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, 10 insertions, 9 deletions

diff --git a/drivers/block/paride/pt.c b/drivers/block/paride/pt.c
index bc5825fdeaab..e4dda282e0a6 100644
--- a/drivers/block/paride/pt.c
+++ b/drivers/block/paride/pt.c
@@ -146,7 +146,7 @@ static int (*drives[4])[6] = {&drive0, &drive1, &drive2, &drive3};
 #include <linux/mtio.h>
 #include <linux/device.h>
 #include <linux/sched.h>	/* current, TASK_*, schedule_timeout() */
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 
 #include <asm/uaccess.h>
 
@@ -189,6 +189,7 @@ module_param_array(drive3, int, NULL, 0);
 #define ATAPI_MODE_SENSE	0x1a
 #define ATAPI_LOG_SENSE		0x4d
 
+static DEFINE_MUTEX(pt_mutex);
 static int pt_open(struct inode *inode, struct file *file);
 static long pt_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 static int pt_release(struct inode *inode, struct file *file);
@@ -650,9 +651,9 @@ static int pt_open(struct inode *inode, struct file *file)
 	struct pt_unit *tape = pt + unit;
 	int err;
 
-	lock_kernel();
+	mutex_lock(&pt_mutex);
 	if (unit >= PT_UNITS || (!tape->present)) {
-		unlock_kernel();
+		mutex_unlock(&pt_mutex);
 		return -ENODEV;
 	}
 
@@ -681,12 +682,12 @@ static int pt_open(struct inode *inode, struct file *file)
 	}
 
 	file->private_data = tape;
-	unlock_kernel();
+	mutex_unlock(&pt_mutex);
 	return 0;
 
 out:
 	atomic_inc(&tape->available);
-	unlock_kernel();
+	mutex_unlock(&pt_mutex);
 	return err;
 }
 
@@ -704,15 +705,15 @@ static long pt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		switch (mtop.mt_op) {
 
 		case MTREW:
-			lock_kernel();
+			mutex_lock(&pt_mutex);
 			pt_rewind(tape);
-			unlock_kernel();
+			mutex_unlock(&pt_mutex);
 			return 0;
 
 		case MTWEOF:
-			lock_kernel();
+			mutex_lock(&pt_mutex);
 			pt_write_fm(tape);
-			unlock_kernel();
+			mutex_unlock(&pt_mutex);
 			return 0;
 
 		default: