scsi: autoconvert trivial BKL users to private mutex

All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
if grep -q 'include.*linux.mutex.h' ${file} ; then
sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
else
sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
fi
sed -i ${file} \
-e "/^#include.*linux.mutex.h/,$ {
1,/^\(static\|int\|long\)/ {
/^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }" \
-e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
-e '/[ ]*cycle_kernel_lock();/d'
else
sed -i -e '/include.*\<smp_lock.h\>/d' ${file} \
-e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <[e-mail]>
Cc: [e-mail]
Cc: "James E.J. Bottomley" <[e-mail]>

drivers/message/fusion/mptctl.c

···
 #include <linux/pci.h>
 #include <linux/delay.h>	/* for mdelay */
 #include <linux/miscdevice.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/compat.h>
 
 #include <asm/io.h>
···
 
 /*=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*/
 
+static DEFINE_MUTEX(mpctl_mutex);
 static u8 mptctl_id = MPT_MAX_PROTOCOL_DRIVERS;
 static u8 mptctl_taskmgmt_id = MPT_MAX_PROTOCOL_DRIVERS;
 
···
 	MPT_ADAPTER	*ioc;
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&mpctl_mutex);
 	list_for_each_entry(ioc, &ioc_list, list)
 		ioc->aen_event_read_flag=0;
 
 	ret = fasync_helper(fd, filep, mode, &async_queue);
-	unlock_kernel();
+	mutex_unlock(&mpctl_mutex);
 	return ret;
 }
 
···
 mptctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	long ret;
-	lock_kernel();
+	mutex_lock(&mpctl_mutex);
 	ret = __mptctl_ioctl(file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&mpctl_mutex);
 	return ret;
 }
 
···
 static long compat_mpctl_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 {
 	long ret;
-	lock_kernel();
+	mutex_lock(&mpctl_mutex);
 	switch (cmd) {
 	case MPTIOCINFO:
 	case MPTIOCINFO1:
···
 		ret = -ENOIOCTLCMD;
 		break;
 	}
-	unlock_kernel();
+	mutex_unlock(&mpctl_mutex);
 	return ret;
 }
 

drivers/message/i2o/i2o_config.c

···
  */
 
 #include <linux/miscdevice.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/compat.h>
 #include <linux/slab.h>
 
···
 
 #define SG_TABLESIZE		30
 
+static DEFINE_MUTEX(i2o_cfg_mutex);
 static long i2o_cfg_ioctl(struct file *, unsigned int, unsigned long);
 
 static spinlock_t i2o_config_lock;
···
 				 unsigned long arg)
 {
 	int ret;
-	lock_kernel();
+	mutex_lock(&i2o_cfg_mutex);
 	switch (cmd) {
 	case I2OGETIOPS:
 		ret = i2o_cfg_ioctl(file, cmd, arg);
···
 		ret = -ENOIOCTLCMD;
 		break;
 	}
-	unlock_kernel();
+	mutex_unlock(&i2o_cfg_mutex);
 	return ret;
 }
 
···
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&i2o_cfg_mutex);
 	switch (cmd) {
 	case I2OGETIOPS:
 		ret = i2o_cfg_getiops(arg);
···
 		osm_debug("unknown ioctl called!\n");
 		ret = -EINVAL;
 	}
-	unlock_kernel();
+	mutex_unlock(&i2o_cfg_mutex);
 	return ret;
 }
 
···
 	if (!tmp)
 		return -ENOMEM;
 
-	lock_kernel();
+	mutex_lock(&i2o_cfg_mutex);
 	file->private_data = (void *)(i2o_cfg_info_id++);
 	tmp->fp = file;
 	tmp->fasync = NULL;
···
 	spin_lock_irqsave(&i2o_config_lock, flags);
 	open_files = tmp;
 	spin_unlock_irqrestore(&i2o_config_lock, flags);
-	unlock_kernel();
+	mutex_unlock(&i2o_cfg_mutex);
 
 	return 0;
 }
···
 	struct i2o_cfg_info *p;
 	int ret = -EBADF;
 
