..6e1563c 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -49,6 +49,7 @@
 #include <linux/device.h>
 #include <linux/tty.h>
 #include <linux/kmod.h>
+#include <linux/smp_lock.h>
 
 /*
  * Head entry for the doubly linked miscdevice list
@@ -118,6 +119,7 @@ static int misc_open(struct inode * inode, struct file * file)
 	int err = -ENODEV;
 	const struct file_operations *old_fops, *new_fops = NULL;
 	
+	lock_kernel();
 	mutex_lock(&misc_mtx);
 	
 	list_for_each_entry(c, &misc_list, list) {
@@ -155,6 +157,7 @@ static int misc_open(struct inode * inode, struct file * file)
 	fops_put(old_fops);
 fail:
 	mutex_unlock(&misc_mtx);
+	unlock_kernel();
 	return err;
 }
 
diff --git a/drivers/char/mwave/mwavedd.c b/drivers/char/mwave/mwavedd.c
index 8d14823..50243fc 100644
--- a/drivers/char/mwave/mwavedd.c
+++ b/drivers/char/mwave/mwavedd.c
@@ -56,6 +56,7 @@
 #include <linux/serial.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 #include <linux/delay.h>
 #include <linux/serial_8250.h>
 #include "smapi.h"
@@ -100,6 +101,7 @@ static int mwave_open(struct inode *inode, struct file *file)
 	PRINTK_2(TRACE_MWAVE,
 		"mwavedd::mwave_open, exit return retval %x\n", retval);
 
+	cycle_kernel_lock();
 	return retval;
 }
 
diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index 98dec38..197cd7a 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -107,6 +107,7 @@
 #include <linux/init.h>
 #include <linux/proc_fs.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -333,12 +334,14 @@ nvram_ioctl(struct inode *inode, struct file *file,
 static int
 nvram_open(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	spin_lock(&nvram_state_lock);
 
 	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
 	    (nvram_open_mode & NVRAM_EXCL) ||
 	    ((file->f_mode & 2) && (nvram_open_mode & NVRAM_WRITE))) {
 		spin_unlock(&nvram_state_lock);
+		unlock_kernel();
 		return -EBUSY;
 	}
 
@@ -349,6 +352,7 @@ nvram_open(struct inode *inode, struct file *file)
 	nvram_open_cnt++;
 
 	spin_unlock(&nvram_state_lock);
+	unlock_kernel();
 
 	return 0;
 }
diff --git a/drivers/char/pc8736x_gpio.c b/drivers/char/pc8736x_gpio.c
index ecfaf18..b930de5 100644
--- a/drivers/char/pc8736x_gpio.c
+++ b/drivers/char/pc8736x_gpio.c
@@ -20,6 +20,7 @@
 #include <linux/mutex.h>
 #include <linux/nsc_gpio.h>
 #include <linux/platform_device.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 #define DEVNAME "pc8736x_gpio"
@@ -217,6 +218,7 @@ static int pc8736x_gpio_open(struct inode *inode, struct file *file)
 	unsigned m = iminor(inode);
 	file->private_data = &pc8736x_gpio_ops;
 
+	cycle_kernel_lock();
 	dev_dbg(&pdev->dev, "open %d\n", m);
 
 	if (m >= PC8736X_GPIO_CT)
diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 3aab837..f6e6aca 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -66,6 +66,7 @@
 #include <linux/poll.h>
 #include <linux/major.h>
 #include <linux/ppdev.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 #define PP_VERSION "ppdev: user-space parallel port driver"
@@ -638,6 +639,7 @@ static int pp_open (struct inode * inode, struct file * file)
 	unsigned int minor = iminor(inode);
 	struct pp_struct *pp;
 
+	cycle_kernel_lock();
 	if (minor >= PARPORT_MAX)
 		return -ENXIO;
 
diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index bbfa0e2..505fcbe 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -19,6 +19,7 @@
 #include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 
@@ -53,6 +54,7 @@ static int raw_open(struct inode *inode, struct file *filp)
 		return 0;
 	}
 
+	lock_kernel();
 	mutex_lock(&raw_mutex);
 
