From 369a46325d07061e0f66e16a1f59ef4f526a6464 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:52:04 +0100
Subject: [PATCH] [S390] tape: remove BKL from tape driver

Replace BLK with a per device mutex.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 drivers/s390/char/tape.h       |  3 +++
 drivers/s390/char/tape_block.c |  2 +-
 drivers/s390/char/tape_char.c  | 45 ++++++++++++++++++++++--------------------
 drivers/s390/char/tape_core.c  |  1 +
 4 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/drivers/s390/char/tape.h b/drivers/s390/char/tape.h
index fbe41e0..7a242f0 100644
--- a/drivers/s390/char/tape.h
+++ b/drivers/s390/char/tape.h
@@ -212,6 +212,9 @@ struct tape_device {
 	struct tape_class_device *	nt;
 	struct tape_class_device *	rt;
 
+	/* Device mutex to serialize tape commands. */
+	struct mutex			mutex;
+
 	/* Device discipline information. */
 	struct tape_discipline *	discipline;
 	void *				discdata;
diff --git a/drivers/s390/char/tape_block.c b/drivers/s390/char/tape_block.c
index c97c6aa..4799cc2 100644
--- a/drivers/s390/char/tape_block.c
+++ b/drivers/s390/char/tape_block.c
@@ -54,7 +54,7 @@ static const struct block_device_operations tapeblock_fops = {
 	.owner		 = THIS_MODULE,
 	.open		 = tapeblock_open,
 	.release	 = tapeblock_release,
-	.locked_ioctl           = tapeblock_ioctl,
+	.ioctl		 = tapeblock_ioctl,
 	.media_changed   = tapeblock_medium_changed,
 	.revalidate_disk = tapeblock_revalidate_disk,
 };
diff --git a/drivers/s390/char/tape_char.c b/drivers/s390/char/tape_char.c
index d44e698..23d773a 100644
--- a/drivers/s390/char/tape_char.c
+++ b/drivers/s390/char/tape_char.c
@@ -33,8 +33,7 @@ static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
 static int tapechar_open(struct inode *,struct file *);
 static int tapechar_release(struct inode *,struct file *);
-static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
-			  unsigned long);
+static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
 static long tapechar_compat_ioctl(struct file *, unsigned int,
 			  unsigned long);
 
@@ -43,7 +42,7 @@ static const struct file_operations tape_fops =
 	.owner = THIS_MODULE,
 	.read = tapechar_read,
 	.write = tapechar_write,
-	.ioctl = tapechar_ioctl,
+	.unlocked_ioctl = tapechar_ioctl,
 	.compat_ioctl = tapechar_compat_ioctl,
 	.open = tapechar_open,
 	.release = tapechar_release,
@@ -284,26 +283,20 @@ tapechar_open (struct inode *inode, struct file *filp)
 	if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 		return -ENODEV;
 
-	lock_kernel();
 	minor = iminor(filp->f_path.dentry->d_inode);
 	device = tape_find_device(minor / TAPE_MINORS_PER_DEV);
 	if (IS_ERR(device)) {
 		DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n");
-		rc = PTR_ERR(device);
-		goto out;
+		return PTR_ERR(device);
 	}
 
-
 	rc = tape_open(device);
 	if (rc == 0) {
 		filp->private_data = device;
-		rc = nonseekable_open(inode, filp);
-	}
-	else
+		nonseekable_open(inode, filp);
+	} else
 		tape_put_device(device);
 
-out:
-	unlock_kernel();
 	return rc;
 }
 
@@ -350,16 +343,11 @@ tapechar_release(struct inode *inode, struct file *filp)
  * Tape device io controls.
  */
 static int
-tapechar_ioctl(struct inode *inp, struct file *filp,
-	       unsigned int no, unsigned long data)
+__tapechar_ioctl(struct tape_device *device,
+		 unsigned int no, unsigned long data)
 {
-	struct tape_device *device;
 	int rc;
 
-	DBF_EVENT(6, "TCHAR:ioct\n");
-
-	device = (struct tape_device *) filp->private_data;
-
 	if (no == MTIOCTOP) {
 		struct mtop op;
 
@@ -452,15 +440,30 @@ tapechar_ioctl(struct inode *inp, struct file *filp,
 }
 
 static long
+tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
+{
+	struct tape_device *device;
+	long rc;
+
+	DBF_EVENT(6, "TCHAR:ioct\n");
+
+	device = (struct tape_device *) filp->private_data;
+	mutex_lock(&device->mutex);
+	rc = __tapechar_ioctl(device, no, data);
+	mutex_unlock(&device->mutex);
+	return rc;
+}
+
+static long
 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 {
 	struct tape_device *device = filp->private_data;
 	int rval = -ENOIOCTLCMD;
 
 	if (device->discipline->ioctl_fn) {
-		lock_kernel();
+		mutex_lock(&device->mutex);
 		rval = device->discipline->ioctl_fn(device, no, data);
-		unlock_kernel();
+		mutex_unlock(&device->mutex);
 		if (rval == -EINVAL)
 			rval = -ENOIOCTLCMD;
 	}
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index a7b7e72..f5d6802 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -492,6 +492,7 @@ tape_alloc_device(void)
 		kfree(device);
 		return ERR_PTR(-ENOMEM);
 	}
+	mutex_init(&device->mutex);
 	INIT_LIST_HEAD(&device->req_queue);
 	INIT_LIST_HEAD(&device->node);
 	init_waitqueue_head(&device->state_change_wq);
-- 
1.8.2.3