cgroup: a bunch of cleanups

index 5f76829..7e818a3 100644
@@ -448,9 +448,6 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
 
 int cgroup_task_count(const struct cgroup *cgrp);
 
-/* Return true if cgrp is a descendant of the task's cgroup */
-int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task);
-
 /*
  * Control Group taskset, used to pass around set of tasks to cgroup_subsys
  * methods.

index e72c44e..02b02ca 100644
@@ -5036,34 +5036,6 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
 	put_css_set_taskexit(cg);
 }
 
-/**
- * cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp
- * @cgrp: the cgroup in question
- * @task: the task in question
- *
- * See if @cgrp is a descendant of @task's cgroup in the appropriate
- * hierarchy.
- *
- * If we are sending in dummytop, then presumably we are creating
- * the top cgroup in the subsystem.
- *
- * Called only by the ns (nsproxy) cgroup.
- */
-int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task)
-{
-	int ret;
-	struct cgroup *target;
-
-	if (cgrp == dummytop)
-		return 1;
-
-	target = task_cgroup_from_root(task, cgrp->root);
-	while (cgrp != target && cgrp!= cgrp->top_cgroup)
-		cgrp = cgrp->parent;
-	ret = (cgrp == target);
-	return ret;
-}
-
 static void check_for_release(struct cgroup *cgrp)
 {
 	/* All of these checks rely on RCU to keep the cgroup

index 02b02ca..71bc33d 100644
@@ -4347,10 +4347,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
 {
 	struct dentry *d = cgrp->dentry;
 	struct cgroup *parent = cgrp->parent;
-	DEFINE_WAIT(wait);
 	struct cgroup_event *event, *tmp;
 	struct cgroup_subsys *ss;
-	LIST_HEAD(tmp_list);
 
 	lockdep_assert_held(&d->d_inode->i_mutex);
 	lockdep_assert_held(&cgroup_mutex);

index 71bc33d..be524ac 100644
@@ -4170,17 +4170,8 @@ static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
 	if (!(css->flags & CSS_ONLINE))
 		return;
 
-	/*
-	 * css_offline() should be called with cgroup_mutex unlocked.  See
-	 * 3fa59dfbc3 ("cgroup: fix potential deadlock in pre_destroy") for
-	 * details.  This temporary unlocking should go away once
-	 * cgroup_mutex is unexported from controllers.
-	 */
-	if (ss->css_offline) {
-		mutex_unlock(&cgroup_mutex);
+	if (ss->css_offline)
 		ss->css_offline(cgrp);
-		mutex_lock(&cgroup_mutex);
-	}
 
 	cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;
 }

index be524ac..58ae040 100644
@@ -3400,35 +3400,14 @@ static void pidlist_free(void *p)
 	else
 		kfree(p);
 }
-static void *pidlist_resize(void *p, int newcount)
-{
-	void *newlist;
-	/* note: if new alloc fails, old p will still be valid either way */
-	if (is_vmalloc_addr(p)) {
-		newlist = vmalloc(newcount * sizeof(pid_t));
-		if (!newlist)
-			return NULL;
-		memcpy(newlist, p, newcount * sizeof(pid_t));
-		vfree(p);
-	} else {
-		newlist = krealloc(p, newcount * sizeof(pid_t), GFP_KERNEL);
-	}
-	return newlist;
-}
 
 /*
  * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
- * If the new stripped list is sufficiently smaller and there's enough memory
- * to allocate a new buffer, will let go of the unneeded memory. Returns the
- * number of unique elements.
+ * Returns the number of unique elements.
  */
-/* is the size difference enough that we should re-allocate the array? */
-#define PIDLIST_REALLOC_DIFFERENCE(old, new) ((old) - PAGE_SIZE >= (new))
-static int pidlist_uniq(pid_t **p, int length)
+static int pidlist_uniq(pid_t *list, int length)
 {
 	int src, dest = 1;
-	pid_t *list = *p;
-	pid_t *newlist;
 
