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>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/block/paride/pg.c b/drivers/block/paride/pg.c
index c397b3ddba9b..bed29cb9e6d9 100644
--- a/drivers/block/paride/pg.c
+++ b/drivers/block/paride/pg.c
@@ -162,7 +162,7 @@ enum {D_PRT, D_PRO, D_UNI, D_MOD, D_SLV, D_DLY};
 #include <linux/pg.h>
 #include <linux/device.h>
 #include <linux/sched.h>	/* current, TASK_* */
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/jiffies.h>
 
 #include <asm/uaccess.h>
@@ -193,6 +193,7 @@ module_param_array(drive3, int, NULL, 0);
 
 #define ATAPI_IDENTIFY		0x12
 
+static DEFINE_MUTEX(pg_mutex);
 static int pg_open(struct inode *inode, struct file *file);
 static int pg_release(struct inode *inode, struct file *file);
 static ssize_t pg_read(struct file *filp, char __user *buf,
@@ -518,7 +519,7 @@ static int pg_open(struct inode *inode, struct file *file)
 	struct pg *dev = &devices[unit];
 	int ret = 0;
 
-	lock_kernel();
+	mutex_lock(&pg_mutex);
 	if ((unit >= PG_UNITS) || (!dev->present)) {
 		ret = -ENODEV;
 		goto out;
@@ -547,7 +548,7 @@ static int pg_open(struct inode *inode, struct file *file)
 	file->private_data = dev;
 
 out:
-	unlock_kernel();
+	mutex_unlock(&pg_mutex);
 	return ret;
 }