Diagnosis from Christian Vogel <vogel@skunk.physik.uni-erlangen.de>

cpu_idle() tests pm_idle() just once then falls into the

	while (!need_resched())
		idle();

loop.

Problem is, that loop never terminates (need_resched() always returns false
on preemptive kernels).

The other problem is that ACPI updates pm_idle _after_ cpu_idle() has taken a
local copy.  So we always call default_idle(), even when pm_idle is pointing
at a new idle handler.

So fix it to pick up changed values of pm_idle() each time around the inner
loop.

install_page() is a library function which we expect will be used by all
drivers which implement vm_operations.populate().  Therefore it should be
exported to kernel modules.

Petr Vandrovec has a project which involves sparse mappings of device memory
which can use remap_file_pages().  It needs install_page().

From: Wim Van Sebroeck <wim@iguana.be>

The first patch convert these watchdog modules to the new module_param syntax.

The second patch fixes machzwd.c (you need to declare the variable before
using the module_param subroutine).

From: Adrian Bunk <bunk@fs.tum.de>

A 16bit number can _never_ be > 65536.  So don't bother to check for it.

From: Andries.Brouwer@cwi.nl

A few days ago I needed a serial line and couldnt find the option in
menuconfig.  Turned out that SERIAL_8250 depends on EXPERIMENTAL.  I
suppose that dependence should be removed.

From: Francois Romieu <romieu@fr.zoreil.com>

The wan driver I maintain was hit by hdlc changes too. Please
apply patch below. It is diffed against plain -test2 but it
applies equally as well against -test2-mm2.

More important changes will come in a near future for this
driver but I'd rather keep the changes separated.

Description:
- after the hdlc changes, dscc4 module doesn't need to set
  hdlc->proto(.id) itself anymore;
- MOD_{INC/DEC}_USE_COUNT removal;
- SET_NETDEV_DEV() use;

From: Krzysztof Halasa <khc@pm.waw.pl>

The following patch upgrades generic HDLC to support "new" protocol
handlers.

From: Adrian Bunk <bunk@fs.tum.de>

Fix ACPI compile error if doing processor probing only: acpi_find_bmc is
only available #ifdef CONFIG_ACPI_INTERPRETER.

nvidia-agp needs it.

The module device table is not NULL-terminated, so we run off the end during
probing and oops.

Also, move all those static decls out of .h and into .c

From: Herbert Potzl <herbert@13thfloor.at>

quota.h typo fix

From: Dave Olien <dmo@osdl.org>

It wasn't initializing the devfs_name member of the gendisk structures to
contain the root name of the logical disk.

From: Arun Sharma <arun.sharma@intel.com>

A script such as

  #!/bin/foo.bar
  ...

where /bin/foo.bar is handled by binfmt_misc, is not handled correctly i.e.
the interpreter of foo.bar doesn't receive the correct arguments.

The binfmt_misc handler requires that bprm->filename is appropriately
filled so that the argv[1] could be correctly passed to the interpreter.

However, binfmt_script, as it exists today doesn't populate bprm->filename
correctly.

Another motivation for this patch is the output of ps.  Emulators which use
binfmt_misc may want to keep the output of ps consistent with native
execution.  This requires preserving bprm->filename.  The attached patch
guarantees this even if we have to go through several binfmt handlers
(think of finite loops involving binfmt_script and binfmt_misc).

From: Adrian Bunk <bunk@fs.tum.de>

Fix compile error introduced by the HDLC update.

From: Adrian Bunk <bunk@fs.tum.de>

drivers/net/pcmcia/com20020_cs.c wasn't updated to the module owner
field changes

From: <ffrederick@prov-liege.be>

Add the necessary locking around uid_hash_insert() in uid_cache_init().

(It's an initcall, and the chances of another CPU racing with us here are
basically zero.  But it's good for documentary purposes and the code gets
dropped later anyway...)

From: <ffrederick@prov-liege.be>

The special_file() macro is being duplicated in JFS.  Move it to fs.h.

This function tries to allocate increasingly large buffers, but it gets the
bounds wrong by a factor of PAGE_SIZE.  It causes boot-time devfs mounting
to fail.

