From cfdb00a77ea7d5fb922fd985e5dfbcb36873411b Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 31 May 2010 22:38:40 +0200
Subject: [PATCH] s390/block: kill the big kernel lock

The dasd and dcssblk drivers gained the big
kernel lock in the recent pushdown from the
block layer, but they don't really need it,
so remove the calls without a replacement.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
---
 drivers/s390/block/dasd.c       |  6 ------
 drivers/s390/block/dasd_ioctl.c | 17 ++---------------
 drivers/s390/block/dcssblk.c    |  5 -----
 3 files changed, 2 insertions(+), 26 deletions(-)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 8373ca0de8e0..38e6fa9a2012 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -21,7 +21,6 @@
 #include <linux/hdreg.h>
 #include <linux/async.h>
 #include <linux/mutex.h>
-#include <linux/smp_lock.h>
 
 #include <asm/ccwdev.h>
 #include <asm/ebcdic.h>
@@ -2236,7 +2235,6 @@ static int dasd_open(struct block_device *bdev, fmode_t mode)
 	if (!block)
 		return -ENODEV;
 
-	lock_kernel();
 	base = block->base;
 	atomic_inc(&block->open_count);
 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
@@ -2271,14 +2269,12 @@ static int dasd_open(struct block_device *bdev, fmode_t mode)
 		goto out;
 	}
 
-	unlock_kernel();
 	return 0;
 
 out:
 	module_put(base->discipline->owner);
 unlock:
 	atomic_dec(&block->open_count);
-	unlock_kernel();
 	return rc;
 }
 
@@ -2286,10 +2282,8 @@ static int dasd_release(struct gendisk *disk, fmode_t mode)
 {
 	struct dasd_block *block = disk->private_data;
 
-	lock_kernel();
 	atomic_dec(&block->open_count);
 	module_put(block->base->discipline->owner);
-	unlock_kernel();
 	return 0;
 }
 
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 1557214944f7..26075e95b1ba 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -16,7 +16,6 @@
 #include <linux/major.h>
 #include <linux/fs.h>
 #include <linux/blkpg.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <asm/compat.h>
 #include <asm/ccwdev.h>
@@ -370,9 +369,8 @@ static int dasd_ioctl_readall_cmb(struct dasd_block *block, unsigned int cmd,
 	return ret;
 }
 
-static int
-dasd_do_ioctl(struct block_device *bdev, fmode_t mode,
-	      unsigned int cmd, unsigned long arg)
+int dasd_ioctl(struct block_device *bdev, fmode_t mode,
+	       unsigned int cmd, unsigned long arg)
 {
 	struct dasd_block *block = bdev->bd_disk->private_data;
 	void __user *argp;
@@ -430,14 +428,3 @@ dasd_do_ioctl(struct block_device *bdev, fmode_t mode,
 		return -EINVAL;
 	}
 }
-
-int dasd_ioctl(struct block_device *bdev, fmode_t mode,
-	       unsigned int cmd, unsigned long arg)
-{
-	int rc;
-
-	lock_kernel();
-	rc = dasd_do_ioctl(bdev, mode, cmd, arg);
-	unlock_kernel();
-	return rc;
-}
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 2bd72aa34c59..9b43ae94beba 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -14,7 +14,6 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/blkdev.h>
-#include <linux/smp_lock.h>
 #include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
@@ -776,7 +775,6 @@ dcssblk_open(struct block_device *bdev, fmode_t mode)
 	struct dcssblk_dev_info *dev_info;
 	int rc;
 
-	lock_kernel();
 	dev_info = bdev->bd_disk->private_data;
 	if (NULL == dev_info) {
 		rc = -ENODEV;
@@ -786,7 +784,6 @@ dcssblk_open(struct block_device *bdev, fmode_t mode)
 	bdev->bd_block_size = 4096;
 	rc = 0;
 out:
-	unlock_kernel();
 	return rc;
 }
 
@@ -797,7 +794,6 @@ dcssblk_release(struct gendisk *disk, fmode_t mode)
 	struct segment_info *entry;
 	int rc;
 
-	lock_kernel();
 	if (!dev_info) {
 		rc = -ENODEV;
 		goto out;
@@ -815,7 +811,6 @@ dcssblk_release(struct gendisk *disk, fmode_t mode)
 	up_write(&dcssblk_devices_sem);
 	rc = 0;
 out:
-	unlock_kernel();
 	return rc;
 }