Relax the requirements on the writeback_mapping a_op.

This function is passed the number of pages which it should write.  The
current fs-writeback.c code will get confused if the address_space
writes back more pages than it was asked to.

With this change the address_space may write more pages than required
if that is convenient.  Extent-based fileystems may wish to do this.

Pages which are under writeout to swap are locked, and not
PageWriteback().  So page allocators do not throttle against them in
shrink_caches().

This causes enormous list scans and general coma under really heavy
swapout loads.

One fix would be to teach shrink_cache() to wait on PG_locked for swap
pages.  The other approach is to set both PG_locked and PG_writeback
for swap pages so they can be handled in the same manner as file-backed
pages in shrink_cache().

This patch takes the latter approach.

Fix bug in the loop driver.

When presented with a multipage BIO, loop is overindexing the first
page in the BIO rather than advancing to the second page.  It scribbles
on the backing file and/or on kernel memory.

This happens with multipage BIO-based pagecache I/O and presumably with
O_DIRECT also.

The fix is much-needed with the multipage-BIO patches - using that code
on loop-backed filesystems has rather messy results.

The set_page_dirty() in the ext3_writepage() failure path isn't right.
set_page_dirty() will alter buffer states - it's a "whole page"
dirtying.

__set_page_dirty_buffers() is emitting warnings when it refuses to set
dirty a non-uptodate buffer against a partially-mapped page.

All we want to do in there is to move the page back onto
mapping->dirty_pages, without altering the state of its buffers.

Fix bug in block_truncate_page().

When buffers are attached to an uptodate page, they are marked as
being uptodate.  To preserve buffer/page state coherency.  Dirtiness
is handled in the same way.

But block_truncate_page() assumes that a buffer which is unmapped and
uptodate is over a hole.  That's not the case, and the net effect is
that block_truncate_page() is failing to zero the block outside the
truncation point.

This only happens if the page has a disk mapping but has no attached
buffers on entry to block_truncate_page().  That's never the case in
current kernels, so the problem does not exhibit (it _does_ exhibit
with direct-to-BIO bypass-the-buffers I/O).

There are actually three possible states of buffer mappedness:

- Buffer has a disk mapping            (buffer_mapped(bh) == true)

- buffer is over a hole	               (buffer_mapped(bh) == false)

- don't know.  Need to run get_block() (buffer_mapped(bh) == false)

This ambiguity could be resolved by added another buffer state bit
(BH_mapping_state_known?) but given that we already elide the get_block
calls for the common case (buffer outside i_size) it is unlikely that
the complexity is worthwhile.

- Fix the fix to the fix to the sector_t printing in buffer_io_error()

- A few microoptimisations in buffer.c.  Replace:

	set_buffer_foo(bh);

  with

	if (!buffer_foo(bh))
		set_buffer_foo(bh);

  when buffer_fooness is likely.  To avoid the buslocked rmw, and to
  avoid dirtying a cacheline.


- export write_mapping_buffers() - filesystems which put buffers on
  mapping->private_list need this function for I/O scheduling reasons.

I'm sick of searching my mail archives to find that email addr.

Hello all,
    The following patch fixes two compile warnings 'defined but not used'.
Since the label and int are only used for IPCONFIG_DYNAMIC, appropriate
fixes were made to remove the warnings.

johnpol@2ka.mipt.ru: 40) request_region check, 31-40:
  You say, i'm frezy :)

  	Evgeniy Polyakov ( s0mbre )

johnpol@2ka.mipt.ru: 30) request_region check, 21-30:
  here is one more trivial check.

  	Evgeniy Polyakov ( s0mbre )

Tim Schmielau <tim@physik3.uni-rostock.de>: trivial irq.h comment fix:

  Now THIS is a trivial patch: (though admittedly quite useless;-)

  include/linux/irq.h starts with
    #ifndef __irq_h
  but ends with a comment
    #endif /* __asm_h */

  Tim

Tim Schmielau <tim@physik3.uni-rostock.de>: provide HZ from jiffies.h:
  Most files that include <jiffies.h> also need HZ defined, which is
  quite reasonable. So don't require the to include <asm/param.h>
  themselves.

Rusty Russell <rusty@rustcorp.com.au>: Trivial ALPHA patch to remove minmax macros:
  Change over to standard max and ALIGN macros.

Rusty Russell <rusty@rustcorp.com.au>: Finally squish those chrp_start.c warnings:
  They finally irritated me enough to patch.  2.5, should apply against 2.4.

Peter Chubb <peter@chubb.wattle.id.au>: Fix compilation warning in do_mounts.c:

  	change_floppy() is unused if you don't have the floppy device
  compiled into the kernel --- so why not #ifdef it out?

Rusty Russell <rusty@rustcorp.com.au>: 2.5.17 Warning removal for ppc:
  test_and_set_bit now expect an "unsigned long", so we want
  &spinlock->lock rather than &spinlock (even though they are
  equivalent).

  Rusty.

(Included in 2.4)
Pavel Machek <pavel@ucw.cz>: trivial: vmscan extra {}s:
  Hi!

