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/telephony/ixj.c b/drivers/telephony/ixj.c
index b53deee..b1e4699 100644
--- a/drivers/telephony/ixj.c
+++ b/drivers/telephony/ixj.c
@@ -257,7 +257,7 @@
 #include <linux/fs.h>		/* everything... */
 #include <linux/errno.h>	/* error codes */
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/mm.h>
 #include <linux/ioport.h>
 #include <linux/interrupt.h>
@@ -277,6 +277,7 @@
 #define TYPE(inode) (iminor(inode) >> 4)
 #define NUM(inode) (iminor(inode) & 0xf)
 
+static DEFINE_MUTEX(ixj_mutex);
 static int ixjdebug;
 static int hertz = HZ;
 static int samplerate = 100;
@@ -6655,9 +6656,9 @@ static long do_ixj_ioctl(struct file *file_p, unsigned int cmd, unsigned long ar
 static long ixj_ioctl(struct file *file_p, unsigned int cmd, unsigned long arg)
 {
 	long ret;
-	lock_kernel();
+	mutex_lock(&ixj_mutex);
 	ret = do_ixj_ioctl(file_p, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&ixj_mutex);
 	return ret;
 }