USB: 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 <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 @@
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 @@
dev = usb_get_intfdata(interface);
if (!dev) {
mutex_unlock(&open_disc_mutex);
- unlock_kernel();
+ mutex_unlock(&lcd_mutex);
return -ENODEV;
}
@@ -101,13 +101,13 @@
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 @@
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;