[PATCH 03/18] s390/block: kill the big kernel lock

From: Arnd Bergmann
Date: Tue Sep 14 2010 - 15:41:47 EST


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@xxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux-s390@xxxxxxxxxxxxxxx
---
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 8373ca0..38e6fa9 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 1557214..26075e9 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 2bd72aa..9b43ae9 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;
}

--
1.7.1

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