A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.

This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests.  It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

sas_ata_strategy_handler() adds the works of the ata error handler to
system_unbound_wq. This workqueue asynchronously runs work items, so the
ata error handler will be performed concurrently on different CPUs. In
this case, ->host_failed will be decreased simultaneously in
scsi_eh_finish_cmd() on different CPUs, and become abnormal.

It will lead to permanently inequality between ->host_failed and
->host_busy, and scsi error handler thread won't start running. IO
errors after that won't be handled.

Since all scmds must have been handled in the strategy handler, just
remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after
the strategy handler to fix this race.

Fixes: 50824d6c5657 ("[SCSI] libsas: async ata-eh")
Cc: stable@vger.kernel.org
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Whenever a sense code is set it would need to be evaluated to
update the error mask.

tj: Cosmetic formatting updates.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

__GFP_WAIT was used to signal that the caller was in atomic context and
could not sleep.  Now it is possible to distinguish between true atomic
context and callers that are not willing to sleep.  The latter should
clear __GFP_DIRECT_RECLAIM so kswapd will still wake.  As clearing
__GFP_WAIT behaves differently, there is a risk that people will clear the
wrong flags.  This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly
indicate what it does -- setting it allows all reclaim activity, clearing
them prevents it.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull SCSI target updates from Nicholas Bellinger:
 "Here are the outstanding target-pending updates for v4.3-rc1.

  Mostly bug-fixes and minor changes this round.  The fallout from the
  big v4.2-rc1 RCU conversion have (thus far) been minimal.

  The highlights this round include:

   - Move sense handling routines into scsi_common code (Sagi)

   - Return ABORTED_COMMAND sense key for PI errors (Sagi)

   - Add tpg_enabled_sendtargets attribute for disabled iscsi-target
     discovery (David)

   - Shrink target struct se_cmd by rearranging fields (Roland)

   - Drop iSCSI use of mutex around max_cmd_sn increment (Roland)

   - Replace iSCSI __kernel_sockaddr_storage with sockaddr_storage (Andy +
     Chris)

   - Honor fabric max_data_sg_nents I/O transfer limit (Arun + Himanshu +
     nab)

   - Fix EXTENDED_COPY >= v4.1 regression OOPsen (Alex + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (37 commits)
  target: use stringify.h instead of own definition
  target/user: Fix UFLAG_UNKNOWN_OP handling
  target: Remove no-op conditional
  target/user: Remove unused variable
  target: Fix max_cmd_sn increment w/o cmdsn mutex regressions
  target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sess
  target/qla2xxx: Honor max_data_sg_nents I/O transfer limit
  target/iscsi: Replace __kernel_sockaddr_storage with sockaddr_storage
  target/iscsi: Replace conn->login_ip with login_sockaddr
  target/iscsi: Keep local_ip as the actual sockaddr
  target/iscsi: Fix np_ip bracket issue by removing np_ip
  target: Drop iSCSI use of mutex around max_cmd_sn increment
  qla2xxx: Update tcm_qla2xxx module description to 24xx+
  iscsi-target: Add tpg_enabled_sendtargets for disabled discovery
  drivers: target: Drop unlikely before IS_ERR(_OR_NULL)
  target: check DPO/FUA usage for COMPARE AND WRITE
  target: Shrink struct se_cmd by rearranging fields
  target: Remove cmd->se_ordered_id (unused except debug log lines)
  target: add support for START_STOP_UNIT SCSI opcode
  target: improve unsupported opcode message
  ...

Pull second round of SCSI updates from James Bottomley:
 "There's one late arriving patch here (added today), fixing a build
  issue which the scsi_dh patch set in here uncovered.  Other than that,
  everything has been incubated in -next and the checkers for a week.

  The major pieces of this patch are a set patches facilitating better
  integration between scsi and scsi_dh (the device handling layer used
  by multi-path; all the dm parts are acked by Mike Snitzer).

