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[PATCH] pidspace: is_init()

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This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().

Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.

Eric's original description:

	There are a lot of places in the kernel where we test for init
	because we give it special properties.  Most  significantly init
	must not die.  This results in code all over the kernel test
	->pid == 1.

	Introduce is_init to capture this case.

	With multiple pid spaces for all of the cases affected we are
	looking for only the first process on the system, not some other
	process that has pid == 1.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Sukadev Bhattiprolu
2006-09-29 02:00:07 -07:00
committed by Linus Torvalds
parent 959ed340f4
commit f400e198b2
29 changed files with 41 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/sched.h
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@ -1033,6 +1033,16 @@ static inline int pid_alive(struct task_struct *p)
return p->pids[PIDTYPE_PID].pid != NULL;
}
/**
* is_init - check if a task structure is the first user space
* task the kernel created.
* @p: Task structure to be checked.
*/
static inline int is_init(struct task_struct *tsk)
{
return tsk->pid == 1;
}
extern void free_task(struct task_struct *tsk);
#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)