drivers: 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.
These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.
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>
diff --git a/drivers/hwmon/fschmd.c b/drivers/hwmon/fschmd.c
index b7ca2a9..d4d4ca6 100644
--- a/drivers/hwmon/fschmd.c
+++ b/drivers/hwmon/fschmd.c
@@ -38,7 +38,6 @@
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
-#include <linux/smp_lock.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
@@ -50,6 +49,7 @@
#include <linux/kref.h>
/* Addresses to scan */
+static DEFINE_MUTEX(watchdog_mutex);
static const unsigned short normal_i2c[] = { 0x73, I2C_CLIENT_END };
/* Insmod parameters */
@@ -858,7 +858,7 @@
int i, ret = 0;
struct fschmd_data *data = filp->private_data;
- lock_kernel();
+ mutex_lock(&watchdog_mutex);
switch (cmd) {
case WDIOC_GETSUPPORT:
ident.firmware_version = data->revision;
@@ -915,7 +915,7 @@
default:
ret = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&watchdog_mutex);
return ret;
}
diff --git a/drivers/hwmon/w83793.c b/drivers/hwmon/w83793.c
index 697202e..8e540ad 100644
--- a/drivers/hwmon/w83793.c
+++ b/drivers/hwmon/w83793.c
@@ -35,7 +35,6 @@
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
-#include <linux/smp_lock.h>
#include <linux/hwmon-vid.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
@@ -52,6 +51,7 @@
#define WATCHDOG_TIMEOUT 2 /* 2 minute default timeout */
/* Addresses to scan */
+static DEFINE_MUTEX(watchdog_mutex);
static const unsigned short normal_i2c[] = { 0x2c, 0x2d, 0x2e, 0x2f,
I2C_CLIENT_END };
@@ -1333,7 +1333,7 @@
int val, ret = 0;
struct w83793_data *data = filp->private_data;
- lock_kernel();
+ mutex_lock(&watchdog_mutex);
switch (cmd) {
case WDIOC_GETSUPPORT:
if (!nowayout)
@@ -1387,7 +1387,7 @@
default:
ret = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&watchdog_mutex);
return ret;
}