From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932340AbWBVQLt (ORCPT ); Wed, 22 Feb 2006 11:11:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932345AbWBVQLt (ORCPT ); Wed, 22 Feb 2006 11:11:49 -0500 Received: from mx1.redhat.com ([66.187.233.31]:16087 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932340AbWBVQLs (ORCPT ); Wed, 22 Feb 2006 11:11:48 -0500 Message-ID: <43FC8D8C.1060904@ce.jp.nec.com> Date: Wed, 22 Feb 2006 11:13:00 -0500 From: "Jun'ichi Nomura" User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Neil Brown , Alasdair Kergon , Lars Marowsky-Bree , Greg KH CC: linux-kernel@vger.kernel.org, device-mapper development Subject: [PATCH 1/3] sysfs representation of stacked devices (common) (rev.2) References: <43FC8C00.5020600@ce.jp.nec.com> In-Reply-To: <43FC8C00.5020600@ce.jp.nec.com> Content-Type: multipart/mixed; boundary="------------070700030507020902080804" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------070700030507020902080804 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit This patch adds bd_claim_by_kobject and bd_release_from_kobject which create/remove symlinks between the claimed bdev and the holder. -- Jun'ichi Nomura, NEC Solutions (America), Inc. --------------070700030507020902080804 Content-Type: text/x-patch; name="common.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="common.patch" Adding bd_claim_by_kobject/bd_release_from_kobject for use by stacked device drivers (dm and md) Signed-off-by: Jun'ichi Nomura --- linux-2.6.15/include/linux/fs.h 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.15/include/linux/fs.h 2006-02-21 19:04:46.000000000 -0500 @@ -373,6 +373,8 @@ struct block_device { struct list_head bd_inodes; void * bd_holder; int bd_holders; + struct kobject bd_holder_dir; + struct list_head bd_holder_list; struct block_device * bd_contains; unsigned bd_block_size; struct hd_struct * bd_part; @@ -1351,6 +1353,8 @@ extern int blkdev_get(struct block_devic extern int blkdev_put(struct block_device *); extern int bd_claim(struct block_device *, void *); extern void bd_release(struct block_device *); +extern int bd_claim_by_kobject(struct block_device *, void *, struct kobject *); +extern void bd_release_from_kobject(struct block_device *, struct kobject *); /* fs/char_dev.c */ extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *); --- linux-2.6.15/include/linux/genhd.h 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.15/include/linux/genhd.h 2006-02-21 11:38:01.000000000 -0500 @@ -114,6 +114,7 @@ struct gendisk { int number; /* more of the same */ struct device *driverfs_dev; struct kobject kobj; + struct kobject slave_dir; struct timer_rand_state *random; int policy; --- linux-2.6.15/fs/block_dev.c 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.15/fs/block_dev.c 2006-02-22 09:48:37.000000000 -0500 @@ -443,7 +443,159 @@ void bd_forget(struct inode *inode) spin_unlock(&bdev_lock); } -int bd_claim(struct block_device *bdev, void *holder) +/* + * Functions for bd_claim_by_kobject / bd_release_from_kobject + * + * If a kobject is passed to bd_claim_by_kobject() + * and the kobject has a parent directory, + * following symlinks are created: + * o from the kobject to the claimed bdev + * o from "holders" directory of the bdev to the parent of the kobject + * bd_release_from_kobject() removes these symlinks. + * + * Example: + * If /dev/dm-0 maps to /dev/sda, kobject corresponding to + * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: + * /sys/block/dm-0/slaves/sda --> /sys/block/sda + * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 + */ + +static inline struct kobject * bdev_get_kobj(struct block_device *bdev) +{ + if (!bdev) + return NULL; + else if (bdev->bd_contains != bdev) + return kobject_get(&bdev->bd_part->kobj); + else + return kobject_get(&bdev->bd_disk->kobj); +} + +static inline void add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_create_link(from, to, kobject_name(to)); +} + +static inline void del_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_remove_link(from, kobject_name(to)); +} + +static void link_bd_holder(struct block_device *bdev, struct kobject *holder) +{ + struct kobject *kobj; + + if (!holder->parent) + return; + + kobj = bdev_get_kobj(bdev); + add_symlink(holder, kobj); + add_symlink(&bdev->bd_holder_dir, holder->parent); + kobject_put(kobj); +} + +static void unlink_bd_holder(struct block_device *bdev, struct kobject *holder) +{ + struct kobject *kobj; + + if (!holder->parent) + return; + + kobj = bdev_get_kobj(bdev); + del_symlink(holder, kobj); + del_symlink(&bdev->bd_holder_dir, holder->parent); + kobject_put(kobj); +} + +/* This