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/char/genrtc.c b/drivers/char/genrtc.c
index b6c2cc1..2aa69f9 100644
--- a/drivers/char/genrtc.c
+++ b/drivers/char/genrtc.c
@@ -52,7 +52,7 @@
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <asm/uaccess.h>
@@ -66,6 +66,7 @@
* ioctls.
*/
+static DEFINE_MUTEX(gen_rtc_mutex);
static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);
/*
@@ -337,9 +338,9 @@
{
int ret;
- lock_kernel();
+ mutex_lock(&gen_rtc_mutex);
ret = gen_rtc_ioctl(file, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&gen_rtc_mutex);
return ret;
}
@@ -352,16 +353,16 @@
static int gen_rtc_open(struct inode *inode, struct file *file)
{
- lock_kernel();
+ mutex_lock(&gen_rtc_mutex);
if (gen_rtc_status & RTC_IS_OPEN) {
- unlock_kernel();
+ mutex_unlock(&gen_rtc_mutex);
return -EBUSY;
}
gen_rtc_status |= RTC_IS_OPEN;
gen_rtc_irq_data = 0;
irq_active = 0;
- unlock_kernel();
+ mutex_unlock(&gen_rtc_mutex);
return 0;
}