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/sbus/char/jsflash.c b/drivers/sbus/char/jsflash.c
index 4942050..13f48e2 100644
--- a/drivers/sbus/char/jsflash.c
+++ b/drivers/sbus/char/jsflash.c
@@ -27,7 +27,7 @@
*/
#include <linux/module.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
@@ -68,6 +68,8 @@
#define JSF_PART_BITS 2 /* 2 bits of minors to cover JSF_NPART */
#define JSF_PART_MASK 0x3 /* 2 bits mask */
+static DEFINE_MUTEX(jsf_mutex);
+
/*
* Access functions.
* We could ioremap(), but it's easier this way.
@@ -225,7 +227,7 @@
{
loff_t ret;
- lock_kernel();
+ mutex_lock(&jsf_mutex);
switch (orig) {
case 0:
file->f_pos = offset;
@@ -238,7 +240,7 @@
default:
ret = -EINVAL;
}
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return ret;
}
@@ -384,18 +386,18 @@
static long jsf_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
- lock_kernel();
+ mutex_lock(&jsf_mutex);
int error = -ENOTTY;
void __user *argp = (void __user *)arg;
if (!capable(CAP_SYS_ADMIN)) {
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return -EPERM;
}
switch (cmd) {
case JSFLASH_IDENT:
if (copy_to_user(argp, &jsf0.id, JSFIDSZ)) {
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return -EFAULT;
}
break;
@@ -407,7 +409,7 @@
break;
}
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return error;
}
@@ -418,17 +420,17 @@
static int jsf_open(struct inode * inode, struct file * filp)
{
- lock_kernel();
+ mutex_lock(&jsf_mutex);
if (jsf0.base == 0) {
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return -ENXIO;
}
if (test_and_set_bit(0, (void *)&jsf0.busy) != 0) {
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return -EBUSY;
}
- unlock_kernel();
+ mutex_unlock(&jsf_mutex);
return 0; /* XXX What security? */
}