  This also includes driver updates for mp3sas, scsi_debug and an
  assortment of bug fixes"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (50 commits)
  scsi_dh: fix randconfig build error
  scsi: fix scsi_error_handler vs. scsi_host_dev_release race
  fcoe: Convert use of __constant_htons to htons
  mpt2sas: setpci reset kernel oops fix
  pm80xx: Don't override ts->stat on IO_OPEN_CNX_ERROR_HW_RESOURCE_BUSY
  lpfc: Fix possible use-after-free and double free in lpfc_mbx_cmpl_rdp_page_a2()
  bfa: Fix incorrect de-reference of pointer
  bfa: Fix indentation
  scsi_transport_sas: Remove check for SAS expander when querying bay/enclosure IDs.
  scsi_debug: resp_request: remove unused variable
  scsi_debug: fix REPORT LUNS Well Known LU
  scsi_debug: schedule_resp fix input variable check
  scsi_debug: make dump_sector static
  scsi_debug: vfree is null safe so drop the check
  scsi_debug: use SCSI_W_LUN_REPORT_LUNS instead of SAM2_WLUN_REPORT_LUNS;
  scsi_debug: define pr_fmt() for consistent logging
  mpt2sas: Refcount fw_events and fix unsafe list usage
  mpt2sas: Refcount sas_device objects and fix unsafe list usage
  scsi_dh: return SCSI_DH_NOTCONN in scsi_dh_activate()
  scsi_dh: don't allow to detach device handlers at runtime
  ...

b9d5c6b7ef57 ("[SCSI] cleanup setting task state in
scsi_error_handler()") has introduced a race between scsi_error_handler
and scsi_host_dev_release resulting in the hang when the device goes
away because scsi_error_handler might miss a wake up:

CPU0					CPU1
scsi_error_handler			scsi_host_dev_release
  					  kthread_stop()
  kthread_should_stop()
    test_bit(KTHREAD_SHOULD_STOP)
					    set_bit(KTHREAD_SHOULD_STOP)
					    wake_up_process()
					    wait_for_completion()

  set_current_state(TASK_INTERRUPTIBLE)
  schedule()

The most straightforward solution seems to be to invert the ordering of
the set_current_state and kthread_should_stop.

The issue has been noticed during reboot test on a 3.0 based kernel but
the current code seems to be affected in the same way.

[jejb: additional comment added]
Cc: <stable@vger.kernel.org> # 3.6+
Reported-and-debugged-by: Mike Mayer <Mike.Meyer@teradata.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

Pull first round of SCSI updates from James Bottomley:
 "This includes one new driver: cxlflash plus the usual grab bag of
  updates for the major drivers: qla2xxx, ipr, storvsc, pm80xx, hptiop,
  plus a few assorted fixes.

  There's another tranch coming, but I want to incubate it another few
  days in the checkers, plus it includes a mpt2sas separated lifetime
  fix, which Avago won't get done testing until Friday"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (85 commits)
  aic94xx: set an error code on failure
  storvsc: Set the error code correctly in failure conditions
  storvsc: Allow write_same when host is windows 10
  storvsc: use storage protocol version to determine storage capabilities
  storvsc: use correct defaults for values determined by protocol negotiation
  storvsc: Untangle the storage protocol negotiation from the vmbus protocol negotiation.
  storvsc: Use a single value to track protocol versions
  storvsc: Rather than look for sets of specific protocol versions, make decisions based on ranges.
  cxlflash: Remove unused variable from queuecommand
  cxlflash: shift wrapping bug in afu_link_reset()
  cxlflash: off by one bug in cxlflash_show_port_status()
  cxlflash: Virtual LUN support
  cxlflash: Superpipe support
  cxlflash: Base error recovery support
  qla2xxx: Update driver version to 8.07.00.26-k
  qla2xxx: Add pci device id 0x2261.
  qla2xxx: Fix missing device login retries.
  qla2xxx: do not clear slot in outstanding cmd array
  qla2xxx: Remove decrement of sp reference count in abort handler.
  qla2xxx: Add support to show MPI and PEP FW version for ISP27xx.
  ...

Add a ->handler and a ->handler_data field to struct scsi_device and kill
this indirection.  Also move struct scsi_device_handler to scsi_dh.h so that
changes to it don't require rebuilding every SCSI LLDD.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>