scsi: 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: linux-scsi@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index d6532187f616..e805c8fda239 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -22,7 +22,6 @@
 #include <linux/chio.h>			/* here are all the ioctls */
 #include <linux/mutex.h>
 #include <linux/idr.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 
 #include <scsi/scsi.h>
@@ -44,6 +43,7 @@ MODULE_LICENSE("GPL");
 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);
 MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);
 
+static DEFINE_MUTEX(ch_mutex);
 static int init = 1;
 module_param(init, int, 0444);
 MODULE_PARM_DESC(init, \
@@ -581,19 +581,19 @@ ch_open(struct inode *inode, struct file *file)
 	scsi_changer *ch;
 	int minor = iminor(inode);
 
-	lock_kernel();
+	mutex_lock(&ch_mutex);
 	spin_lock(&ch_index_lock);
 	ch = idr_find(&ch_index_idr, minor);
 
 	if (NULL == ch || scsi_device_get(ch->device)) {
 		spin_unlock(&ch_index_lock);
-		unlock_kernel();
+		mutex_unlock(&ch_mutex);
 		return -ENXIO;
 	}
 	spin_unlock(&ch_index_lock);
 
 	file->private_data = ch;
-	unlock_kernel();
+	mutex_unlock(&ch_mutex);
 	return 0;
 }