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, 8 insertions, 7 deletions

diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c
index 278b352ae78d..54de1d1af1a7 100644
--- a/drivers/scsi/osst.c
+++ b/drivers/scsi/osst.c
@@ -51,7 +51,7 @@ static const char * osst_version = "0.99.4";
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
 #include <linux/jiffies.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <asm/dma.h>
 #include <asm/system.h>
@@ -80,6 +80,7 @@ static const char * osst_version = "0.99.4";
 #include "osst_options.h"
 #include "osst_detect.h"
 
+static DEFINE_MUTEX(osst_int_mutex);
 static int max_dev = 0;
 static int write_threshold_kbs = 0;
 static int max_sg_segs = 0;
@@ -4807,9 +4808,9 @@ static int os_scsi_tape_open(struct inode * inode, struct file * filp)
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&osst_int_mutex);
 	ret = __os_scsi_tape_open(inode, filp);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 	return ret;
 }
 
@@ -4943,9 +4944,9 @@ static long osst_ioctl(struct file * file,
 	char		    * name  = tape_name(STp);
 	void	    __user  * p     = (void __user *)arg;
 
-	lock_kernel();
+	mutex_lock(&osst_int_mutex);
 	if (mutex_lock_interruptible(&STp->lock)) {
-		unlock_kernel();
+		mutex_unlock(&osst_int_mutex);
 		return -ERESTARTSYS;
 	}
 
@@ -5260,14 +5261,14 @@ static long osst_ioctl(struct file * file,
 	mutex_unlock(&STp->lock);
 
 	retval = scsi_ioctl(STp->device, cmd_in, p);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 	return retval;
 
 out:
 	if (SRpnt) osst_release_request(SRpnt);
 
 	mutex_unlock(&STp->lock);
-	unlock_kernel();
+	mutex_unlock(&osst_int_mutex);
 
 	return retval;
 }