When smsc911x uses GPIO as the interrupt controller, and if both are
loaded as modules, we get following error:

"smsc911x: Could not allocate irq resource"

This issue is because of smsc911x using platform_get_resource to get
device tree based irq resource.

commit "9ec36caf

 (of/irq: do irq resolution in platform_get_irq)" and
commit "7085a7 (drivers: platform: parse IRQ flags from resources)" add
support in platform_get_irq to resolve irq and irq_flags respectively
for both modern device tree and legacy static platform data platforms.

Modify smsc911x driver to use platform_get_irq to pick up irq resource
correctly and use irq_get_trigger_type to get the IRQ trigger flags.

Signed-off-by: Kamlakant Patel <kamlakant.patel@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The code in __netdev_upper_dev_link() has an over-stringent
loop detection logic that actually prevents valid configurations
from working correctly.

In particular, the logic returns an error if an upper device
is already in the list of all upper devices for a given dev.
This particular check seems to be a overzealous as it disallows
perfectly valid configurations.  For example:
  # ip l a link eth0 name eth0.10 type vlan id 10
  # ip l a dev br0 typ bridge
  # ip l s eth0.10 master br0
  # ip l s eth0 master br0  <--- Will fail

If you switch the last two commands (add eth0 first), then both
will succeed.  If after that, you remove eth0 and try to re-add
it, it will fail!

It appears to be enough to simply check adj_list to keeps things
safe.

I've tried stacking multiple devices multiple times in all different
combinations, and either rx_handler registration prevented the stacking
of the device linking cought the error.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Veaceslav Falico <vfalico@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As German phone operators are discontinuing ISDN service, neither
Hansjörg nor I will be able to maintain the Gigaset ISDN drivers
any longer. Paul Bolle offered to step into the breach for odd
fixes.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Acked-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a macvlan device is placed in promiscuous mode, it currently
just sets it's multicast mask to permissive, but doesn't change
the state of the lower device.  As a result, not all multicast
traffic can be received on such device.  Additionally, none of
a vlan traffic can be received on such device as well.
This patch propagates the promiscuous mode setting to lower device
so that lower device may receive all packets that macvlan may
be interested in.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit c243d7e2

.

That patch is solving a non-existant problem while creating a
real problem.  Just because a socket is allocated in the init
name space doesn't mean that it gets hashed in the init name space.

When we unhash it the name space must be the same as the one
we had when we hashed it.  So this patch is completely bogus
and causes socket leaks.

Reported-by: Andrey Wagin <avagin@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alexander Duyck says:

====================
Clean-up some bits related to netpoll

This patch set cleans up some minor items related to netpoll.  The first
patch addresses an Rx clean-up bug that is triggered due to an assumption
that napi->poll wouldn't be called with a budget of 0.  The other two
patches address dev_kfree_skb being called in the xmit path which isn't
valid since netpoll will call ndo_start_xmit with IRQs disabled.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

With netpoll making use of the transmit function it is possible for the
ndo_start_xmit function to be called with irqs disabled.  As such we need
to use dev_kfree_skb_any in the Tx cleanup path for frames that are
dropped.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The function r8169_csum_workaround is called in the ndo_start_xmit path of
the r8169 driver.  As such it should not be using dev_kfree_skb as it is
not irq safe, so instead we should be using dev_kfree_skb_any for freeing
in the dropped path, and dev_consume_skb_any for any frames that were
transmitted.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The netpoll path will call napi->poll with a budget of 0 in order to clean
the Tx rings only.  This change updates the fm10k driver so that it will
correctly support that instead of cleaning 1 Rx frame if a budget of 0 is
received.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add the missing unregister for the mv88e6352_switch_driver.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'linux-can-fixes-for-4.1-20150501' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can



Marc Kleine-Budde says:

====================
this is a pull request of a single patch for net/master.

The patch is contributed by Jeppe Ledet-Pedersen, it fixes the
extended frame handling in the xilinx driver.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

This file is built off of a tristate Kconfig option and also contains
modular function calls so it should explicitly include module.h to
avoid compile breakage during header shuffles done in the future.

Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rdma_conn_param private data is copied using memcpy after headers such
as cma_hdr (see cma_resolve_ib_udp as example). so the start of the
private data is aligned to the end of the structure that come before. if
this structure end with u32 the meaning is that the start of the private
data will be 4 bytes aligned. structures that use u8/u16/u32/u64 are
naturally aligned but in case the structure start is not 8 bytes aligned,
all u64 members of this structure will not be aligned. to solve this issue
we must use special macros that allow unaligned access to those
unaligned members.

Addresses the following kernel log seen when attempting to use RDMA:

Kernel unaligned access at TPC[10507a88] rds_ib_cm_connect_complete+0x1bc/0x1e0 [rds_rdma]

Acked-by: Chien Yen <chien.yen@oracle.com>
Signed-off-by: shamir rabinovitch <shamir.rabinovitch@oracle.com>
[Minor tweaks for top of tree by:]
Signed-off-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We currently limit the hash table size to 64K which is very bad
as even 10 years ago it was relatively easy to generate millions
of sockets.

Since the hash table is naturally limited by memory allocation
failure, we don't really need an explicit limit so this patch
removes it.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Under presence of TSO/GSO/GRO packets, codel at low rates can be quite
useless. In following example, not a single packet was ever dropped,
while average delay in codel queue is ~100 ms !

qdisc codel 0: parent 1:12 limit 16000p target 5.0ms interval 100.0ms
 Sent 134376498 bytes 88797 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 13626b 3p requeues 0
  count 0 lastcount 0 ldelay 96.9ms drop_next 0us
  maxpacket 9084 ecn_mark 0 drop_overlimit 0

This comes from a confusion of what should be the minimal backlog. It is
pretty clear it is not 64KB or whatever max GSO packet ever reached the
qdisc.

codel intent was to use MTU of the device.

After the fix, we finally drop some packets, and rtt/cwnd of my single
TCP flow are meeting our expectations.

qdisc codel 0: parent 1:12 limit 16000p target 5.0ms interval 100.0ms
 Sent 102798497 bytes 67912 pkt (dropped 1365, overlimits 0 requeues 0)
 backlog 6056b 3p requeues 0
  count 1 lastcount 1 ldelay 36.3ms drop_next 0us
  maxpacket 10598 ecn_mark 0 drop_overlimit 0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kathleen Nichols <nichols@pollere.com>
Cc: Dave Taht <dave.taht@gmail.com>
Cc: Van Jacobson <vanj@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Receive packet length needs to be adjust by 2 on RX to accomodate
    the two padding bytes in altera_tse driver.  From Vlastimil Setka.

 2) If rx frame is dropped due to out of memory in macb driver, we leave
    the receive ring descriptors in an undefined state.  From Punnaiah
    Choudary Kalluri

 3) Some netlink subsystems erroneously signal NLM_F_MULTI.  That is
    only for dumps.  Fix from Nicolas Dichtel.

 4) Fix mis-use of raw rt->rt_pmtu value in ipv4, one must always go via
    the ipv4_mtu() helper.  From Herbert Xu.

 5) Fix null deref in bridge netfilter, and miscalculated lengths in
    jump/goto nf_tables verdicts.  From Florian Westphal.

 6) Unhash ping sockets properly.

 7) Software implementation of BPF divide did 64/32 rather than 64/64
    bit divide.  The JITs got it right.  Fix from Alexei Starovoitov.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (30 commi...

Here the "other side" refers to the guest or host.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With my job change kernel work will be "own time"; I'm keeping lguest
and modules (and the virtio standards work), but virtio kernel has to
go.

This makes it clear that Michael is in charge.  He's good, but having
me watch over his shoulder won't help.

Good luck Michael!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull Ceph RBD fix from Sage Weil.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: end I/O the entire obj_request on error

If we don't do that, then the poison value is left in the ->pprev
backlink.

This can cause crashes if we do a disconnect, followed by a connect().

Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Wen Xu <hotdog3645@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When we end I/O struct request with error, we need to pass
obj_request->length as @nr_bytes so that the entire obj_request worth
of bytes is completed.  Otherwise block layer ends up confused and we
trip on

    rbd_assert(more ^ (which == img_request->obj_request_count));

in rbd_img_obj_callback() due to more being true no matter what.  We
already do it in most cases but we are missing some, in particular
those where we don't even get a chance to submit any obj_requests, due
to an early -ENOMEM for example.

A number of obj_request->xferred assignments seem to be redundant but
I haven't touched any of obj_request->xferred stuff to keep this small
and isolated.

Cc: Alex Elder <elder@linaro.org>
Cc: stable@vger.kernel.org # 3.10+
Reported-by: Shawn Edwards <lesser.evil@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Pull btrfs fixes from Chris Mason:
 "A few more btrfs fixes.

  These range from corners Filipe found in the new free space cache
  writeback to a grab bag of fixes from the list"

* 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: btrfs_release_extent_buffer_page didn't free pages of dummy extent
  Btrfs: fill ->last_trans for delayed inode in btrfs_fill_inode.
  btrfs: unlock i_mutex after attempting to delete subvolume during send
  btrfs: check io_ctl_prepare_pages return in __btrfs_write_out_cache
  btrfs: fix race on ENOMEM in alloc_extent_buffer
  btrfs: handle ENOMEM in btrfs_alloc_tree_block
  Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole
  Btrfs: don't check for delalloc_bytes in cache_save_setup
  Btrfs: fix deadlock when starting writeback of bg caches
  Btrfs: fix race between start dirty bg cache writeout and bg deletion

Pull arm64 fixes from Will Deacon:
 "Not too much here, but we've addressed a couple of nasty issues in the
  dma-mapping code as well as adding the halfword and byte variants of
  load_acquire/store_release following on from the CSD locking bug that
  you fixed in the core.

   - fix perf devicetree warnings at probe time

   - fix memory leak in __dma_free()

   - ensure DMA buffers are always zeroed

   - show IRQ trigger in /proc/interrupts (for parity with ARM)

   - implement byte and halfword access for smp_{load_acquire,store_release}"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: perf: Fix the pmu node name in warning message
  arm64: perf: don't warn about missing interrupt-affinity property for PPIs
  arm64: add missing PAGE_ALIGN() to __dma_free()
  arm64: dma-mapping: always clear allocated buffers
  ARM64: Enable CONFIG_GENERIC_IRQ_SHOW_LEVEL
  arm64: add missing data types in smp_load_acquire/smp_store_release

Using IDR_SRR in RXFIFO_ID to test for the presence of data is only
valid for standard frames. For extended frames the bit is always 1 and
IDR_RTR should be used instead. This patch switches the check to use
CAN_RTR_FLAG which is correctly set when reading the ID.

The patch also changes the DW1/DW2 to be read unconditionally, since
this is necessary to remove the frame from the RXFIFO.

Signed-off-by: Jeppe Ledet-Pedersen <jlp@gomspace.com>
Acked-by: Kedareswara rao Appana <appanad@xilinx.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Pull power management and ACPI fixes from Rafael Wysocki:
 "Three regression fixes this time, one for a recent regression in the
  cpuidle core affecting multiple systems, one for an inadvertently
  added duplicate typedef in ACPICA that breaks compilation with GCC 4.5
  and one for an ACPI Smart Battery Subsystem driver regression
  introduced during the 3.18 cycle (stable-candidate).

  Specifics:

   - Fix for a regression in the cpuidle core introduced by one of the
     recent commits in the clockevents_notify() removal series that put
     a call to a function which had to be executed with disabled
     interrupts into a code path running with enabled interrupts (Rafael
     J Wysocki)

   - Fix for a build problem in ACPICA (with GCC 4.5) introduced by one
     of the recent ACPICA tools commits that added a duplicate typedef
     to one of the ACPICA's header files by mistake (Olaf Hering)

   - Fix for a regression in the ACPI SBS (Smart Battery Subsystem)
     driver introduced during the 3.18 development cycle causing the
     smart battery manager to be marked as not present when it should be
     marked as present (Chris Bainbridge)"

* tag 'pm+acpi-4.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: Run tick_broadcast_exit() with disabled interrupts
  ACPI / SBS: Enable battery manager when present
  ACPICA: remove duplicate u8 typedef

Pull sound fixes from Takashi Iwai:
 "One nice fix is Peter's patch to make the old good SB Audigy PCI to
  work with 32bit DMA instead of 31bit.  This allows the MIDI synth
  running on modern machines again.  Along with it, a few fixes for
  emu10k1 have merged.

