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authorArnd Bergmann <arnd@arndb.de>2010-08-07 12:25:34 -0400
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 12:25:34 -0400
commit6e9624b8caec290d28b4c6d9ec75749df6372b87 (patch)
tree47225b544e1da82742795553dc4e8aa70c17afdc /drivers/s390/block
parent8a6cfeb6deca3a8fefd639d898b0d163c0b5d368 (diff)
block: push down BKL into .open and .release
The open and release block_device_operations are currently called with the BKL held. In order to change that, we must first make sure that all drivers that currently rely on this have no regressions. This blindly pushes the BKL into all .open and .release operations for all block drivers to prepare for the next step. The drivers can subsequently replace the BKL with their own locks or remove it completely when it can be shown that it is not needed. The functions blkdev_get and blkdev_put are the only remaining users of the big kernel lock in the block layer, besides a few uses in the ioctl code, none of which need to serialize with blkdev_{get,put}. Most of these two functions is also under the protection of bdev->bd_mutex, including the actual calls to ->open and ->release, and the common code does not access any global data structures that need the BKL. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'drivers/s390/block')
-rw-r--r--drivers/s390/block/dasd.c6
-rw-r--r--drivers/s390/block/dcssblk.c5
2 files changed, 11 insertions, 0 deletions
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 17b033d0e050..1a84fae155e1 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -21,6 +21,7 @@
21#include <linux/hdreg.h> 21#include <linux/hdreg.h>
22#include <linux/async.h> 22#include <linux/async.h>
23#include <linux/mutex.h> 23#include <linux/mutex.h>
24#include <linux/smp_lock.h>
24 25
25#include <asm/ccwdev.h> 26#include <asm/ccwdev.h>
26#include <asm/ebcdic.h> 27#include <asm/ebcdic.h>
@@ -2235,6 +2236,7 @@ static int dasd_open(struct block_device *bdev, fmode_t mode)
2235 if (!block) 2236 if (!block)
2236 return -ENODEV; 2237 return -ENODEV;
2237 2238
2239 lock_kernel();
2238 base = block->base; 2240 base = block->base;
2239 atomic_inc(&block->open_count); 2241 atomic_inc(&block->open_count);
2240 if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) { 2242 if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
@@ -2269,12 +2271,14 @@ static int dasd_open(struct block_device *bdev, fmode_t mode)
2269 goto out; 2271 goto out;
2270 } 2272 }
2271 2273
2274 unlock_kernel();
2272 return 0; 2275 return 0;
2273 2276
2274out: 2277out:
2275 module_put(base->discipline->owner); 2278 module_put(base->discipline->owner);
2276unlock: 2279unlock:
2277 atomic_dec(&block->open_count); 2280 atomic_dec(&block->open_count);
2281 unlock_kernel();
2278 return rc; 2282 return rc;
2279} 2283}
2280 2284
@@ -2282,8 +2286,10 @@ static int dasd_release(struct gendisk *disk, fmode_t mode)
2282{ 2286{
2283 struct dasd_block *block = disk->private_data; 2287 struct dasd_block *block = disk->private_data;
2284 2288
2289 lock_kernel();
2285 atomic_dec(&block->open_count); 2290 atomic_dec(&block->open_count);
2286 module_put(block->base->discipline->owner); 2291 module_put(block->base->discipline->owner);
2292 unlock_kernel();
2287 return 0; 2293 return 0;
2288} 2294}
2289 2295
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 9b43ae94beba..2bd72aa34c59 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -14,6 +14,7 @@
14#include <linux/init.h> 14#include <linux/init.h>
15#include <linux/slab.h> 15#include <linux/slab.h>
16#include <linux/blkdev.h> 16#include <linux/blkdev.h>
17#include <linux/smp_lock.h>
17#include <linux/completion.h> 18#include <linux/completion.h>
18#include <linux/interrupt.h> 19#include <linux/interrupt.h>
19#include <linux/platform_device.h> 20#include <linux/platform_device.h>
@@ -775,6 +776,7 @@ dcssblk_open(struct block_device *bdev, fmode_t mode)
775 struct dcssblk_dev_info *dev_info; 776 struct dcssblk_dev_info *dev_info;
776 int rc; 777 int rc;
777 778
779 lock_kernel();
778 dev_info = bdev->bd_disk->private_data; 780 dev_info = bdev->bd_disk->private_data;
779 if (NULL == dev_info) { 781 if (NULL == dev_info) {
780 rc = -ENODEV; 782 rc = -ENODEV;
@@ -784,6 +786,7 @@ dcssblk_open(struct block_device *bdev, fmode_t mode)
784 bdev->bd_block_size = 4096; 786 bdev->bd_block_size = 4096;
785 rc = 0; 787 rc = 0;
786out: 788out:
789 unlock_kernel();
787 return rc; 790 return rc;
788} 791}
789 792
@@ -794,6 +797,7 @@ dcssblk_release(struct gendisk *disk, fmode_t mode)
794 struct segment_info *entry; 797 struct segment_info *entry;
795 int rc; 798 int rc;
796 799
800 lock_kernel();
797 if (!dev_info) { 801 if (!dev_info) {
798 rc = -ENODEV; 802 rc = -ENODEV;
799 goto out; 803 goto out;
@@ -811,6 +815,7 @@ dcssblk_release(struct gendisk *disk, fmode_t mode)
811 up_write(&dcssblk_devices_sem); 815 up_write(&dcssblk_devices_sem);
812 rc = 0; 816 rc = 0;
813out: 817out:
818 unlock_kernel();
814 return rc; 819 return rc;
815} 820}
816 821