Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751539AbdFBVyu (ORCPT ); Fri, 2 Jun 2017 17:54:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:38582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbdFBVyq (ORCPT ); Fri, 2 Jun 2017 17:54:46 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A0A4623A25 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=shli@fb.com From: Shaohua Li To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Cc: tj@kernel.org, gregkh@linuxfoundation.org, hch@lst.de, axboe@fb.com, rostedt@goodmis.org, lizefan@huawei.com, Kernel-team@fb.com, Shaohua Li Subject: [PATCH 06/11] cgroup: export fhandle info for a cgroup Date: Fri, 2 Jun 2017 14:53:59 -0700 Message-Id: <38a747029c2a04d7e49dd7518f3caf2ac8ec24b5.1496432591.git.shli@fb.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4054 Lines: 128 From: Shaohua Li Add an API to export cgroup fhandle info. We don't export a full 'struct file_handle', there are unrequired info. Sepcifically, cgroup is always a directory, so we don't need a 'FILEID_INO32_GEN_PARENT' type fhandle, we only need export the inode number and generation number just like what generic_fh_to_parent does. And we can avoid the overhead of getting an inode too, since kernfs_node has all the info required. Signed-off-by: Shaohua Li --- fs/kernfs/mount.c | 11 +++++++++++ include/linux/cgroup-defs.h | 2 ++ include/linux/cgroup.h | 8 ++++++++ include/linux/kernfs.h | 8 ++++++++ kernel/cgroup/cgroup.c | 3 +++ 5 files changed, 32 insertions(+) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 11c5aba..d24d816 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -65,6 +65,17 @@ const struct super_operations kernfs_sops = { .show_path = kernfs_sop_show_path, }; +/* + * A special version of export_encode_fh(). This will avoid to get inode and + * then do the fhandle encoding. This function must match with export_encode_fh + * and the kernfs node should be a directory. + */ +void kernfs_encode_node_id(struct kernfs_node *kn, struct kernfs_node_id *id) +{ + id->ino = kn->ino; + id->gen = kn->generation; +} + static struct inode *kernfs_fh_get_inode(struct super_block *sb, u64 ino, u32 generation) { diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 2174594..8b6d9e2 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -308,6 +308,8 @@ struct cgroup { /* used to store eBPF programs */ struct cgroup_bpf bpf; + struct kernfs_node_id node_id; + /* ids of the ancestors at each level including self */ int ancestor_ids[]; }; diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index ed2573e..c30dda8 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -589,6 +589,10 @@ static inline void cgroup_kthread_ready(void) current->no_cgroup_migration = 0; } +static inline struct kernfs_node_id *cgroup_get_node_id(struct cgroup *cgrp) +{ + return &cgrp->node_id; +} #else /* !CONFIG_CGROUPS */ struct cgroup_subsys_state; @@ -611,6 +615,10 @@ static inline int cgroup_init_early(void) { return 0; } static inline int cgroup_init(void) { return 0; } static inline void cgroup_init_kthreadd(void) {} static inline void cgroup_kthread_ready(void) {} +static inline struct kernfs_node_id *cgroup_get_node_id(struct cgroup *cgrp) +{ + return NULL; +} static inline bool task_under_cgroup_hierarchy(struct task_struct *task, struct cgroup *ancestor) diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index 15c805f..932d89f 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -247,6 +247,12 @@ struct kernfs_ops { #endif }; +/* match with 'struct fid' */ +struct kernfs_node_id { + u32 ino; + u32 gen; +}; + #ifdef CONFIG_KERNFS static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) @@ -339,6 +345,8 @@ struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns); void kernfs_init(void); +void kernfs_encode_node_id(struct kernfs_node *kn, struct kernfs_node_id *id); + #else /* CONFIG_KERNFS */ static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 206d8df..489672d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1692,6 +1692,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags) goto exit_root_id; } root_cgrp->kn = root->kf_root->kn; + kernfs_encode_node_id(root_cgrp->kn, &root_cgrp->node_id); ret = css_populate_dir(&root_cgrp->self); if (ret) @@ -4209,6 +4210,8 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) /* let's create and online css's */ kernfs_activate(kn); + kernfs_encode_node_id(kn, &cgrp->node_id); + ret = 0; goto out_unlock; -- 2.9.3