1 files changed, 3 insertions, 250 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8bd9cfdc70d7..4bccaa7dda35 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -56,11 +56,8 @@
 #include <linux/pid_namespace.h>
 #include <linux/idr.h>
 #include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
-#include <linux/eventfd.h>
-#include <linux/poll.h>
 #include <linux/flex_array.h> /* used in cgroup_attach_task */
 #include <linux/kthread.h>
-#include <linux/file.h>
 
 #include <linux/atomic.h>
 
@@ -156,36 +153,6 @@ struct css_id {
         unsigned short stack[0]; /* Array of Length (depth+1) */
 };
 
-/*
- * cgroup_event represents events which userspace want to receive.
- */
-struct cgroup_event {
-        /*
-         * css which the event belongs to.
-         */
-        struct cgroup_subsys_state *css;
-        /*
-         * Control file which the event associated.
-         */
-        struct cftype *cft;
-        /*
-         * eventfd to signal userspace about the event.
-         */
-        struct eventfd_ctx *eventfd;
-        /*
-         * Each of these stored in a list by the cgroup.
-         */
-        struct list_head list;
-        /*
-         * All fields below needed to unregister event when
-         * userspace closes eventfd.
-         */
-        poll_table pt;
-        wait_queue_head_t *wqh;
-        wait_queue_t wait;
-        struct work_struct remove;
-};
-
 /* The list of hierarchy roots */
 
 static LIST_HEAD(cgroup_roots);
@@ -235,8 +202,8 @@ static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
  * keep accessing it outside the said locks.  This function may return
  * %NULL if @cgrp doesn't have @subsys_id enabled.
  */
-static struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp,
-                                              struct cgroup_subsys *ss)
+struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp,
+                                       struct cgroup_subsys *ss)
 {
         if (ss)
                 return rcu_dereference_check(cgrp->subsys[ss->subsys_id],
@@ -2663,7 +2630,7 @@ static const struct inode_operations cgroup_dir_inode_operations = {
 /*
  * Check if a file is a control file
  */
-static inline struct cftype *__file_cft(struct file *file)
+struct cftype *__file_cft(struct file *file)
 {
         if (file_inode(file)->i_fop != &cgroup_file_operations)
                 return ERR_PTR(-EINVAL);
@@ -3949,202 +3916,6 @@ static void cgroup_dput(struct cgroup *cgrp)
         deactivate_super(sb);
 }
 
