Commit 7667aa06 added logic to wait for
the last queue of the group to become busy (have at least one request),
so that the group does not lose out for not being continuously
backlogged. The commit did not check for the condition that the last
queue already has some requests. As a result, if the queue already has
requests, wait_busy is set. Later on, cfq_select_queue() checks the
flag, and decides that since the queue has a request now and wait_busy
is set, the queue is expired.  This results in early expiration of the
queue.

This patch fixes the problem by adding a check to see if queue already
has requests. If it does, wait_busy is not set. As a result, time slices
do not expire early.

The queues with more than one request are usually buffered writers.
Testing shows improvement in isolation between buffered writers.

Cc: stable@kernel.org
Signed-off-by: NJustin TerAvest <teravest@google.com>
Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

o Jeff Moyer was doing some testing on a RAM backed disk and
  blkiocg_lookup_group() showed up high overhead after memcpy(). Similarly
  somebody else reported that blkiocg_lookup_group() is eating 6% extra
  cpu. Though looking at the code I can't think why the overhead of
  this function is so high. One thing is that it is called with very high
  frequency (once for every IO).

o For lot of folks blkio controller will be compiled in but they might
  not have actually created cgroups. Hence optimize the case of root
  cgroup where we can avoid calling blkiocg_lookup_group() if IO is happening
  in root group (common case).
Reported-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

o Rename a function to give it more approprate name. We are calculating
  cfq queue slice and function name gives the impression as if cfq group
  slice length is being calculated.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Signed-off-by: NStephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Change Makefile to use <modules>-y instead of <modules>-objs because -objs
is deprecated and should now be switched.  According to
(documentation/kbuild/makefiles.txt).
Signed-off-by: NTracey Dent <tdent48227@gmail.com>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Performing
$ sudo mount -o loop -o umask=0 /dev/sdb1 /mnt/
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

$ sudo modprobe -r loop

results in oops:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
 IP: [<ffffffff812479d4>] do_raw_spin_lock+0x14/0x122
 Process modprobe (pid: 6189, threadinfo ffff88009a898000, task ffff880154a88000)
 Call Trace:
  [<ffffffff81486788>] _raw_spin_lock_irq+0x4a/0x51
  [<ffffffff8123404b>] ? blk_throtl_exit+0x3b/0xa0
  [<ffffffff8105b120>] ? cancel_delayed_work_sync+0xd/0xf
  [<ffffffff8123404b>] blk_throtl_exit+0x3b/0xa0
  [<ffffffff81229bc8>] blk_release_queue+0x21/0x65
  [<ffffffff8123bb06>] kobject_release+0x51/0x66
  [<ffffffff8123bab5>] ? kobject_release+0x0/0x66
  [<ffffffff8123ce1e>] kref_put+0x43/0x4d
  [<ffffffff8123ba27>] kobject_put+0x47/0x4b
  [<ffffffff8122717c>] blk_cleanup_queue+0x56/0x5b
  [<ffffffffa01c3824>] loop_exit+0x68/0x844 [loop]
  [<ffffffff8107cccc>] sys_delete_module+0x1e8/0x25b
  [<ffffffff814864c9>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81002112>] system_call_fastpath+0x16/0x1b

because of an attempt to acquire NULL queue_lock.
I added the same lines as in blk_queue_make_request -
index 44e18c0..49e6a54 100644`fall back to embedded per-queue lock'.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Change Makefile to use <modules>-y instead of <modules>-objs because -objs
is deprecated and should now be switched.  According to
(documentation/kbuild/makefiles.txt).
Signed-off-by: NTracey Dent <tdent48227@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Now if we enable blktrace, cfq has too many messages output to the
trace buffer. It is fine if we don't specify any action mask.
But if I do like this:
blktrace /dev/sdb -a issue -a complete -o - | blkparse -i -
I only want to see 'D' and 'C', while with the following command
dd if=/mnt/ocfs2/test of=/dev/null bs=4k count=1 iflag=direct

