Commit 820e45db authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by Linus Torvalds
Browse files

statically initialize struct pid for swapper 



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: default avatarSukadev 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: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e713d0da

include/linux/init_task.h

+27 −0
Original line number Diff line number Diff line
@@ -88,6 +88,28 @@ extern struct nsproxy init_nsproxy; 


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

 * 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),		\

	.fs_excl	= ATOMIC_INIT(0),				\

	.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_LOCKDEP							\

}

include/linux/pid.h

+2 −0
Original line number Diff line number Diff line
@@ -51,6 +51,8 @@ struct pid 
	struct rcu_head rcu;

};



extern struct pid init_struct_pid;



struct pid_link

{

	struct hlist_node node;

kernel/pid.c

+2 −0
Original line number Diff line number Diff line
@@ -27,11 +27,13 @@ 
#include <linux/bootmem.h>

#include <linux/hash.h>

#include <linux/pid_namespace.h>

#include <linux/init_task.h>



#define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift)

static struct hlist_head *pid_hash;

static int pidhash_shift;

static struct kmem_cache *pid_cachep;

struct pid init_struct_pid = INIT_STRUCT_PID;



int pid_max = PID_MAX_DEFAULT;

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