 	/*
 	 * we presume the 0th element is unique, so i starts at 1. trivial

@@ -3449,16 +3428,6 @@ static int pidlist_uniq(pid_t **p, int length)
 		dest++;
 	}
 after:
-	/*
-	 * if the length difference is large enough, we want to allocate a
-	 * smaller buffer to save memory. if this fails due to out of memory,
-	 * we'll just stay with what we've got.
-	 */
-	if (PIDLIST_REALLOC_DIFFERENCE(length, dest)) {
-		newlist = pidlist_resize(list, dest);
-		if (newlist)
-			*p = newlist;
-	}
 	return dest;
 }
 

@@ -3554,7 +3523,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
 	/* now sort & (if procs) strip out duplicates */
 	sort(array, length, sizeof(pid_t), cmppid, NULL);
 	if (type == CGROUP_FILE_PROCS)
-		length = pidlist_uniq(&array, length);
+		length = pidlist_uniq(array, length);
 	l = cgroup_pidlist_find(cgrp, type);
 	if (!l) {
 		pidlist_free(array);

index 58ae040..3206137 100644
@@ -3938,12 +3938,6 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
 	if (ret)
 		goto fail;
 
-	if (efile->f_op->poll(efile, &event->pt) & POLLHUP) {
-		event->cft->unregister_event(cgrp, event->cft, event->eventfd);
-		ret = 0;
-		goto fail;
-	}
-
 	/*
 	 * Events should be removed after rmdir of cgroup directory, but before
 	 * destroying subsystem state objects. Let's take reference to cgroup

index 7e818a3..1f75a59 100644
@@ -9,11 +9,8 @@
  */
 
 #include <linux/sched.h>
-#include <linux/cpumask.h>
-#include <linux/nodemask.h>
 #include <linux/rcupdate.h>
 #include <linux/rculist.h>
-#include <linux/cgroupstats.h>
 #include <linux/prio_heap.h>
 #include <linux/rwsem.h>
 #include <linux/idr.h>

@@ -22,6 +19,7 @@
 
 #ifdef CONFIG_CGROUPS
 
+struct cgroupstats;
 struct cgroupfs_root;
 struct cgroup_subsys;
 struct inode;

index 7e818a3..1f75a59 100644
@@ -9,11 +9,8 @@
  */
 
 #include <linux/sched.h>
-#include <linux/cpumask.h>
-#include <linux/nodemask.h>
 #include <linux/rcupdate.h>
 #include <linux/rculist.h>
-#include <linux/cgroupstats.h>
 #include <linux/prio_heap.h>
 #include <linux/rwsem.h>
 #include <linux/idr.h>

@@ -22,6 +19,7 @@
 
 #ifdef CONFIG_CGROUPS
 
+struct cgroupstats;
 struct cgroupfs_root;
 struct cgroup_subsys;
 struct inode;

index 3206137..4b92b9a 100644
@@ -2076,7 +2076,7 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
 	if (!group)
 		return -ENOMEM;
 	/* pre-allocate to guarantee space while iterating in rcu read-side. */
-	retval = flex_array_prealloc(group, 0, group_size - 1, GFP_KERNEL);
+	retval = flex_array_prealloc(group, 0, group_size, GFP_KERNEL);
 	if (retval)
 		goto out_free_group_list;
 

index 1f75a59..013c6ce 100644
@@ -691,7 +691,8 @@ struct task_struct *cgroup_iter_next(struct cgroup *cgrp,
 					struct cgroup_iter *it);
 void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it);
 int cgroup_scan_tasks(struct cgroup_scanner *scan);
-int cgroup_attach_task(struct cgroup *, struct task_struct *);
+int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
+		       bool threadgroup);
 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
 
 /*

205 lines not on this page · raw message

index ace5bfc..c55763b 100644
@@ -2008,7 +2008,7 @@ static void cpuset_do_move_task(struct task_struct *tsk,
 	struct cgroup *new_cgroup = scan->data;
 
 	cgroup_lock();
-	cgroup_attach_task(new_cgroup, tsk);
+	cgroup_attach_task(new_cgroup, tsk, false);
 	cgroup_unlock();
 }