Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU changes from Paul E. McKenney:

  - Initialization/Kconfig updates: hide most Kconfig options from unsuspecting users.
    There's now a single high level configuration option:

      *
      * RCU Subsystem
      *
      Make expert-level adjustments to RCU configuration (RCU_EXPERT) [N/y/?] (NEW)

    Which if answered in the negative, leaves us with a single interactive
    configuration option:

      Offload RCU callback processing from boot-selected CPUs (RCU_NOCB_CPU) [N/y/?] (NEW)

    All the rest of the RCU options are configured automatically.

  - Remove all uses of RCU-protected array indexes: replace the
    rcu_[access|dereference]_index_check() APIs with READ_ONCE() and rcu_lockdep_assert().

  - RCU CPU-hotplug cleanups.

  - Updates to Tiny RCU: a race fix and further code shrinkage.

  - RCU torture-testing updates: fixes, speedups, cleanups and
    documentation updates.

  - Miscellaneous fixes.

  - Documentation updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull networking fixes from David Miller:

 1) Various VTI tunnel (mark handling, PMTU) bug fixes from Alexander
    Duyck and Steffen Klassert.

 2) Revert ethtool PHY query change, it wasn't correct.  The PHY address
    selected by the driver running the PHY to MAC connection decides
    what PHY address GET ethtool operations return information from.

 3) Fix handling of sequence number bits for encryption IV generation in
    ESP driver, from Herbert Xu.

 4) UDP can return -EAGAIN when we hit a bad checksum on receive, even
    when there are other packets in the receive queue which is wrong.
    Just respect the error returned from the generic socket recv
    datagram helper.  From Eric Dumazet.

 5) Fix BNA driver firmware loading on big-endian systems, from Ivan
    Vecera.

 6) Fix regression in that we were inheriting the congestion control of
    the listening socket for new connections, the intended behavior
    always was to use the default in this case.  From Neal Cardwell.

 7) Fix NULL deref in brcmfmac driver, from Arend van Spriel.

 8) OTP parsing fix in iwlwifi from Liad Kaufman.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  vti6: Add pmtu handling to vti6_xmit.
  Revert "net: core: 'ethtool' issue with querying phy settings"
  bnx2x: Move statistics implementation into semaphores
  xen: netback: read hotplug script once at start of day.
  xen: netback: fix printf format string warning
  Revert "netfilter: ensure number of counters is >0 in do_replace()"
  net: dsa: Properly propagate errors from dsa_switch_setup_one
  tcp: fix child sockets to use system default congestion control if not set
  udp: fix behavior of wrong checksums
  sfc: free multiple Rx buffers when required
  bna: fix soft lock-up during firmware initialization failure
  bna: remove unreasonable iocpf timer start
  bna: fix firmware loading on big-endian machines
  bridge: fix br_multicast_query_expired() bug
  via-rhine: Resigning as maintainer
  brcmfmac: avoid null pointer access when brcmf_msgbuf_get_pktid() fails
  mac80211: Fix mac80211.h docbook comments
  iwlwifi: nvm: fix otp parsing in 8000 hw family
  iwlwifi: pcie: fix tracking of cmd_in_flight
  ip_vti/ip6_vti: Preserve skb->mark after rcv_cb call
  ...

Pull Sparc fixes from David Miller:

 1) Setup the core/threads/sockets bitmaps correctly so that 'lscpus'
    and friends operate properly.  Frtom Chris Hyser.

 2) The bit that normally means "Cached Virtually" on sun4v systems,
    actually changes meaning in M7 and later chips.  Fix from Khalid
    Aziz.

 3) One some PCI-E systems we need to probe different OF properties to
    fill in the PCI slot information properly, from Eric Snowberg.

 4) Kill an extraneous memset after kzalloc(), from Christophe Jaillet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE
  sparc64: pci slots information is not populated in sysfs
  sparc: kernel: GRPCI2: Remove a useless memset
  sparc64: Setup sysfs to mark LDOM sockets, cores and threads correctly

Pull virtio fix from Michael Tsirkin:
 "Last-minute virtio fix for 4.1

  This tweaks an exported user-space header to fix build breakage for
  userspace using it"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  include/uapi/linux/virtio_balloon.h: include linux/virtio_types.h

Pablo Neira Ayuso says:

====================
Netfilter fix for net

The following patch reverts the ebtables chunk that enforces counters that was
introduced in the recently applied d26e2c9f ('Revert "netfilter: ensure
number of counters is >0 in do_replace()"') since this breaks ebtables.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'wireless-drivers-for-davem-2015-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers

Kalle Valo says:

====================
iwlwifi:

* fix OTP parsing 8260
* fix powersave handling for 8260

brcmfmac:

* fix null pointer crash
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

We currently rely on the PMTU discovery of xfrm.
However if a packet is localy sent, the PMTU mechanism
of xfrm tries to to local socket notification what
might not work for applications like ping that don't
check for this. So add pmtu handling to vti6_xmit to
report MTU changes immediately.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit f96dee13.

