Linus, betcha cannot find a more trivial (but correct) patch...

This showstopper is against 2.5.21 - please apply.

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

Todd R. Eigenschink <todd@tekinteractive.com> reported 2.4 swapoff
kernel BUG at filemap.c:122 to LKML 24 May.  Other problems on that
system may have contributed, but yes, despite __delete_from_swap_cache
doing ClearPageDirty before __remove_inode_page to avoid the BUG(),
a concurrent zap_pte_range might race to set_page_dirty.  So skip
that oops in PageSwapCache case.  Remove the prior ClearPageDirty?
maybe but not without deeper thought: let stay for now.

Recent testing has shown that BUG() check in try_to_unuse is unsafe.
delete_from_swap_cache does final swap_free just after removing page
from swap cache, and add_to_swap_cache does swap_duplicate just before
putting page into swap cache, therefore swapin_readahead may resurrect
a dying swap entry and assign a new page to it.  That's fine, there's
no need to change this ordering; but it does mean that try_to_unuse's
page may have left the swap cache yet its swap_map count still be set.
That BUG() has done good service for swapoff sanity, but now abandon it.

Burton Windle <bwindle@fint.org> reported Kernel memory leak with
swapon/swapoff? LKML 31 May.  swapon uses rw_swap_page_nolock to read
swap_header page (peculiar! should probably rework that sometime),
nothing freed the buffers from the page, thus page also never freed.

Remove /* SMP-safe */ comments before shmem_truncate and shmem_mknod:
don't know who or why put there, but they seem to imply that the rest
of shmem.c is unsafe.

Several simple speedups to tmpfs swapoff: without patch, swapoff of a
kernel tree in tmpfs might take take 2 minutes, with patch 4 seconds.
Inline search go no further than necessary; only search inode when it
has swapped pages; start next search from same inode; list in order.

(There's a "list_move_tail" in this patch: not available in 2.5.21,
but I believe you now have it in your ongoing tree.)

shmem_mknod should not update directory times if it cannot get an inode.

shmem_symlink was letting a long symlink overwrite its vfs_inode, now
included within struct shmem_inode_info - oops! and failed long symlink
inodes were freed but still left on the shmem_inodes list, causing oops
in swapoff at shutdown (if not earlier).

shmem_rename was not maintaining the correct link count on the
parent directories when a directory was moved from one to another.
This patch from Christoph Rohland <cr@sap.com>, already in 2.5-dj.

 - Bunch of cleanups by Bartlomiej (accounts for over a half of the patch):

    cmd64x.c:
	- kill SPLIT_BYTE() macro
	- kill wrappers for cmd64x_config_drive_for_dma()
	- misc cleanups

    cy82c693.c:
	- kill obsolete comments
	- clean cy82c693_tune_drive() and calc_clk()
	- misc cleanups

    hpt34x.c:
	- kill obsolete comment
	- kill SPLIT_BYTE()
	- kill hpt34x_clear_chipset()
	- simplify hpt34x_tune_drive()

    hpt366.c:
	- kill hpt_min_rev()
	- kill redundant hpt368_tune_chipset() and hpt374_tune_chipset()
	- fix badlists checking in config_chipset_for_dma()
	- misc cleanups

    pdc202xx.c:
	- clean registers decoding
	- clean pdc202xx_tune_chipset()
	- kill pdc202xx_udma_irq_status(), use generic udma_pci_irq_status()
	- rationalize pdc202xx_reset()
	- kill UDMA_SPEED_FLAG() and PDC_CLOCK() macros,
	  do it right by defining constants PDC_UDMA and PDC_CLK
	- kill init_high_16() inline, no need to hide internals
	- clean pdc202xx_init_chipset()
	- split ata66_pdc202xx() and pdc202xx_init_chipset()
	- clean config_chipset_for_dma()
	- misc cleanups

 - Fix plug in of CF cards. The previously used sub device driver attach method
   lookup was entirely hosed.

 - Enforce indentation style on ide-cs.c. Enable debugging there. (Makes the
   patch quite big...)

This makes the IO bitmap allocations a separately allocated structure,
shrinking the default task size.

We alloc it in sys_ioperm() and copy_thread() and frees in
exit_thread().  It also gets rid of the IO_BITMAP_SIZE+1 crap, as only
the tss actually needs the tail long, and we weren't copying it into the
bitmap anyways.

The utime and utimes should do exactly the smae permission check
according to SUSv3.
	"The effective user ID of the process shall match the owner of the file,
or has write access to the file or appropriate privileges to use this call
in this manner."

utimes when passed a NULL second argument would fail on a read only
file even if the file is owned by the caller.

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

The following comes from James Bottemley, as he updated the SCSI layer
to use the generic tagging.

Basically just put blk_queue_tag_request() into ll_rw_blk.c and name it
something more sane, blk_queue_find_tag(). In addition, remove REQ_CMD
requirement in blk_queue_start_tag() -- this is actually IDE specific
(we can only tag read/write requests there...), SCSI actually requires
everything to be tagged once enabled. It's replaced with a safety check
for an already tagged request.

