Based off of a patch from Stuart MacDonald <stuartm@connecttech.com>

This cleans up the error path in the open() call to make a bit more
sense.

This fixes a stupid error in the timeout value when downloading firmware
to a device.  The WhiteHEAT device now works properly with this patch.

Like the header says, this patch fixes up the various Transfer- and
Transport-level return codes.  There were a lot of places in the various
subdrivers that were not particularly careful about distinguishing the
two; it would help if the people currently maintaining those drivers could
take a look at my changes to make sure I haven't screwed anything up.

# Converted US_BULK_TRANSFER_xxx to USB_STOR_XFER_xxx, to make it more
# easily distinguishable from USB_STOR_TRANSPORT_xxx.  (Also, in the
# future these codes may apply to control transfers as well as to bulk
# transfers.)
#
# Changed USB_STOR_XFER_FAILED to USB_STOR_XFER_ERROR, since it implies
# a transport error rather than a transport failure.
#
# Added a USB_STOR_XFER_STALLED code, to indicate a transfer that was
# terminated by an endpoint stall.

This patch is in preparation for one in which usb_stor_transfer_partial()
and usb_stor_transfer() are replaced by usb_stor_bulk_transfer_buf() and
usb_stor_bulk_transfer_srb() respectively, with slightly different
argument lists.  Ultimately the subdrivers will be able to use these
routines in place of the slightly specialized versions they have now and
in place of the ones in raw_bulk.c.

compile fails with the following message:

	> In file included from ohci-hcd.c:136:
	> ohci-dbg.c:318: parse error
	> make[3]: *** [ohci-hcd.o] Error 1

due to a missing #include <linux/version.h>

Here is a trivial patch for this.

is it guarenteed that callers have zero'd out the device
before this is invoked?  Else the following is necessary to
prevent potential OOPS's derefencing interface->dev.driver in
the generic device layer.

Here's an EHCI update, I'll send separate patches to sync 2.4 with
this version.  Changes in this version include:

  - An earlier locking update would give trouble on SPARC, where
    irqsave "flags" aren't flags.  This resolves that issue by
    adding a module parameter to limit work done with irqs off.
    (Some net drivers do the same thing.)

  - Optionally (now #ifdef DEBUG) collects some statistics on IRQs
    and URBs.  There are more IAA interrupts than I want to see,
    during extended usb-storage loading.

  - Adds a commented-out workaround for a problem I've seen on one
    VT8235.  Seems likely an issue with this specific motherboard;
    another tester hasn't reported such issues.

  - Includes the jiffies time_after() patch from Tim Schmielau.

  - Minor tweaks to the hcd portability (get rid of another #if).

  - Minor doc/diagnostic/... updates

This USB patch updates the OHCI driver:

  - converts to relying on td_list shadowing the hardware's
    schedule; only collecting the donelist needs dma_to_td(),
    and td list handling works much like EHCI or UHCI.

  - leaves faulted endpoint queues (bulk/intr) disabled until
    the relevant drivers had a chance to clean up.

  - fixes minor bugs (unreported) in the affected code:
      * byteswap problem when unlinking urbs ... symptom would
        be data toggle confusion (since 2.4.2x) on big-endian cpus
      * latent bug if folk unlinked queue in LIFO order, not FIFO

  - removes unnecessary debug code; mostly de-BUG()ged

The interesting fix is the "leave queues halted" one.  As
discussed on email a while back, this HCD fault handling
policy (also followed by EHCI) is sufficient to let device
drivers implement the two key fault handling policies that
seem to be necessary:

    (a) Datagram style, where issues on one I/O won't affect
        the next unless the device halted the endpoint.  The
        device driver can ignore most errors other than -EPIPE.

    (b) Stream style, where for example it'd be wrong to ever
        let block N+1 overwrite block N on the disk.  Once
        the first URB fails, the rest would just be unlinked
        in the completion handler.

As a consequence of using the td_list, you can now see urb
queuing in action in the driverfs 'async' file.  At least, if
you look at the right time, or use drivers (networking, etc)
that queue (bulk) reads for a long time.

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

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

Convert the VM to not wait on other people's dirty data.

 - If we find a dirty page and its queue is not congested, do some writeback.

 - If we find a dirty page and its queue _is_ congested then just
   refile the page.

 - If we find a PageWriteback page then just refile the page.

 - There is additional throttling for write(2) callers.  Within
   generic_file_write(), record their backing queue in ->current.
   Within page reclaim, if this tasks encounters a page which is dirty
   or under writeback onthis queue, block on it.  This gives some more
   writer throttling and reduces the page refiling frequency.

It's somewhat CPU expensive - under really heavy load we only get a 50%
reclaim rate in pages coming off the tail of the LRU.  This can be
fixed by splitting the inactive list into reclaimable and
non-reclaimable lists.  But the CPU load isn't too bad, and latency is
much, much more important in these situations.

Example: with `mem=512m', running 4 instances of `dbench 100', 2.5.34
took 35 minutes to compile a kernel.  With this patch, it took three
minutes, 45 seconds.

I haven't done swapcache or MAP_SHARED pages yet.  If there's tons of
dirty swapcache or mmap data around we still stall heavily in page
reclaim.  That's less important.

This patch also has a tweak for swapless machines: don't even bother
bringing anon pages onto the inactive list if there is no swap online.

The key concept here is that pdflush does not block on request queues
any more.  Instead, it circulates across the queues, keeping any
non-congested queues full of write data.  When all queues are full,
pdflush takes a nap, to be woken when *any* queue exits write
congestion.

