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Update 2.6.x-xfs to 2.6.23-rc4.

Also update fs/xfs with external mainline changes.
There were 12 such missing commits that I detected:

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commit ad690ef9e690f6c31f7d310b09ef1314bcec9033
Author: Al Viro <viro@ftp.linux.org.uk>
    xfs ioctl __user annotations

commit 20c2df83d25c6a95affe6157a4c9cac4cf5ffaac
Author: Paul Mundt <lethal@linux-sh.org>
    mm: Remove slab destructors from kmem_cache_create().

commit d0217ac04ca6591841e5665f518e38064f4e65bd
Author: Nick Piggin <npiggin@suse.de>
    mm: fault feedback #1

commit 54cb8821de07f2ffcd28c380ce9b93d5784b40d7
Author: Nick Piggin <npiggin@suse.de>
    mm: merge populate and nopage into fault (fixes nonlinear)

commit d00806b183152af6d24f46f0c33f14162ca1262a
Author: Nick Piggin <npiggin@suse.de>
    mm: fix fault vs invalidate race for linear mappings

commit a569425512253992cc64ebf8b6d00a62f986db3e
Author: Christoph Hellwig <hch@infradead.org>
    knfsd: exportfs: add exportfs.h header

commit 831441862956fffa17b9801db37e6ea1650b0f69
Author: Rafael J. Wysocki <rjw@sisk.pl>
    Freezer: make kernel threads nonfreezable by default

commit 8e1f936b73150f5095448a0fee6d4f30a1f9001d
Author: Rusty Russell <rusty@rustcorp.com.au>
    mm: clean up and kernelify shrinker registration

commit 5ffc4ef45b3b0a57872f631b4e4ceb8ace0d7496
Author: Jens Axboe <jens.axboe@oracle.com>
    sendfile: remove .sendfile from filesystems that use generic_file_sendfile()

commit 8bb7844286fb8c9fce6f65d8288aeb09d03a5e0d
Author: Rafael J. Wysocki <rjw@sisk.pl>
    Add suspend-related notifications for CPU hotplug

commit 59c51591a0ac7568824f541f57de967e88adaa07
Author: Michael Opdenacker <michael@free-electrons.com>
    Fix occurrences of "the the "

commit 0ceb331433e8aad9c5f441a965d7c681f8b9046f
Author: Dmitriy Monakhov <dmonakhov@openvz.org>
    mm: move common segment checks to separate helper function
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Merge of 2.6.x-xfs-melb:linux:29656b by kenmcd.

Kernel driver max6875
=====================

Supported chips:
  * Maxim MAX6874, MAX6875
    Prefix: 'max6875'
    Addresses scanned: None (see below)
    Datasheet:
        http://pdfserv.maxim-ic.com/en/ds/MAX6874-MAX6875.pdf

Author: Ben Gardner <bgardner@wabtec.com>


Description
-----------

The Maxim MAX6875 is an EEPROM-programmable power-supply sequencer/supervisor.
It provides timed outputs that can be used as a watchdog, if properly wired.
It also provides 512 bytes of user EEPROM.

At reset, the MAX6875 reads the configuration EEPROM into its configuration
registers.  The chip then begins to operate according to the values in the
registers.

The Maxim MAX6874 is a similar, mostly compatible device, with more intputs
and outputs:
             vin     gpi    vout
MAX6874        6       4       8
MAX6875        4       3       5

See the datasheet for more information.


Sysfs entries
-------------

eeprom        - 512 bytes of user-defined EEPROM space.


General Remarks
---------------

Valid addresses for the MAX6875 are 0x50 and 0x52.
Valid addresses for the MAX6874 are 0x50, 0x52, 0x54 and 0x56.
The driver does not probe any address, so you must force the address.

Example:
$ modprobe max6875 force=0,0x50

The MAX6874/MAX6875 ignores address bit 0, so this driver attaches to multiple
addresses.  For example, for address 0x50, it also reserves 0x51.
The even-address instance is called 'max6875', the odd one is 'max6875 subclient'.


Programming the chip using i2c-dev
----------------------------------

Use the i2c-dev interface to access and program the chips.
Reads and writes are performed differently depending on the address range.

The configuration registers are at addresses 0x00 - 0x45.
Use i2c_smbus_write_byte_data() to write a register and
i2c_smbus_read_byte_data() to read a register.
The command is the register number.

Examples:
To write a 1 to register 0x45:
  i2c_smbus_write_byte_data(fd, 0x45, 1);

To read register 0x45:
  value = i2c_smbus_read_byte_data(fd, 0x45);


The configuration EEPROM is at addresses 0x8000 - 0x8045.
The user EEPROM is at addresses 0x8100 - 0x82ff.

Use i2c_smbus_write_word_data() to write a byte to EEPROM.

The command is the upper byte of the address: 0x80, 0x81, or 0x82.
The data word is the lower part of the address or'd with data << 8.
  cmd = address >> 8;
  val = (address & 0xff) | (data << 8);

Example:
To write 0x5a to address 0x8003:
  i2c_smbus_write_word_data(fd, 0x80, 0x5a03);


Reading data from the EEPROM is a little more complicated.
Use i2c_smbus_write_byte_data() to set the read address and then
i2c_smbus_read_byte() or i2c_smbus_read_i2c_block_data() to read the data.

Example:
To read data starting at offset 0x8100, first set the address:
  i2c_smbus_write_byte_data(fd, 0x81, 0x00);

And then read the data
  value = i2c_smbus_read_byte(fd);

  or

  count = i2c_smbus_read_i2c_block_data(fd, 0x84, 16, buffer);

The block read should read 16 bytes.
0x84 is the block read command.

See the datasheet for more details.