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![Jiebin Sun](/assets/img/avatar_default.png)
The msg_bytes and msg_hdrs atomic counters are frequently updated when IPC msg queue is in heavy use, causing heavy cache bounce and overhead. Change them to percpu_counter greatly improve the performance. Since there is one percpu struct per namespace, additional memory cost is minimal. Reading of the count done in msgctl call, which is infrequent. So the need to sum up the counts in each CPU is infrequent. Apply the patch and test the pts/stress-ng-1.4.0 -- system v message passing (160 threads). Score gain: 3.99x CPU: ICX 8380 x 2 sockets Core number: 40 x 2 physical cores Benchmark: pts/stress-ng-1.4.0 -- system v message passing (160 threads) [akpm@linux-foundation.org: coding-style cleanups] [jiebin.sun@intel.com: avoid negative value by overflow in msginfo] Link: https://lkml.kernel.org/r/20220920150809.4014944-1-jiebin.sun@intel.com [akpm@linux-foundation.org: fix min() warnings] Link: https://lkml.kernel.org/r/20220913192538.3023708-3-jiebin.sun@intel.com Signed-off-by: Jiebin Sun <jiebin.sun@intel.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> Cc: Alexey Gladkov <legion@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dennis Zhou <dennis@kernel.org> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vasily Averin <vasily.averin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
241 lines
5.3 KiB
C
241 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/ipc/namespace.c
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* Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
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*/
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#include <linux/ipc.h>
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#include <linux/msg.h>
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#include <linux/ipc_namespace.h>
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#include <linux/rcupdate.h>
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#include <linux/nsproxy.h>
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#include <linux/slab.h>
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#include <linux/cred.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/user_namespace.h>
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#include <linux/proc_ns.h>
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#include <linux/sched/task.h>
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#include "util.h"
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static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
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{
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return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
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}
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static void dec_ipc_namespaces(struct ucounts *ucounts)
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{
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dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
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}
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static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
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struct ipc_namespace *old_ns)
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{
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struct ipc_namespace *ns;
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struct ucounts *ucounts;
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int err;
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err = -ENOSPC;
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ucounts = inc_ipc_namespaces(user_ns);
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if (!ucounts)
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goto fail;
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err = -ENOMEM;
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ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT);
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if (ns == NULL)
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goto fail_dec;
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err = ns_alloc_inum(&ns->ns);
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if (err)
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goto fail_free;
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ns->ns.ops = &ipcns_operations;
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refcount_set(&ns->ns.count, 1);
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ns->user_ns = get_user_ns(user_ns);
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ns->ucounts = ucounts;
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err = mq_init_ns(ns);
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if (err)
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goto fail_put;
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err = -ENOMEM;
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if (!setup_mq_sysctls(ns))
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goto fail_put;
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if (!setup_ipc_sysctls(ns))
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goto fail_mq;
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err = msg_init_ns(ns);
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if (err)
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goto fail_put;
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sem_init_ns(ns);
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shm_init_ns(ns);
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return ns;
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fail_mq:
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retire_mq_sysctls(ns);
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fail_put:
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put_user_ns(ns->user_ns);
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ns_free_inum(&ns->ns);
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fail_free:
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kfree(ns);
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fail_dec:
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dec_ipc_namespaces(ucounts);
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fail:
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return ERR_PTR(err);
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}
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struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct user_namespace *user_ns, struct ipc_namespace *ns)
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{
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if (!(flags & CLONE_NEWIPC))
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return get_ipc_ns(ns);
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return create_ipc_ns(user_ns, ns);
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}
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/*
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* free_ipcs - free all ipcs of one type
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* @ns: the namespace to remove the ipcs from
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* @ids: the table of ipcs to free
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* @free: the function called to free each individual ipc
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*
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* Called for each kind of ipc when an ipc_namespace exits.
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*/
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void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
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void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
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{
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struct kern_ipc_perm *perm;
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int next_id;
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int total, in_use;
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down_write(&ids->rwsem);
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in_use = ids->in_use;
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for (total = 0, next_id = 0; total < in_use; next_id++) {
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perm = idr_find(&ids->ipcs_idr, next_id);
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if (perm == NULL)
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continue;
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rcu_read_lock();
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ipc_lock_object(perm);
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free(ns, perm);
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total++;
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}
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up_write(&ids->rwsem);
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}
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static void free_ipc_ns(struct ipc_namespace *ns)
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{
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/* mq_put_mnt() waits for a grace period as kern_unmount()
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* uses synchronize_rcu().
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*/
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mq_put_mnt(ns);
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sem_exit_ns(ns);
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msg_exit_ns(ns);
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shm_exit_ns(ns);
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retire_mq_sysctls(ns);
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retire_ipc_sysctls(ns);
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dec_ipc_namespaces(ns->ucounts);
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put_user_ns(ns->user_ns);
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ns_free_inum(&ns->ns);
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kfree(ns);
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}
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static LLIST_HEAD(free_ipc_list);
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static void free_ipc(struct work_struct *unused)
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{
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struct llist_node *node = llist_del_all(&free_ipc_list);
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struct ipc_namespace *n, *t;
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llist_for_each_entry_safe(n, t, node, mnt_llist)
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free_ipc_ns(n);
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}
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/*
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* The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
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*/
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static DECLARE_WORK(free_ipc_work, free_ipc);
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/*
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* put_ipc_ns - drop a reference to an ipc namespace.
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* @ns: the namespace to put
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*
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* If this is the last task in the namespace exiting, and
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* it is dropping the refcount to 0, then it can race with
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* a task in another ipc namespace but in a mounts namespace
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* which has this ipcns's mqueuefs mounted, doing some action
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* with one of the mqueuefs files. That can raise the refcount.
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* So dropping the refcount, and raising the refcount when
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* accessing it through the VFS, are protected with mq_lock.
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*
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* (Clearly, a task raising the refcount on its own ipc_ns
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* needn't take mq_lock since it can't race with the last task
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* in the ipcns exiting).
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*/
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void put_ipc_ns(struct ipc_namespace *ns)
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{
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if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) {
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mq_clear_sbinfo(ns);
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spin_unlock(&mq_lock);
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if (llist_add(&ns->mnt_llist, &free_ipc_list))
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schedule_work(&free_ipc_work);
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}
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}
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static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
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{
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return container_of(ns, struct ipc_namespace, ns);
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}
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static struct ns_common *ipcns_get(struct task_struct *task)
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{
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struct ipc_namespace *ns = NULL;
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struct nsproxy *nsproxy;
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task_lock(task);
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nsproxy = task->nsproxy;
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if (nsproxy)
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ns = get_ipc_ns(nsproxy->ipc_ns);
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task_unlock(task);
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return ns ? &ns->ns : NULL;
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}
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static void ipcns_put(struct ns_common *ns)
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{
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return put_ipc_ns(to_ipc_ns(ns));
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}
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static int ipcns_install(struct nsset *nsset, struct ns_common *new)
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{
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struct nsproxy *nsproxy = nsset->nsproxy;
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struct ipc_namespace *ns = to_ipc_ns(new);
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if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
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!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
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return -EPERM;
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put_ipc_ns(nsproxy->ipc_ns);
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nsproxy->ipc_ns = get_ipc_ns(ns);
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return 0;
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}
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static struct user_namespace *ipcns_owner(struct ns_common *ns)
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{
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return to_ipc_ns(ns)->user_ns;
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}
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const struct proc_ns_operations ipcns_operations = {
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.name = "ipc",
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.type = CLONE_NEWIPC,
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.get = ipcns_get,
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.put = ipcns_put,
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.install = ipcns_install,
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.owner = ipcns_owner,
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};
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