We're getting asserion failures in commit in data=journal mode.

journal_unmap_buffer() has unexpectedly donated this buffer to the committing
transaction, and the commit-time assertion doesn't expect that to happen.  It
doesn't happen in 2.4 because both paths are under lock_journal().

Simply remove the assertion: the commit code will uncheckpoint the buffer and
then recheckpoint it if needed.

From: Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>

Fix compile error in 2.6.0-test2 when Netfilter IP connection tracking
is enabled.

From: Manfred Spraul <manfred@colorfullife.com>

Eli Barzilay noticed that select() for tty devices is broken: For
stopped tty devices, select says POLLOUT and write fails with -EAGAIN.

    http://marc.theaimsgroup.com/?l=linux-kernel&m=105902461110282&w=2

I've tracked this back to normal_poll in drivers/char/n_tty.c:

 > if (tty->driver->chars_in_buffer(tty) < WAKEUP_CHARS)
 >                mask |= POLLOUT | POLLWRNORM;

It assumes that a following write will succeed if less than 256 bytes
are in the write buffer right now. This assumption is wrong for
con_write_room: if the console is stopped, it returns 0 bytes buffer
size (con_write_room()). Ditto for pty_write_room.

From: florin@iucha.net (Florin Iucha)

Fix compilation of net/ipv4/netfilter/ipt_helper.c by including the
proper header files.

From: Nathan Scott <nathans@sgi.com>

This patch adds a mechanism by which a filesystem can register an interest in
the completion of direct I/O.  The completion routine will be given the
inode, an offset and a length, and an optional filesystem-private field.

We have extended the use of the buffer_head-based interface (i.e.
get_block_t) for direct I/O such that the b_private field is now utilised.
It is defined to be initially zero at the start of I/O, and will be passed
into the filesystem unmodified by the VFS with each map request, while
setting up the direct I/O.  Once I/O has completed the final value of this
pointer will be passed into a filesystems I/O completion handler.  This
mechanism can be used to keep track of all of the mapping requests which
encompass an individual direct I/O request.

This has been implemented specifically for XFS, but is done so as to be as
generic as possible.  XFS uses this mechanism to provide support for
unwritten extents - these are file extents which have been pre-allocated
on-disk, but not yet written to (once written, these become regular file
extents, but only once I/O is complete).

From: Nikita Danilov <Nikita@Namesys.COM>

Use zone->pressure (rathar than scanning priority) to determine when to
start reclaiming mapped pages in refill_inactive_zone().  When using
priority every call to try_to_free_pages() starts with scanning parts of
active list and skipping mapped pages (because reclaim_mapped evaluates to
0 on low priorities) no matter how high memory pressure is.

From: Nikita Danilov <Nikita@Namesys.COM>

The vmscan logic at present will scan the inactive list with increasing
priority until a threshold is triggered.  At that threshold we start
unmapping pages from pagetables.

The problem is that each time someone calls into this code, the priority is
initially low, so some mapped pages will be refiled event hough we really
should be unmapping them now.

Nikita's patch adds the `pressure' field to struct zone.  it is a decaying
average of the zone's memory pressure and allows us to start unmapping pages
immediately on entry to page reclaim, based on measurements which were made
in earlier reclaim attempts.

kswapd currently takes a throttling nap even if it freed all the pages it
was asked to free.

Change it so we only throttle if reclaim is not being sufficiently
successful.

We're currently just setting the referenced bit when modifying pagecache in
write().

Consequently overwritten (and redirtied) pages are remaining on the inactive
list.  The net result is that a lot of dirty pages are reaching the tail of
the LRU in page reclaim and are getting written via the writepage() in there.

But a core design objective is to minimise the amount of IO via that path,
and to maximise the amount of IO via balance_dirty_pages().  Because the
latter has better IO patterns.

This may explain the bad IO patterns which Gerrit talked about at KS.

From: Andrey Borzenkov <arvidjaar@mail.ru>

A while back Andrey fixed a devfs bug in which we were running
remove_wait_queue() against a wait_queue_head which was on another process's
stack, and which had gone out of scope.

The patch reverts that fix and does it the same way as 2.4: just leave the
waitqueue struct dangling on the waitqueue_head: there is no need to touch it
at all.

It adds a big comment explaining why we are doing this nasty thing.

From: Hans-Joachim Hetscher <me@privacy.net>

the Hamradio 6pack driver wasn't modified to work with the 1000 HZ
internal kernel timebase.