-/*
- * Unregister event and free resources.
- *
- * Gets called from workqueue.
- */
-static void cgroup_event_remove(struct work_struct *work)
-{
-        struct cgroup_event *event = container_of(work, struct cgroup_event,
-                        remove);
-        struct cgroup_subsys_state *css = event->css;
-
-        remove_wait_queue(event->wqh, &event->wait);
-
-        event->cft->unregister_event(css, event->cft, event->eventfd);
-
-        /* Notify userspace the event is going away. */
-        eventfd_signal(event->eventfd, 1);
-
-        eventfd_ctx_put(event->eventfd);
-        kfree(event);
-        css_put(css);
-}
-
-/*
- * Gets called on POLLHUP on eventfd when user closes it.
- *
- * Called with wqh->lock held and interrupts disabled.
- */
-static int cgroup_event_wake(wait_queue_t *wait, unsigned mode,
-                int sync, void *key)
-{
-        struct cgroup_event *event = container_of(wait,
-                        struct cgroup_event, wait);
-        struct cgroup *cgrp = event->css->cgroup;
-        unsigned long flags = (unsigned long)key;
-
-        if (flags & POLLHUP) {
-                /*
-                 * If the event has been detached at cgroup removal, we
-                 * can simply return knowing the other side will cleanup
-                 * for us.
-                 *
-                 * We can't race against event freeing since the other
-                 * side will require wqh->lock via remove_wait_queue(),
-                 * which we hold.
-                 */
-                spin_lock(&cgrp->event_list_lock);
-                if (!list_empty(&event->list)) {
-                        list_del_init(&event->list);
-                        /*
-                         * We are in atomic context, but cgroup_event_remove()
-                         * may sleep, so we have to call it in workqueue.
-                         */
-                        schedule_work(&event->remove);
-                }
-                spin_unlock(&cgrp->event_list_lock);
-        }
-
-        return 0;
-}
-
-static void cgroup_event_ptable_queue_proc(struct file *file,
-                wait_queue_head_t *wqh, poll_table *pt)
-{
-        struct cgroup_event *event = container_of(pt,
-                        struct cgroup_event, pt);
-
-        event->wqh = wqh;
-        add_wait_queue(wqh, &event->wait);
-}
-
-/*
- * Parse input and register new cgroup event handler.
- *
- * 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,
-                                      struct cftype *cft, const char *buffer)
-{
-        struct cgroup *cgrp = dummy_css->cgroup;
-        struct cgroup_event *event;
-        struct cgroup_subsys_state *cfile_css;
-        unsigned int efd, cfd;
-        struct fd efile;
-        struct fd cfile;
-        char *endp;
-        int ret;
-
-        efd = simple_strtoul(buffer, &endp, 10);
-        if (*endp != ' ')
-                return -EINVAL;
-        buffer = endp + 1;
-
-        cfd = simple_strtoul(buffer, &endp, 10);
-        if ((*endp != ' ') && (*endp != '\0'))
-                return -EINVAL;
-        buffer = endp + 1;
-
-        event = kzalloc(sizeof(*event), GFP_KERNEL);
-        if (!event)
-                return -ENOMEM;
-
-        INIT_LIST_HEAD(&event->list);
-        init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc);
-        init_waitqueue_func_entry(&event->wait, cgroup_event_wake);
-        INIT_WORK(&event->remove, cgroup_event_remove);
-
-        efile = fdget(efd);
-        if (!efile.file) {
-                ret = -EBADF;
-                goto out_kfree;
-        }
-
-        event->eventfd = eventfd_ctx_fileget(efile.file);
-        if (IS_ERR(event->eventfd)) {
-                ret = PTR_ERR(event->eventfd);
-                goto out_put_efile;
-        }
-
-        cfile = fdget(cfd);
-        if (!cfile.file) {
-                ret = -EBADF;
-                goto out_put_eventfd;
-        }
-
-        /* the process need read permission on control file */
-        /* AV: shouldn't we check that it's been opened for read instead? */
-        ret = inode_permission(file_inode(cfile.file), MAY_READ);
-        if (ret < 0)
-                goto out_put_cfile;
-
-        event->cft = __file_cft(cfile.file);
-        if (IS_ERR(event->cft)) {
-                ret = PTR_ERR(event->cft);
-                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.
-         */
-        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))
-                ret = 0;
-
-        rcu_read_unlock();
-        if (ret)
-                goto out_put_cfile;
-
-        if (!event->cft->register_event || !event->cft->unregister_event) {
-                ret = -EINVAL;
-                goto out_put_css;
-        }
-
-        ret = event->cft->register_event(event->css, event->cft,
-                        event->eventfd, buffer);
-        if (ret)
-                goto out_put_css;
-
-        efile.file->f_op->poll(efile.file, &event->pt);
-
-        spin_lock(&cgrp->event_list_lock);
-        list_add(&event->list, &cgrp->event_list);
-        spin_unlock(&cgrp->event_list_lock);
-
-        fdput(cfile);
-        fdput(efile);
-
-        return 0;
-
-out_put_css:
-        css_put(event->css);
-out_put_cfile:
-        fdput(cfile);
-out_put_eventfd:
-        eventfd_ctx_put(event->eventfd);
-out_put_efile:
-        fdput(efile);
-out_kfree:
-        kfree(event);
-
-        return ret;
-}
-
 static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
                                       struct cftype *cft)
 {
@@ -4170,11 +3941,6 @@ static struct cftype cgroup_base_files[] = {
                 .mode = S_IRUGO | S_IWUSR,
         },
         {
-                .name = "cgroup.event_control",
-                .write_string = cgroup_write_event_control,
-                .mode = S_IWUGO,
-        },
-        {
                 .name = "cgroup.clone_children",
                 .flags = CFTYPE_INSANE,
                 .read_u64 = cgroup_clone_children_read,
@@ -4666,7 +4432,6 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
         __releases(&cgroup_mutex) __acquires(&cgroup_mutex)
 {
         struct dentry *d = cgrp->dentry;
-        struct cgroup_event *event, *tmp;
         struct cgroup_subsys *ss;
         struct cgroup *child;
         bool empty;
@@ -4741,18 +4506,6 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
         dget(d);
         cgroup_d_remove_dir(d);
 
-        /*
-         * Unregister events and notify userspace.
-         * Notify userspace about cgroup removing only after rmdir of cgroup
-         * directory to avoid race between userspace and kernelspace.
-         */
-        spin_lock(&cgrp->event_list_lock);
-        list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) {
-                list_del_init(&event->list);
-                schedule_work(&event->remove);
-        }
-        spin_unlock(&cgrp->event_list_lock);
-
         return 0;
 };