Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750814AbWCDA4k (ORCPT ); Fri, 3 Mar 2006 19:56:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750946AbWCDA4k (ORCPT ); Fri, 3 Mar 2006 19:56:40 -0500 Received: from mx1.redhat.com ([66.187.233.31]:53155 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1750814AbWCDA4U (ORCPT ); Fri, 3 Mar 2006 19:56:20 -0500 Message-ID: <4408E607.2010300@ce.jp.nec.com> Date: Fri, 03 Mar 2006 19:57:43 -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: Alasdair Kergon , Neil Brown , Greg KH , linux-kernel@vger.kernel.org CC: Lars Marowsky-Bree , akpm@osdl.org, device-mapper development Subject: [PATCH 3/6] bd_claim_by_kobject References: <4408E33E.1080703@ce.jp.nec.com> In-Reply-To: <4408E33E.1080703@ce.jp.nec.com> Content-Type: multipart/mixed; boundary="------------080505040400050701020003" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8292 Lines: 297 This is a multi-part message in MIME format. --------------080505040400050701020003 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit This patch is part of dm/md sysfs dependency tree. This adds bd_claim_by_kobject() function which takes kobject as additional signature of holder device and creates sysfs symlinks between holder device and claimed device. bd_release_from_kobject() is a counter part of bd_claim_by_kobject. Thanks, -- Jun'ichi Nomura, NEC Solutions (America), Inc. --------------080505040400050701020003 Content-Type: text/x-patch; name="03-bd_claim_by_kobj.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="03-bd_claim_by_kobj.patch" Adding bd_claim_by_kobject() function which takes kobject as additional signature of holder device and creates sysfs symlinks between holder device and claimed device. bd_release_from_kobject() is a counter part of bd_claim_by_kobject. Signed-off-by: Jun'ichi Nomura fs/block_dev.c | 196 +++++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/fs.h | 3 2 files changed, 197 insertions(+), 2 deletions(-) --- linux-2.6.16-rc5.orig/include/linux/fs.h 2006-02-27 00:09:35.000000000 -0500 +++ linux-2.6.16-rc5/include/linux/fs.h 2006-03-02 10:29:55.000000000 -0500 @@ -401,6 +401,7 @@ struct block_device { struct list_head bd_inodes; void * bd_holder; int bd_holders; + struct list_head bd_holder_list; struct block_device * bd_contains; unsigned bd_block_size; struct hd_struct * bd_part; @@ -1380,6 +1381,8 @@ 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-2.6.16-rc5.orig/fs/block_dev.c 2006-02-27 00:09:35.000000000 -0500 +++ linux-2.6.16-rc5/fs/block_dev.c 2006-03-02 10:29:55.000000000 -0500 @@ -269,6 +269,7 @@ static void init_once(void * foo, kmem_c sema_init(&bdev->bd_mount_sem, 1); INIT_LIST_HEAD(&bdev->bd_inodes); INIT_LIST_HEAD(&bdev->bd_list); + INIT_LIST_HEAD(&bdev->bd_holder_list); inode_init_once(&ei->vfs_inode); } } @@ -443,7 +444,179 @@ 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 struct kobject * bdev_get_holder(struct block_device *bdev) +{ + if (!bdev) + return NULL; + else if (bdev->bd_contains != bdev) + return kobject_get(bdev->bd_part->holder_dir); + else + return kobject_get(bdev->bd_disk->holder_dir); +} + +static inline void add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + kobject_get(from); + kobject_get(to); + 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)); + kobject_put(from); + kobject_put(to); +} + +static inline int bd_claim_grab_dirs(struct block_device *bdev, + struct kobject *holder, + struct kobject **sdir, struct kobject **sdev, + struct kobject **hdir, struct kobject **hdev) +{ + *sdir = kobject_get(holder); + if (!*sdir) + return 0; + + *hdev = kobject_get((*sdir)->parent); + if (!*hdev) + goto fail_put_sdir; + + *sdev = bdev_get_kobj(bdev); + if (!*sdev) + goto fail_put_hdev; + + *hdir = bdev_get_holder(bdev); + if (!*hdir) + goto fail_put_sdev; + + return 1; + +fail_put_sdev: + kobject_put(*sdev); +fail_put_hdev: + kobject_put(*hdev); +fail_put_sdir: + kobject_put(*sdir); + + return 0; +} + +static inline void bd_claim_release_dirs( + struct kobject *sdir, struct kobject *sdev, + struct kobject *hdir, struct kobject *hdev) +{ + kobject_put(hdir); + kobject_put(sdev); + kobject_put(hdev); + kobject_put(sdir); +} + +static void link_bd_holder(struct block_device *bdev, struct kobject *holder) +{ + struct kobject *sdir, *sdev, *hdir, *hdev; + + if (bd_claim_grab_dirs(bdev, holder, &sdir, &sdev, &hdir, &hdev)) { + add_symlink(sdir, sdev); + add_symlink(hdir, hdev); + bd_claim_release_dirs(sdir, sdev, hdir, hdev); + } + + return; +} + +static void unlink_bd_holder(struct block_device *bdev, struct kobject *holder) +{ + struct kobject *sdir, *sdev, *hdir, *hdev; + + if (bd_claim_grab_dirs(bdev, holder, &sdir, &sdev, &hdir, &hdev)) { + del_symlink(sdir, sdev); + del_symlink(hdir, hdev); + bd_claim_release_dirs(sdir, sdev, hdir, hdev); + } +} + +/* 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; + } + } + + 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; + } + } + + return 0; +} + +int bd_claim_by_kobject(struct block_device *bdev, void *holder, struct kobject *kobj) { int res; spin_lock(&bdev_lock); @@ -464,6 +637,9 @@ 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 +654,20 @@ 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 +675,13 @@ 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); /* --------------080505040400050701020003-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/