  In ASoC side, there is one fix in the common code, but it's just
  trivial additions of static inline functions for CONFIG_PM=n.  The
  rest are various device-specific small fixes.

  Last but not least, a few HD-audio fixes are included, as usual, too"

* tag 'sound-4.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (23 commits)
  ASoC: rt5677: fixed wrong DMIC ref clock
  ALSA: emu10k1: Emu10k2 32 bit DMA mode
  ALSA: emux: Fix mutex deadlock in OSS emulation
  ASoC: Update email-id of Rajeev Kumar
  ASoC: rt5645: Fix mask for setting RT5645_DMIC_2_DP_GPIO12 bit
  ALSA: hda - Fix missing va_end() call in snd_hda_codec_pcm_new()
  ALSA: emux: Fix mutex deadlock at unloading
  ALSA: emu10k1: Fix card shortname string buffer overflow
  ALSA: hda - Add mute-LED mode control to Thinkpad
  ALSA: hda - Fix mute-LED fixed mode
  ALSA: hda - Fix click noise at start on Dell XPS13
  ASoC: rt5645: Add ACPI match ID
  ASoC: rt5677: add register patch for PLL
  ASoC: Intel: fix the makefile for atom code
  ASoC: dapm: Enable autodisable on SOC_DAPM_SINGLE_TLV_AUTODISABLE
  ASoC: add static inline funcs to fix a compiling issue
  ASoC: Intel: sst_byt: remove kfree for memory allocated with devm_kzalloc
  ASoC: samsung: s3c24xx-i2s: Fix return value check in s3c24xx_iis_dev_probe()
  ASoC: tfa9879: Fix return value check in tfa9879_i2c_probe()
  ASoC: fsl_ssi: Fix platform_get_irq() error handling
  ...

RGMII-ID uses an internal delay within the transmitter or receiver. This
feature is phy specific. The rest of the communication is normal RGMII.

So the fec driver has to check for all RGMII modes, not only
'PHY_INTERFACE_MODE_RGMII'.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

When system is out of memory, refilling of RX buffers fails while
the driver continue to pass the received packets to the kernel stack.
At some point, when all RX buffers deplete, driver may fall into a
sleep, and not recover when memory for new RX buffers is once again
availible. This is because hardware does not have valid descriptors,
so no interrupt will be generated for the driver to return to work
in napi context. Fix it by schedule the napi poll function from
stats_task delayed workqueue, as long as the allocations fail.

Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

While testing this driver with DEBUG_LOCKDEP and DEBUG_SPINLOCK
enabled did not produce any traces, it would be more prudent in the
case of tx_clean_lock to use spin_[un]lock_bh, since this lock is
manipulated in both the process and softirq contexts.

This patch was tested for functionality and regressions with netperf
and DEBUG_LOCKDEP and DEBUG_SPINLOCK enabled.

Signed-off-by: Tony Camuso <tcamuso@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Addresses the following kernel logs seen during boot:

Kernel unaligned access at TPC[100ee150] mlx4_QUERY_HCA+0x80/0x248 [mlx4_core]
Kernel unaligned access at TPC[100f071c] mlx4_QUERY_ADAPTER+0x100/0x12c [mlx4_core]
Kernel unaligned access at TPC[100f071c] mlx4_QUERY_ADAPTER+0x100/0x12c [mlx4_core]
Kernel unaligned access at TPC[100f071c] mlx4_QUERY_ADAPTER+0x100/0x12c [mlx4_core]
Kernel unaligned access at TPC[100f071c] mlx4_QUERY_ADAPTER+0x100/0x12c [mlx4_core]

Signed-off-by: David Ahern <david.ahern@oracle.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Fixes: 9e311e77

 ("net/mlx4_en: Use affinity hint")
Acked-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'asoc-v4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v4.1

A few fixes for v4.1, none earth shattering and mostly driver related
except for one change to fix !PM builds for Intel platforms which is
done by adding stubs in the core so other platforms don't run into the
same issue.

Pull kvm changes from Paolo Bonzini:
 "Remove from guest code the handling of task migration during a pvclock
  read; instead use the correct protocol in KVM.

  This removes the need for task migration notifiers in core scheduler
  code"

[ The scheduler people really hated the migration notifiers, so this was
  kind of required  - Linus ]

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  x86: pvclock: Really remove the sched notifier for cross-cpu migrations
  kvm: x86: fix kvmclock update protocol

Pull device mapper bugfixes from Mike Snitzer:
 "Fix two bugs in the request-based DM blk-mq support that was added
  during the 4.1 merge"

* tag 'dm-4.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix free_rq_clone() NULL pointer when requeueing unmapped request
  dm: only initialize the request_queue once

Change default key details to be more obviously unspecified.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull tty/serial fixes from Greg KH:
 "Here are some small tty/serial driver fixes for 4.1-rc2.

  They include some minor fixes that resolve reported issues, and a new
  device quirk.

  All have been in linux-next succesfully"

* tag 'tty-4.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: 8250_pci: Add support for 16 port Exar boards
  serial: samsung: fix serial console break
  tty/serial: at91: maxburst was missing for dma transfers
  serial: of-serial: Remove device_type = "serial" registration
  serial: xilinx: Use platform_get_irq to get irq description structure
  serial: core: Fix kernel-doc build warnings
  tty: Re-add external interface for tty_set_termios()

Pull USB fixes from Greg KH:
 "Here are a number of small USB fixes for 4.2-rc2.  They revert one
  problem patch, fix some minor things, and add some new quirks for
  "broken" devices.

  All have been in linux-next successfully"

* tag 'usb-4.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  cdc-acm: prevent infinite loop when parsing CDC headers.
  Revert "usb: host: ehci-msm: Use devm_ioremap_resource instead of devm_ioremap"
  usb: chipidea: otg: remove mutex unlock and lock while stop and start role
  uas: Set max_sectors_240 quirk for ASM1053 devices
  uas: Add US_FL_MAX_SECTORS_240 flag
  uas: Allow uas_use_uas_driver to return usb-storage flags

Merge tag 'renesas-sh-drivers-for-v4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas

Pull SH driver updates from Simon Horman:

 - remove test for now unsupported sh7372 SoC

 - disable PM runtime for multi-platform r8a73a4 and sh73a0 SoCs with
   genpd

* tag 'renesas-sh-drivers-for-v4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  drivers: sh: Remove test for now unsupported sh7372
  drivers: sh: Disable PM runtime for multi-platform r8a73a4 with genpd
  drivers: sh: Disable PM runtime for multi-platform sh73a0 with genpd

Commit 02233342 ("dm: optimize dm_mq_queue_rq to _not_ use kthread if
using pure blk-mq") mistakenly removed free_rq_clone()'s clone->q check
before testing clone->q->mq_ops.  It was an oversight to discontinue
that check for 1 of the 2 use-cases for free_rq_clone():
1) free_rq_clone() called when an unmapped original request is requeued
2) free_rq_clone() called in the request-based IO completion path

The clone->q check made sense for case #1 but not for #2.  However, we
cannot just reinstate the check as it'd mask a serious bug in the IO
completion case #2 -- no in-flight request should have an uninitialized
request_queue (basic block layer refcounting _should_ ensure this).

The NULL pointer seen for case #1 is detailed here:
https://www.redhat.com/archives/dm-devel/2015-April/msg00160.html



Fix this free_rq_clone() NULL pointer by simply checking if the
mapped_device's type is DM_TYPE_MQ_REQUEST_BASED (clone's queue is
blk-mq) rather than checking clone->q->mq_ops.  This avoids the need to
dereference clone->q, but a WARN_ON_ONCE is added to let us know if an
uninitialized clone request is being completed.

Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>