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: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NSukadev 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: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Major cleanup of all s390 inline assemblies. They now have a common
coding style. Quite a few have been shortened, mainly by using register
asm variables. Use of the EX_TABLE macro helps  as well. The atomic ops,
bit ops and locking inlines new use the Q-constraint if a newer gcc
is used.  That results in slightly better code.

Thanks to Christian Borntraeger for proof reading the changes.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Lock for mmap_sem is missing on page fault retry for init task
when it fails due to out of memory.
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NMichael Grundy <grundym@us.ibm.com>
Signed-off-by: NDavid Wilder <dwilder@us.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Sanitize some s390 Kconfig options.  We have ARCH_S390, ARCH_S390X,
ARCH_S390_31, 64BIT, S390_SUPPORT and COMPAT.  Replace these 6 options by
S390, 64BIT and COMPAT.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

"extern inline" -> "static inline"
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove pagex pseudo page fault code.  It does not work together with the
system call speedup that makes the complete system call path enabled for
interrupts.  To make pagex and the syscall speedup code work together we would
have to add code to the program check handler to do a critical section cleanup
like the asynchronous interrupt code.  This would make program checks slower.
Not what we want.

Newer versions of z/VM have the improved pfault pseudo page fault interface.
This replaces the old pagex interface and does not have the problem.  So its
better to just rip out the pagex code.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There is a race in pfault_interrupt.  That function gets called two times for
each pfault notification.  Once with a subcode of 0 to indicate that a real
page is not available and once with a subcode of 0x80 to indicate that the
page is present again.

Since the two external interrupts can be delivered on two different cpus the
order in which the two calls are made is unpredictable.  It is possible that
the subcode 0x80 interrupt is completed before the subcode 0x00 interrupt has
done the wake_up() call.

To avoid calling wake_up() on an already removed task structure proper task
structure reference counting is needed.  Increase the reference counter in the
subcode 0x00 interrupt before setting pfault_wait to zero and return the
reference after the wake_up call.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The condition for no context in do_exception checks for hard and soft
interrupts by using in_interrupt() but not for preemption.  This is bad for
the users of __copy_from/to_user_inatomic because the fault handler might call
schedule although the preemption count is != 0.  Use in_atomic() instead
in_interrupt().
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!