This patch refactors existing traditional iscsi RX side PDU handling
to use iscsit_transport, and exports the necessary logic for external
transport modules.

This includes:

- Refactor iscsit_handle_scsi_cmd() into PDU setup / processing
- Add updated iscsit_handle_scsi_cmd() for tradtional iscsi code
- Add iscsit_set_unsoliticed_dataout() wrapper
- Refactor iscsit_handle_data_out() into PDU check / processing
- Add updated iscsit_handle_data_out() for tradtional iscsi code
- Add iscsit_handle_nop_out() + iscsit_handle_task_mgt_cmd() to
  accept pre-allocated struct iscsi_cmd
- Add iscsit_build_r2ts_for_cmd() caller for iscsi_target_transport
  to handle ISTATE_SEND_R2T for TX immediate queue
- Refactor main traditional iscsi iscsi_target_rx_thread() PDU switch
  into iscsi_target_rx_opcode() using iscsit_allocate_cmd()
- Turn iscsi_target_rx_thread() process context into NOP for
  ib_isert side work-queue.

v5 changes:

- Make iscsit_handle_scsi_cmd() static (Fengguang)
- Fix iscsit_handle_scsi_cmd() exception se_cmd leak (nab)

v3 changes:
- Add extra target_put_sess_cmd call in iscsit_add_reject_from_cmd
  after completion

v2 changes:

- Disable iscsit_ack_from_expstatsn() usage for RDMAExtentions=Yes
- Disable iscsit_allocate_datain_req() usage for RDMAExtentions=Yes
- Add target_get_sess_cmd() reference counting to
  iscsit_setup_scsi_cmd()
- Add TFO->lio_check_stop_free() fabric API caller
- Add export of iscsit_stop_dataout_timer() symbol
- Add iscsit_build_r2ts_for_cmd() for iscsit_transport->iscsit_get_dataout()
- Convert existing usage of iscsit_build_r2ts_for_cmd() to
  ->iscsit_get_dataout()
- Drop RDMAExtentions=Yes specific check in iscsit_build_r2ts_for_cmd()
- Fix RDMAExtentions -> RDMAExtensions typo (andy)
- Pass correct dump_payload value into iscsit_get_immediate_data()
  for iscsit_handle_scsi_cmd()
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch converts struct iscsi_cmd memory allocation + free to use
->iscsit_alloc_cmd() iscsit_transport API caller, and export
iscsit_allocate_cmd() symbols

Also add iscsi_cmd->release_cmd() to be used seperately from
iscsit_transport for connection/session shutdown.

v2 changes:

- Remove unnecessary checks in iscsit_alloc_cmd (asias)
- Drop iscsit_transport->iscsit_free_cmd() usage
- Drop iscsit_transport->iscsit_unmap_cmd() usage
- Add iscsi_cmd->release_cmd()
- Convert lio_release_cmd() to use iscsi_cmd->release_cmd()
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch performs the initial conversion of existing traditional iscsi
to use iscsit_transport API callers.  This includes:

- iscsi-np cleanups for iscsit_transport_type
- Add iscsi-np transport calls w/ ->iscsit_setup_up() and ->iscsit_free_np()
- Convert login thread process context to use ->iscsit_accept_np() for
  connections with pre-allocated struct iscsi_conn
- Convert existing socket accept code to iscsit_accept_np()
- Convert login RX/TX callers to use ->iscsit_get_login_rx() and
  ->iscsit_put_login_tx() to exchange request/response PDUs
- Convert existing socket login RX/TX calls into iscsit_get_login_rx()
  and iscsit_put_login_tx()
- Change iscsit_close_connection() to invoke ->iscsit_free_conn() +
  iscsit_put_transport() calls.
- Add iscsit_register_transport() + iscsit_unregister_transport() calls
  to module init/exit

v4 changes:

- Add missing iscsit_put_transport() call in iscsi_target_setup_login_socket()
  failure case

v2 changes:

- Update module init/exit to use register_transport() + unregister_transport()
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch addresses a v3.5+ regression in iscsi-target where TX thread
process context -> handle_response_queue() execution is allowed to run
unbounded while servicing constant outgoing flow of ISTATE_SEND_DATAIN
response state.

