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authorArnd Bergmann <arnd@arndb.de>2010-06-02 14:28:52 +0200
committerArnd Bergmann <arnd@arndb.de>2010-10-05 15:01:04 +0200
commit613655fa39ff6957754fa8ceb8559980920eb8ee (patch)
treead19600cb81207b24188683d7fc4ae88013339d1 /drivers/char/mmtimer.c
parent609146fdb319cebce93be550938ab852f7bade90 (diff)
downloadleg-kernel-613655fa39ff6957754fa8ceb8559980920eb8ee.tar.gz
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>
Diffstat (limited to 'drivers/char/mmtimer.c')
-rw-r--r--drivers/char/mmtimer.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index ea7c99fa978f..fe4697844ec1 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -32,7 +32,7 @@
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/math64.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
@@ -59,6 +59,7 @@ extern unsigned long sn_rtc_cycles_per_second;
#define rtc_time() (*RTC_COUNTER_ADDR)
+static DEFINE_MUTEX(mmtimer_mutex);
static long mmtimer_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
@@ -371,7 +372,7 @@ static long mmtimer_ioctl(struct file *file, unsigned int cmd,
{
int ret = 0;
- lock_kernel();
+ mutex_lock(&mmtimer_mutex);
switch (cmd) {
case MMTIMER_GETOFFSET: /* offset of the counter */
@@ -414,7 +415,7 @@ static long mmtimer_ioctl(struct file *file, unsigned int cmd,
ret = -ENOTTY;
break;
}
- unlock_kernel();
+ mutex_unlock(&mmtimer_mutex);
return ret;
}