 	/*
@@ -79,6 +81,7 @@ static int raw_open(struct inode *inode, struct file *filp)
 			bdev->bd_inode->i_mapping;
 	filp->private_data = bdev;
 	mutex_unlock(&raw_mutex);
+	unlock_kernel();
 	return 0;
 
 out2:
diff --git a/drivers/char/rtc.c b/drivers/char/rtc.c
index 909cac9..fa92a8a 100644
--- a/drivers/char/rtc.c
+++ b/drivers/char/rtc.c
@@ -73,6 +73,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 #include <linux/sysctl.h>
 #include <linux/wait.h>
 #include <linux/bcd.h>
@@ -734,6 +735,7 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  * needed here. Or anywhere else in this driver. */
 static int rtc_open(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	spin_lock_irq(&rtc_lock);
 
 	if (rtc_status & RTC_IS_OPEN)
@@ -743,10 +745,12 @@ static int rtc_open(struct inode *inode, struct file *file)
 
 	rtc_irq_data = 0;
 	spin_unlock_irq(&rtc_lock);
+	unlock_kernel();
 	return 0;
 
 out_busy:
 	spin_unlock_irq(&rtc_lock);
+	unlock_kernel();
 	return -EBUSY;
 }
 
diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c
index 99e5272..1d91005 100644
--- a/drivers/char/scx200_gpio.c
+++ b/drivers/char/scx200_gpio.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
@@ -51,6 +52,7 @@ static int scx200_gpio_open(struct inode *inode, struct file *file)
 	unsigned m = iminor(inode);
 	file->private_data = &scx200_gpio_ops;
 
+	cycle_kernel_lock();
 	if (m >= MAX_PINS)
 		return -EINVAL;
 	return nonseekable_open(inode, file);
diff --git a/drivers/char/snsc.c b/drivers/char/snsc.c
index 8fe099a..0b799ac 100644
--- a/drivers/char/snsc.c
+++ b/drivers/char/snsc.c
@@ -21,6 +21,7 @@
 #include <linux/poll.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <asm/sn/io.h>
 #include <asm/sn/sn_sal.h>
 #include <asm/sn/module.h>
@@ -104,6 +105,7 @@ scdrv_open(struct inode *inode, struct file *file)
 	file->private_data = sd;
 
 	/* hook this subchannel up to the system controller interrupt */
+	lock_kernel();
 	rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
 			 IRQF_SHARED | IRQF_DISABLED,
 			 SYSCTL_BASENAME, sd);
@@ -111,9 +113,10 @@ scdrv_open(struct inode *inode, struct file *file)
 		ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 		kfree(sd);
 		printk("%s: irq request failed (%d)\n", __func__, rv);
+		unlock_kernel();
 		return -EBUSY;
 	}
-
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/drivers/char/sonypi.c b/drivers/char/sonypi.c
index 58533de..85e0eb7 100644
--- a/drivers/char/sonypi.c
+++ b/drivers/char/sonypi.c
@@ -49,6 +49,7 @@
 #include <linux/err.h>
 #include <linux/kfifo.h>
 #include <linux/platform_device.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -906,12 +907,14 @@ static int sonypi_misc_release(struct inode *inode, struct file *file)
 
 static int sonypi_misc_open(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	mutex_lock(&sonypi_device.lock);
 	/* Flush input queue on first open */
 	if (!sonypi_device.open_count)
 		kfifo_reset(sonypi_device.fifo);
 	sonypi_device.open_count++;
 	mutex_unlock(&sonypi_device.lock);
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/drivers/char/tb0219.c b/drivers/char/tb0219.c
index 4c431cb..6062b62 100644
--- a/drivers/char/tb0219.c
+++ b/drivers/char/tb0219.c
@@ -21,6 +21,7 @@
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/smp_lock.h>
 
 #include <asm/io.h>
 #include <asm/reboot.h>
@@ -236,6 +237,7 @@ static int tanbac_tb0219_open(struct inode *inode, struct file *file)
 {
 	unsigned int minor;
 
