linux_dsm_epyc7002/include/linux/ipc_namespace.h
Giuseppe Scrivano e1eb26fa62 ipc/namespace.c: use a work queue to free_ipc
the reason is to avoid a delay caused by the synchronize_rcu() call in
kern_umount() when the mqueue mount is freed.

the code:

    #define _GNU_SOURCE
    #include <sched.h>
    #include <error.h>
    #include <errno.h>
    #include <stdlib.h>

    int main()
    {
        int i;

        for (i = 0; i < 1000; i++)
            if (unshare(CLONE_NEWIPC) < 0)
                error(EXIT_FAILURE, errno, "unshare");
    }

goes from

	Command being timed: "./ipc-namespace"
	User time (seconds): 0.00
	System time (seconds): 0.06
	Percent of CPU this job got: 0%
	Elapsed (wall clock) time (h:mm:ss or m:ss): 0:08.05

to

	Command being timed: "./ipc-namespace"
	User time (seconds): 0.00
	System time (seconds): 0.02
	Percent of CPU this job got: 96%
	Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.03

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Link: http://lkml.kernel.org/r/20200225145419.527994-1-gscrivan@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08 11:05:56 -07:00

170 lines
4.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __IPC_NAMESPACE_H__
#define __IPC_NAMESPACE_H__
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/rwsem.h>
#include <linux/notifier.h>
#include <linux/nsproxy.h>
#include <linux/ns_common.h>
#include <linux/refcount.h>
#include <linux/rhashtable-types.h>
struct user_namespace;
struct ipc_ids {
int in_use;
unsigned short seq;
struct rw_semaphore rwsem;
struct idr ipcs_idr;
int max_idx;
int last_idx; /* For wrap around detection */
#ifdef CONFIG_CHECKPOINT_RESTORE
int next_id;
#endif
struct rhashtable key_ht;
};
struct ipc_namespace {
refcount_t count;
struct ipc_ids ids[3];
int sem_ctls[4];
int used_sems;
unsigned int msg_ctlmax;
unsigned int msg_ctlmnb;
unsigned int msg_ctlmni;
atomic_t msg_bytes;
atomic_t msg_hdrs;
size_t shm_ctlmax;
size_t shm_ctlall;
unsigned long shm_tot;
int shm_ctlmni;
/*
* Defines whether IPC_RMID is forced for _all_ shm segments regardless
* of shmctl()
*/
int shm_rmid_forced;
struct notifier_block ipcns_nb;
/* The kern_mount of the mqueuefs sb. We take a ref on it */
struct vfsmount *mq_mnt;
/* # queues in this ns, protected by mq_lock */
unsigned int mq_queues_count;
/* next fields are set through sysctl */
unsigned int mq_queues_max; /* initialized to DFLT_QUEUESMAX */
unsigned int mq_msg_max; /* initialized to DFLT_MSGMAX */
unsigned int mq_msgsize_max; /* initialized to DFLT_MSGSIZEMAX */
unsigned int mq_msg_default;
unsigned int mq_msgsize_default;
/* user_ns which owns the ipc ns */
struct user_namespace *user_ns;
struct ucounts *ucounts;
struct llist_node mnt_llist;
struct ns_common ns;
} __randomize_layout;
extern struct ipc_namespace init_ipc_ns;
extern spinlock_t mq_lock;
#ifdef CONFIG_SYSVIPC
extern void shm_destroy_orphaned(struct ipc_namespace *ns);
#else /* CONFIG_SYSVIPC */
static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
#endif /* CONFIG_SYSVIPC */
#ifdef CONFIG_POSIX_MQUEUE
extern int mq_init_ns(struct ipc_namespace *ns);
/*
* POSIX Message Queue default values:
*
* MIN_*: Lowest value an admin can set the maximum unprivileged limit to
* DFLT_*MAX: Default values for the maximum unprivileged limits
* DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
* an attribute to the open call and the queue must be created
* HARD_*: Highest value the maximums can be set to. These are enforced
* on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
* suitably high)
*
* POSIX Requirements:
* Per app minimum openable message queues - 8. This does not map well
* to the fact that we limit the number of queues on a per namespace
* basis instead of a per app basis. So, make the default high enough
* that no given app should have a hard time opening 8 queues.
* Minimum maximum for HARD_MSGMAX - 32767. I bumped this to 65536.
* Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this. However,
* we have run into a situation where running applications in the wild
* require this to be at least 5MB, and preferably 10MB, so I set the
* value to 16MB in hopes that this user is the worst of the bunch and
* the new maximum will handle anyone else. I may have to revisit this
* in the future.
*/
#define DFLT_QUEUESMAX 256
#define MIN_MSGMAX 1
#define DFLT_MSG 10U
#define DFLT_MSGMAX 10
#define HARD_MSGMAX 65536
#define MIN_MSGSIZEMAX 128
#define DFLT_MSGSIZE 8192U
#define DFLT_MSGSIZEMAX 8192
#define HARD_MSGSIZEMAX (16*1024*1024)
#else
static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
#endif
#if defined(CONFIG_IPC_NS)
extern struct ipc_namespace *copy_ipcs(unsigned long flags,
struct user_namespace *user_ns, struct ipc_namespace *ns);
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{
if (ns)
refcount_inc(&ns->count);
return ns;
}
extern void put_ipc_ns(struct ipc_namespace *ns);
#else
static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
struct user_namespace *user_ns, struct ipc_namespace *ns)
{
if (flags & CLONE_NEWIPC)
return ERR_PTR(-EINVAL);
return ns;
}
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{
return ns;
}
static inline void put_ipc_ns(struct ipc_namespace *ns)
{
}
#endif
#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
struct ctl_table_header;
extern struct ctl_table_header *mq_register_sysctl_table(void);
#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
static inline struct ctl_table_header *mq_register_sysctl_table(void)
{
return NULL;
}
#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
#endif