mac: 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.

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>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
index e58c3d3..290cb32 100644
--- a/drivers/macintosh/smu.c
+++ b/drivers/macintosh/smu.c
@@ -19,7 +19,6 @@
  *    the userland interface
  */
 
-#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
@@ -97,6 +96,7 @@ struct smu_device {
  * I don't think there will ever be more than one SMU, so
  * for now, just hard code that
  */
+static DEFINE_MUTEX(smu_mutex);
 static struct smu_device	*smu;
 static DEFINE_MUTEX(smu_part_access);
 static int smu_irq_inited;
@@ -1095,12 +1095,12 @@ static int smu_open(struct inode *inode, struct file *file)
 	pp->mode = smu_file_commands;
 	init_waitqueue_head(&pp->wait);
 
-	lock_kernel();
+	mutex_lock(&smu_mutex);
 	spin_lock_irqsave(&smu_clist_lock, flags);
 	list_add(&pp->list, &smu_clist);
 	spin_unlock_irqrestore(&smu_clist_lock, flags);
 	file->private_data = pp;
-	unlock_kernel();
+	mutex_unlock(&smu_mutex);
 
 	return 0;
 }