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authorArnd Bergmann <arnd@arndb.de>2010-06-02 16:28:52 +0400
committerArnd Bergmann <arnd@arndb.de>2010-10-05 17:01:04 +0400
commit613655fa39ff6957754fa8ceb8559980920eb8ee (patch)
treead19600cb81207b24188683d7fc4ae88013339d1 /drivers/char/nvram.c
parent609146fdb319cebce93be550938ab852f7bade90 (diff)
downloadlinux-613655fa39ff6957754fa8ceb8559980920eb8ee.tar.xz
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/nvram.c')
-rw-r--r--drivers/char/nvram.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index 66d2917b003f..166f1e7aaa7e 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -109,10 +109,11 @@
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <asm/system.h>
+static DEFINE_MUTEX(nvram_mutex);
static DEFINE_SPINLOCK(nvram_state_lock);
static int nvram_open_cnt; /* #times opened */
static int nvram_open_mode; /* special open modes */
@@ -308,7 +309,7 @@ static long nvram_ioctl(struct file *file, unsigned int cmd,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- lock_kernel();
+ mutex_lock(&nvram_mutex);
spin_lock_irq(&rtc_lock);
for (i = 0; i < NVRAM_BYTES; ++i)
@@ -316,7 +317,7 @@ static long nvram_ioctl(struct file *file, unsigned int cmd,
__nvram_set_checksum();
spin_unlock_irq(&rtc_lock);
- unlock_kernel();
+ mutex_unlock(&nvram_mutex);
return 0;
case NVRAM_SETCKS:
@@ -325,11 +326,11 @@ static long nvram_ioctl(struct file *file, unsigned int cmd,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- lock_kernel();
+ mutex_lock(&nvram_mutex);
spin_lock_irq(&rtc_lock);
__nvram_set_checksum();
spin_unlock_irq(&rtc_lock);
- unlock_kernel();
+ mutex_unlock(&nvram_mutex);
return 0;
default: