- use ll_rw_block().

- use READA

- export it to modules.

- xfs printk warning fix (dev_t is ulong on ppc64)

- unused var in serial_remove() (Daniele Bellucci <bellucda@tiscali.it>)

From: Mikael Pettersson <mikpe@csd.uu.se>

This patch fixes two p->thread_info->cpu occurrences in kernel/sched.c to
use the task_cpu(p) macro instead, which is optimised on UP.  Although one
of the occurrences is under #ifdef CONFIG_SMP, it's bad style to use the
raw non-optimisable form in non-arch code.

in the networking code.

From YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

Architecture specific flat loader code for v850 moved into its
own v850 flat.h header. This patch also adds supporti for a number
of relocation cases that need to be handled at laod time.

Most of this code is originally from Miles Bader <miles@gnu.org>.

Architecture specific flat loader code for m68knommu moved into its
own m68knommu flat.h header. Part of the shared library flat loader
update.

Architecture specific flat loader code for H8/300 moved into its
own H8/300 flat.h header.

This patch adds shared library support to the MMU application
loader, binfmt_flat. This is not new, it is a forward port from the
same support in 2.4.x kernels with MMUless support, and has been
running for well over a year now. The code support is conditionally
compiled on CONFIG_BINFMT_FLAT_SHARED. This change also abstracts
a bit more architecture dependent code into the separate flat.h
includes.

Basically relocations within an application also carry a tag to
identify what they refer too (this code or which shared library).
This is patched as before at load/run-time with an appropriate
address.

Unify access_ok for all m68knommu targets. All targets use the
common linker script and have common end symbols. So now we can
just use a simple check.

Remove "%d0" register from clobber list of down_trylock() for
m68knommu. It is not used by the asm code here at all.

Force PAGE_SIZE for the m68knommu architecture to be an unsigned long.
This makes it consistent with all other architectures and cleans up
a load of compiler warnings.

Conditionally copy the ROMfs filesystem on the Motorola M5307C3
target board only if using a ROMfs.

Allow setting boot time parameters at configuration for Motorola
5282 targets.

This improves cold-cache program startup noticeably for me, and
simplifies the read-ahead logic at the same time. The rules for
read-ahead are:

 - if the vma is marked random, we just do the regular one-page case. 
   Obvious.

 - if the vma is marked "linear access", we use the regular readahead
   code. No change in behaviour there (well, we also only consider it a 
   _miss_ if it was marked linear access - the "readahead" and
   "readaround"  things are now totally independent of each other)

 - otherwise, we look at how many hits/misses we've had for this 
   particular file open for mmap, and if we've had noticeably more
   misses than hits, we don't bother with read-around.

In particular, this means that the "real" read-ahead logic literally
only needs to worry about finding sequential accesses, and does not
have to worry about the common executable mmap access patthers that 
have very different behaviour.

Some constant tweaking may be a good idea.

in add_timer_internal() we simply leave the timer pending forever if the
expiry is in more than 0xffffffff jiffies. This means more than 48 days on
eg. ia64 - which is not an unrealistic timeout. IIRC crond is happy to use
extremely large timeouts.

It's better to time out early (if you can call 48 days "early") than to
not time out at all.

This offers a generic do_div64() that actually does the right thing,
unlike some architectures that "optimized" the 64-by-32 divide into
just a 32-bit divide.

Both ppc and sh were already providing an assembly optimized
__div64_32().  I called my function the same, so that their optimized
versions will automatically override mine in lib.a.

I've only tested extensively on m68knommu (uClinux) and made
sure generated code is reasonably short. Should be ok also on
parisc, since it's the same algorithm they were using before.

 - add generic C implementations of the do_div() for 32bit and 64bit
   archs in asm-generic/div64.h;

 - add generic library support function __div64_32() to handle the
   full 64/32 case on 32bit archs;

 - kill multiple copies of generic do_div() in architecture
   specific subdirs. Most copies were either buggy or not doing
   what they were supposed to do;

 - ensure all surviving instances of do_div() have their parameters
   correctly parenthesized to avoid funny side-effects;

Fix arbitration between net open and tty open.

