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/char/pcmcia/cm4040_cs.c b/drivers/char/pcmcia/cm4040_cs.c
index 815cde1d0570..04c0a895740e 100644
--- a/drivers/char/pcmcia/cm4040_cs.c
+++ b/drivers/char/pcmcia/cm4040_cs.c
@@ -24,7 +24,7 @@
 #include <linux/fs.h>
 #include <linux/delay.h>
 #include <linux/poll.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/wait.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -49,6 +49,7 @@
 			   __func__ , ## args);		\
 	} while (0)
 
+static DEFINE_MUTEX(cm4040_mutex);
 static char *version =
 "OMNIKEY CardMan 4040 v1.1.0gm5 - All bugs added by Harald Welte";
 
@@ -444,7 +445,7 @@ static int cm4040_open(struct inode *inode, struct file *filp)
 	if (minor >= CM_MAX_DEV)
 		return -ENODEV;
 
-	lock_kernel();
+	mutex_lock(&cm4040_mutex);
 	link = dev_table[minor];
 	if (link == NULL || !pcmcia_dev_present(link)) {
 		ret = -ENODEV;
@@ -473,7 +474,7 @@ static int cm4040_open(struct inode *inode, struct file *filp)
 	DEBUGP(2, dev, "<- cm4040_open (successfully)\n");
 	ret = nonseekable_open(inode, filp);
 out:
-	unlock_kernel();
+	mutex_unlock(&cm4040_mutex);
 	return ret;
 }