It isn't right, ethtool is meant to manage one PHY instance
per netdevice at a time, and this is selected by the SET
command.  Therefore by definition the GET command must only
return the settings for the configured and selected PHY.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit dff173de ("bnx2x: Fix statistics locking scheme") changed the
bnx2x locking around statistics state into using a mutex - but the lock
is being accessed via a timer which is forbidden.

[If compiled with CONFIG_DEBUG_MUTEXES, logs show a warning about
accessing the mutex in interrupt context]

This moves the implementation into using a semaphore [with size '1']
instead.
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When we come to tear things down in netback_remove() and generate the
uevent it is possible that the xenstore directory has already been
removed (details below).

In such cases netback_uevent() won't be able to read the hotplug
script and will write a xenstore error node.

A recent change to the hypervisor exposed this race such that we now
sometimes lose it (where apparently we didn't ever before).

Instead read the hotplug script configuration during setup and use it
for the lifetime of the backend device.

The apparently more obvious fix of moving the transition to
state=Closed in netback_remove() to after the uevent does not work
because it is possible that we are already in state=Closed (in
reaction to the guest having disconnected as it shutdown). Being
already in Closed means the toolstack is at liberty to start tearing
down the xenstore directories. In principal it might be possible to
arrange to unregister the device sooner (e.g on transition to Closing)
such that xenstore would still be there but this state machine is
fragile and prone to anger...

A modern Xen system only relies on the hotplug uevent for driver
domains, when the backend is in the same domain as the toolstack it
will run the necessary setup/teardown directly in the correct sequence
wrt xenstore changes.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/xen-netback/netback.c: In function ‘xenvif_tx_build_gops’:
drivers/net/xen-netback/netback.c:1253:8: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘int’ [-Wformat=]
        (txreq.offset&~PAGE_MASK) + txreq.size);
        ^

PAGE_MASK's type can vary by arch, so a cast is needed.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
----
v2: Cast to unsigned long, since PAGE_MASK can vary by arch.
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This partially reverts commit 1086bbe9 ("netfilter: ensure number of
counters is >0 in do_replace()") in net/bridge/netfilter/ebtables.c.

Setting rules with ebtables does not work any more with 1086bbe9 place.

There is an error message and no rules set in the end.

e.g.

~# ebtables -t nat -A POSTROUTING --src 12:34:56:78:9a:bc -j DROP
Unable to update the kernel. Two possible causes:
1. Multiple ebtables programs were executing simultaneously. The ebtables
   userspace tool doesn't by default support multiple ebtables programs
running

Reverting the ebtables part of 1086bbe9 makes this work again.
Signed-off-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Fixes userspace compilation error:

error: unknown type name ‘__virtio16’
  __virtio16 tag;
Signed-off-by: Mikko Rapeli <mikko.rapeli@iki.fi>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

Bit 9 of TTE is CV (Cacheable in V-cache) on sparc v9 processor while
the same bit 9 is MCDE (Memory Corruption Detection Enable) on M7
processor. This creates a conflicting usage of the same bit. Kernel
sets TTE.cv bit on all pages for sun4v architecture which works well
for sparc v9 but enables memory corruption detection on M7 processor
which is not the intent. This patch adds code to determine if kernel
is running on M7 processor and takes steps to not enable memory
corruption detection in TTE erroneously.
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add PCI slot numbers within sysfs for PCIe hardware.  Larger
PCIe systems with nested PCI bridges and slots further
down on these bridges were not being populated within sysfs.
This will add ACPI style PCI slot numbers for these systems
since the OF 'slot-names' information is not available on
all PCIe platforms.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

grpci2priv is allocated using kzalloc, so there is no need to memset it.
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

While shuffling some code around, dsa_switch_setup_one() was introduced,
and it was modified to return either an error code using ERR_PTR() or a
NULL pointer when running out of memory or failing to setup a switch.

This is a problem for its caler: dsa_switch_setup() which uses IS_ERR()
and expects to find an error code, not a NULL pointer, so we still try
to proceed with dsa_switch_setup() and operate on invalid memory
addresses. This can be easily reproduced by having e.g: the bcm_sf2
driver built-in, but having no such switch, such that drv->setup will
fail.

Fix this by using PTR_ERR() consistently which is both more informative
and avoids for the caller to use IS_ERR_OR_NULL().