-	lock_kernel();
+	mutex_lock(&i2o_cfg_mutex);
 	for (p = open_files; p; p = p->next)
 		if (p->q_id == id)
 			break;
 
 	if (p)
 		ret = fasync_helper(fd, fp, on, &p->fasync);
-	unlock_kernel();
+	mutex_unlock(&i2o_cfg_mutex);
 	return ret;
 }
 
···
 	struct i2o_cfg_info *p, **q;
 	unsigned long flags;
 
-	lock_kernel();
+	mutex_lock(&i2o_cfg_mutex);
 	spin_lock_irqsave(&i2o_config_lock, flags);
 	for (q = &open_files; (p = *q) != NULL; q = &p->next) {
 		if (p->q_id == id) {
···
 		}
 	}
 	spin_unlock_irqrestore(&i2o_config_lock, flags);
-	unlock_kernel();
+	mutex_unlock(&i2o_cfg_mutex);
 
 	return 0;
 }

drivers/scsi/3w-9xxx.c

···
 #include <linux/pci.h>
 #include <linux/time.h>
 #include <linux/mutex.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <asm/io.h>
 #include <asm/irq.h>
···
 
 /* Globals */
 #define TW_DRIVER_VERSION "2.26.02.014"
+static DEFINE_MUTEX(twa_chrdev_mutex);
 static TW_Device_Extension *twa_device_extension_list[TW_MAX_SLOT];
 static unsigned int twa_device_extension_count;
 static int twa_major = -1;
···
 	int retval = TW_IOCTL_ERROR_OS_EFAULT;
 	void __user *argp = (void __user *)arg;
 
-	lock_kernel();
+	mutex_lock(&twa_chrdev_mutex);
 
 	/* Only let one of these through at a time */
 	if (mutex_lock_interruptible(&tw_dev->ioctl_lock)) {
···
 out2:
 	mutex_unlock(&tw_dev->ioctl_lock);
 out:
-	unlock_kernel();
+	mutex_unlock(&twa_chrdev_mutex);
 	return retval;
 } /* End twa_chrdev_ioctl() */
 
···
 	unsigned int minor_number;
 	int retval = TW_IOCTL_ERROR_OS_ENODEV;
 
-	cycle_kernel_lock();
 	minor_number = iminor(inode);
 	if (minor_number >= twa_device_extension_count)
 		goto out;

drivers/scsi/3w-sas.c

···
 #include <linux/pci.h>
 #include <linux/time.h>
 #include <linux/mutex.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <asm/io.h>
 #include <asm/irq.h>
···
 
 /* Globals */
 #define TW_DRIVER_VERSION "3.26.02.000"
+static DEFINE_MUTEX(twl_chrdev_mutex);
 static TW_Device_Extension *twl_device_extension_list[TW_MAX_SLOT];
 static unsigned int twl_device_extension_count;
 static int twl_major = -1;
···
 	int retval = -EFAULT;
 	void __user *argp = (void __user *)arg;
 
-	lock_kernel();
+	mutex_lock(&twl_chrdev_mutex);
 
 	/* Only let one of these through at a time */
 	if (mutex_lock_interruptible(&tw_dev->ioctl_lock)) {
···
 out2:
 	mutex_unlock(&tw_dev->ioctl_lock);
 out:
-	unlock_kernel();
+	mutex_unlock(&twl_chrdev_mutex);
 	return retval;
 } /* End twl_chrdev_ioctl() */
 
···
 		goto out;
 	}
 
-	cycle_kernel_lock();
 	minor_number = iminor(inode);
 	if (minor_number >= twl_device_extension_count)
 		goto out;

drivers/scsi/3w-xxxx.c

···
 
 #include <linux/module.h>
 #include <linux/reboot.h>
-#include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/moduleparam.h>
···
 
 /* Globals */
 #define TW_DRIVER_VERSION "1.26.02.003"
+static DEFINE_MUTEX(tw_mutex);
 static TW_Device_Extension *tw_device_extension_list[TW_MAX_SLOT];
 static int tw_device_extension_count = 0;
 static int twe_major = -1;
···
 
 	dprintk(KERN_WARNING "3w-xxxx: tw_chrdev_ioctl()\n");
 
-	lock_kernel();
+	mutex_lock(&tw_mutex);
 	/* Only let one of these through at a time */
 	if (mutex_lock_interruptible(&tw_dev->ioctl_lock)) {
-		unlock_kernel();
+		mutex_unlock(&tw_mutex);
 		return -EINTR;
 	}
 
