This patch remove blk_register_filter and blk_unregister_filter in
gendisk, and adds them to sd.c, sr.c. and ide-cd.c
The commit 
abf5439370491dd6fbb4fe1a7939680d2a9bc9d4 moved cmdfilter
from gendisk to request_queue. It turned out that in some subsystems
multiple gendisks share a single request_queue. So we get:
Using physmap partition information
Creating 3 MTD partitions on "physmap-flash":
0x00000000-0x01c00000 : "User FS"
0x01c00000-0x01c40000 : "booter"
kobject (
8511c410): tried to init an initialized object, something is seriously wrong.
Call Trace:
[<
8036644c>] dump_stack+0x8/0x34
[<
8021f050>] kobject_init+0x50/0xcc
[<
8021fa18>] kobject_init_and_add+0x24/0x58
[<
8021d20c>] blk_register_filter+0x4c/0x64
[<
8021c194>] add_disk+0x78/0xe0
[<
8027d14c>] add_mtd_blktrans_dev+0x254/0x278
[<
8027c8f0>] blktrans_notify_add+0x40/0x78
[<
80279c00>] add_mtd_device+0xd0/0x150
[<
8027b090>] add_mtd_partitions+0x568/0x5d8
[<
80285458>] physmap_flash_probe+0x2ac/0x334
[<
802644f8>] driver_probe_device+0x12c/0x244
[<
8026465c>] __driver_attach+0x4c/0x84
[<
80263c64>] bus_for_each_dev+0x58/0xac
[<
802633ec>] bus_add_driver+0xc4/0x24c
[<
802648e0>] driver_register+0xcc/0x184
[<
80100460>] _stext+0x60/0x1bc
In the long term, we need to fix such subsystems but we need a quick
fix now. This patch add the command filter support to only sd and sr
though it might be useful for other SG_IO users (such as cciss).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reported-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
 
        return 0;
 }
+EXPORT_SYMBOL(blk_register_filter);
 
 void blk_unregister_filter(struct gendisk *disk)
 {
        kobject_put(&filter->kobj);
        kobject_put(disk->holder_dir->parent);
 }
-
+EXPORT_SYMBOL(blk_unregister_filter);
 
                            disk->minors, NULL, exact_match, exact_lock, disk);
        register_disk(disk);
        blk_register_queue(disk);
-       blk_register_filter(disk);
 
        bdi = &disk->queue->backing_dev_info;
        bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
 
 void unlink_gendisk(struct gendisk *disk)
 {
-       blk_unregister_filter(disk);
        sysfs_remove_link(&disk->dev.kobj, "bdi");
        bdi_unregister(&disk->queue->backing_dev_info);
        blk_unregister_queue(disk);
 
 
        ide_proc_unregister_driver(drive, info->driver);
 
+       blk_unregister_filter(info->disk);
        del_gendisk(info->disk);
 
        ide_cd_put(info);
        g->fops = &idecd_ops;
        g->flags |= GENHD_FL_REMOVABLE;
        add_disk(g);
+       blk_register_filter(g);
        return 0;
 
 out_free_cd:
 
 
        dev_set_drvdata(dev, sdkp);
        add_disk(gd);
+       blk_register_filter(gd);
        sd_dif_config_host(sdkp);
 
        sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
        struct scsi_disk *sdkp = dev_get_drvdata(dev);
 
        device_del(&sdkp->dev);
+       blk_unregister_filter(sdkp->disk);
        del_gendisk(sdkp->disk);
        sd_shutdown(dev);
 
 
        dev_set_drvdata(dev, cd);
        disk->flags |= GENHD_FL_REMOVABLE;
        add_disk(disk);
+       blk_register_filter(disk);
 
        sdev_printk(KERN_DEBUG, sdev,
                    "Attached scsi CD-ROM %s\n", cd->cdi.name);
 {
        struct scsi_cd *cd = dev_get_drvdata(dev);
 
+       blk_unregister_filter(cd->disk);
        del_gendisk(cd->disk);
 
        mutex_lock(&sr_ref_mutex);