Fixes: df197195 ("net: dsa: split dsa_switch_setup into two functions")
Reported-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Linux 3.17 and earlier are explicitly engineered so that if the app
doesn't specifically request a CC module on a listener before the SYN
arrives, then the child gets the system default CC when the connection
is established. See tcp_init_congestion_control() in 3.17 or earlier,
which says "if no choice made yet assign the current value set as
default". The change ("net: tcp: assign tcp cong_ops when tcp sk is
created") altered these semantics, so that children got their parent
listener's congestion control even if the system default had changed
after the listener was created.

This commit returns to those original semantics from 3.17 and earlier,
since they are the original semantics from 2007 in 4d4d3d1e ("[TCP]:
Congestion control initialization."), and some Linux congestion
control workflows depend on that.

In summary, if a listener socket specifically sets TCP_CONGESTION to
"x", or the route locks the CC module to "x", then the child gets
"x". Otherwise the child gets current system default from
net.ipv4.tcp_congestion_control. That's the behavior in 3.17 and
earlier, and this commit restores that.

Fixes: 55d8694f ("net: tcp: assign tcp cong_ops when tcp sk is created")
Cc: Florian Westphal <fw@strlen.de>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Glenn Judd <glenn.judd@morganstanley.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

We have two problems in UDP stack related to bogus checksums :

1) We return -EAGAIN to application even if receive queue is not empty.
   This breaks applications using edge trigger epoll()

2) Under UDP flood, we can loop forever without yielding to other
   processes, potentially hanging the host, especially on non SMP.

This patch is an attempt to make things better.

We might in the future add extra support for rt applications
wanting to better control time spent doing a recv() in a hostile
environment. For example we could validate checksums before queuing
packets in socket receive queue.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When Rx packet data must be dropped, all the buffers
associated with that Rx packet must be freed. Extend
and rename efx_free_rx_buffer() to efx_free_rx_buffers()
and loop through all the fragments.
By doing so this patch fixes a possible memory leak.
Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull vfs fix from Al Viro:
 "Off-by-one in d_walk()/__dentry_kill() race fix.

  It's very hard to hit; possible in the same conditions as the original
  bug, except that you need the skipped branch to contain all the
  remaining evictables, so that the d_walk()-calling loop in
  d_invalidate() decides there's nothing more to do and doesn't go for
  another pass - otherwise that next pass will sweep the sucker.

  So it's not too urgent, but seeing that the fix is obvious and the
  original commit has spread into all -stable branches..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  d_walk() might skip too much

Pull ARM fixes from Russell King:
 "Three fixes this time around:

   - fix a memory leak which occurs when probing performance monitoring
     unit interrupts

   - fix handling of non-PMD aligned end of RAM causing boot failures

   - fix missing syscall trace exit path with syscall tracing enabled
     causing a kernel oops in the audit code"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8357/1: perf: fix memory leak when probing PMU PPIs
  ARM: fix missing syscall trace exit
  ARM: 8356/1: mm: handle non-pmd-aligned end of RAM

Pull MIPS fixes from Ralf Baechle:
 "MIPS fixes for 4.1 all across the tree"

* 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/ralf/linux:
  MIPS: strnlen_user.S: Fix a CPU_DADDI_WORKAROUNDS regression
  MIPS: BMIPS: Fix bmips_wr_vec()
  MIPS: ath79: fix build problem if CONFIG_BLK_DEV_INITRD is not set
  MIPS: Fuloong 2E: Replace CONFIG_USB_ISP1760_HCD by CONFIG_USB_ISP1760
  MIPS: irq: Use DECLARE_BITMAP
  ttyFDC: Fix to use native endian MMIO reads
  MIPS: Fix CDMM to use native endian MMIO reads

Pull turbostat tool fixes from Len Brown:
 "Just one minor kernel dependency in this batch -- added a #define to
  msr-index.h"

* 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  tools/power turbostat: update version number to 4.7
  tools/power turbostat: allow running without cpu0
  tools/power turbostat: correctly decode of ENERGY_PERFORMANCE_BIAS
  tools/power turbostat: enable turbostat to support Knights Landing (KNL)
  tools/power turbostat: correctly display more than 2 threads/core

Pull SCSI target fixes from Nicholas Bellinger:
 "These are mostly minor fixes, with the exception of the following that
  address fall-out from recent v4.1-rc1 changes:

   - regression fix related to the big fabric API registration changes
     and configfs_depend_item() usage, that required cherry-picking one
     of HCH's patches from for-next to address the issue for v4.1 code.

   - remaining TCM-USER -v2 related changes to enforce full CDB
     passthrough from Andy + Ilias.