···
 	dma_free_coherent(&tw_dev->tw_pci_dev->dev, data_buffer_length_adjusted+sizeof(TW_New_Ioctl) - 1, cpu_addr, dma_handle);
 out:
 	mutex_unlock(&tw_dev->ioctl_lock);
-	unlock_kernel();
+	mutex_unlock(&tw_mutex);
 	return retval;
 } /* End tw_chrdev_ioctl() */
 
···
 {
 	unsigned int minor_number;
 
-	cycle_kernel_lock();
 	dprintk(KERN_WARNING "3w-xxxx: tw_ioctl_open()\n");
 
 	minor_number = iminor(inode);

drivers/scsi/aacraid/linit.c

···
 #include <linux/moduleparam.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/spinlock.h>
 #include <linux/syscalls.h>
 #include <linux/delay.h>
···
 MODULE_LICENSE("GPL");
 MODULE_VERSION(AAC_DRIVER_FULL_VERSION);
 
+static DEFINE_MUTEX(aac_mutex);
 static LIST_HEAD(aac_devices);
 static int aac_cfg_major = -1;
 char aac_driver_version[] = AAC_DRIVER_FULL_VERSION;
···
 	unsigned minor_number = iminor(inode);
 	int err = -ENODEV;
 
-	lock_kernel();  /* BKL pushdown: nothing else protects this list */
+	mutex_lock(&aac_mutex);  /* BKL pushdown: nothing else protects this list */
 	list_for_each_entry(aac, &aac_devices, entry) {
 		if (aac->id == minor_number) {
 			file->private_data = aac;
···
 			break;
 		}
 	}
-	unlock_kernel();
+	mutex_unlock(&aac_mutex);
 
 	return err;
 }
···
 	int ret;
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
-	lock_kernel();
+	mutex_lock(&aac_mutex);
 	ret = aac_do_ioctl(file->private_data, cmd, (void __user *)arg);
-	unlock_kernel();
+	mutex_unlock(&aac_mutex);
 
 	return ret;
 }
···
 static long aac_compat_do_ioctl(struct aac_dev *dev, unsigned cmd, unsigned long arg)
 {
 	long ret;
-	lock_kernel();
+	mutex_lock(&aac_mutex);
 	switch (cmd) {
 	case FSACTL_MINIPORT_REV_CHECK:
 	case FSACTL_SENDFIB:
···
 		ret = -ENOIOCTLCMD;
 		break;
 	}
-	unlock_kernel();
+	mutex_unlock(&aac_mutex);
 	return ret;
 }
 

drivers/scsi/ch.c

···
 #include <linux/chio.h>			/* here are all the ioctls */
 #include <linux/mutex.h>
 #include <linux/idr.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 
 #include <scsi/scsi.h>
···
 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);
 MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);
 
+static DEFINE_MUTEX(ch_mutex);
 static int init = 1;
 module_param(init, int, 0444);
 MODULE_PARM_DESC(init, \
···
 	scsi_changer *ch;
 	int minor = iminor(inode);
 
-	lock_kernel();
+	mutex_lock(&ch_mutex);
 	spin_lock(&ch_index_lock);
 	ch = idr_find(&ch_index_idr, minor);
 
 	if (NULL == ch || scsi_device_get(ch->device)) {
 		spin_unlock(&ch_index_lock);
-		unlock_kernel();
+		mutex_unlock(&ch_mutex);
 		return -ENXIO;
 	}
 	spin_unlock(&ch_index_lock);
 
 	file->private_data = ch;
-	unlock_kernel();
+	mutex_unlock(&ch_mutex);
 	return 0;
 }
 

drivers/scsi/dpt_i2o.c

···
 #include <linux/kernel.h>	/* for printk */
 #include <linux/sched.h>
 #include <linux/reboot.h>
-#include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/dma-mapping.h>
 
···
  * Needed for our management apps
  *============================================================================
  */
+static DEFINE_MUTEX(adpt_mutex);
 static dpt_sig_S DPTI_sig = {
 	{'d', 'P', 't', 'S', 'i', 'G'}, SIG_VERSION,
 #ifdef __i386__
···
 	int minor;
 	adpt_hba* pHba;
 
