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/ip2/ip2main.c b/drivers/char/ip2/ip2main.c
index d4b71e8..dfbdf49 100644
--- a/drivers/char/ip2/ip2main.c
+++ b/drivers/char/ip2/ip2main.c
@@ -98,7 +98,7 @@
#include <linux/major.h>
#include <linux/wait.h>
#include <linux/device.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/firmware.h>
#include <linux/platform_device.h>
@@ -138,6 +138,7 @@
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+static DEFINE_MUTEX(ip2_mutex);
static const struct file_operations ip2mem_proc_fops;
static const struct file_operations ip2_proc_fops;
@@ -2897,7 +2898,7 @@
printk (KERN_DEBUG "IP2IPL: ioctl cmd %d, arg %ld\n", cmd, arg );
#endif
- lock_kernel();
+ mutex_lock(&ip2_mutex);
switch ( iplminor ) {
case 0: // IPL device
@@ -2961,7 +2962,7 @@
rc = -ENODEV;
break;
}
- unlock_kernel();
+ mutex_unlock(&ip2_mutex);
return rc;
}
@@ -2982,7 +2983,6 @@
#ifdef IP2DEBUG_IPL
printk (KERN_DEBUG "IP2IPL: open\n" );
#endif
- cycle_kernel_lock();
return 0;
}