[PATCH] cgroups: fix pid namespace bug, fix

From: Li Zefan
Date: Thu Jul 02 2009 - 21:40:46 EST


- add get_pid_ns()/put_pid_ns()
- remove prefix "pids_"

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
kernel/cgroup.c | 30 +++++++++++++++++-------------
1 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 13dddb4..ba675de 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2213,13 +2213,13 @@ struct cgroup_pids {
/* The cgroup those pids belong to */
struct cgroup *cgrp;
/* The namepsace those pids belong to */
- struct pid_namespace *pid_ns;
+ struct pid_namespace *ns;
/* Array of process ids in the cgroup */
pid_t *tasks_pids;
/* How many files are using the this tasks_pids array */
- int pids_use_count;
+ int use_count;
/* Length of the current tasks_pids array */
- int pids_length;
+ int length;
};

static int cmppid(const void *a, const void *b)
@@ -2248,7 +2248,7 @@ static void *cgroup_tasks_start(struct seq_file *s, loff_t *pos)

down_read(&cgrp->pids_mutex);
if (pid) {
- int end = cp->pids_length;
+ int end = cp->length;

while (index < end) {
int mid = (index + end) / 2;
@@ -2262,7 +2262,7 @@ static void *cgroup_tasks_start(struct seq_file *s, loff_t *pos)
}
}
/* If we're off the end of the array, we're done */
- if (index >= cp->pids_length)
+ if (index >= cp->length)
return NULL;
/* Update the abstract position to be the actual pid that we found */
iter = cp->tasks_pids + index;
@@ -2281,7 +2281,7 @@ static void *cgroup_tasks_next(struct seq_file *s, void *v, loff_t *pos)
{
struct cgroup_pids *cp = s->private;
int *p = v;
- int *end = cp->tasks_pids + cp->pids_length;
+ int *end = cp->tasks_pids + cp->length;

/*
* Advance to the next pid in the array. If this goes off the
@@ -2313,9 +2313,10 @@ static void release_cgroup_pid_array(struct cgroup_pids *cp)
struct cgroup *cgrp = cp->cgrp;

down_write(&cgrp->pids_mutex);
- BUG_ON(!cp->pids_use_count);
- if (!--cp->pids_use_count) {
+ BUG_ON(!cp->use_count);
+ if (!--cp->use_count) {
list_del(&cp->list);
+ put_pid_ns(cp->ns);
kfree(cp->tasks_pids);
kfree(cp);
}
@@ -2352,7 +2353,7 @@ static struct file_operations cgroup_tasks_operations = {
static int cgroup_tasks_open(struct inode *unused, struct file *file)
{
struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
- struct pid_namespace *pid_ns = task_active_pid_ns(current);
+ struct pid_namespace *ns;
struct cgroup_pids *cp;
pid_t *pidarray;
int npids;
@@ -2381,9 +2382,12 @@ static int cgroup_tasks_open(struct inode *unused, struct file *file)
*/
down_write(&cgrp->pids_mutex);

+ ns = get_pid_ns(current->nsproxy->pid_ns);
list_for_each_entry(cp, &cgrp->pids_list, list) {
- if (pid_ns == cp->pid_ns)
+ if (ns == cp->ns) {
+ put_pid_ns(ns);
goto found;
+ }
}

cp = kzalloc(sizeof(*cp), GFP_KERNEL);
@@ -2393,13 +2397,13 @@ static int cgroup_tasks_open(struct inode *unused, struct file *file)
return -ENOMEM;
}
cp->cgrp = cgrp;
- cp->pid_ns = pid_ns;
+ cp->ns = ns;
list_add(&cp->list, &cgrp->pids_list);
found:
kfree(cp->tasks_pids);
cp->tasks_pids = pidarray;
- cp->pids_length = npids;
- cp->pids_use_count++;
+ cp->length = npids;
+ cp->use_count++;
up_write(&cgrp->pids_mutex);

file->f_op = &cgroup_tasks_operations;
--
1.5.4.rc3

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