[PATCH 05/12] usb: autoconvert trivial BKL users to private mutex

[Arnd Bergmann <arnd@arndb.de>]

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 <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: linux-usb@vger.kernel.org
---
 drivers/usb/gadget/printer.c |    7 ++++---
 drivers/usb/misc/iowarrior.c |   15 ++++++++-------
 drivers/usb/misc/rio500.c    |   15 ++++++++-------
 drivers/usb/misc/usblcd.c    |   16 ++++++++--------
 4 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/drivers/usb/gadget/printer.c b/drivers/usb/gadget/printer.c
index 4c3ac5c..04c7bbf 100644
--- a/drivers/usb/gadget/printer.c
+++ b/drivers/usb/gadget/printer.c
@@ -25,7 +25,7 @@
 #include <linux/ioport.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/timer.h>
@@ -70,6 +70,7 @@
 #define DRIVER_DESC		"Printer Gadget"
 #define DRIVER_VERSION		"2007 OCT 06"
 
+static DEFINE_MUTEX(printer_mutex);
 static const char shortname [] = "printer";
 static const char driver_desc [] = DRIVER_DESC;
 
@@ -476,7 +477,7 @@ printer_open(struct inode *inode, struct file *fd)
 	unsigned long		flags;
 	int			ret = -EBUSY;
 
-	lock_kernel();
+	mutex_lock(&printer_mutex);
 	dev = container_of(inode->i_cdev, struct printer_dev, printer_cdev);
 
 	spin_lock_irqsave(&dev->lock, flags);
@@ -492,7 +493,7 @@ printer_open(struct inode *inode, struct file *fd)
 	spin_unlock_irqrestore(&dev->lock, flags);
 
 	DBG(dev, "printer_open returned %x\n", ret);
-	unlock_kernel();
+	mutex_unlock(&printer_mutex);
 	return ret;
 }
 
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 7dc9d3c..8296645 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -18,7 +18,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/usb/iowarrior.h>
 
@@ -61,6 +61,7 @@ MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
 
 /* Module parameters */
+static DEFINE_MUTEX(iowarrior_mutex);
 static int debug = 0;
 module_param(debug, bool, 0644);
 MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");
@@ -493,7 +494,7 @@ static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 		return -ENOMEM;
 
 	/* lock this object */
-	lock_kernel();
+	mutex_lock(&iowarrior_mutex);
 	mutex_lock(&dev->mutex);
 
 	/* verify that the device wasn't unplugged */
@@ -585,7 +586,7 @@ static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 error_out:
 	/* unlock the device */
 	mutex_unlock(&dev->mutex);
-	unlock_kernel();
+	mutex_unlock(&iowarrior_mutex);
 	kfree(buffer);
 	return retval;
 }
@@ -602,12 +603,12 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 
 	dbg("%s", __func__);
 
-	lock_kernel();
+	mutex_lock(&iowarrior_mutex);
 	subminor = iminor(inode);
 
 	interface = usb_find_interface(&iowarrior_driver, subminor);
 	if (!interface) {
-		unlock_kernel();
+		mutex_unlock(&iowarrior_mutex);
 		err("%s - error, can't find device for minor %d", __func__,
 		    subminor);
 		return -ENODEV;
@@ -617,7 +618,7 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 	dev = usb_get_intfdata(interface);
 	if (!dev) {
 		mutex_unlock(&iowarrior_open_disc_lock);
-		unlock_kernel();
+		mutex_unlock(&iowarrior_mutex);
 		return -ENODEV;
 	}
 
@@ -644,7 +645,7 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 
 out:
 	mutex_unlock(&dev->mutex);
-	unlock_kernel();
+	mutex_unlock(&iowarrior_mutex);
 	return retval;
 }
 
diff --git a/drivers/usb/misc/rio500.c b/drivers/usb/misc/rio500.c
index a85771b..cc13ae6 100644
--- a/drivers/usb/misc/rio500.c
+++ b/drivers/usb/misc/rio500.c
@@ -32,7 +32,7 @@
 #include <linux/kernel.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/errno.h>
 #include <linux/random.h>
 #include <linux/poll.h>
@@ -72,6 +72,7 @@ struct rio_usb_data {
 	struct mutex lock;          /* general race avoidance */
 };
 
+static DEFINE_MUTEX(rio500_mutex);
 static struct rio_usb_data rio_instance;
 
 static int open_rio(struct inode *inode, struct file *file)
@@ -79,12 +80,12 @@ static int open_rio(struct inode *inode, struct file *file)
 	struct rio_usb_data *rio = &rio_instance;
 