It is using "snd".  It should be using "sound".

From: jbarnes@sgi.com (Jesse Barnes)

This patch is needed for some discontig boxes since the memory maps may
be built out-of-order.

From: bzzz@tmi.comex.ru

Now we have sync_fs(), the kludge of using write_super() to detect when the
VFS is trying to sync the fs is unneeded.

With this change we don't accidentally run commits in response to kupdate
and bdflush activity and it speedup up some heavy workloads significantly.

From: Alex Tomas <bzzz@tmi.comex.ru>

ext3_getblk() memsets a newly allocated buffer, but forgets to check
whether a different thread brought it uptodate while we waited for the
buffer lock.

It's OK normally because we're serialised by the page lock.  But lustre
apparently is doing something different with getblk and hits this race.

Plus I suspect it's racy with competing O_DIRECT writes.

From: Alex Tomas <bzzz@tmi.comex.ru>

ext3_get_inode_loc() read inode's block only if:

  1) this inode has no copy in memory
  2) inode's block has another valid inode(s)

this optimization allows to avoid needless I/O in two cases:

1) just allocated inode is first valid in the inode's block

2) kernel wants to write inode, but buffer in which inode
   belongs to gets freed by VM

Since Jens changed the block layer to fail readahead if the queue has no
requests free, a few changes suggest themselves.

- It's a bit silly to go and alocate a bunch of pages, build BIOs for them,
  submit the IO only to have it fail, forcing us to free the pages again.

  So the patch changes do_page_cache_readahead() to peek at the queue's
  read_congested state.  If the queue is read-congested we abandon the entire
  readahead up-front without doing all that work.

- If the queue is not read-congested, we go ahead and do the readahead,
  after having set PF_READAHEAD.

  The backing_dev_info's read-congested threshold cuts in when 7/8ths of
  the queue's requests are in flight, so it is probable that the readahead
  abandonment code in __make_request will now almost never trigger.

- The above changes make do_page_cache_readahead() "unreliable", in that it
  may do nothing at all.

  However there are some system calls:

	- fadvise(POSIX_FADV_WILLNEED)
	- madvise(MADV_WILLNEED)
	- sys_readahead()

  In which the user has an expectation that the kernel will actually
  perform the IO.

  So the patch creates a new "force_page_cache_readahead()" which will
  perform the IO regardless of the queue's congestion state.

  Arguably, this is the wrong thing to do: even though the application
  requested readahead it could be that the kernel _should_ abandon the user's
  request because the disk is so busy.

  I don't know.  But for now, let's keep the above syscalls behaviour
  unchanged.  It is trivial to switch back to do_page_cache_readahead()
  later.

Since Jens added the pagecache readahead support in the block layer we've
been getting bogus IO error messages from buffer.c due to __make_request
calling end_io against a non-uptodate buffer.

We can just use PF_READAHEAD to shut that up.  But really, we shouldn't even
have allocated all those pages and submittted the readahead IO if the queue
was congested.   We have the infrastructure to do that now.

From: Dave McCracken <dmccr@us.ibm.com>

This patch solves the race between truncate and page in which can cause stray
anon pages to appear in the truncated region.

The race occurs when a process is sleeping in pagein IO during the truncate:
there's a window after checking i_size in which the paging-in process decides
that the page was an OK one.

This leaves an anon page in the pagetables, and if the file is subsequently
extended we have an anon page floating about inside a file-backed mmap - user
modifications will not be written out.

Apparently this is also needed for the implementation of POSIX semantics for
distributed filesystems.

We use a generation counter in the address_space so the paging-in process can
determine whether there was a truncate which might have shot the new page
down.

It's a bit grubby to be playing with files and inodes in do_no_page(), but we
do need the page_table_lock coverage for this, and rearranging thngs to
provide that coverage to filemap_nopage wasn't very nice either.

From: "Paul E. McKenney" <paulmck@us.ibm.com>

The patch reworks and generalises vmtruncate_list() a bit to create an API
which invalidates a specified portion of an address_space, permitting
distributed filesystems to maintain POSIX semantics when a file mmap()ed on
one client is modified on another client.

From: Chris Mason <mason@suse.com>

unlock_buffer() needs a barrier before the waitqueue_active() optimisation.