-	lock_kernel();
+	mutex_lock(&adpt_mutex);
 	//TODO check for root access
 	//
 	minor = iminor(inode);
 	if (minor >= hba_count) {
-		unlock_kernel();
+		mutex_unlock(&adpt_mutex);
 		return -ENXIO;
 	}
 	mutex_lock(&adpt_configuration_lock);
···
 	}
 	if (pHba == NULL) {
 		mutex_unlock(&adpt_configuration_lock);
-		unlock_kernel();
+		mutex_unlock(&adpt_mutex);
 		return -ENXIO;
 	}
 
···
 
 	pHba->in_use = 1;
 	mutex_unlock(&adpt_configuration_lock);
-	unlock_kernel();
+	mutex_unlock(&adpt_mutex);
 
 	return 0;
 }
···
  
 	inode = file->f_dentry->d_inode;
  
-	lock_kernel();
+	mutex_lock(&adpt_mutex);
 	ret = adpt_ioctl(inode, file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&adpt_mutex);
 
 	return ret;
 }
···
  
 	inode = file->f_dentry->d_inode;
  
-	lock_kernel();
+	mutex_lock(&adpt_mutex);
  
 	switch(cmd) {
 		case DPT_SIGNATURE:
···
 			ret =  -ENOIOCTLCMD;
 	}
  
-	unlock_kernel();
+	mutex_unlock(&adpt_mutex);
  
 	return ret;
 }

drivers/scsi/gdth.c

···
 #include <linux/timer.h>
 #include <linux/dma-mapping.h>
 #include <linux/list.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 
 #ifdef GDTH_RTC
···
 #include <scsi/scsi_host.h>
 #include "gdth.h"
 
+static DEFINE_MUTEX(gdth_mutex);
 static void gdth_delay(int milliseconds);
 static void gdth_eval_mapping(u32 size, u32 *cyls, int *heads, int *secs);
 static irqreturn_t gdth_interrupt(int irq, void *dev_id);
···
 {
     gdth_ha_str *ha;
 
-    lock_kernel();
+    mutex_lock(&gdth_mutex);
     list_for_each_entry(ha, &gdth_instances, list) {
         if (!ha->sdev)
             ha->sdev = scsi_get_host_dev(ha->shost);
     }
-    unlock_kernel();
+    mutex_unlock(&gdth_mutex);
 
     TRACE(("gdth_open()\n"));
     return 0;
···
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&gdth_mutex);
 	ret = gdth_ioctl(file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&gdth_mutex);
 
 	return ret;
 }

drivers/scsi/megaraid.c

···
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/dma-mapping.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <scsi/scsicam.h>
 
···
 MODULE_LICENSE ("GPL");
 MODULE_VERSION(MEGARAID_MODULE_VERSION);
 
+static DEFINE_MUTEX(megadev_mutex);
 static unsigned int max_cmd_per_lun = DEF_CMD_PER_LUN;
 module_param(max_cmd_per_lun, uint, 0);
 MODULE_PARM_DESC(max_cmd_per_lun, "Maximum number of commands which can be issued to a single LUN (default=DEF_CMD_PER_LUN=63)");
···
 static int
 megadev_open (struct inode *inode, struct file *filep)
 {
-	cycle_kernel_lock();
 	/*
 	 * Only allow superuser to access private ioctl interface
 	 */
···
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&megadev_mutex);
 	ret = megadev_ioctl(filep, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&megadev_mutex);
 
 	return ret;
 }

drivers/scsi/megaraid/megaraid_mm.c

···
  */
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include "megaraid_mm.h"
 
 
 // Entry points for char node driver
+static DEFINE_MUTEX(mraid_mm_mutex);
 static int mraid_mm_open(struct inode *, struct file *);
 static long mraid_mm_unlocked_ioctl(struct file *, uint, unsigned long);
 
···
 	 */
 	if (!capable(CAP_SYS_ADMIN)) return (-EACCES);
 
-	cycle_kernel_lock();
 	return 0;
 }
 
···
 	int err;
 
