The implicit transition time tells initiators the min time
to wait before timing out a transition. We currently schedule
the transition to occur in tg_pt_gp_implicit_trans_secs
seconds so there is no room for delays. If
core_alua_do_transition_tg_pt_work->core_alua_update_tpg_primary_metadata
needs to write out info to a remote file, then the initiator can
easily time out the operation.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch allows passthrough backends to use the core/base LIO
ALUA setup and state checks, but still handle the execution of
commands.

This will allow the target_core_user module to execute STPG and RTPG
in userspace, and not have to duplicate the ALUA state checks, path
information (needed so we can check if command is executable on
specific paths) and setup (rtslib sets/updates the configfs ALUA
interface like it does for iblock or file).

For STPG, the target_core_user userspace daemon, tcmu-runner will
still execute the STPG, and to update the core/base LIO state it
will use the existing configfs interface. For RTPG, tcmu-runner
will loop over configfs and/or cache the state.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Pull sched.h split-up from Ingo Molnar:
 "The point of these changes is to significantly reduce the
  <linux/sched.h> header footprint, to speed up the kernel build and to
  have a cleaner header structure.

  After these changes the new <linux/sched.h>'s typical preprocessed
  size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
  lines), which is around 40% faster to build on typical configs.

  Not much changed from the last version (-v2) posted three weeks ago: I
  eliminated quirks, backmerged fixes plus I rebased it to an upstream
  SHA1 from yesterday that includes most changes queued up in -next plus
  all sched.h changes that were pending from Andrew.

  I've re-tested the series both on x86 and on cross-arch defconfigs,
  and did a bisectability test at a number of random points.

  I tried to test as many build configurations as possible, but some
  build breakage is probably still left - but it should be mostly
  limited to architectures that have no cross-compiler binaries
  available on kernel.org, and non-default configurations"

* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
  sched/headers: Clean up <linux/sched.h>
  sched/headers: Remove #ifdefs from <linux/sched.h>
  sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
  sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
  sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
  sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
  sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
  sched/core: Remove unused prefetch_stack()
  sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
  sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
  sched/headers: Remove <linux/signal.h> from <linux/sched.h>
  sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
  sched/headers: Remove the runqueue_is_locked() prototype
  sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
  sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
  sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
  ...

It's not used by anything in <linux/sched.h> anymore.

This reduces the preprocessed size of <linux/sched.h> and
speeds up the build a bit.

Also fix code that implicitly relied on headers included by <linux/cgroup-defs.h>.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull SCSI target updates from Nicholas Bellinger:
 "The highlights this round include:

   - enable dual mode (initiator + target) qla2xxx operation. (Quinn +
     Himanshu)

   - add a framework for qla2xxx async fabric discovery. (Quinn +
     Himanshu)

   - enable iscsi PDU DDP completion offload in cxgbit/T6 NICs. (Varun)

   - fix target-core handling of aborted failed commands. (Bart)

   - fix a long standing target-core issue NULL pointer dereference with
     active I/O LUN shutdown. (Rob Millner + Bryant + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (44 commits)
  target: Add counters for ABORT_TASK success + failure
  iscsi-target: Fix early login failure statistics misses
  target: Fix NULL dereference during LUN lookup + active I/O shutdown
  target: Delete tmr from list before processing
  target: Fix handling of aborted failed commands
  uapi: fix linux/target_core_user.h userspace compilation errors
  target: export protocol identifier
  qla2xxx: Fix a warning reported by the "smatch" static checker
  target/iscsi: Fix unsolicited data seq_end_offset calculation
  target/cxgbit: add T6 iSCSI DDP completion feature
  target/cxgbit: Enable DDP for T6 only if data sequence and pdu are in order
  target/cxgbit: Use T6 specific macros to get ETH/IP hdr len
  target/cxgbit: use cxgb4_tp_smt_idx() to get smt idx
  target/iscsi: split iscsit_check_dataout_hdr()
  target: Remove command flag CMD_T_DEV_ACTIVE
  target: Remove command flag CMD_T_BUSY
  target: Move session check from target_put_sess_cmd() into target_release_cmd_kref()
  target: Inline transport_cmd_check_stop()
  target: Remove an overly chatty debug message
  target: Stop execution if CMD_T_STOP has been set
  ...

In the following patches we are going to remove various headers
from sched.h and other headers that sched.h includes.

To make those patches build cleanly prepare the scene by adding
dependencies to various files that learned to rely on those
to-be-removed dependencies.

These changes all make sense standalone: they add a header for
a data type that a particular .c or .h file is using.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This patch introduces two counters for ABORT_TASK success +
failure under:

   /sys/kernel/config/target/core/$HBA/$DEV/statistics/scsi_tgt_dev/

that are useful for diagnosing various backend device latency
and front fabric issues.

Normally when folks see alot of aborts_complete happening,
it means the backend device I/O completion latency is high,
and not returning completions fast enough before host side
timeouts trigger.