  Extra { } look ugly, too, they are not consistant with rest of code and I introduced them :-(

(Included in 2.2)
Pavel Machek <pavel@ucw.cz>: CREDITS not sorted properly:
  Hi!

  Please apply,
  									Pavel

Dan Aloni <da-x@gmx.net>: fs_dcache.c - typo:

Christopher Yeoh <cyeoh@samba.org>: (Made -p1 compliant by rusty) SUSv2 semctl compliance:

  The semctl call with SETVAL currently does not set sempid (at the
  moment sempid is only set during a successful semop call). An
  explanation from Geoff Clare of the Open Group regarding why sempid
  should be set during the semctl call:

  "The spec isn't very clear, but there is a statement on the semget()
  page which I think justifies the assumption made by the test.  It says
  that upon creation, the data structure associated with each semaphore
  in the set is not initialised, and that the semctl() function with
  SETVAL or SETALL can be used to initialise each semaphore.

  Therefore semctl() with SETVAL has to set sempid to *something*, and
  since sempid contains the "process ID of the last operation", setting
  it to anything other than the pid of the calling process would mean
  that sempid contained misleading information.  It could be argued that
  setting it to zero would not be misleading, but zero cannot be the
  process ID of a process, and so is not a valid value for sempid anyway."

  The following patch changes semctl so when called with SETVAL
  sempid is set to the pid of the calling process:

Alexander.Riesen@synopsys.com: xconfig for tulip subsection:
  fixes broken xconfig for tulip drivers.

  P.S. Why the double quotes in comment break it?

Anton Blanchard <anton@samba.org>: Fix autofs on ppc64:

  Define autofs_wqt_t to be an int on ppc64, just like the other mixed
  32/64 bit archs do.

 - Rewritten Artop host chip driver by Vojtech Pavlik. His log entries are:

   Cleanup whitespace.

   Remove superfluous chip entries in chip table.  Remove global variables to
   allow more than one controller.  Remove other forgotten stuff.

   This is a new driver for the Artop (Acard) controllers. It's completely
   untested, as I have never seen the hardware. However, I suspect it is much
   less broken than the previous one ...

   UDMA33 controller cannot detect 80-wire cable.

 - Separate ioctl handling out from ide.c. It's big enough.

 - Move atapi_read and atapi_write to the new atapi module.  Fix the declaration
   of those functions. The data buffer did have the void * type!

 - Separate module handling code out from actual transfer handling code in to a
   new module called main.c. Slowly we are at the stage where the code indeed
   has to be organized logically and not just "sporadically" as was the case
   before.

 - Apply patch by Adam Richter for the ide-scsi.c attach method implementation.
   This particular driver is still broken due to generic SCSI layer issues.

 - Apply true modularization patch for qd65xx.c by Samuel Thibault. Here
   are his notes about it:

   Then, patch-modularize-2.[45] is a proposal for modularizing qd65xx.o. As a
   single module, one can choose to insmod it before being able to do some
   hdparm -p /dev/hd[a-d]. But one can't remove it while tuned, since selectproc
   may be needed.

   I am sorry I wasn't able to test it under 2.5 series, lacking a functionning
   kernel for my test computer, but it seemed to work perfectly under 2.4
   series, and patches are almost the same.

 - Move PCI device id's to where they belong. Patch by Vojtech Pavlik.

 - Don't use BH_Lock in ide-tape.c - somehow this driver scares me sometimes.

o Add 'tag' to request.txt doc
o Add bio design etc discussions

into home.transmeta.com:/home/torvalds/v2.5/linux

They're always the same, so no point in using function pointers.

We rather keep it simple, everything we need is in struct
capi_ctr.

The hardware driver needs to alloc mem anyway, and now can
fill in fields before registering with the CAPI layer.

Basically the same way struct net_device is handled.

In case a driver really wants to put some useful info into
/proc/capi/driver, it could create the proc entry directly.

o Move /proc handling to a file of its own 
o Use <linux/seq_file.h>

into home.transmeta.com:/home/torvalds/v2.5/linux

	- Remove SCO compatibility trick in rio_fw_ioctl, i.e., riocontrol was returning non
          negative errors, now it is, so no need to turn it negative in rio_fw_ioctl. Thanks
          to Rogier Wolff for pointing this out.

into home.transmeta.com:/home/torvalds/v2.5/linux

So I missed at least one file which still relied on implicitly exporting
symbols. Now fixed.

The following allows the ramdisk to work on 2.5.18; maybe we need a
comment in do_open() ?

If d_splice_alias() doesn't find the alias dentry, it returns NULL.
Then, msdos_lookup() dereference the NULL, and Oopses. Fixed here.

The vfat_lookup() part is cleanup only.

FORCE is the de-facto standard name for a prequisite to force
recompilation, so instead of using a mix of 'dummy','FORCE' and
'FORCE_RECOMPILE' use 'FORCE' everywhere.

Also, move figuring out the path relative to the top level dir
into Rules.make, instead of calling an external script. 

It's possible to say "make <subdir>", to descend into that subdir
and recursively build things there. This patch provides this
facility generally without the arch Makefiles needing to duplicate
it for arch/$(ARCH)/somedir.