I will get(with a 2.6.37 vanilla kernel):
  8,16   0        0     0.000000000     0  m   N cfq3805 alloced
  8,16   0        0     0.000004126     0  m   N cfq3805 insert_request
  8,16   0        0     0.000004884     0  m   N cfq3805 add_to_rr
  8,16   0        0     0.000008417     0  m   N cfq workload slice:300
  8,16   0        0     0.000009557     0  m   N cfq3805 set_active wl_prio:0 wl_type:2
  8,16   0        0     0.000010640     0  m   N cfq3805 fifo=          (null)
  8,16   0        0     0.000011193     0  m   N cfq3805 dispatch_insert
  8,16   0        0     0.000012221     0  m   N cfq3805 dispatched a request
  8,16   0        0     0.000012802     0  m   N cfq3805 activate rq, drv=1
  8,16   0        1     0.000013181  3805  D   R 114759 + 8 [dd]
  8,16   0        2     0.000164244     0  C   R 114759 + 8 [0]
  8,16   0        0     0.000167997     0  m   N cfq3805 complete rqnoidle 0
  8,16   0        0     0.000168782     0  m   N cfq3805 set_slice=100
  8,16   0        0     0.000169874     0  m   N cfq3805 arm_idle: 8 group_idle: 0
  8,16   0        0     0.000170189     0  m   N cfq schedule dispatch
  8,16   0        0     0.000397938     0  m   N cfq3805 slice expired t=0
  8,16   0        0     0.000399763     0  m   N cfq3805 sl_used=1 disp=1 charge=1 iops=0 sect=8
  8,16   0        0     0.000400227     0  m   N cfq3805 del_from_rr
  8,16   0        0     0.000400882     0  m   N cfq3805 put_queue

See, there are 19 lines while I only need 2. I don't think it is
appropriate for a user.

So this patch will disable any messages if the BLK_TC_NOTIFY isn't set.
Now the output for the same command will look like:
  8,16   0        1     0.000000000  4908  D   R 114759 + 8 [dd]
  8,16   0        2     0.000146827     0  C   R 114759 + 8 [0]

Yes, it is what I want to see.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: NTao Ma <boyu.mt@taobao.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: (lm93) Add support for LM94

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Validate cpu early in perf_event_alloc()
  perf: Find_get_context: fix the per-cpu-counter check
  perf: Fix contexted inheritance

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Clear irqstack thread_info
  x86: Make relocatable kernel work with new binutils

* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus: (26 commits)
  MIPS: Malta: enable Cirrus FB console
  MIPS: add CONFIG_VIRTUALIZATION for virtio support
  MIPS: Implement __read_mostly
  MIPS: ath79: add common WMAC device for AR913X based boards
  MIPS: ath79: Add initial support for the Atheros AP81 reference board
  MIPS: ath79: add common SPI controller device
  SPI: Add SPI controller driver for the Atheros AR71XX/AR724X/AR913X SoCs
  MIPS: ath79: add common GPIO buttons device
  MIPS: ath79: add common watchdog device
  MIPS: ath79: add common GPIO LEDs device
  MIPS: ath79: add initial support for the Atheros PB44 reference board
  MIPS: ath79: utilize the MIPS multi-machine support
  MIPS: ath79: add GPIOLIB support
  MIPS: Add initial support for the Atheros AR71XX/AR724X/AR931X SoCs
  MIPS: jump label: Add MIPS support.
  MIPS: Use WARN() in uasm for better diagnostics.
  MIPS: Optimize TLB handlers for Octeon CPUs
  MIPS: Add LDX and LWX instructions to uasm.
  MIPS: Use BBIT instructions in TLB handlers
  MIPS: Declare uasm bbit0 and bbit1 functions.
  ...

This patch adds basic support for LM94 to the LM93 driver. LM94 specific
sensors and features are not supported.
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>
Acked-by: NJean Delvare <khali@linux-fr.org>

Starting from perf_event_alloc()->perf_init_event(), the kernel
assumes that event->cpu is either -1 or the valid CPU number.

Change perf_event_alloc() to validate this argument early. This
also means we can remove the similar check in
find_get_context().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: gregkh@suse.de
Cc: stable@kernel.org
LKML-Reference: <20110118161032.GC693@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If task == NULL, find_get_context() should always check that cpu
is correct.

Afaics, the bug was introduced by 38a81da2 "perf events: Clean
up pid passing", but even before that commit "&& cpu != -1" was
not exactly right, -ESRCH from find_task_by_vpid() is not
accurate.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: gregkh@suse.de
Cc: stable@kernel.org
LKML-Reference: <20110118161008.GB693@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

While most users of a physical Malta board are using the serial port
as the console, a lot of QEMU users would prefer to interact with a
graphical console. Enable the Cirrus FB support in the Malta default
configuration to make that possible. Note that the default console will
still be the serial port, users have to pass "console=tty0" to the
kernel to use the Cirrus FB.
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2001/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add CONFIG_VIRTUALIZATION to the MIPS architecture and include the
the virtio code there. Used to enable the virtio drivers under QEMU.
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2002/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Just do what everyone else is doing by placing __read_mostly things in
the .data.read_mostly section.

mips_io_port_base can not be read-only (const) and writable
(__read_mostly) at the same time.  One of them has to go, so I chose
to eliminate the __read_mostly.  It will still get stuck in a portion
of memory that is not adjacent to things that are written, and thus
not be on a dirty cache line, for whatever that is worth.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/1702/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add common platform_device and helper code to make the registration
of the built-in wireless MAC easier on the Atheros AR9130/AR9132
based boards. Also register the WMAC device on the AR81 board.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Imre Kaloz <kaloz@openwrt.org>,
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1962/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1952/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Several boards are using the built-in SPI controller of the
AR71XX/AR724X/AR913X SoCs. This patch adds common platform_device
and helper code to register it. Additionally, the patch registers
the SPI bus on the PB44 board.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1956/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The Atheros AR71XX/AR724X/AR913X SoCs have a built-in SPI controller. This
patch implements a driver for that.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: spi-devel-general@lists.sourceforge.net
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: linux-mips@linux-mips.org
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1960/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Almost all boards have one or more push buttons connected to GPIO lines.
This patch adds common code to register a platform_device for them.

The patch also adds support for the buttons on the PB44 board.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1954/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

All supported SoCs have a built-in hardware watchdog driver. This patch
registers a platform_device for that to make it usable.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1955/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Almost all boards have one or more LEDs connected to GPIO lines. This
patch adds common code to register a platform_device for them.

The patch also adds support for the LEDs on the PB44 board.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1953/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1950/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1949/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch implements generic GPIO routines for the built-in
GPIO controllers of the Atheros AR71XX/AR724X/AR913X SoCs.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1948/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch adds initial support for various Atheros SoCs based on the
MIPS 24Kc core. The following models are supported at the moment:

  - AR7130
  - AR7141
  - AR7161
  - AR9130
  - AR9132
  - AR7240
  - AR7241
  - AR7242

The current patch contains minimal support only, but the resulting
kernel can boot into user-space with using of an initramfs image on
various boards which are using these SoCs. Support for more built-in
devices and individual boards will be implemented in further patches.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NImre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1947/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

In order not to be left behind, we add jump label support for MIPS.

Tested on 64-bit big endian (Octeon), and 32-bit little endian
(malta/qemu).
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Patchwork: https://patchwork.linux-mips.org/patch/1923/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

On the off chance that uasm ever warns about overflow, there is no way
to know what the offending instruction is.

Change the printks to WARNs, so we can get a nice stack trace.  It has
the added benefit of being much more noticeable than the short single
line warning message, so is less likely to be ignored.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1905/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Octeon can use scratch registers in the TLB handlers.  Octeon II can
use LDX instructions.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1904/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Needed by Octeon II optimized TLB handlers.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Pachwork: https://patchwork.linux-mips.org/patch/1903/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

If the CPU supports BBIT0 and BBIT1, use them in TLB handlers as they
are more efficient than an AND followed by an branch and then
restoring the clobbered register.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1873/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

these are already defined, but declaring them allow them to be used
outside of uasm.c.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1872/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Decide at runtime to use either Context or KScratch to hold the PGD
pointer.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1876/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1875/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Probe c0_config4 for KScratch registers and report them in /proc/cpuinfo.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1877/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch adds a generic solution to support multiple machines based on
a given SoC within a single kernel image. It is implemented already for
several other architectures but MIPS has no generic support for that yet.

[Ralf: This competes with DT but DT is a much more complex solution and this
code has been used by OpenWRT for a long time so for now DT is a bad reason
to stop the merge but longer term this should be migrated to DT.]
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: kaloz@openwrt.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1814/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>