The only caller of exit_sighand(tsk) is copy_process's error path.  We can
call __exit_sighand() directly and kill exit_sighand().

This 'tsk' was not yet registered in pid_hash[] or init_task.tasks, it has no
external references, nobody can see it, and

	IF (clone_flags & CLONE_SIGHAND)
		At least 'current' has a reference to ->sighand, this
		means atomic_dec_and_test(sighand->count) can't be true.

	ELSE
		Nobody can see this ->sighand, this means we can free it
		without any locking.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In my opinion this patch cleans up the code.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add lock_task_sighand() helper and converts group_send_sig_info() to use
it.  Hopefully we will have more users soon.

This patch also removes '!sighand->count' and '!p->usage' checks, I think
they both are bogus, racy and unneeded (but probably it makes sense to
restore them as BUG_ON()s).

->sighand is cleared and it's ->count is decremented in release_task() with
sighand->siglock held, so it is a bug to have '!p->usage || !->count' after
we already locked and verified it is the same.  On the other hand, an
already dead task without ->sighand can have a non-zero ->usage due to
ptrace, for example.

If we read the stale value of ->sighand we must see the change after
spin_lock(), because that change was done while holding that same old
->sighand.siglock.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch borrows a clever Hugh's 'struct anon_vma' trick.

Without tasklist_lock held we can't trust task->sighand until we locked it
and re-checked that it is still the same.

But this means we don't need to defer 'kmem_cache_free(sighand)'.  We can
return the memory to slab immediately, all we need is to be sure that
sighand->siglock can't dissapear inside rcu protected section.

To do so we need to initialize ->siglock inside ctor function,
SLAB_DESTROY_BY_RCU does the rest.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use ptrace_unlink() instead of open-coding.  No changes in kernel/exit.o
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use NULL instead of (... *)0
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use remove_parent/add_parent instead of open coding.

No changes in kernel/exit.o
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

daemonize() calls set_special_pids(1,1), while init and kernel threads spawned
from init/main.c:init() run with 0,0 special pids.  This patch changes
INIT_SIGNALS() so that that they run with ->pgrp == ->session == 1 also.  This
patch relies on fact that swapper's pid == 1.

Now we have no hashed zero pids in pid_hash[].

User-space visibible change is that now /sbin/init runs with (1,1) special
pids and becomes a session leader.

Quoting Eric W. Biederman:
>
> daemonize consuming pids (1,1) then consumes pgrp 1.  So that when
> /sbin/init calls setsid() it thinks /sbin/init is a process group
> leader and setsid() fails.  So /sbin/init wants pgrp 1 session 1
> but doesn't get it.  I am pretty certain daemonize did not exist so
> /sbin/init got pgrp 1 session 1 in 2.4.
>
> That is the bug that is being fixed.
>
> This patch takes things one step farther and essentially calls
> setsid() for pid == 1 before init is execed.  That is new behavior
> but it cleans up the kernel as we now do not need to support the
> case of a process without a process group or a session.
>
> The only process that could have possibly cared was /sbin/init
> and it already calls setsid() because it doesn't want that.
>
> If this was going to break anything noticeable the change in behavior
> from 2.4 to 2.6 would have already done that.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

fork_idle() does unhash_process() just after copy_process().  Contrary,
boot_cpu's idle thread explicitely registers itself for each pid_type with nr
= 0.

copy_process() already checks p->pid != 0 before process_counts++, I think we
can just skip attach_pid() calls and job control inits for idle threads and
kill unhash_process().  We don't need to cleanup ->proc_dentry in fork_idle()
because with this patch idle threads are never hashed in
kernel/pid.c:pid_hash[].

We don't need to hash pid == 0 in pidmap_init().  free_pidmap() is never
called with pid == 0 arg, so it will never be reused.  So it is still possible
to use pid == 0 in any PIDTYPE_xxx namespace from kernel/pid.c's POV.

However with this patch we don't hash pid == 0 for PIDTYPE_PID case.  We still
have have PIDTYPE_PGID/PIDTYPE_SID entries with pid == 0: /sbin/init and
kernel threads which don't call daemonize().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Both SET_LINKS() and SET_LINKS/REMOVE_LINKS() have exactly one caller, and
these callers already check thread_group_leader().

