From 006f4ac49742b5f70ef7e39176fd42a500144ccc Mon Sep 17 00:00:00 2001 From: Zefan Li Date: Thu, 18 Sep 2014 16:03:15 +0800 Subject: [PATCH] cgroup: simplify proc_cgroup_show() Use the ONE macro instead of REG, and we can simplify proc_cgroup_show(). Signed-off-by: Zefan Li Signed-off-by: Tejun Heo --- fs/proc/base.c | 19 ++----------------- include/linux/cgroup.h | 3 ++- kernel/cgroup.c | 18 +++--------------- 3 files changed, 7 insertions(+), 33 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index baf852b648ad..6b96892015ec 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -376,21 +376,6 @@ static const struct file_operations proc_lstats_operations = { #endif -#ifdef CONFIG_CGROUPS -static int cgroup_open(struct inode *inode, struct file *file) -{ - struct pid *pid = PROC_I(inode)->pid; - return single_open(file, proc_cgroup_show, pid); -} - -static const struct file_operations proc_cgroup_operations = { - .open = cgroup_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; -#endif - #ifdef CONFIG_PROC_PID_CPUSET static int cpuset_open(struct inode *inode, struct file *file) @@ -2576,7 +2561,7 @@ static const struct pid_entry tgid_base_stuff[] = { REG("cpuset", S_IRUGO, proc_cpuset_operations), #endif #ifdef CONFIG_CGROUPS - REG("cgroup", S_IRUGO, proc_cgroup_operations), + ONE("cgroup", S_IRUGO, proc_cgroup_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), @@ -2922,7 +2907,7 @@ static const struct pid_entry tid_base_stuff[] = { REG("cpuset", S_IRUGO, proc_cpuset_operations), #endif #ifdef CONFIG_CGROUPS - REG("cgroup", S_IRUGO, proc_cgroup_operations), + ONE("cgroup", S_IRUGO, proc_cgroup_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 51958d0fb88f..77a1d37b742b 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -37,7 +37,8 @@ extern void cgroup_exit(struct task_struct *p); extern int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); -extern int proc_cgroup_show(struct seq_file *, void *); +extern int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *tsk); /* define the enumeration of all cgroup subsystems */ #define SUBSYS(_x) _x ## _cgrp_id, diff --git a/kernel/cgroup.c b/kernel/cgroup.c index db19a4884a7f..df7733b48d2e 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5030,12 +5030,9 @@ core_initcall(cgroup_wq_init); * - Print task's cgroup paths into seq_file, one line for each hierarchy * - Used for /proc//cgroup. */ - -/* TODO: Use a proper seq_file iterator */ -int proc_cgroup_show(struct seq_file *m, void *v) +int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *tsk) { - struct pid *pid; - struct task_struct *tsk; char *buf, *path; int retval; struct cgroup_root *root; @@ -5045,14 +5042,6 @@ int proc_cgroup_show(struct seq_file *m, void *v) if (!buf) goto out; - retval = -ESRCH; - pid = m->private; - tsk = get_pid_task(pid, PIDTYPE_PID); - if (!tsk) - goto out_free; - - retval = 0; - mutex_lock(&cgroup_mutex); down_read(&css_set_rwsem); @@ -5082,11 +5071,10 @@ int proc_cgroup_show(struct seq_file *m, void *v) seq_putc(m, '\n'); } + retval = 0; out_unlock: up_read(&css_set_rwsem); mutex_unlock(&cgroup_mutex); - put_task_struct(tsk); -out_free: kfree(buf); out: return retval; -- 2.20.1