Both unionfs and memcgroups pose challenges to tmpfs and shmem.  To help fix,
it's best to move the swap swizzling functions from swap_state.c to shmem.c.
As a preliminary to that, move swap stats updating down into
__add_to_swap_cache, which will remain internal to swap_state.c.

Well, actually, just move down the incrementation of add_total: remove
noent_race and exist_race completely, they are relics of my 2.4.11 testing.
Alt-SysRq-m users will be thrilled if 2.6.25 is at last free of "race M+N"s.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When tmpfs is mounted with a size less than one page, the number of blocks
is set to 0 which makes the tmpfs mount unlimited.  This can lead to a
quick and surprising death if someone typos a tmpfs mount command and
writes too much.

tmpfs can still be mounted as unlimited if size or nr_blocks is exactly 0,
as Documentation/filesystems/tmpfs.txt says.

Hugh: do this by rounding size up instead of down in all cases: which
slightly expands other odd-sized tmpfs mounts, but in a consistent way.
Signed-off-by: NMichael Marineau <mike@marineau.org>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The shmem_sb_info structure has a number of free_inodes. This
value is altered in appropriate places under spinlock and with
the sbi->max_inodes != 0 check.

Consolidate these manipulations into two helpers.

This is minus 42 bytes of shmem.o and minus 4 :) lines of code.

[akpm@linux-foundation.org: fix error return values]
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provided that CONFIG_HIGHPTE is not set, unuse_pte_range can reduce latency
in swapoff by scanning the page table preemptibly: so long as unuse_pte is
careful to recheck that entry under pte lock.

(To tell the truth, this patch was not inspired by any cries for lower
latency here: rather, this restructuring permits a future memory controller
patch to allocate with GFP_KERNEL in unuse_pte, where before it could not.
But it would be wrong to tuck this change away inside a memcgroup patch.)
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

valid_swaphandles is supposed to do a quick pass over the swap map entries
neigbouring the entry which swapin_readahead is targetting, to determine for
it a range worth reading all together.  But since it always starts its search
from the beginning of the swap "cluster", a reject (free entry) there
immediately curtails the readaround, and every swapin_readahead from that
cluster is for just a single page.  Instead scan forwards and backwards around
the target entry.

Use better names for some variables: a swap_info pointer is usually called
"si" not "swapdev".  And at the end, if only the target page should be read,
return count of 0 to disable readaround, to avoid the unnecessarily repeated
call to read_swap_cache_async.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@surriel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the old aops, writing to a tmpfs file had to use its own special method:
the generic method would pass in a fresh page to prepare_write when the right
page was there in swapcache - which was inefficient to handle, even once we'd
concocted the code to handle it.

With the new aops, the generic method uses shmem_write_end, which lets
shmem_getpage find the right page: so now abandon shmem_file_write in favour
of the generic method.  Yes, that does do several things that tmpfs hasn't
really needed (notably balance_dirty_pages_ratelimited, which ramfs also
calls); but more use of common code is preferable.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In the new aops, write_begin is supposed to return the page locked: though
I've seen no ill effects, that's been overlooked in the case of
shmem_write_begin, and should be fixed.  Then shmem_write_end must unlock the
page: do so _after_ updating i_size, as we found to be important in other
filesystems (though since shmem pages don't go the usual writeback route, they
never suffered from that corruption).

For shmem_write_begin to return the page locked, we need shmem_getpage to
return the page locked in SGP_WRITE case as well as SGP_CACHE case: let's
simplify the interface and return it locked even when SGP_READ.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove SGP_QUICK from the sgp_type enum: it was for shmem_populate and has no
users now.  Remove SGP_FAULT from the enum: SGP_CACHE does just as well (and
shmem_getpage is about to return with page always locked).
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Building in a filesystem on a loop device on a tmpfs file can hang when
swapping, the loop thread caught in that infamous throttle_vm_writeout.

In theory this is a long standing problem, which I've either never seen in
practice, or long ago suppressed the recollection, after discounting my load
and my tmpfs size as unrealistically high.  But now, with the new aops, it has
become easy to hang on one machine.

Loop used to grab_cache_page before the old prepare_write to tmpfs, which
seems to have been enough to free up some memory for any swapin needed; but
the new write_begin lets tmpfs find or allocate the page (much nicer, since
grab_cache_page missed tmpfs pages in swapcache).

When allocating a fresh page, tmpfs respects loop's mapping_gfp_mask, which
has __GFP_IO|__GFP_FS stripped off, and throttle_vm_writeout is designed to
break out when __GFP_IO or GFP_FS is unset; but when tmfps swaps in,
read_swap_cache_async allocates with GFP_HIGHUSER_MOVABLE regardless of the
mapping_gfp_mask - hence the hang.

So, pass gfp_mask down the line from shmem_getpage to shmem_swapin to
swapin_readahead to read_swap_cache_async to add_to_swap_cache.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

swapin_readahead has never sat well in mm/memory.c: move it to mm/swap_state.c
beside its kindred read_swap_cache_async.  Why were its args in a different
order?  rearrange them.  And since it was always followed by a
read_swap_cache_async of the target page, fold that in and return struct
page*.  Then CONFIG_SWAP=n no longer needs valid_swaphandles and
read_swap_cache_async stubs.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For three years swapin_readahead has been cluttered with fanciful CONFIG_NUMA
code, advancing addr, and stepping on to the next vma at the boundary, to line
up the mempolicy for each page allocation.

It _might_ be a good idea to allocate swap more according to vma layout; but
the fact is, that's not how we do it at all, 2.6 even less than 2.4: swap is
allocated as needed for pages as they sink to the bottom of the inactive LRUs.
 Sometimes that may match vma layout, but not so often that it's worth going
to these misleading vma->vm_next lengths: rip all that out.

Originally I intended to retain the incrementation of addr, but correct its
initial value: valid_swaphandles generally supplies an offset below the target
addr (this is readaround rather than readahead), but addr has not been
adjusted accordingly, so in the interleave case it has usually been allocating
the target page from the "wrong" node (though that may not matter very much).

But look at the equivalent shmem_swapin code: either by oversight or by
design, though it has all the apparatus for choosing a new mempolicy per page,
it uses the same idx throughout, choosing the same mempolicy and interleave
node for each page of the cluster.

Which is actually a much better strategy: each node has its own LRUs and its
own kswapd, so if you're betting on any particular relationship between swap
and node, the best bet is that nearby swap entries belong to pages from the
same node - even when the mempolicy of the target page is to interleave.  And
examining a map of nodes corresponding to swap entries on a numa=fake system
bears this out.  (We could later tweak swap allocation to make it even more
likely, but this patch is merely about removing cruft.)

So, neither adjust nor increment addr in swapin_readahead, and then
shmem_swapin can use it too; the pseudo-vma to pass policy need only be set up
once per cluster, and so few fields of pvma are used, let's skip the memset -
from shmem_alloc_page also.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allow sticky directory mount option for hugetlbfs.  This allows admin
to create a shared hugetlbfs mount point for multiple users, while
prevent accidental file deletion that users may step on each other.
It is similiar to default tmpfs mount option, or typical option used
on /tmp.
Signed-off-by: NKen Chen <kenchen@google.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <hermes@gibson.dropbear.id.au>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The constructor for buffer_head slabs was removed recently.  We need the
constructor back in slab defrag in order to insure that slab objects always
have a definite state even before we allocated them.

I think we mistakenly merged the removal of the constuctor into a cleanup
patch.  You (ie: akpm) had a test that showed that the removal of the
constructor led to a small regression.  The prior state makes things easier
for slab defrag.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Both slab defrag and the large blocksize patches need to ability to take
refcounts on compound pages.  May be useful in other places as well.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The page array is repeatedly indexed both in vunmap and vmalloc_area_node().
Add a temporary variable to make it easier to read (and easier to patch
later).
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Checking if an address is a vmalloc address is done in a couple of places.
Define a common version in mm.h and replace the other checks.

Again the include structures suck.  The definition of VMALLOC_START and
VMALLOC_END is not available in vmalloc.h since highmem.c cannot be included
there.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pgtable.h does not include highmem.h but uses various constants from
highmem.h.  We cannot include highmem.h because highmem.h will in turn include
many other include files that also depend on pgtable.h

So move the definitions from highmem.h into pgtable.h.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make vmalloc functions work the same way as kfree() and friends that
take a const void * argument.

[akpm@linux-foundation.org: fix consts, coding-style]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We already have page table manipulation for vmalloc in vmalloc.c. Move the
vmalloc_to_page() function there as well.

Move the definitions for vmalloc related functions in mm.h to a newly created
section.  A better place would be vmalloc.h but mm.h is basic and may depend
on these functions.  An alternative would be to include vmalloc.h in mm.h
(like done for vmstat.h).
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Simplify page cache zeroing of segments of pages through 3 functions

zero_user_segments(page, start1, end1, start2, end2)

        Zeros two segments of the page. It takes the position where to
        start and end the zeroing which avoids length calculations and
	makes code clearer.

zero_user_segment(page, start, end)

        Same for a single segment.

zero_user(page, start, length)

        Length variant for the case where we know the length.