Cleanup missed bits of CUA device removal changes.

Fix arbitration between net open and tty open.

Clean up unused locals resulting from latest tty changes.

Fix arbitration between net open and tty open.

Cleanup unused local resulting from latest tty changes.

From Mikael Petterson:


  Booting kernel 2.5.74 on a PowerMac with CONFIG_BLK_DEV_IDE_PMAC=y
  results in an oops during IDE init, and the box then reboots.

  The patch below updates drivers/ide/ppc/pmac.c to also set up the
  hwif->ide_dma_queued_off and hwif->ide_dma_queued_on function
  pointers, which fixes the oops. Tested on my ancient PM4400.

I no longer have the time/interest in nbd, and Paul agreed to take it
over.

The compat ioctls for device mapper were not being enabled due to an
incorrect config option.

This tweaks the mmap read-ahead behaviour so that the prefaulting
is largely pointless.

 - double the minimum readaround chunksize in page_cache_readaround().

 - when a seek is detected, collapse the window more slowly.

i2o_scsi.c now needs pci.h.

From: ilmari@ilmari.org (Dagfinn Ilmari Mannsaker)

It turns out that net/bluetooth/rfcomm/sock.c (and
net/bluetooth/hci_sock.c) had been left out when net_proto_family gained an
owner field, here's a patch that fixes them both.

From: junkio@cox.net

Sigh.  Is there a gcc option to tell it to not accept this incompatible C99
extension?

From: Arvind Kandhare <arvind.kan@wipro.com>

When switch_uid is called, the reference count of the new user is
incremented twice.  I think the increment in the switch_uid is done because
of the reparent_to_init() function which does not increase the __count for
root user.

But if switch_uid is called from any other function, the reference count is
already incremented by the caller by calling alloc_uid for the new user.
Hence the count is incremented twice.  The user struct will not be deleted
even when there are no processes holding a reference count for it.  This
does not cause any problem currently because nothing is dependent on timely
deletion of the user struct.

From: Davide Libenzi <davidel@xmailserver.org>

- Inline eventpoll_release() so that __fput() does not need to call in
  epoll code if the file itself is not registered inside an epoll fd

- Add <linux/types.h> inclusion due __u32 and __u64 usage

- Fix debug printf that would otherwise panic if enabled with the new
  epoll code

From: Davide Libenzi <davidel@xmailserver.org>

- Remove a couple of impossible debug checks (unsigneds cannot be
  negative!)

- If __alloc_bootmem_core() fails with a goal and unaligned node_boot_start
  it'll loop fovever.

If de_thread() fails in flush_old_exec() then we try to fail the execve().

That is a bad move, because exec_mmap() has already switched the current
process over to the new mm.  The new process is not yet sufficiently set up
to handle the error and the kernel doublefaults and dies.  exec_mmap() is the
point of no return.

Change flush_old_exec() to call de_thread() before running exec_mmap() so the
execing program sees the error.  I added fault injection to both de_thread()
and exec_mmap() - everything now survives OK.

From: Nick Piggin <piggin@cyberone.com.au>

Add some comments to the request allocation code.

- pass gfp_flags to get_io_context(): not all callers are forced to use
  GFP_ATOMIC().

- fix locking in get_io_context(): bump the refcount whilein the exclusive
  region.

- don't go oops in get_io_context() if the kmalloc failed.

- in as_get_io_context(): fail the whole thing if we were unable to
  allocate the AS-specific part.

- as_remove_queued_request() cleanup

From: Nick Piggin <piggin@cyberone.com.au>

The following patch gets batching working how it should be.

After a process is woken up, it is allowed to allocate up to 32 requests
for 20ms.  It does not stop other processes submitting requests if it isn't
submitting though.  This should allow less context switches, and allow
batches of requests from each process to be sent to the io scheduler
instead of 1 request from each process.

tiobench sequential writes are more than tripled, random writes are nearly
doubled over mm1.  In earlier tests I generally saw better CPU efficiency
but it doesn't show here.  There is still debug to be taken out.  Its also
only on UP.

                                Avg     Maximum     Lat%   Lat%   CPU
 Identifier    Rate  (CPU%)  Latency   Latency     >2s    >10s   Eff
 ------------------- ------ --------- ---------- ------- ------ ----
 -2.5.71-mm1   11.13 3.783%    46.10    24668.01   0.84   0.02   294
 +2.5.71-mm1   13.21 4.489%    37.37     5691.66   0.76   0.00   294

 Random Reads
 ------------------- ------ --------- ---------- ------- ------ ----
 -2.5.71-mm1    0.97 0.582%   519.86     6444.66  11.93   0.00   167
 +2.5.71-mm1    1.01 0.604%   484.59     6604.93  10.73   0.00   167

 Sequential Writes
 ------------------- ------ --------- ---------- ------- ------ ----
 -2.5.71-mm1    4.85 4.456%    77.80    99359.39   0.18   0.13   109
 +2.5.71-mm1   14.11 14.19%    10.07    22805.47   0.09   0.04    99

 Random Writes
 ------------------- ------ --------- ---------- ------- ------ ----
 -2.5.71-mm1    0.46 0.371%    14.48     6173.90   0.23   0.00   125
 +2.5.71-mm1    0.86 0.744%    24.08     8753.66   0.31   0.00   115

It decreases context switch rate on IBM's 8-way on ext2 tiobench 64 threads
from ~2500/s to ~140/s on their regression tests.

From: Nick Piggin <piggin@cyberone.com.au>

Generalise the AS-specific per-process IO context so that other IO schedulers
could use it.

From: Nick Piggin <piggin@cyberone.com.au>

This patch fixes the request batching fairness/starvation issue.  Its not
clear what is going on with 2.4, but it seems that its a problem around this
area.

Anyway, previously:

	* request queue fills up
	* process 1 calls get_request, sleeps
	* a couple of requests are freed
	* process 2 calls get_request, proceeds
	* a couple of requests are freed
	* process 2 calls get_request...

Now as unlikely as it seems, it could be a problem.  Its a fairness problem
that process 2 can skip ahead of process 1 anyway.

With the patch:

	* request queue fills up
	* any process calling get_request will sleep
	* once the queue gets below the batch watermark, processes
	  start being worken, and may allocate.


This patch includes Chris Mason's fix to only clear queue_full when all tasks
have been woken.  Previously I think starvation and unfairness could still
occur.

With this change to the blk-fair-batches patch, Chris is showing some much
improved numbers for 2.4 - 170 ms max wait vs 2700ms without blk-fair-batches
for a dbench 90 run.  He didn't indicate how much difference his patch alone
made, but it is an important fix I think.

From: Nick Piggin <piggin@cyberone.com.au>

If there are no requess in flight against the target device and
get_request() fails, nothing will wake us up.  Fix.

From: Nick Piggin <piggin@cyberone.com.au>


This patch implements a hint so that AS can tell the request allocator to
allocate a request even if there are none left (the accounting is quite
flexible and easily handles overallocations).

elv_may_queue semantics have changed from "the elevator does _not_ want
another request allocated" to "the elevator _insists_ that another request is
allocated".  I couldn't see any harm ;)

Now in practice, AS will only allow _1_ request over the limit, because as
soon as the request is sent to AS, it stops anticipating.

From: Nick Piggin <piggin@cyberone.com.au>

Now that we are counting requests (not requests free), this patch changes
the congested & batch watermarks to be more logical.  Also a minor fix to
the sysfs code.

From: Nick Piggin <piggin@cyberone.com.au>

This gets rid of the global queue_nr_requests and usage of BLKDEV_MAX_RQ
(the latter is now only used to set the queues' defaults).

The queue depth becomes per-queue, controlled by a sysfs entry.