is a mere directory in sysfs. No methods are needed. */ +static struct kobj_type bd_holder_ktype = { + .release = NULL, + .sysfs_ops = NULL, + .default_attrs = NULL, +}; + +static inline void add_holder_dir(struct block_device *bdev) +{ + struct kobject *kobj = &bdev->bd_holder_dir; + + kobj->ktype = &bd_holder_ktype; + kobject_set_name(kobj, "holders"); + kobj->parent = bdev_get_kobj(bdev); + kobject_init(kobj); + kobject_add(kobj); + kobject_put(kobj->parent); +} + +static inline void del_holder_dir(struct block_device *bdev) +{ + /* + * Don't kobject_unregister to avoid memory allocation + * in kobject_hotplug. + */ + kobject_del(&bdev->bd_holder_dir); + kobject_put(&bdev->bd_holder_dir); +} + +/* bd_holder_list is protected by bdev_lock */ +struct bd_holder { + struct list_head list; /* chain of holders of the bdev */ + int count; /* references from the holder */ + struct kobject *kobj; /* holder kobject */ +}; + +static int add_bd_holder(struct block_device *bdev, struct kobject *kobj) +{ + struct bd_holder *bo; + + list_for_each_entry(bo, &bdev->bd_holder_list, list) { + if (bo->kobj == kobj) { + bo->count++; + return 0; + } + } + + if (list_empty(&bdev->bd_holder_list)) + add_holder_dir(bdev); + + bo = kmalloc(sizeof(*bo), GFP_KERNEL); + if (!bo) + return -ENOMEM; + + bo->count = 1; + bo->kobj = kobj; + list_add_tail(&bo->list, &bdev->bd_holder_list); + link_bd_holder(bdev, kobj); + + return 0; +} + +static int del_bd_holder(struct block_device *bdev, struct kobject *kobj) +{ + struct bd_holder *bo; + + list_for_each_entry(bo, &bdev->bd_holder_list, list) { + if (bo->kobj == kobj) { + bo->count--; + BUG_ON(bo->count < 0); + if (!bo->count) { + unlink_bd_holder(bdev, kobj); + list_del(&bo->list); + kfree(bo); + } + break; + } + } + + if (list_empty(&bdev->bd_holder_list)) + del_holder_dir(bdev); + + return 0; +} + +int bd_claim_by_kobject(struct block_device *bdev, void *holder, struct kobject *kobj) { int res; spin_lock(&bdev_lock); @@ -464,6 +616,9 @@ int bd_claim(struct block_device *bdev, res = 0; /* is a partition of an un-held device */ /* now impose change */ + if (res == 0 && kobj) + res = add_bd_holder(bdev, kobj); + if (res==0) { /* note that for a whole device bd_holders * will be incremented twice, and bd_holder will @@ -478,11 +633,20 @@ int bd_claim(struct block_device *bdev, return res; } +EXPORT_SYMBOL(bd_claim_by_kobject); + +int bd_claim(struct block_device *bdev, void *holder) +{ + return bd_claim_by_kobject(bdev, holder, NULL); +} + EXPORT_SYMBOL(bd_claim); -void bd_release(struct block_device *bdev) +void bd_release_from_kobject(struct block_device *bdev, struct kobject *kobj) { spin_lock(&bdev_lock); + if (kobj) + del_bd_holder(bdev, kobj); if (!--bdev->bd_contains->bd_holders) bdev->bd_contains->bd_holder = NULL; if (!--bdev->bd_holders) @@ -490,6 +654,13 @@ void bd_release(struct block_device *bde spin_unlock(&bdev_lock); } +EXPORT_SYMBOL(bd_release_from_kobject); + +void bd_release(struct block_device *bdev) +{ + bd_release_from_kobject(bdev, NULL); +} + EXPORT_SYMBOL(bd_release); /* @@ -578,6 +749,7 @@ static int do_open(struct block_device * if (!bdev->bd_openers) { bdev->bd_disk = disk; bdev->bd_contains = bdev; + INIT_LIST_HEAD(&bdev->bd_holder_list); if (!part) { struct backing_dev_info *bdi; if (disk->fops->open) { --- linux-2.6.15/fs/partitions/check.c 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.15/fs/partitions/check.c 2006-02-21 14:30:23.000000000 -0500 @@ -293,6 +293,13 @@ struct kobj_type ktype_part = { .sysfs_ops = &part_sysfs_ops, }; +/* This is a mere directory in sysfs. No methods are needed. */ +static struct kobj_type slave_ktype = { + .release = NULL, + .sysfs_ops = NULL, + .default_attrs = NULL, +}; + void delete_partition(struct gendisk *disk, int part) { struct hd_struct *p = disk->part[part-1]; @@ -343,6 +350,12 @@ static void disk_sysfs_symlinks(struct g sysfs_create_link(&disk->kobj,&target->kobj,"device"); sysfs_create_link(&target->kobj,&disk->kobj,"block"); } + + /* create subdirectory for symlinks to underlying device */ + disk->slave_dir.ktype = &slave_ktype; + kobject_set_name(&disk->slave_dir, "slaves"); + disk->slave_dir.parent = &disk->kobj; + kobject_register(&disk->slave_dir); } /* Not exported, helper to add_disk(). */ @@ -460,6 +473,7 @@ void del_gendisk(struct gendisk *disk) devfs_remove_disk(disk); + kobject_unregister(&disk->slave_dir); if (disk->driverfs_dev) { sysfs_remove_link(&disk->kobj, "device"); sysfs_remove_link(&disk->driverfs_dev->kobj, "block"); --------------070700030507020902080804--