+	cycle_kernel_lock();
 	minor = iminor(inode);
 	switch (minor) {
 	case 0:
diff --git a/drivers/char/tlclk.c b/drivers/char/tlclk.c
index 35e5803..8f2284b 100644
--- a/drivers/char/tlclk.c
+++ b/drivers/char/tlclk.c
@@ -36,6 +36,7 @@
 #include <linux/ioport.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 #include <linux/timer.h>
 #include <linux/sysfs.h>
 #include <linux/device.h>
@@ -204,11 +205,14 @@ static int tlclk_open(struct inode *inode, struct file *filp)
 {
 	int result;
 
-	if (test_and_set_bit(0, &useflags))
-		return -EBUSY;
+	lock_kernel();
+	if (test_and_set_bit(0, &useflags)) {
+		result = -EBUSY;
 		/* this legacy device is always one per system and it doesn't
 		 * know how to handle multiple concurrent clients.
 		 */
+		goto out;
+	}
 
 	/* Make sure there is no interrupt pending while
 	 * initialising interrupt handler */
@@ -218,13 +222,14 @@ static int tlclk_open(struct inode *inode, struct file *filp)
 	 * we can't share this IRQ */
 	result = request_irq(telclk_interrupt, &tlclk_interrupt,
 			     IRQF_DISABLED, "telco_clock", tlclk_interrupt);
-	if (result == -EBUSY) {
+	if (result == -EBUSY)
 		printk(KERN_ERR "tlclk: Interrupt can't be reserved.\n");
-		return -EBUSY;
-	}
-	inb(TLCLK_REG6);	/* Clear interrupt events */
+	else
+		inb(TLCLK_REG6);	/* Clear interrupt events */
 
-	return 0;
+out:
+	unlock_kernel();
+	return result;
 }
 
 static int tlclk_release(struct inode *inode, struct file *filp)
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index a5d8bcb..e1fc193 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -26,6 +26,7 @@
 #include <linux/poll.h>
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 
 #include "tpm.h"
 
@@ -897,6 +898,7 @@ int tpm_open(struct inode *inode, struct file *file)
 	int rc = 0, minor = iminor(inode);
 	struct tpm_chip *chip = NULL, *pos;
 
+	lock_kernel();
 	spin_lock(&driver_lock);
 
 	list_for_each_entry(pos, &tpm_chip_list, list) {
@@ -926,16 +928,19 @@ int tpm_open(struct inode *inode, struct file *file)
 	if (chip->data_buffer == NULL) {
 		chip->num_opens--;
 		put_device(chip->dev);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
 	atomic_set(&chip->data_pending, 0);
 
 	file->private_data = chip;
+	unlock_kernel();
 	return 0;
 
 err_out:
 	spin_unlock(&driver_lock);
+	unlock_kernel();
 	return rc;
 }
 EXPORT_SYMBOL_GPL(tpm_open);
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 7501310..047a173 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2665,7 +2665,7 @@ static void release_dev(struct file *filp)
  *		 ->siglock protects ->signal/->sighand
  */
 
-static int tty_open(struct inode *inode, struct file *filp)
+static int __tty_open(struct inode *inode, struct file *filp)
 {
 	struct tty_struct *tty;
 	int noctty, retval;
@@ -2779,6 +2779,19 @@ got_driver:
 	return 0;
 }
 
+/* BKL pushdown: scary code avoidance wrapper */
+static int tty_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	lock_kernel();
+	ret = __tty_open(inode, filp);
+	unlock_kernel();
+	return ret;
+}
+
+
+
 #ifdef CONFIG_UNIX98_PTYS
 /**
  *	ptmx_open		-	open a unix 98 pty master
@@ -2792,7 +2805,7 @@ got_driver:
  *		allocated_ptys_lock handles the list of free pty numbers
  */
 
-static int ptmx_open(struct inode *inode, struct file *filp)
+static int __ptmx_open(struct inode *inode, struct file *filp)
 {
 	struct tty_struct *tty;
 	int retval;
@@ -2831,6 +2844,16 @@ out:
 	devpts_kill_index(index);
 	return retval;
 }
+
+static int ptmx_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	lock_kernel();
+	ret = __ptmx_open(inode, filp);
+	unlock_kernel();
+	return ret;
+}
 #endif
 
