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memcg: cgroup_write_event_control() now knows @css is for memcg

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@css for cgroup_write_event_control() is now always for memcg and the
target file should be a memcg file too.  Drop code which assumes @css
is dummy_css and the target file may belong to different subsystems.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
This commit is contained in:
Tejun Heo 2013-11-22 18:20:42 -05:00
parent 79bd9814e5
commit b5557c4c3b
1 changed files with 11 additions and 16 deletions
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27
mm/memcontrol.c
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@ -6056,10 +6056,10 @@ static void cgroup_event_ptable_queue_proc(struct file *file,
* Input must be in format '<event_fd> <control_fd> <args>'.
* Interpretation of args is defined by control file implementation.
*/
static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
static int cgroup_write_event_control(struct cgroup_subsys_state *css,
struct cftype *cft, const char *buffer)
{
struct cgroup *cgrp = dummy_css->cgroup;
struct cgroup *cgrp = css->cgroup;
struct cgroup_event *event;
struct cgroup_subsys_state *cfile_css;
unsigned int efd, cfd;
@ -6082,6 +6082,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
if (!event)
return -ENOMEM;
event->css = css;
INIT_LIST_HEAD(&event->list);
init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc);
init_waitqueue_func_entry(&event->wait, cgroup_event_wake);
@ -6117,23 +6118,17 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
goto out_put_cfile;
}
if (!event->cft->ss) {
ret = -EBADF;
goto out_put_cfile;
}
/*
* Determine the css of @cfile, verify it belongs to the same
* cgroup as cgroup.event_control, and associate @event with it.
* Remaining events are automatically removed on cgroup destruction
* but the removal is asynchronous, so take an extra ref.
* Verify @cfile should belong to @css. Also, remaining events are
* automatically removed on cgroup destruction but the removal is
* asynchronous, so take an extra ref on @css.
*/
rcu_read_lock();
ret = -EINVAL;
event->css = cgroup_css(cgrp, event->cft->ss);
cfile_css = css_from_dir(cfile.file->f_dentry->d_parent, event->cft->ss);
if (event->css && event->css == cfile_css && css_tryget(event->css))
cfile_css = css_from_dir(cfile.file->f_dentry->d_parent,
&mem_cgroup_subsys);
if (cfile_css == css && css_tryget(css))
ret = 0;
rcu_read_unlock();
@ -6145,7 +6140,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
goto out_put_css;
}
ret = event->cft->register_event(event->css, event->cft,
ret = event->cft->register_event(css, event->cft,
event->eventfd, buffer);
if (ret)
goto out_put_css;
@ -6162,7 +6157,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
return 0;
out_put_css:
css_put(event->css);
css_put(css);
out_put_cfile:
fdput(cfile);
out_put_eventfd: