Convert cpu_to_beXX(beXX_to_cpu(E1) + E2) to use beXX_add_cpu().

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: NBob Copeland <me@bobcopeland.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If prepare_reply() succeeds we have allocated memory for 'rep_skb'.  If
nla_reserve() then subsequently fails and returns NULL we fail to release
the memory we allocated, thus causing a leak.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Because udev use is so widespread, making the old static mapping the
default is too conservative, given the severe limitations it places on
usable AoE addresses.  Storage virtualization and larger shelves have made
the old limitations too confining.

These changes make the dynamic block device minor numbers the default,
removing the limitations on usable AoE addresses.

The static arrangement is still available with aoe_dyndevs=0, and the
aoe-stat tool from the userland aoetools package, the user space
counterpart to the aoe driver, recognizes the case where there is a
mismatch between the minor number in sysfs and the minor number in a
special device file.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In general, specific is better when it comes to messages about AoE usage
problems.  Also, explicit checks for the AoE broadcast addresses are
added.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The old mapping between AoE target shelf and slot addresses and the block
device minor number is retained as a backwards-compatible feature, with a
new "aoe_dyndevs" module parameter available for enabling dynamic block
device minor numbers.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The ATA over Ethernet protocol uses a major (shelf) and minor (slot)
address to identify a particular storage target.  These changes remove an
artificial limitation the aoe driver imposes on the use of AoE addresses.
For example, without these changes, the slot address has a maximum of 15,
but users commonly use slot numbers much greater than that.

The AoE shelf and slot address space is often used sparsely.  Instead of
using a static mapping between AoE addresses and the block device minor
number, the block device minor numbers are now allocated on demand.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The old area has a new URL.  Also, now that the driver can perform better,
it is worth mentioning the VM settings that help aoe to sink dirty pages
out early, avoiding unecessary memory pressure when much I/O is going on.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The internal version number of the aoe driver appears in a console message
when the driver loads and is usually obtained by the user with the
userland aoe-version tool, part of the aoetools.[1]

Although this patchset includes bugfixes backported from higher-numbered
versions published on the coraid.com website, it is a form of version 49.

1. http://aoetools.sourceforge.net/Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This change removes some unused code and attempts to increase code
consistency.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This change eliminates the danger that the user could rmmod the driver for
a network interface that is being used for AoE by the aoe driver.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In the driver code, "target" and aoetgt refer to a particular remote
interface on the AoE storage target.  The latter is identified by its AoE
major and minor addresses.  Commands that are being sent to an AoE storage
target {major, minor} can be sent or retransmitted to any of the remote
MAC addresses associated with the AoE storage target.

That is, frames are naturally associated with not an aoetgt (AoE major,
AoE minor, remote MAC address) but an aoedev (AoE major, AoE minor).
Making the code reflect that reality simplifies the driver, especially
when the path to a remote MAC address becomes unusable.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A guard is inserted to prevent AoE minor addresses (slot addresses) higher
than 15 to be used, as they are not yet supported by the driver.

There is a change coming that will allow the aoe driver to overcome this
limit by using system device minor numbers dynamically, but until then,
this guard prevents unexpected targets from being used by the driver when
AoE targets with high minor numbers are on the AoE network.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The discovery process begins with an optional AoE config query command and
an AoE config query response.  Normally when an aoe device is already
open, the config query response does not trigger an ATA identify device
command to be sent out, since the response contains storage capacity
information that, if changed, could surprise the user of the device.

The userland "aoe-revalidate" tool uses a character device to trigger an
AoE config query for a particular AoE storage target and an ATA device
identify command, even when the device is open.

This change causes the config query to go out first, reflecting the normal
discovery sequence.  The responses could come back in any order, so this
change is fairly cosmetic.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The aoe_deadsecs module parameter allows the user to specify a hard limit
on the number of seconds an AoE command can be retransmitted before the
AoE block device is considered to have failed.

Using aoe_deadsecs to determine the time we try using a different remote
interface helps to ensure that the hard limit is not reached before we've
tried to recover by sending to a different remote port.

As a data storage target, the AoE target is unambiguously identified by
its {major, minor} AoE address tuple, and an AoE target can have multiple
MAC addresses.  However, note that "target" in the driver code and
comments means a {major, minor, MAC address} tuple, as in "somewhere to
send packets".
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Users with several network interfaces dedicated to AoE generally do not
configure them to support different-sized AoE data payloads on purpose.

For a given AoE target, there will be a set of local network interfaces
that can reach it.  Using only the payload that will fit in the
smallest-sized MTU of all those local interfaces greatly simplifies the
driver, especially in failure scenarios.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The dev_queue_xmit function needs to have interrupts enabled, so the most
simple way to get the locking right but still fulfill that requirement is
to use a process that can call dev_queue_xmit serially over queued
transmissions.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To allow users to choose an elevator algorithm for their particular
workloads, change from a make_request-style driver to an
I/O-request-queue-handler-style driver.

We have to do a couple of things that might be surprising.  We manipulate
the page _count directly on the assumption that we still have no guarantee
that users of the block layer are prohibited from submitting bios
containing pages with zero reference counts.[1] If such a prohibition now
exists, I can get rid of the _count manipulation.

Just as before this patch, we still keep track of the sk_buffs that the
network layer still hasn't finished yet and cap the resources we use with
a "pool" of skbs.[2]

Now that the block layer maintains the disk stats, the aoe driver's
diskstats function can go away.

1. https://lkml.org/lkml/2007/3/1/374
2. https://lkml.org/lkml/2007/7/6/241Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make the frames the aoe driver uses to track the relationship between bios
and packets more flexible and detached, so that they can be passed to an
"aoe_ktio" thread for completion of I/O.

The frames are handled much like skbs, with a capped amount of
preallocation so that real-world use cases are likely to run smoothly and
degenerate gracefully even under memory pressure.

Decoupling I/O completion from the receive path and serializing it in a
process makes it easier to think about the correctness of the locking in
the driver, especially in the case of a remote MAC address becoming
unusable.

[dan.carpenter@oracle.com: cleanup an allocation a bit]
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tAdd adds the ability to work with large packets composed of a number of
segments, using the scatter gather feature of the block layer (biovecs)
and the network layer (skb frag array).  The motivation is the performance
gained by using a packet data payload greater than a page size and by
using the network card's scatter gather feature.

Users of the out-of-tree aoe driver already had these changes, but since
early 2011, they have complained of increased memory utilization and
higher CPU utilization during heavy writes.[1] The commit below appears
related, as it disables scatter gather on non-IP protocols inside the
harmonize_features function, even when the NIC supports sg.

  commit f01a5236
  Author: Jesse Gross <jesse@nicira.com>
  Date:   Sun Jan 9 06:23:31 2011 +0000

      net offloading: Generalize netif_get_vlan_features().

With that regression in place, transmits always linearize sg AoE packets,
but in-kernel users did not have this patch.  Before 2.6.38, though, these
changes were working to allow sg to increase performance.

1. http://www.spinics.net/lists/linux-mm/msg15184.htmlSigned-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add discard support to nbd.  If the nbd-server supports discard, it will
send NBD_FLAG_SEND_TRIM to the client.  The client will then set the flag
in the kernel via NBD_SET_FLAGS, which tells the kernel to enable discards
for the device (QUEUE_FLAG_DISCARD).

If discard support is enabled, then when the nbd client system receives a
discard request, this will be passed along to the nbd-server.  When the
discard request is received by the nbd-server, it will perform:

	fallocate(.. FALLOC_FL_PUNCH_HOLE ..)

To punch a hole in the backend storage, which is no longer needed.
Signed-off-by: NPaul Clements <paul.clements@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a set-flags ioctl, allowing various option flags to be set on an nbd
device.  This allows the nbd-client to set the device flags (to enable
read-only mode, or enable discard support, etc.).

Flags are typically specified by the nbd-server.  During the negotiation
phase of the nbd connection, the server sends its flags to the client.
The client then uses NBD_SET_FLAGS to inform the kernel of the options.

Also included is a one-line fix to debug output for the set-timeout ioctl.
Signed-off-by: NPaul Clements <paul.clements@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the single global destination ID counter with per-net allocation
mechanism to allow independent destID management for each available
RapidIO network.  Using bitmap based mechanism instead of counters allows
destination ID release and reuse in systems that support hot-swap.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make RIONET driver multi-net safe/capable by introducing per-net lists of
RapidIO network peers.  Rework registration of network adapters to support
all available RIO master port devices.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Modify mport initialization routine to run the RapidIO discovery process
asynchronously.  This allows to have an arbitrary order of enumerating and
discovering ports in systems with multiple RapidIO controllers without
creating a deadlock situation if enumerator port is registered after a
discovering one.

Making netID matching to mportID ensures consistent net ID assignment in
multiport RapidIO systems with asynchronous discovery process (global
counter implementation is affected by race between threads).

[akpm@linux-foundation.org: tweak code layput]
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Modify handling of device lists to resolve issues caused by using single
global list of RIO devices during enumeration/discovery.  The most common
sign of existing issue is incorrect contents of switch routing tables in
systems with multiple mport controllers while single-port configuration
performs as expected.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following set of patches provides modifications targeting support of
multiple RapidIO master port (mport) devices on a CPU-side of
RapidIO-capable board.  While the RapidIO subsystem code has definitions
suitable for multi-controller/multi-net support, the existing
implementation cannot be considered ready for multiple mport
configurations.

=========== NOTES: =============

a) The patches below do not address RapidIO side view of multiport
   processing elements defined in Part 6 of RapidIO spec Rev.2.1 (section
   6.4.1).  These devices have Base Device ID CSR (0x60) and Component Tag
   CSR (0x6C) shared by all SRIO ports.  For example, Freescale's P4080,
   P3041 and P5020 have a dual-port SRIO controller implemented according
   the specification.  Enumeration/discovery of such devices from RapidIO
   side may require device-specific fixups.

b) Devices referenced above may also require implementation specific
   code to setup a host device ID for mport device.  These operations are
   not addressed by patches in this package.

=================================

Details about provided patches:

1. Fix blocking wait for discovery ready

   While it does not happen on PowerPC based platforms, there is
   possibility of stalled CPU warning dump on x86 based platforms that run
   RapidIO discovery process if they wait too long for being enumerated.

   Currently users can avoid it by disabling the soft-lockup detector
   using "nosoftlockup" kernel parameter OR by ensuring that enumeration
   is completed before soft-lockup is detected.

   This patch eliminates blocking wait and keeps a scheduler running.
   It also is required for patch 3 below which introduces asynchronous
   discovery process.

2. Use device lists handling on per-net basis

   This patch allows to correctly support multiple RapidIO nets and
   resolves possible issues caused by using single global list of devices
   during RapidIO system enumeration/discovery.  The most common sign of
   existing issue is incorrect contents of switch routing tables in
   systems with multiple mport controllers while single-port configuration
   performs as expected.

   The patch does not eliminate the global RapidIO device list but
   changes some routines in enumeration/discovery to use per-net device
   lists instead.  This way compatibility with upper layer RIO routines is
   preserved.

3.  Run discovery as an asynchronous process

   This patch modifies RapidIO initialization routine to asynchronously
   run the discovery process for each corresponding mport.  This allows
   having an arbitrary order of enumerating and discovering mports without
   creating a deadlock situation if an enumerator port was registered
   after a discovering one.

   On boards with multiple discovering mports it also eliminates order
   dependency between mports and may reduce total time of RapidIO
   subsystem initialization.

   Making netID matching to mportID ensures consistent netID assignment
   in multiport RapidIO systems with asynchronous discovery process
   (global counter implementation is affected by race between threads).

4. Rework RIONET to support multiple RIO master ports

   In the current version of the driver rionet_probe() has comment "XXX
   Make multi-net safe".  Now it is a good time to address this comment.

   This patch makes RIONET driver multi-net safe/capable by introducing
   per-net lists of RapidIO network peers.  It also enables to register
   network adapters for all available mport devices.

5. Add destination ID allocation mechanism

   The patch replaces a single global destination ID counter with
   per-net allocation mechanism to allow independent destID management for
   each available RapidIO network.  Using bitmap based mechanism instead
   of counters allows destination ID release and reuse in systems that
   support hot-swap.

This patch:

Fix blocking wait loop in the RapidIO discovery routine to avoid warning
dumps about stalled CPU on x86 platforms.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Apply port RX/TX enable operations only to active switch ports.

RapidIO specification (Part 6: LP-Serial Physical Layer) recommends to
keep Output Port Enable (TX) and Input Port Enable (RX) control bits in
disabled state (0b0) after device reset.  It also allows to have
implementation specific reset state for these bits.

This patch ensures that TX/RX enable action is applied only to active
switch's ports while preserving an initial state of inactive ones.

This patch is intended to keep inactive switch ports with inbound and
outbound packet transfers disabled to block unexpected packets during hot
insertion event.  While it does not fix any visible malfunction it is
intended to prevent such events in future.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add Tsi721 routines to support RapidIO subsystem's inbound memory mapping
interface (RapidIO to system's local memory).
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add common inbound memory mapping/unmapping interface. This allows to make
local memory space accessible from the RapidIO side using hardware mapping
capabilities of RapidIO bridging devices. The new interface is intended to
enable data transfers between RapidIO devices in combination with DMA engine
support.

This patch is based on patch submitted by Li Yang <leoli@freescale.com>
(https://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/071210.html)
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert a nonnegative error return code to a negative one, as returned
elsewhere in the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// </smpl>
Signed-off-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Reported-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Cc: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Modify RapidIO mport device name assignment to include device name of PCIe
side of Tsi721 bridge.  The new name format is intended to provide
definitive reference between RapidIO and PCIe sides of the bridge in
systems with multiple Tsi721 bridges.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix multicast packet transmit logic to account for repetitive transmission
of single skb:
- correct check for available buffers (this bug may produce NULL pointer
  crash dump in case of heavy traffic);
- update skb user count (incorrect user counter causes a warning dump from
  net_tx_action routine during multicast transfers in systems with three or
  more rionet participants).
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The inclusion of <generated/utsrelease.h> is unnecessary.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This cleanup also fixes the following sparse warning:

  fs/proc/root.c:64:45: warning: Using plain integer as NULL pointer
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The use of if (!head) BUG(); can be replaced with the single line
BUG_ON(!head).
Signed-off-by: NPrasad Joshi <prasadjoshi.linux@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>