This is a merge of the two things that are needed for the plugging as it
stands in 2.5.21. The first is fixing the locking to be both clearer and
safe (Andrew repeatedly broke the old version). The second is a few
changes that allow make_request_fn drivers to utilize plugging. This is
needed for umem and raid, for instance, that have their private
plugging.

- i've extended the scheduler context-switch mechanism with the following
  per-arch defines:

        prepare_arch_schedule(prev_task);
        finish_arch_schedule(prev_task);
        prepare_arch_switch(rq);
        finish_arch_switch(rq);

- plus switch_to() takes 3 parameters again:

        switch_to(prev, next, last);

- schedule_tail() has the 'prev' task parameter again, it must be passed
  over in switch_to() and passed in to the fork() startup path.

architectures that need to unlock the runqueue before doing the switch can
do the following:

 #define prepare_arch_schedule(prev)             task_lock(prev)
 #define finish_arch_schedule(prev)              task_unlock(prev)
 #define prepare_arch_switch(rq)                 spin_unlock(&(rq)->lock)
 #define finish_arch_switch(rq)                  __sti()

this way the task-lock makes sure that a task is not scheduled on some
other CPU before the switch-out finishes, but the runqueue lock is
dropped. (Local interrupts are kept disabled in this variant, just to
exclude things like TLB flushes - if that matters.)

architectures that can hold the runqueue lock during context-switch can do
the following simplification:

 #define prepare_arch_schedule(prev)             do { } while(0)
 #define finish_arch_schedule(prev)              do { } while(0)
 #define prepare_arch_switch(rq)                 do { } while(0)
 #define finish_arch_switch(rq)                  spin_unlock_irq(&(rq)->lock)

further optimizations possible in the 'simple' variant:

- an architecture does not have to handle the 'last' parameter in
  switch_to() if the 'prev' parameter is unused in finish_arch_schedule().
  This way the inlined return value of context_switch() too gets optimized
  away at compile-time.

- an architecture does not have to pass the 'prev' pointer to
  schedule_tail(), if the 'prev' parameter is unused in
  finish_arch_schedule().

the x86 architecture makes use of these optimizations.

Via this solution we have a reasonably flexible context-switch setup which
falls back to the current (faster) code on x86, but on other platforms the
runqueue lock can be dropped before doing the context-switch as well.

        Ingo

NOTE: i have coded and tested the 'complex' variant on x86 as well to make
      sure it works for you on Sparc64 - but since x86's switch_mm() is
      not too subtle it can use the simpler variant. [ The following
      things had to be done to make x86 arch use the complex variant: the
      4 complex macros have to be used in system.h, entry.S has to
      'pushl %ebx' and 'addl $4, %esp' around the call to schedule_tail(),
      and switch_to() had to be reverted to the 3-parameter variant
      present in the 2.4 kernels.

NOTE2: prepare_to_switch() functionality has been moved into the
       prepare_arch_switch() macro.

NOTE3: please use macros for prepare|finish_arch_switch() so that we can
       keep the scheduler data structures internal to sched.c.

Silly oversight - read_pages needs to pass the file *
down to ->readpage().

- If we're PF_MEMALLOC and BIO allocation failed, fall back to try
  to allocate a smaller BIO (from a different mempool)

- When writepages() gets confused, call a_ops->writepage()
  instead of going directly to block_write_full_page().  It
  gives the fs more flexibility, and XFS may want this.

It will need swapops.h for swp_entry().

Fix the order of inodes being marked dirty in a couple of corner cases.

The only impact of this bug is that the on-disk copies of i_version
might got out of sync for a directory, or that an error inserting an
inode into a directory might leave its i_nlinks incorrect on disk for a
short interval.  Neither problem will cause trouble for ext3 during
normal operation, but the nlink problem might cause e2fsck to emit
unnecessary warnings if we crash while the incorrect version of the
inode is in the journal.

Removes the put_iode optimisation.  It's racy, as
Chris pointed out.

ext3 will remount the fs readonly if it runs out of inode
space.  It shouldn't do that - it should just return -ENOSPC.

Cset exclude: bcrl@redhat.com|ChangeSet|20020429021546|12619

This allows compilation without ACPI_DEBUG defined.

This adds an export so that processor.o and thermal.o can be compiled as
modules

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

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

A couple of targets were still in the main part of the Makefile,
even though they did not need .config to exist for execution.

Move them into the noconfig section of the Makefile, allowing them
to be executed before make *config.

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

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

Unreversed allocations on the error path and the like.

 - Inline locks_notify_blocked.
 - Remove a couple of now-bogus comments.
 - Remove the obsolete F_SHLCK and F_EXLCK cases.
 - Remove the last remaining reference to FL_BROKEN.

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

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

Contributed by Greg Banks.