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statically initialize struct pid for swapper

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Statically initialize a struct pid for the swapper process (pid_t == 0) and
attach it to init_task.  This is needed so task_pid(), task_pgrp() and
task_session() interfaces work on the swapper process also.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: <containers@lists.osdl.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sukadev Bhattiprolu 2007-05-10 22:23:00 -07:00 committed by Linus Torvalds
parent e713d0dab2
commit 820e45db23
3 changed files with 31 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

27
include/linux/init_task.h
View file

@ -88,6 +88,28 @@ extern struct nsproxy init_nsproxy;
extern struct group_info init_groups; extern struct group_info init_groups;
#define INIT_STRUCT_PID { \
.count = ATOMIC_INIT(1), \
.nr = 0, \
/* Don't put this struct pid in pid_hash */ \
.pid_chain = { .next = NULL, .pprev = NULL }, \
.tasks = { \
{ .first = &init_task.pids[PIDTYPE_PID].node }, \
{ .first = &init_task.pids[PIDTYPE_PGID].node }, \
{ .first = &init_task.pids[PIDTYPE_SID].node }, \
}, \
.rcu = RCU_HEAD_INIT, \
}
#define INIT_PID_LINK(type) \
{ \
.node = { \
.next = NULL, \
.pprev = &init_struct_pid.tasks[type].first, \
}, \
.pid = &init_struct_pid, \
}
/* /*
* INIT_TASK is used to set up the first task table, touch at * INIT_TASK is used to set up the first task table, touch at
* your own risk!. Base=0, limit=0x1fffff (=2MB) * your own risk!. Base=0, limit=0x1fffff (=2MB)
@ -139,6 +161,11 @@ extern struct group_info init_groups;
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \ .cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \ .fs_excl = ATOMIC_INIT(0), \
.pi_lock = __SPIN_LOCK_UNLOCKED(tsk.pi_lock), \ .pi_lock = __SPIN_LOCK_UNLOCKED(tsk.pi_lock), \
.pids = { \
[PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID), \
[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \
[PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \
}, \
INIT_TRACE_IRQFLAGS \ INIT_TRACE_IRQFLAGS \
INIT_LOCKDEP \ INIT_LOCKDEP \
} }

2
include/linux/pid.h
View file

@ -51,6 +51,8 @@ struct pid
struct rcu_head rcu; struct rcu_head rcu;
}; };
extern struct pid init_struct_pid;
struct pid_link struct pid_link
{ {
struct hlist_node node; struct hlist_node node;

2
kernel/pid.c
View file

@ -27,11 +27,13 @@
#include <linux/bootmem.h> #include <linux/bootmem.h>
#include <linux/hash.h> #include <linux/hash.h>
#include <linux/pid_namespace.h> #include <linux/pid_namespace.h>
#include <linux/init_task.h>
#define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift) #define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift)
static struct hlist_head *pid_hash; static struct hlist_head *pid_hash;
static int pidhash_shift; static int pidhash_shift;
static struct kmem_cache *pid_cachep; static struct kmem_cache *pid_cachep;
struct pid init_struct_pid = INIT_STRUCT_PID;
int pid_max = PID_MAX_DEFAULT; int pid_max = PID_MAX_DEFAULT;