This is the first of a series of patches to driverfs to _not_ use the vfs layer for file creation
and deletion. 
The VFS layer is allowing files and directories to be removed from userspace, which we don't want 
at all. 

Per Al Viro's suggesting, I am pushing the necessary checks from the vfs_* functions into the 
driverfs functions, and calling them directly from the kernel interface to driverfs.

This is the first, for file creation

- in mkdir: we already hold parent directory's semaphore (c.f. driverfs_create_dir)
- in create: ditto (c.f. driverfs_create_file)
- in unlink: ditto (c.f. driverfs_remove_file) and file's i_sem is taken in vfs_unlink
- un lseek: take inode's i_sem (though I think we can replace this with a common lseek function...later)

Inexplicably, xor.c enabled interrupts...
 thanks to akmp

Here it is my first LK patch.
tested even. :)

the global irq-lock debugging

cpqfcTSinit.c:
  Fix usage of Scsi_Cmnd->request so it will compile.

into penguin.transmeta.com:/home/penguin/torvalds/repositories/kernel/linux

 - introduce new type of context-switch locking, this is a must-have for
   ia64 and sparc64.

 - load_balance() bug noticed by Scott Rhine and myself: scan the
   whole list to find imbalance number of tasks, not just the tail
   of the list.

 - sched_yield() fix: use current->array not rq->active.

into penguin.transmeta.com:/home/penguin/torvalds/repositories/kernel/linux

into penguin.transmeta.com:/home/penguin/torvalds/repositories/kernel/linux

into kroah.com:/home/greg/linux/BK/pci_hp-2.5

into penguin.transmeta.com:/home/penguin/torvalds/repositories/kernel/linux

No commit message

into atnf.csiro.au:/workaholix1/kernel/v2.5/rgooch-2.5

Switch to set_current_state() and move before add_wait_queue().
Updated README from master HTML file.
Fixed devfs entry leak in <devfs_readdir> when *readdir fails.

The patch below consolidates some duplicate code, reduces some
indentation, and adds a freeing of a page in mem_read() that could be left
unfreed, as far as I can see.

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

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

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

make cpqarray and cciss use these

Heading Rusty off at the pass...

This also changes and array initialiser...

get_spare recently became static and no-one told md_k.h

Sync_sbs tries to access the ->sb for the first rdev of an mddev.
This can oops as the wrong arg is given to list_entry, and also
if a define was faound to be failed, as failed devices have their ->sb
removed.  But that removal isn't necessary, so now an rdev will always
have an ->sb.

Define container_of which cast from member to struct with some type checking.

This is much like list_entry but is cearly for things other than lists.

List_entry now uses container_of.

  new vendor/device ID;
  redundant check removed from probe();

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

 The old form of designated initializers are obsolete: we need to
 replace them with the ISO C forms before 2.6.  Gcc has always supported
 both forms anyway.

Dawson Engler's Stanford Checker reported this missing unlock to
LKML 11 July (amongst "56 potential lock/unlock bugs in 2.5.8").

Found by Simon Trimmer <simon@veritas.com>: shmem_file_write
failure path duplicates kunmap, causing oops holding kmap_lock.

Trivial: vfs_link in 2.5 checks S_ISDIR first, shmem_link
need not repeat it, but test crept back in at some stage.

Martin Schwidefsky <schwidefsky@de.ibm.com> reported "Bug with shared
memory" to LKML 14 May: hang due to schedule in truncate_list_pages
called from .... shm_destroy holding shm_lock spinlock.  shm_destroy
needs that lock for shm_rmid, but it can be safely unlocked once link
from id to shp has been removed.

Here is a quick fix.  I would like to synchronize with the irq handler
changes as well.  Becouse right now I know that preemption is killing
the disk subsystem when moving data between disks using different
request queues...  In esp.  It get's me in to do_request() with a queue
in unplugged state.  (Not everything is my fault, after all :-).

into kleikamp.austin.ibm.com:/home/shaggy/bk/jfs-2.5

 - init thread needs to have preempt_count of 1 until sched_init().
   (William Lee Irwin III)
 - clean up the irq-mask macros. (Linus)
 - add barrier() to irq_enter() and irq_exit(). (based on Oleg Nesterov's
   comment.)
 - move the irqs-off check into preempt_schedule() and remove
   CONFIG_DEBUG_IRQ_SCHEDULE.
 - remove spin_unlock_no_resched() and comment the affected places more
   agressively.
 - slab.c needs to spin_unlock_no_resched(), instead of spin_unlock(). (It
   also has to check for preemption in the right spot.) This should fix
   the memory corruption.
 - irq_exit() needs to run softirqs if interrupts not active - in the
   previous patch it ran them when preempt_count() was 0, which is
   incorrect.
 - spinlock macros are updated to enable preemption after enabling
   interrupts. Besides avoiding false positive warnings, this also
 - fork.c has to call scheduler_tick() with preemption disabled -
   otherwise scheduler_tick()'s spin_unlock can preempt!
 - irqs_disabled() macro introduced.
 - [ all other local_irq_enable() or sti instances conditional on
     CONFIG_DEBUG_IRQ_SCHEDULE are to fix false positive warnings. ]
 - fix buggy in_softirq(). Fortunately the bug made the test broader,
   which didnt result in algorithmical breakage, just suboptimal
   performance.
 - move do_softirq() processing into irq_exit() => this also fixes the
   softirq processing bugs present in apic.c IRQ handlers that did not
   test for softirqs after irq_exit().
 - simplify local_bh_enable().