This implements what we discussed, basically just maintaing a plug list
from the block layer as a direct parallel to the tq_disk task queue we
had before.  blk_run_queues() now splices the blk_plug_list to avoid
holding the blk_plug_lock across all the request_fn calls.

This patch provides the ability for a block driver to signal it's too
busy to receive more work and temporarily halt the request queue. In
concept it's similar to the networking netif_{start,stop}_queue helpers.

To do this cleanly, I've ripped out the old tq_disk task queue. Instead
an internal list of plugged queues is maintained which will honor the
current queue state (see QUEUE_FLAG_STOPPED bit). Execution of
request_fn has been moved to tasklet context. blk_run_queues() provides
similar functionality to the old run_task_queue(&tq_disk).

Now, this only works at the request_fn level and not at the
make_request_fn level. This is on purpose: drivers working at the
make_request_fn level are essentially providing a piece of the block
level infrastructure themselves. There are basically two reasons for
doing make_request_fn style setups:

o block remappers. start/stop functionality will be done at the target
  device in this case, which is the level that will signal hardware full
  (or continue) anyways.

o drivers who wish to receive single entities of "buffers" and not
  merged requests etc. This could use the start/stop functionality. I'd
  suggest _still_ using a request_fn for these, but set the queue
  options so that no merging etc ever takes place. This has the added
  bonus of providing the usual request depletion throttling at the block
  level.

Didn't get the net/ conversion quite right, and apparently overlooked
one subdir in sound/. Now fixed.

Use the new

	obj-$(CONFIG_FOO) += foo/

syntax to descend into a subdir and link in the result, if
CONFIG_FOO=y.

Build the headers only when we need them during the build, not always
at 'make dep' time.

We use O_TARGET everywhere else, so let's just convert the remaining
users (They get the implicit built-in.o O_TARGET now)

(plus a bit of rearranging in the ISDN Makefiles) 

If a Makefile defines neither O_TARGET nor L_TARGET, let's assume a
default of 'built-in.o'. The goal of this is, of course, to eventually
get rid of O_TARGET completely.

 - move the contents of bdev_get_queue() into do_open() and
   check_partitions() and cache the result in new field of struct
   block_device

 - clean it at the same places that reset ->bd_op, etc.

 - make bdev_get_queue() return cached pointer.

 - kill the last caller of get_hardsect_size() (switching it to
   bdev_hardsect_size()).

 - kill blk_get_queue() and switching to bdev_get_queue()

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

  - make sure return codes are negative (i.e. return -ENOMEM and not return ENOMEM et al)

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

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

Fixes a warning in ieee1394_types.h and an error in include/linux/usb.h

into tp1.ruhr-uni-bochum.de:/home/kai/kernel/v2.5/linux-2.5.misc

This kills unneccessary include from ide-disk.c, kills #ifdef from
reiserfs/journal.c, makes suspend_device local as it should be,
abstains from suspending devices two times in a row (typo), and makes
sure we do not run_task_queue() while we hold spinlock.

I asked Gabor if he'd like me to maintain swsusp, and he liked that
idea [<quote>Would you please take over maintaining? I offered this in
the list a while ago anyway.</quote>].

These are cleanups. They do not change any code, except killing
printk's.

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

 - Apply host chip driver cleanups by Bartomiej Zonierkiewicz.

 - Take the draft device type driver implementation from Adam Richter and make
    it actually work with some of the drivers we have at hand. Quite a lot
    of it was fixed by me as well to have the desired effects.

    We have added a attach method for the sub device type drivers to make it
    possible dor sub device type drivers to attach devices to the overall
    infrastructure. UNIX has something like this SCSI code is implementing
    something like this, just for some unknown reasons Linux block device
    operations don't have it...

 - ide_drive_t is finally gone. Please use struct ata_device instead.

    Hint the ide.h specific byte type should go over time as well, sine there
    is no need to invent something already handled by the kernel. Please use
    the unambigious u8 type instead where possible.

 - Add a bit of documentation about cabling issues. ide.txt needs a lot of
   improvement at some time still.

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

__initcalls are supposed to return a value.
Statically initialize the struct instead of doing strcpy() at runtime.

Needs static, otherwise one gets multiple definitions in the final
vmlinux image.

No more need to include buffer_head.h in fs.h.  Finally.