block: autoconvert trivial BKL users to private mutex

The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.

This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.

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, 6 insertions, 5 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index ab735a605cf3..3ff06f475eef 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -41,7 +41,7 @@
 #include <linux/cdrom.h>
 #include <linux/module.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/scatterlist.h>
 
 #include <xen/xen.h>
@@ -69,6 +69,7 @@ struct blk_shadow {
 	unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 };
 
+static DEFINE_MUTEX(blkfront_mutex);
 static const struct block_device_operations xlvbd_block_fops;
 
 #define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
@@ -1201,7 +1202,7 @@ static int blkif_open(struct block_device *bdev, fmode_t mode)
 	struct blkfront_info *info;
 	int err = 0;
 
-	lock_kernel();
+	mutex_lock(&blkfront_mutex);
 
 	info = disk->private_data;
 	if (!info) {
@@ -1219,7 +1220,7 @@ static int blkif_open(struct block_device *bdev, fmode_t mode)
 	mutex_unlock(&info->mutex);
 
 out:
-	unlock_kernel();
+	mutex_unlock(&blkfront_mutex);
 	return err;
 }
 
@@ -1229,7 +1230,7 @@ static int blkif_release(struct gendisk *disk, fmode_t mode)
 	struct block_device *bdev;
 	struct xenbus_device *xbdev;
 
-	lock_kernel();
+	mutex_lock(&blkfront_mutex);
 
 	bdev = bdget_disk(disk, 0);
 	bdput(bdev);
@@ -1263,7 +1264,7 @@ static int blkif_release(struct gendisk *disk, fmode_t mode)
 	}
 
 out:
-	unlock_kernel();
+	mutex_unlock(&blkfront_mutex);
 	return 0;
 }