  Also included is a target_core_pscsi driver fix from Andy that
  addresses a long standing issue with a Scsi_Host reference being
  leaked on PSCSI device shutdown"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iser-target: Fix error path in isert_create_pi_ctx()
  target: Use a PASSTHROUGH flag instead of transport_types
  target: Move passthrough CDB parsing into a common function
  target/user: Only support full command pass-through
  target/user: Update example code for new ABI requirements
  target/pscsi: Don't leak scsi_host if hba is VIRTUAL_HOST
  target: Fix se_tpg_tfo->tf_subsys regression + remove tf_subsystem
  target: Drop signal_pending checks after interruptible lock acquire
  target: Add missing parentheses
  target: Fix bidi command handling
  target/user: Disallow full passthrough (pass_level=0)
  ISCSI: fix minor memory leak

Merge tag 'hwmon-for-linus-v4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Some late hwmon patches, all headed for -stable

   - fix sysfs attribute initialization in nct6775 and nct6683 drivers

   - do not attempt to auto-detect tmp435 on I2C address 0x37

   - ensure iio channel is of type IIO_VOLTAGE in ntc_thermistor driver"

* tag 'hwmon-for-linus-v4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (nct6683) Add missing sysfs attribute initialization
  hwmon: (nct6775) Add missing sysfs attribute initialization
  hwmon: (tmp401) Do not auto-detect chip on I2C address 0x37
  hwmon: (ntc_thermistor) Ensure iio channel is of type IIO_VOLTAGE

Ivan Vecera says:

====================
bna: misc bugfixes

These patches fix several bugs found during device initialization debugging.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Bug in the driver initialization causes soft-lockup if firmware
initialization timeout is reached. Polling function bfa_ioc_poll_fwinit()
incorrectly calls bfa_nw_iocpf_timeout() when the timeout is reached.
The problem is that bfa_nw_iocpf_timeout() calls again
bfa_ioc_poll_fwinit()... etc. The bfa_ioc_poll_fwinit() should directly
send timeout event for iocpf and the same should be done if firmware
download into HW fails.

Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Driver starts iocpf timer prior bnad_ioceth_enable() call and this is
unreasonable. This piece of code probably originates from Brocade/Qlogic
out-of-box driver during initial import into upstream. This driver uses
only one timer and queue to implement multiple timers and this timer is
started at this place. The upstream driver uses multiple timers instead
of this.

Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Firmware required by bna is stored in appropriate files as sequence
of LE32 integers. After loading by request_firmware() they need to be
byte-swapped on big-endian arches. Without this conversion the NIC
is unusable on big-endian machines.

Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'mac80211-for-davem-2015-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211

Johannes Berg says:

====================
This just has a single docbook build fix. In my confusion
I'd already sent the same fix for -next, but Ben Hutchings
noted it's necessary in 4.1.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

br_multicast_query_expired() querier argument is a pointer to
a struct bridge_mcast_querier :

struct bridge_mcast_querier {
        struct br_ip addr;
        struct net_bridge_port __rcu    *port;
};

Intent of the code was to clear port field, not the pointer to querier.

Fixes: 2cd41431 ("bridge: memorize and export selected IGMP/MLD querier port")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Acked-by: Linus Lüssing <linus.luessing@c0d3.blue>
Cc: Linus Lüssing <linus.luessing@web.de>
Cc: Steinar H. Gunderson <sesse@samfundet.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

We don't assign pi_ctx to desc->pi_ctx until we're certain to succeed
in the function.  That means the cleanup path should use the local
pi_ctx variable, not desc->pi_ctx.

This was detected by Coverity (CID 1260062).
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

It seems like we only care if a transport is passthrough or not. Convert
transport_type to a flags field and replace TRANSPORT_PLUGIN_* with a
flag, TRANSPORT_FLAG_PASSTHROUGH.
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Aside from whether they handle BIDI ops or not, parsing of the CDB by
kernel and user SCSI passthrough modules should be identical. Move this
into a new passthrough_parse_cdb() and call it from tcm-pscsi and tcm-user.
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

After much discussion, give up on only passing a subset of SCSI commands
to userspace and pass them all. Based on what pscsi is doing, make sure
to set SCF_SCSI_DATA_CDB for I/O ops, and define attributes identical to
pscsi.

Make hw_block_size configurable via dev param.

Remove mention of command filtering from tcmu-design.txt.
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

We now require that the userspace handler set a bit if the command is not
handled.

Update calls to tcmu_hdr_get_op for v2.
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

See https://bugzilla.redhat.com/show_bug.cgi?id=1025672

We need to put() the reference to the scsi host that we got in
pscsi_configure_device(). In VIRTUAL_HOST mode it is associated with
the dev_virt, not the hba_virt.
Signed-off-by: Andy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org # 2.6.38+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

There is just one configfs subsystem in the target code, so we might as
well add two helpers to reference / unreference it from the core code
instead of passing pointers to it around.

This fixes a regression introduced for v4.1-rc1 with commit 9ac8928e,
where configfs_depend_item() callers using se_tpg_tfo->tf_subsys would
fail, because the assignment from the original target_core_subsystem[]
is no longer happening at target_register_template() time.

(Fix target_core_exit_configfs pointer dereference - Sagi)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>