This code can keep sixty spindles saturated - we've never been able to
do that before.

 - Add the `nonblocking' flag to struct writeback_control, and teach
   the writeback paths to honour it.

 - Add the `encountered_congestion' flag to struct writeback_control
   and teach the writeback paths to set it.

So as soon as a mapping's backing_dev_info indicates that it is getting
congested, bale out of writeback.  And don't even start writeback
against filesystems whose queues are congested.

 - Convert pdflush's background_writeback() function to use
   nonblocking writeback.

This way, a single pdflush thread will circulate around all the
dirty queues, keeping them filled.

 - Convert the pdlfush `kupdate' function to do the same thing.

This solves the problem of pdflush thread pool exhaustion.

It solves the problem of pdflush startup latency.

It solves the (minor) problem wherein `kupdate' writeback only writes
back a single disk at a time (it was getting blocked on each queue in
turn).

It probably means that we only ever need a single pdflush thread.

Use the new queue congestion detector in ext2_preread_inode().  Don't
try the speculative read if the read queue is congested.

Also, don't try it if the disk is write-congested.  Presumably it is
more important to get the dirty memory cleaned out.

The patch provides a means for the VM to be able to determine whether a
request queue is in a "congested" state.  If it is congested, then a
write to (or read from) the queue may cause blockage in
get_request_wait().

So the VM can do:

	if (!bdi_write_congested(page->mapping->backing_dev_info))
		writepage(page);

This is not exact.  The code assumes that if the request queue still
has 1/4 of its capacity (queue_nr_requests) available then a request
will be non-blocking.  There is a small chance that another CPU could
zoom in and consume those requests.  But on the rare occasions where
that may happen the result will mereley be some unexpected latency -
it's not worth doing anything elaborate to prevent this.

The patch decreases the size of `batch_requests'.  batch_requests is
positively harmful - when a "heavy" writer and a "light" writer are
both writing to the same queue, batch_requests provides a means for the
heavy writer to massively stall the light writer.  Instead of waiting
for one or two requests to come free, the light writer has to wait for
32 requests to complete.

Plus batch_requests generally makes things harder to tune, understand
and predict.  I wanted to kill it altogether, but Jens says that it is
important for some hardware - it allows decent size requests to be
submitted.

The VM changes which go along with this code cause batch_requests to be
not so painful anyway - the only processes which sleep in
get_request_wait() are the ones which we elect, by design, to wait in
there - typically heavy writers.


The patch changes the meaning of `queue_nr_requests'.  It used to mean
"total number of requests per queue".  Half of these are for reads, and
half are for writes.  This always confused the heck out of me, and the
code needs to divide queue_nr_requests by two all over the place.

So queue_nr_requests now means "the number of write requests per queue"
and "the number of read requests per queue".  ie: I halved it.

Also, queue_nr_requests was converted to static scope.  Nothing else
uses it.


The accuracy of bdi_read_congested() and bdi_write_congested() depends
upon the accuracy of mapping->backing_dev_info.  With complex block
stacking arrangements it is possible that ->backing_dev_info is
pointing at the wrong queue.  I don't know.

But the cost of getting this wrong is merely latency, and if it is a
problem we can fix it up in the block layer, by getting stacking
devices to communicate their congestion state upwards in some manner.

__set_page_dirty_buffers() is calling __mark_inode_dirty under
mapping->private_lock.

We don't need to hold ->private_lock across that call.  It's only there
to pin page->buffers.

This simplifies the VM locking heirarchy.

When I converted ext3 to use to use direct-to-BIO writeback for
data=writeback mode I forgot that we need to hold a transaction open on
behalf of MAP_SHARED pages.  The fileystem is BUGging in get_block()
because there is no transaction open.

So let's forget that idea for now and send data=writeback mode back to
ext3_writepage.

into nuts.ninka.net:/home/davem/src/BK/sparc-2.5

into nuts.ninka.net:/home/davem/src/BK/net-2.5

into nuts.ninka.net:/home/davem/src/BK/net-2.5

Slowly killing the ugly struct forest.

With this llc_ui_sockets is almost not needed anymore, next
changesets will deal with the dataunit/xid/test primitives, that
are still using it.

It is the same bug fixed some months ago in tcp_v6_get_port,
i.e. we can't touch ipv6 private areas without checking if
the socket is AF_INET6.

into nuts.ninka.net:/home/davem/src/BK/net-2.5

it is an ex-parrot

assorted compile fixes

mtdblock switched to use of gendisks + compile fixes

z2ram.c switched to use of gendisks

ataflop.c switched to use of gendisks

amiflop.c switched to use of gendisks

macroectomy a-la pf.c and pcd.c ones, ditto for passing pointers to
structures instead of minors.

pd.c fed through Lindent

dumb expansion of macro - it had #define CURRENT current_req

tapeblock never assignes anything to its elements of blk_size[][]; we could
not bother allocating it in the first place.

More trivial fixes: typos in partitions/check.c, block/floppy.c and
acorn/block/fd1772.c + replacement of #define with inline in block/floppy.c
(fd_eject()).

Some trivial fixes for some typos introduced by Al's gendisk changes..

 - missing comma in cdu31a
 - missing semicolon in cdu31a
 - comma instead of colon in gscd
 - semicolon instead of comma in mcd
 - missing closing bracket in sonycd535

From Andries.