Re: [PATCH v2] cgroups: fix pid namespace bug, fix

From: Serge E. Hallyn
Date: Thu Jul 02 2009 - 23:05:48 EST


Quoting Li Zefan (lizf@xxxxxxxxxxxxxx):
> - add get_pid_ns()/put_pid_ns()
> - remove prefix "pids_"
>
> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>

Reviewed-by: Serge Hallyn <serue@xxxxxxxxxx>

thanks,
-serge

> ---
> kernel/cgroup.c | 28 +++++++++++++++-------------
> 1 files changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 13dddb4..250dac0 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 = current->nsproxy->pid_ns;
> struct cgroup_pids *cp;
> pid_t *pidarray;
> int npids;
> @@ -2382,7 +2383,7 @@ static int cgroup_tasks_open(struct inode *unused, struct file *file)
> down_write(&cgrp->pids_mutex);
>
> list_for_each_entry(cp, &cgrp->pids_list, list) {
> - if (pid_ns == cp->pid_ns)
> + if (ns == cp->ns)
> goto found;
> }
>
> @@ -2393,13 +2394,14 @@ static int cgroup_tasks_open(struct inode *unused, struct file *file)
> return -ENOMEM;
> }
> cp->cgrp = cgrp;
> - cp->pid_ns = pid_ns;
> + cp->ns = ns;
> + get_pid_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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