cgroups: clean up cgroup_pidlist_find() a bit
Don't call get_pid_ns() before we locate/alloc the ns. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Serge Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -2597,7 +2597,8 @@ static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
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{
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{
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struct cgroup_pidlist *l;
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struct cgroup_pidlist *l;
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/* don't need task_nsproxy() if we're looking at ourself */
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/* don't need task_nsproxy() if we're looking at ourself */
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struct pid_namespace *ns = get_pid_ns(current->nsproxy->pid_ns);
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struct pid_namespace *ns = current->nsproxy->pid_ns;
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/*
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/*
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* We can't drop the pidlist_mutex before taking the l->mutex in case
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* We can't drop the pidlist_mutex before taking the l->mutex in case
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* the last ref-holder is trying to remove l from the list at the same
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* the last ref-holder is trying to remove l from the list at the same
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@ -2607,8 +2608,6 @@ static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
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mutex_lock(&cgrp->pidlist_mutex);
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mutex_lock(&cgrp->pidlist_mutex);
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list_for_each_entry(l, &cgrp->pidlists, links) {
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list_for_each_entry(l, &cgrp->pidlists, links) {
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if (l->key.type == type && l->key.ns == ns) {
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if (l->key.type == type && l->key.ns == ns) {
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/* found a matching list - drop the extra refcount */
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put_pid_ns(ns);
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/* make sure l doesn't vanish out from under us */
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/* make sure l doesn't vanish out from under us */
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down_write(&l->mutex);
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down_write(&l->mutex);
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mutex_unlock(&cgrp->pidlist_mutex);
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mutex_unlock(&cgrp->pidlist_mutex);
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@ -2619,13 +2618,12 @@ static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
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l = kmalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
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l = kmalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
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if (!l) {
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if (!l) {
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mutex_unlock(&cgrp->pidlist_mutex);
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mutex_unlock(&cgrp->pidlist_mutex);
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put_pid_ns(ns);
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return l;
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return l;
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}
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}
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init_rwsem(&l->mutex);
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init_rwsem(&l->mutex);
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down_write(&l->mutex);
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down_write(&l->mutex);
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l->key.type = type;
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l->key.type = type;
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l->key.ns = ns;
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l->key.ns = get_pid_ns(ns);
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l->use_count = 0; /* don't increment here */
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l->use_count = 0; /* don't increment here */
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l->list = NULL;
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l->list = NULL;
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l->owner = cgrp;
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l->owner = cgrp;
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