 /**
@@ -2886,15 +2909,16 @@ static int tty_fasync(int fd, struct file *filp, int on)
 {
 	struct tty_struct *tty;
 	unsigned long flags;
-	int retval;
+	int retval = 0;
 
+	lock_kernel();
 	tty = (struct tty_struct *)filp->private_data;
 	if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
-		return 0;
+		goto out;
 
 	retval = fasync_helper(fd, filp, on, &tty->fasync);
 	if (retval <= 0)
-		return retval;
+		goto out;
 
 	if (on) {
 		enum pid_type type;
@@ -2912,12 +2936,15 @@ static int tty_fasync(int fd, struct file *filp, int on)
 		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		retval = __f_setown(filp, pid, type, 0);
 		if (retval)
-			return retval;
+			goto out;
 	} else {
 		if (!tty->fasync && !waitqueue_active(&tty->read_wait))
 			tty->minimum_to_wake = N_TTY_BUF_SIZE;
 	}
-	return 0;
+	retval = 0;
+out:
+	unlock_kernel();
+	return retval;
 }
 
 /**
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c
index 83aeedd..eebfad2 100644
--- a/drivers/char/vc_screen.c
+++ b/drivers/char/vc_screen.c
@@ -34,6 +34,7 @@
 #include <linux/kbd_kern.h>
 #include <linux/console.h>
 #include <linux/device.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/byteorder.h>
@@ -460,9 +461,13 @@ static int
 vcs_open(struct inode *inode, struct file *filp)
 {
 	unsigned int currcons = iminor(inode) & 127;
+	int ret = 0;
+	
+	lock_kernel();
 	if(currcons && !vc_cons_allocated(currcons-1))
-		return -ENXIO;
-	return 0;
+		ret = -ENXIO;
+	unlock_kernel();
+	return ret;
 }
 
 static const struct file_operations vcs_fops = {
diff --git a/drivers/char/viotape.c b/drivers/char/viotape.c
index c39ddaf..977f7d3 100644
--- a/drivers/char/viotape.c
+++ b/drivers/char/viotape.c
@@ -46,6 +46,7 @@
 #include <linux/completion.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
@@ -687,6 +688,7 @@ static int viotap_open(struct inode *inode, struct file *file)
 	if (op == NULL)
 		return -ENOMEM;
 
+	lock_kernel();
 	get_dev_info(file->f_path.dentry->d_inode, &devi);
 
 	/* Note: We currently only support one mode! */
@@ -717,6 +719,7 @@ static int viotap_open(struct inode *inode, struct file *file)
 
 free_op:
 	free_op_struct(op);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/drivers/char/vr41xx_giu.c b/drivers/char/vr41xx_giu.c
index e5ed091..ffe9b4e 100644
--- a/drivers/char/vr41xx_giu.c
+++ b/drivers/char/vr41xx_giu.c
@@ -27,6 +27,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 
@@ -547,6 +548,7 @@ static int gpio_open(struct inode *inode, struct file *file)
 {
 	unsigned int pin;
 
+	cycle_kernel_lock();
 	pin = iminor(inode);
 	if (pin >= giu_nr_pins)
 		return -EBADF;
diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index 3edf1fc..1e1b81e 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -85,6 +85,7 @@
 #include <linux/poll.h>
 #include <linux/proc_fs.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 #include <linux/sysctl.h>
 #include <linux/version.h>
 #include <linux/fs.h>
@@ -504,11 +505,12 @@ static int hwicap_open(struct inode *inode, struct file *file)
 	struct hwicap_drvdata *drvdata;
 	int status;
 
+	lock_kernel();
 	drvdata = container_of(inode->i_cdev, struct hwicap_drvdata, cdev);
 
 	status = mutex_lock_interruptible(&drvdata->sem);
 	if (status)
-		return status;
+		goto out;
 
 	if (drvdata->is_open) {
 		status = -EBUSY;
@@ -528,6 +530,8 @@ static int hwicap_open(struct inode *inode, struct file *file)
 
  error:
 	mutex_unlock(&drvdata->sem);
+ out:
+	unlock_kernel();
 	return status;
 }