 	/* inconsistant: mraid_mm_compat_ioctl doesn't take the BKL */
-	lock_kernel();
+	mutex_lock(&mraid_mm_mutex);
 	err = mraid_mm_ioctl(filep, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&mraid_mm_mutex);
 
 	return err;
 }

drivers/scsi/megaraid/megaraid_sas.c

···
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
-#include <linux/smp_lock.h>
 #include <linux/uio.h>
 #include <linux/slab.h>
 #include <asm/uaccess.h>
···
  */
 static int megasas_mgmt_open(struct inode *inode, struct file *filep)
 {
-	cycle_kernel_lock();
 	/*
 	 * Allow only those users with admin rights
 	 */

drivers/scsi/mpt2sas/mpt2sas_ctl.c

···
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/compat.h>
 #include <linux/poll.h>
 
···
 #include "mpt2sas_base.h"
 #include "mpt2sas_ctl.h"
 
+static DEFINE_MUTEX(_ctl_mutex);
 static struct fasync_struct *async_queue;
 static DECLARE_WAIT_QUEUE_HEAD(ctl_poll_wait);
 
···
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&_ctl_mutex);
 	ret = _ctl_ioctl_main(file, cmd, (void __user *)arg);
-	unlock_kernel();
+	mutex_unlock(&_ctl_mutex);
 	return ret;
 }
 
···
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&_ctl_mutex);
 	if (cmd == MPT2COMMAND32)
 		ret = _ctl_compat_mpt_command(file, cmd, arg);
 	else
 		ret = _ctl_ioctl_main(file, cmd, (void __user *)arg);
-	unlock_kernel();
+	mutex_unlock(&_ctl_mutex);
 	return ret;
 }
 #endif

drivers/scsi/osst.c

···
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
 #include <linux/jiffies.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <asm/dma.h>
 #include <asm/system.h>
···
 #include "osst_options.h"
 #include "osst_detect.h"
 
+static DEFINE_MUTEX(osst_int_mutex);
 static int max_dev = 0;
 static int write_threshold_kbs = 0;
 static int max_sg_segs = 0;
···
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&osst_int_mutex);
 	ret = __os_scsi_tape_open(inode, filp);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 	return ret;
 }
 
···
 	char		    * name  = tape_name(STp);
 	void	    __user  * p     = (void __user *)arg;
 
-	lock_kernel();
+	mutex_lock(&osst_int_mutex);
 	if (mutex_lock_interruptible(&STp->lock)) {
-		unlock_kernel();
+		mutex_unlock(&osst_int_mutex);
 		return -ERESTARTSYS;
 	}
 
···
 	mutex_unlock(&STp->lock);
 
 	retval = scsi_ioctl(STp->device, cmd_in, p);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 	return retval;
 
 out:
 	if (SRpnt) osst_release_request(SRpnt);
 
 	mutex_unlock(&STp->lock);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 
 	return retval;
 }

drivers/scsi/scsi_tgt_if.c

···
 #include <linux/miscdevice.h>
 #include <linux/gfp.h>
 #include <linux/file.h>
-#include <linux/smp_lock.h>
 #include <net/tcp.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
···
 {
 	tx_ring.tr_idx = rx_ring.tr_idx = 0;
 
-	cycle_kernel_lock();
 	return 0;
 }
 

drivers/scsi/sg.c

···
 #include <linux/blkdev.h>
 #include <linux/delay.h>
 #include <linux/blktrace_api.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 
 #include "scsi.h"
 #include <scsi/scsi_dbg.h>
···
 
 static int sg_add(struct device *, struct class_interface *);
 static void sg_remove(struct device *, struct class_interface *);
+
+static DEFINE_MUTEX(sg_mutex);
 
 static DEFINE_IDR(sg_index_idr);
 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
···
 	int res;
 	int retval;
 
-	lock_kernel();
+	mutex_lock(&sg_mutex);
 	nonseekable_open(inode, filp);
 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
 	sdp = sg_get_dev(dev);
···
 sg_put:
 	if (sdp)
 		sg_put_dev(sdp);
-	unlock_kernel();
+	mutex_unlock(&sg_mutex);
 	return retval;
 }
 
···
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&sg_mutex);
 	ret = sg_ioctl(filp, cmd_in, arg);
-	unlock_kernel();
+	mutex_unlock(&sg_mutex);
 
 	return ret;
 }