This patch kills theese macros, they mix two different things: setting
process's parent and registering it in init_task.tasks list.  Callers are
updated to do these actions by hand.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There are places where kernel uses REMOVE_LINKS/SET_LINKS while changing
process's ->parent.  Use add_parent/remove_parent instead, they don't abuse
of global process list.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

add_parent(p, parent) is always called with parent == p->parent, and it makes
no sense to do it differently.  This patch removes this argument.

No changes in affected .o files.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

'child_reaper' arg is not used in choose_new_parent().

"->exit_state >= EXIT_ZOMBIE" check is a leftover, was
valid when EXIT_ZOMBIE lived in ->state var.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

switch_exec_pids is only called from de_thread by way of exec, and it is
only called when we are exec'ing from a non thread group leader.

Currently switch_exec_pids gives the leader the pid of the thread and
unhashes and rehashes all of the process groups.  The leader is already in
the EXIT_DEAD state so no one cares about it's pids.  The only concern for
the leader is that __unhash_process called from release_task will function
correctly.  If we don't touch the leader at all we know that
__unhash_process will work fine so there is no need to touch the leader.

For the task becomming the thread group leader, we just need to give it the
pid of the old thread group leader, add it to the task list, and attach it
to the session and the process group of the thread group.

Currently de_thread is also adding the task to the task list which is just
silly.

Currently the only leader of __detach_pid besides detach_pid is
switch_exec_pids because of the ugly extra work that was being
performed.

So this patch removes switch_exec_pids because it is doing too much, it is
creating an unnecessary special case in pid.c, duing work duplicated in
de_thread, and generally obscuring what it is going on.

The necessary work is added to de_thread, and it seems to be a little
clearer there what is going on.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I'm not really certain what the thinking was but the code obviously wanted to
walk processes other than just those in it's session, for purposes of do_SAK.
Just walking those tasks that don't have a session assigned sounds at the very
least incomplete.

So modify the code to kill everything in the session and anything else that
might have the tty open.  Hopefully this helps if the do_SAK functionality is
ever finished.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We already have the tasklist_lock so there is no need for us to reacquire it
with send_group_sig_info.  reader/writer locks allow multiple readers and thus
recursion so the old code was ok just wastful.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The kill_sl function doesn't exist in the kernel so a prototype is completely
unnecessary.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I think it is enough to take tasklist_lock for reading while changing
child_reaper:

	Reparenting needs write_lock(tasklist_lock)

	Only one thread in a thread group can do exec()

	sighand->siglock garantees that get_signal_to_deliver()
	will not see a stale value of child_reaper.

This means that we can change child_reaper earlier, without calling
zap_other_threads() twice.

"child_reaper = current" is a NOOP when init does exec from main thread, we
don't care.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

After looking at the problem of init calling exec some more I figured out
an easy way to make the code work.

The actual symptom without out this patch is that all threads will die
except pid == 1, and the thread calling exec.  The thread calling exec will
wait forever for pid == 1 to die.

Since pid == 1 does not install a handler for SIGKILL it will never die.

This modifies the tests for init from current->pid == 1 to the equivalent
current == child_reaper.  And then it causes exec in the ugly case to
modify child_reaper.

The only weird symptom is that you wind up with an init process that
doesn't have the oldest start time on the box.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

* master.kernel.org:/home/rmk/linux-2.6-arm:
  [ARM] 3388/1: ixp23xx: add core ixp23xx support
  [ARM] 3417/1: add support for logicpd pxa270 card engine
  [ARM] 3387/1: ixp23xx: add defconfig
  [ARM] 3377/2: add support for intel xsc3 core
  [ARM] Move ice-dcc code into misc.c
  [ARM] Fix decompressor serial IO to give CRLF not LFCR
  [ARM] proc-v6: mark page table walks outer-cacheable, shared.  Enable NX.
  [ARM] nommu: trivial patch for arch/arm/lib/Makefile
  [ARM] 3416/1: Update LART site URL
  [ARM] 3415/1: Akita: Add missing EXPORT_SYMBOL
  [ARM] 3414/1: ep93xx: reset ethernet controller before uncompressing

* master.kernel.org:/home/rmk/linux-2.6-serial:
  [SERIAL] Provide Cirrus EP93xx AMBA PL010 serial support.
  [SERIAL] amba-pl010: allow platforms to specify modem control method
  [SERIAL] Remove obsoleted au1x00_uart driver
  [SERIAL] Small time UART configuration fix for AU1100 processor

Patch from Lennert Buytenhek

This patch adds support for the Intel ixp23xx series of CPUs.  The
ixp23xx is an XSC3 based CPU with 512K of L2 cache, a 64bit 66MHz PCI
interface, two DDR RAM interfaces, QDR RAM interfaces, two gigabit
MACs, two 10/100 MACs, expansion bus, four microengines, a Media and
Switch Fabric unit almost identical to the one on the ixp2400, two
xscale (8250ish) UARTs and a bunch of other stuff.