And normally when folks see alot of aborts_no_task, it means
completions are being posted by target-core into fabric driver
code, but the responses aren't making it back to the host.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

When transport_clear_lun_ref() is shutting down a se_lun via
configfs with new I/O in-flight, it's possible to trigger a
NULL pointer dereference in transport_lookup_cmd_lun() due
to the fact percpu_ref_get() doesn't do any __PERCPU_REF_DEAD
checking before incrementing lun->lun_ref.count after
lun->lun_ref has switched to atomic_t mode.

This results in a NULL pointer dereference as LUN shutdown
code in core_tpg_remove_lun() continues running after the
existing ->release() -> core_tpg_lun_ref_release() callback
completes, and clears the RCU protected se_lun->lun_se_dev
pointer.

During the OOPs, the state of lun->lun_ref in the process
which triggered the NULL pointer dereference looks like
the following on v4.1.y stable code:

struct se_lun {
  lun_link_magic = 4294932337,
  lun_status = TRANSPORT_LUN_STATUS_FREE,

  .....

  lun_se_dev = 0x0,
  lun_sep = 0x0,

  .....

  lun_ref = {
    count = {
      counter = 1
    },
    percpu_count_ptr = 3,
    release = 0xffffffffa02fa1e0 <core_tpg_lun_ref_release>,
    confirm_switch = 0x0,
    force_atomic = false,
    rcu = {
      next = 0xffff88154fa1a5d0,
      func = 0xffffffff8137c4c0 <percpu_ref_switch_to_atomic_rcu>
    }
  }
}

To address this bug, use percpu_ref_tryget_live() to ensure
once __PERCPU_REF_DEAD is visable on all CPUs and ->lun_ref
has switched to atomic_t, all new I/Os will fail to obtain
a new lun->lun_ref reference.

Also use an explicit percpu_ref_kill_and_confirm() callback
to block on ->lun_ref_comp to allow the first stage and
associated RCU grace period to complete, and then block on
->lun_ref_shutdown waiting for the final percpu_ref_put()
to drop the last reference via transport_lun_remove_cmd()
before continuing with core_tpg_remove_lun() shutdown.

Reported-by: Rob Millner <rlm@daterainc.com>
Tested-by: Rob Millner <rlm@daterainc.com>
Cc: Rob Millner <rlm@daterainc.com>
Tested-by: Vaibhav Tandon <vst@datera.io>
Cc: Vaibhav Tandon <vst@datera.io>
Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Pull rdma updates from Doug Ledford:
 "First set of updates for 4.11 kernel merge window

   - Add new Broadcom bnxt_re RoCE driver
   - rxe driver updates
   - ioctl cleanups
   - ETH_P_IBOE declaration cleanup
   - IPoIB changes
   - Add port state cache
   - Allow srpt driver to accept guids as port names in config
   - Update to hfi1 driver
   - Update to srp driver
   - Lots of misc minor changes all over"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (114 commits)
  RDMA/bnxt_re: fix for "bnxt_en: Update to firmware interface spec 1.7.0."
  rdma_cm: fail iwarp accepts w/o connection params
  IB/srp: Drain the send queue before destroying a QP
  IB/core: Add support for draining IB_POLL_DIRECT completion queues
  IB/srp: Improve an error path
  IB/srp: Make a diagnostic message more informative
  IB/srp: Document locking conventions
  IB/srp: Fix race conditions related to task management
  IB/srp: Avoid that duplicate responses trigger a kernel bug
  IB/SRP: Avoid using IB_MR_TYPE_SG_GAPS
  RDMA/qedr: Fix some error handling
  RDMA/bnxt_re: add DCB dependency
  IB/hns: include linux/module.h
  IB/vmw_pvrdma: Expose vendor error to ULPs
  vmw_pvrdma: switch to pci_alloc_irq_vectors
  IB/hfi1: use size_t for passing array length
  IB/ipoib: Remove redudant label
  IB/ipoib: remove the unnecessary memory free
  IB/mthca: switch to pci_alloc_irq_vectors
  IB/hfi1: Code reuse with memdup_copy
  ...

Split iscsit_check_dataout_hdr() into two functions
1. __iscsit_check_dataout_hdr() - This function
   validates data out hdr.
2. iscsit_check_dataout_hdr() - This function finds
   iSCSI cmd using iscsit_find_cmd_from_itt_or_dump(),
   then it calls __iscsit_check_dataout_hdr() to
   validate iSCSI hdr.

This split is required to support Chelsio T6 iSCSI
DDP completion feature. T6 adapters reduce number of
completions to host by generating single completion
for all directly placed(DDP) iSCSI pdus in a sequence,
DDP completion contains iSCSI hdr of the last pdu in a
sequence.

On receiving DDP completion cxgbit driver will first
find iSCSI cmd using iscsit_find_cmd_from_itt_or_dump()
then updates cmd->write_data_done, cmd->next_burst_len,
cmd->data_sn and calls  __iscsit_check_dataout_hdr()
to validate iSCSI hdr.

(Move XRDSL check ahead of itt lookup / dump - nab)

Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>