From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 01/12] cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax Date: Thu, 15 Aug 2013 12:02:19 -0400 Message-ID: <1376582550-12548-2-git-send-email-tj@kernel.org> References: <1376582550-12548-1-git-send-email-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=b5myaLGupXYlR58+1GJOvoUb4Rh4Q9WYDBb1m3YsQ+w=; b=ixL7+leZj7lM7aDkEhYuraVHXeqRWt/hDhatuSe3aU6jqB8OxtaIgd1YnNzSWrslMO O89uBHvO1PrzSi7TBI4upoYmtmvEtpxjx/k8wKrH97lt1LeIiLqQ3nxiD7aUyVrfTSCY V6BkHz89t7BuCqF26nLOBGkxadezG02vXO0SCshHrf/2BPK8FEUuStcfZru+42jXCTyP 8FthjC2PY6YQr5hoSd9KFbYiws9q24dZNajMplkf0zn98axeTYEQFlKCquiOu48q4ieM EvkFi5fUckWcdkp/nGSyk4ILnGq9udIcgQq0pIW5jsNquF/OEn+Uwn1TxDuWm+mZeBfy /iZw== In-Reply-To: <1376582550-12548-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, mhocko-AlSwsSmVLrQ@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , Steven Rostedt , Frederic Weisbecker , Ingo Molnar cgroup_css_from_dir() will grow another user. In preparation, make the following changes. * All css functions are prefixed with just "css_", rename it to css_from_dir(). * Take dentry * instead of file * as dentry is what ultimately identifies a cgroup and file may not always be available. Note that the function now checkes whether @dentry->d_inode is NULL as the caller now may specify a negative dentry. * Make it take cgroup_subsys * instead of integer subsys_id. This simplifies the function and allows specifying no subsystem for cgroup->dummy_css. * Make return section a bit less verbose. This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Ingo Molnar --- include/linux/cgroup.h | 3 ++- kernel/cgroup.c | 26 ++++++++++---------------- kernel/events/core.c | 2 +- 3 files changed, 13 insertions(+), 18 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c24bd0b..5029176 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -919,7 +919,8 @@ bool css_is_ancestor(struct cgroup_subsys_state *cg, /* Get id and depth of css */ unsigned short css_id(struct cgroup_subsys_state *css); -struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); +struct cgroup_subsys_state *css_from_dir(struct dentry *dentry, + struct cgroup_subsys *ss); #else /* !CONFIG_CGROUPS */ diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 6499004..007053d 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5700,34 +5700,28 @@ struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id) EXPORT_SYMBOL_GPL(css_lookup); /** - * cgroup_css_from_dir - get corresponding css from file open on cgroup dir - * @f: directory file of interest - * @id: subsystem id of interest + * css_from_dir - get corresponding css from the dentry of a cgroup dir + * @dentry: directory dentry of interest + * @ss: subsystem of interest * * Must be called under RCU read lock. The caller is responsible for * pinning the returned css if it needs to be accessed outside the RCU * critical section. */ -struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) +struct cgroup_subsys_state *css_from_dir(struct dentry *dentry, + struct cgroup_subsys *ss) { struct cgroup *cgrp; - struct inode *inode; - struct cgroup_subsys_state *css; WARN_ON_ONCE(!rcu_read_lock_held()); - inode = file_inode(f); - /* check in cgroup filesystem dir */ - if (inode->i_op != &cgroup_dir_inode_operations) + /* is @dentry a cgroup dir? */ + if (!dentry->d_inode || + dentry->d_inode->i_op != &cgroup_dir_inode_operations) return ERR_PTR(-EBADF); - if (id < 0 || id >= CGROUP_SUBSYS_COUNT) - return ERR_PTR(-EINVAL); - - /* get cgroup */ - cgrp = __d_cgrp(f->f_dentry); - css = cgroup_css(cgrp, id); - return css ? css : ERR_PTR(-ENOENT); + cgrp = __d_cgrp(dentry); + return cgroup_css(cgrp, ss->subsys_id) ?: ERR_PTR(-ENOENT); } #ifdef CONFIG_CGROUP_DEBUG diff --git a/kernel/events/core.c b/kernel/events/core.c index 23261f9..b59ab66 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -593,7 +593,7 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event, rcu_read_lock(); - css = cgroup_css_from_dir(f.file, perf_subsys_id); + css = css_from_dir(f.file->f_dentry, &perf_subsys); if (IS_ERR(css)) { ret = PTR_ERR(css); goto out; -- 1.8.3.1