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/nwflash.c b/drivers/char/nwflash.c
index 043a1c7..a12f524 100644
--- a/drivers/char/nwflash.c
+++ b/drivers/char/nwflash.c
@@ -25,7 +25,6 @@
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/init.h>
-#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
@@ -41,6 +40,7 @@
#define NWFLASH_VERSION "6.4"
+static DEFINE_MUTEX(flash_mutex);
static void kick_open(void);
static int get_flash_id(void);
static int erase_block(int nBlock);
@@ -96,7 +96,7 @@
static long flash_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
- lock_kernel();
+ mutex_lock(&flash_mutex);
switch (cmd) {
case CMD_WRITE_DISABLE:
gbWriteBase64Enable = 0;
@@ -114,10 +114,10 @@
default:
gbWriteBase64Enable = 0;
gbWriteEnable = 0;
- unlock_kernel();
+ mutex_unlock(&flash_mutex);
return -EINVAL;
}
- unlock_kernel();
+ mutex_unlock(&flash_mutex);
return 0;
}
@@ -282,7 +282,7 @@
{
loff_t ret;
- lock_kernel();
+ mutex_lock(&flash_mutex);
if (flashdebug)
printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
(unsigned int) offset, orig);
@@ -317,7 +317,7 @@
default:
ret = -EINVAL;
}
- unlock_kernel();
+ mutex_unlock(&flash_mutex);
return ret;
}