We remove the zero_user_page macro. Issues:

1. Its a macro. Inline functions are preferable.

2. The KM_USER0 macro is only defined for HIGHMEM.

   Having to treat this special case everywhere makes the
   code needlessly complex. The parameter for zeroing is always
   KM_USER0 except in one single case that we open code.

Avoiding KM_USER0 makes a lot of code not having to be dealing
with the special casing for HIGHMEM anymore. Dealing with
kmap is only necessary for HIGHMEM configurations. In those
configurations we use KM_USER0 like we do for a series of other
functions defined in highmem.h.

Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
function could not be a macro. zero_user_* functions introduced
here can be be inline because that constant is not used when these
functions are called.

Also extract the flushing of the caches to be outside of the kmap.

[akpm@linux-foundation.org: fix nfs and ntfs build]
[akpm@linux-foundation.org: fix ntfs build some more]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Teach AVR32 to use the "GPIO Library" when exposing its GPIOs, so that signals
on external chips (like GPIO expanders) can easily be used.

This mostly reorganizes some existing logic, with two minor changes in
behavior:

 - The PSR registers are used instead of the previous "gpio_mask" values,
   matching AT91 behavior and removing some duplication between that role
   and that of "pinmux_mask".

 - NR_IRQs grew to acommodate a bank of external GPIOs.  Eventually this
   number should probably become a board-specific config option.

There's a debugfs dump of status for the built-in GPIOs, showing which pins
have deglitching, pullups, or open drain drive enabled, as well as the ID
string used when requesting each IRQ.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use drivers/gpio/pca9539.c instead.
Signed-off-by: Neric miao <eric.miao@marvell.com>
Acked-by: NBen Gardner <bgardner@wabtec.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds a new-style I2C driver with basic support for the sixteen bit
PCA9539 GPIO expanders.  These chips have multiple registers, push-pull output
drivers, and (not supported in this patch) pin change interrupts.

Board-specific code must provide "pca9539_platform_data" with each chip's
"i2c_board_info".  That provides the GPIO numbers to be used by that chip, and
callbacks for board-specific setup/teardown logic.

Derived from drivers/i2c/chips/pca9539.c (which has no current known users).
This is faster and simpler; it uses 16-bit register access, and cache the
OUTPUT and DIRECTION registers for fast access
Signed-off-by: Neric miao <eric.miao@marvell.com>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NJean Delvare <khali@linux-fr.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Basic driver for 8-bit SPI based MCP23S08 GPIO expander, without support for
IRQs or the shared chipselect mechanism.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a new-style I2C driver for most common 8 and 16 bit I2C based
"quasi-bidirectional" GPIO expanders: pcf8574 or pcf8575, and several
compatible models (mostly faster, supporting I2C at up to 1 MHz).

The driver exposes the GPIO signals using the platform-neutral GPIO
programming interface, so they are easily accessed by other kernel code.  The
lack of such a flexible kernel API has been a big factor in the proliferation
of board-specific drivers for these chips...  stuff that rarely makes it
upstream since it's so ugly.  This driver will let such boards use standard
calls.

Since it's a new-style driver, these devices must be configured as part of
board-specific init.  That eliminates the need for error-prone manual
configuration of module parameters, and makes compatibility with legacy
drivers (pcf8574.c, pc8575.c) for these chips easier (there's a clear
either/or disjunction).
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NJean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds gpiolib support for the PXA architecture:
  - move all GPIO API functions from generic.c into gpio.c
  - convert the gpio_get/set_value macros into inline functions

This makes it easier to hook up GPIOs provided by external chips like
ASICs and CPLDs.
Signed-off-by: NPhilipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
[ Minor ARM fixup from David Brownell folded into this ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update Documentation/gpio.txt, primarily to include the new "gpiolib"
infrastructure.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide new implementation infrastructure that platforms may choose to use
when implementing the GPIO programming interface.  Platforms can update their
GPIO support to use this.  In many cases the incremental cost to access a
non-inlined GPIO should be less than a dozen instructions, with the memory
cost being about a page (total) of extra data and code.  The upside is:

  * Providing two features which were "want to have (but OK to defer)" when
    GPIO interfaces were first discussed in November 2006:

    -	A "struct gpio_chip" to plug in GPIOs that aren't directly supported
	by SOC platforms, but come from FPGAs or other multifunction devices
	using conventional device registers (like UCB-1x00 or SM501 GPIOs,
	and southbridges in PCs with more open specs than usual).