 	/* against disconnect() */
-	lock_kernel();
+	mutex_lock(&rio500_mutex);
 	mutex_lock(&(rio->lock));
 
 	if (rio->isopen || !rio->present) {
 		mutex_unlock(&(rio->lock));
-		unlock_kernel();
+		mutex_unlock(&rio500_mutex);
 		return -EBUSY;
 	}
 	rio->isopen = 1;
@@ -94,7 +95,7 @@ static int open_rio(struct inode *inode, struct file *file)
 	mutex_unlock(&(rio->lock));
 
 	dev_info(&rio->rio_dev->dev, "Rio opened.\n");
-	unlock_kernel();
+	mutex_unlock(&rio500_mutex);
 
 	return 0;
 }
@@ -491,7 +492,7 @@ static void disconnect_rio(struct usb_interface *intf)
 	struct rio_usb_data *rio = usb_get_intfdata (intf);
 
 	usb_set_intfdata (intf, NULL);
-	lock_kernel();
+	mutex_lock(&rio500_mutex);
 	if (rio) {
 		usb_deregister_dev(intf, &usb_rio_class);
 
@@ -501,7 +502,7 @@ static void disconnect_rio(struct usb_interface *intf)
 			/* better let it finish - the release will do whats needed */
 			rio->rio_dev = NULL;
 			mutex_unlock(&(rio->lock));
-			unlock_kernel();
+			mutex_unlock(&rio500_mutex);
 			return;
 		}
 		kfree(rio->ibuf);
@@ -512,7 +513,7 @@ static void disconnect_rio(struct usb_interface *intf)
 		rio->present = 0;
 		mutex_unlock(&(rio->lock));
 	}
-	unlock_kernel();
+	mutex_unlock(&rio500_mutex);
 }
 
 static const struct usb_device_id rio_table[] = {
diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c
index 7828c76..6ae39e3 100644
--- a/drivers/usb/misc/usblcd.c
+++ b/drivers/usb/misc/usblcd.c
@@ -16,7 +16,6 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/errno.h>
 #include <linux/mutex.h>
 #include <asm/uaccess.h>
@@ -30,6 +29,7 @@
 #define IOCTL_GET_DRV_VERSION	2
 
 
+static DEFINE_MUTEX(lcd_mutex);
 static const struct usb_device_id id_table[] = {
 	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
 	{ },
@@ -74,12 +74,12 @@ static int lcd_open(struct inode *inode, struct file *file)
 	struct usb_interface *interface;
 	int subminor, r;
 
-	lock_kernel();
+	mutex_lock(&lcd_mutex);
 	subminor = iminor(inode);
 
 	interface = usb_find_interface(&lcd_driver, subminor);
 	if (!interface) {
-		unlock_kernel();
+		mutex_unlock(&lcd_mutex);
 		err ("USBLCD: %s - error, can't find device for minor %d",
 		     __func__, subminor);
 		return -ENODEV;
@@ -89,7 +89,7 @@ static int lcd_open(struct inode *inode, struct file *file)
 	dev = usb_get_intfdata(interface);
 	if (!dev) {
 		mutex_unlock(&open_disc_mutex);
-		unlock_kernel();
+		mutex_unlock(&lcd_mutex);
 		return -ENODEV;
 	}
 
@@ -101,13 +101,13 @@ static int lcd_open(struct inode *inode, struct file *file)
 	r = usb_autopm_get_interface(interface);
 	if (r < 0) {
 		kref_put(&dev->kref, lcd_delete);
-		unlock_kernel();
+		mutex_unlock(&lcd_mutex);
 		return r;
 	}
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;
-	unlock_kernel();
+	mutex_unlock(&lcd_mutex);
 
 	return 0;
 }
@@ -164,14 +164,14 @@ static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	
 	switch (cmd) {
 	case IOCTL_GET_HARD_VERSION:
-		lock_kernel();
+		mutex_lock(&lcd_mutex);
 		bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
 		sprintf(buf,"%1d%1d.%1d%1d",
 			(bcdDevice & 0xF000)>>12,
 			(bcdDevice & 0xF00)>>8,
 			(bcdDevice & 0xF0)>>4,
 			(bcdDevice & 0xF));
-		unlock_kernel();
+		mutex_unlock(&lcd_mutex);
 		if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 			return -EFAULT;
 		break;
-- 
1.7.1