diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 91c8013..cdb6106 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -12,7 +12,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/backing-dev.h>
 #include <linux/compat.h>
 #include <linux/mount.h>
@@ -23,6 +23,7 @@
 #include <asm/uaccess.h>
 
 #define MTD_INODE_FS_MAGIC 0x11307854
+static DEFINE_MUTEX(mtd_mutex);
 static struct vfsmount *mtd_inode_mnt __read_mostly;
 
 /*
@@ -76,7 +77,7 @@ static int mtd_open(struct inode *inode, struct file *file)
 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
 		return -EACCES;
 
-	lock_kernel();
+	mutex_lock(&mtd_mutex);
 	mtd = get_mtd_device(NULL, devnum);
 
 	if (IS_ERR(mtd)) {
@@ -124,7 +125,7 @@ static int mtd_open(struct inode *inode, struct file *file)
 	file->private_data = mfi;
 
 out:
-	unlock_kernel();
+	mutex_unlock(&mtd_mutex);
 	return ret;
 } /* mtd_open */
 
@@ -838,9 +839,9 @@ static long mtd_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&mtd_mutex);
 	ret = mtd_ioctl(file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&mtd_mutex);
 
 	return ret;
 }
@@ -864,7 +865,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd,
 	void __user *argp = compat_ptr(arg);
 	int ret = 0;
 
-	lock_kernel();
+	mutex_lock(&mtd_mutex);
 
 	switch (cmd) {
 	case MEMWRITEOOB32:
@@ -899,7 +900,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd,
 		ret = mtd_ioctl(file, cmd, (unsigned long)argp);
 	}
 
-	unlock_kernel();
+	mutex_unlock(&mtd_mutex);
 
 	return ret;
 }