    -	Full support for message-based GPIO expanders, where registers are
	accessed through sleeping I/O calls.  Previous support for these
	"cansleep" calls was just stubs.  (One example: the widely used
	pcf8574 I2C chips, with 8 GPIOs each.)

  * Including a non-stub implementation of the gpio_{request,free}() calls,
    making those calls much more useful.  The diagnostic labels are also
    recorded given DEBUG_FS, so /sys/kernel/debug/gpio can show a snapshot
    of all GPIOs known to this infrastructure.

The driver programming interfaces introduced in 2.6.21 do not change at all;
this infrastructure is entirely below those covers.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add an empty drivers/gpio directory for gpiolib infrastructure and GPIO
expanders.  It will be populated by later patches.

This won't be the only place to hold such gpio_chip code.  Many external chips
add a few GPIOs as secondary functionality (such as MFD drivers) and platform
code frequently needs to closely integrate GPIO and IRQ support.

This is placed *early* in the build/link sequence since it's common for other
drivers to depend on GPIOs to do their work, so they must be initialized early
in the device_initcall() sequence.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NJean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a one-line patch to add the following to __scsi_alloc_queue():

dma_set_seg_boundary(dev, shost->dma_boundary);

This is the simplest approach but the result looks odd,
__scsi_alloc_queue() does:

blk_queue_segment_boundary(q, shost->dma_boundary);
dma_set_seg_boundary(dev, shost->dma_boundary);
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));

I think that it would be better to set up segment boundary in the same
way as we did for the maximum segment size. That is, removing
shost->dma_boundary and LLDs call pci_set_dma_seg_boundary (or its
friends).

Then __scsi_alloc_queue() can set up both limits in the same way:

blk_queue_segment_boundary(q, dma_get_seg_boundary(dev));
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));

killing dma_boundary in scsi_host_template needs a large patch for
libata (dma_boundary is used by only libata and sym53c8xx). I'll send
a patch to do that if it is acceptable. James and Jeff?
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes swiotlb not allocate a memory area spanning LLD's segment
boundary.

is_span_boundary() judges whether a memory area spans LLD's segment boundary.
If map_single finds such a area, map_single tries to find the next available
memory area.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds PCI's accessor for segment_boundary_mask in device_dma_parameters.

The default segment_boundary is set to 0xffffffff, same to the block layer's
default value (and the scsi mid layer uses the same value).
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds new accessors for segment_boundary_mask in device_dma_parameters
structure in the same way I did for max_segment_size.  So we can easily change
where to place struct device_dma_parameters in the future.

dma_get_segment boundary returns 0xffffffff if dma_parms in struct device
isn't set up properly.  0xffffffff is the default value used in the block
layer and the scsi mid layer.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This kills unused __clear_bit_string and find_next_zero_string (they
were used by only gart and calgary IOMMUs).
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Muli Ben-Yehuda <mulix@mulix.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch converts gart IOMMU to use the IOMMU helper functions. The
IOMMU doesn't allocate a memory area spanning LLD's segment boundary
anymore.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Muli Ben-Yehuda <mulix@mulix.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch converts calgary IOMMU to use the IOMMU helper
functions. The IOMMU doesn't allocate a memory area spanning LLD's
segment boundary anymore.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Muli Ben-Yehuda <mulix@mulix.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previously, during initialization of the IOMMU tables, the last entry
at each 4GB boundary is marked as used since there are many adapters
which cannot handle DMAing across any 4GB boundary.

The IOMMU doesn't allocate a memory area spanning LLD's segment
boundary anymore. The segment boundary of devices are set to 4GB by
default. So we can remove 4GB boundary protection now.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch converts PPC's IOMMU to use the IOMMU helper functions.  The IOMMU
doesn't allocate a memory area spanning LLD's segment boundary anymore.

iseries_hv_alloc and iseries_hv_map don't have proper device
struct. 4GB boundary is used for them.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds IOMMU helper functions for the free area management.  These
functions take care of LLD's segment boundary limit for IOMMUs.  They would be
useful for IOMMUs that use bitmap for the free area management.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This sets the segment size limit properly via pci_set_dma_max_seg_size
and remove blk_queue_max_segment_size because scsi-ml calls it.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Acked-by: N"Salyzyn, Mark" <mark_salyzyn@adaptec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>