This patch adds the core ixp23xx support code, and support for the
ADI Engineering Roadrunner, Intel IXDP2351, and IP Fabrics Double
Espresso platforms.
Signed-off-by: NDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

Add support for the LogicPD PXA270 Card Engine.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

Add ixp23xx defconfig.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

This patch adds support for the new XScale v3 core.  This is an
ARMv5 ISA core with the following additions:

- L2 cache
- I/O coherency support (on select chipsets)
- Low-Locality Reference cache attributes (replaces mini-cache)
- Supersections (v6 compatible)
- 36-bit addressing (v6 compatible)
- Single instruction cache line clean/invalidate
- LRU cache replacement (vs round-robin)

I attempted to merge the XSC3 support into proc-xscale.S, but XSC3
cores have separate errata and have to handle things like L2, so it
is simpler to keep it separate.

L2 cache support is currently a build option because the L2 enable
bit must be set before we enable the MMU and there is no easy way to
capture command line parameters at this point.

There are still optimizations that can be done such as using LLR for
copypage (in theory using the exisiting mini-cache code) but those
can be addressed down the road.
Signed-off-by: NDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

* master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] cpufreq_conservative: keep ignore_nice_load and freq_step values when reselected
  [CPUFREQ] powernow: remove private for_each_cpu_mask()
  [CPUFREQ] hotplug cpu fix for powernow-k8
  [PATCH] cpufreq_ondemand: add range check
  [PATCH] cpufreq_ondemand: keep ignore_nice_load value when it is reselected
  [PATCH] cpufreq_ondemand: Warn if it cannot run due to too long transition latency
  [PATCH] cpufreq_conservative: alternative initialise approach
  [PATCH] cpufreq_conservative: make for_each_cpu() safe
  [PATCH] cpufreq_conservative: alter default responsiveness
  [PATCH] cpufreq_conservative: aligning of codebase with ondemand

* 'cfq-merge' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [BLOCK] cfq-iosched: seek and async performance fixes
  [PATCH] ll_rw_blk: fix 80-col offender in put_io_context()
  [PATCH] cfq-iosched: small cfq_choose_req() optimization
  [PATCH] [BLOCK] cfq-iosched: change cfq io context linking from list to tree

* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
  [SPARC64]: Implement futex_atomic_cmpxchg_inatomic().

Keep the value of ignore_nice_load and freq_step of the conservative
governor after the governor is deselected and reselected.
Signed-off-by: NMattia Dongili <malattia@linux.it>
Signed-off-by: NDave Jones <davej@redhat.com>

kernel/futex_compat.c: In function `compat_sys_futex':
kernel/futex_compat.c:140: warning: passing arg 1 of `do_futex' makes integer from pointer without a cast
kernel/futex_compat.c:140: warning: passing arg 5 of `do_futex' makes integer from pointer without a cast

Not sure what Ingo was thinking of here.  Put the casts back in.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Get rid of unnessesary casts of kmalloc() return value in sound/
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix a lot of typos.  Eyeballed by jmc@ in OpenBSD.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix a few trivial mistakes in Documentation/cputopology.txt
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix "signed vs unsigned" in nmi_watchdog_tick.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

vfree() does it's own NULL checking, no need for explicit check before
calling it.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There's no need to check pointers for NULL before handing them to vfree().
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

vfree() checks for NULL, no need to do it explicitly.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NZach Brown <zab@zabbo.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There's no need to check the vfree() argument for NULL.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Replace all occurences of 0xff..  in calls to function pci_set_dma_mask()
and pci_set_consistant_dma_mask() with the corresponding DMA_xBIT_MASK from
linux/dma-mapping.h.
Signed-off-by: NMatthias Gehre <M.Gehre@gmx.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

They deal with wrapping correctly and are nicer to read.
Signed-off-by: NMarcelo Feitoza Parisi <marcelo@feitoza.com.br>
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>