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/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
index 566343b..b7d96e6 100644
--- a/drivers/watchdog/cpwd.c
+++ b/drivers/watchdog/cpwd.c
@@ -25,7 +25,7 @@
#include <linux/ioport.h>
#include <linux/timer.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_device.h>
@@ -89,6 +89,7 @@
} devs[WD_NUMDEVS];
};
+static DEFINE_MUTEX(cpwd_mutex);
static struct cpwd *cpwd_device;
/* Sun uses Altera PLD EPF8820ATC144-4
@@ -368,7 +369,7 @@
{
struct cpwd *p = cpwd_device;
- lock_kernel();
+ mutex_lock(&cpwd_mutex);
switch (iminor(inode)) {
case WD0_MINOR:
case WD1_MINOR:
@@ -376,7 +377,7 @@
break;
default:
- unlock_kernel();
+ mutex_unlock(&cpwd_mutex);
return -ENODEV;
}
@@ -386,13 +387,13 @@
IRQF_SHARED, DRIVER_NAME, p)) {
printk(KERN_ERR PFX "Cannot register IRQ %d\n",
p->irq);
- unlock_kernel();
+ mutex_unlock(&cpwd_mutex);
return -EBUSY;
}
p->initialized = true;
}
- unlock_kernel();
+ mutex_unlock(&cpwd_mutex);
return nonseekable_open(inode, f);
}
@@ -482,9 +483,9 @@
case WIOCSTART:
case WIOCSTOP:
case WIOCGSTAT:
- lock_kernel();
+ mutex_lock(&cpwd_mutex);
rval = cpwd_ioctl(file, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&cpwd_mutex);
break;
/* everything else is handled by the generic compat layer */