This ends up preventing memory release of StatSN acknowledged commands
in a timely manner when under heavy large block streaming DATAIN
workloads.

The regression bug was initially introduced with:

commit 6f3c0e69
Author: Andy Grover <agrover@redhat.com>
Date:   Tue Apr 3 15:51:09 2012 -0700

    target/iscsi: Refactor target_tx_thread immediate+response queue loops

Go ahead and follow original iscsi_target_tx_thread() logic and check
to break for immediate queue processing after each DataIN Sequence and/or
Response PDU has been sent.
Reported-by: NBenjamin ESTRABAUD <be@mpstor.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch refactors the sockaddr matching logic in iscsit_get_np() into
a seperate iscsit_check_np_match() that can be used by external code.
Tested-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The function iscsit_build_conn_drop_async_message() is called
from iscsit_close_connection() with spin lock 'sess->conn_lock'
held, so we should use GFP_ATOMIC instead of GFP_KERNEL.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a bug in the hanlding of initiator provided ExpStatSN and
individual iscsi_cmd->stat_sn comparision during iscsi_conn->stat_sn
wrap-around within iscsit_ack_from_expstatsn() code.

This bug would manifest itself as iscsi_cmd descriptors not being Acked
by a lower ExpStatSn, causing them to be leaked until an iSCSI connection
or session reinstatement event occurs to release all commands.

Also fix up two other uses of incorrect CmdSN SNA comparison to use wrapper
usage from include/scsi/iscsi_proto.h.
Signed-off-by: NSteve Hodgson <steve@purestorage.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Pass the sense reason as an explicit return value from the I/O submission
path instead of storing it in struct se_cmd and using negative return
values.  This cleans up a lot of the code pathes, and with the sparse
annotations for the new sense_reason_t type allows for much better
error checking.

(nab: Convert spc_emulate_modesense + spc_emulate_modeselect to use
      sense_reason_t with Roland's MODE SELECT changes)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The sleeping code in iscsi_target_tx_thread() is susceptible to the classic
missed wakeup race:

 - TX thread finishes handle_immediate_queue() and handle_response_queue(),
   thinks both queues are empty.
 - Another thread adds a queue entry and does wake_up_process(), which does
   nothing because the TX thread is still awake.
 - TX thread does schedule_timeout() and sleeps forever.

In practice this can kill an iSCSI connection if for example an initiator
does single-threaded writes and the target misses the wakeup window when
queueing an R2T; in this case the connection will be stuck until the
initiator loses patience and does some task management operation (or kills
the connection entirely).

Fix this by converting to wait_event_interruptible(), which does not
suffer from this sort of race.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Make sure all on the wire types are use as big endian and big endian only so
that sparse can verify all the conversions are done right.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Use the special itt_t type defined by the iscsi headers and the initiator
to make sure it's an opaque value.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Sparse noticed that INADDR_ANY needs to be converted to big endian before
it can be stored in struct sockaddr_in.s_addr.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fix a potential multiple spin-unlock -> deadlock scenario during the
overflow check within iscsit_build_sendtargets_resp() as found by
sparse static checking.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch marks a number of functions static to appease sparse static
checking.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Now that iscsi-target supports a local configurable MaxXmitDataSegmentLength,
go ahead and make ISCSI_OP_SCSI_CMD, ISCSI_OP_SCSI_DATA_OUT, ISCSI_OP_NOOP_OUT
and ISCSI_OP_TEXT PDU payload checks honor conn_ops->MaxXmitDataSegmentLength.

Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds a missing iscsi_reject->ffffffff assignment within
iscsit_send_reject() code to properly follow RFC-3720 Section 10.17
Bytes 16 -> 19 for the PDU format definition of ISCSI_OP_REJECT.

We've not seen any initiators care about this bytes in practice, but
as Ronnie reported this was causing trouble with wireshark packet
decoding lets go ahead and fix this up now.
Reported-by: NRonnie Sahlberg <ronniesahlberg@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Every fabric driver has to supply a se_tfo->set_fabric_sense_len()
method, just so iSCSI can return an offset of 2.  However, every fabric
driver is already allocating a sense buffer and passing it into the
target core, either via transport_init_se_cmd() or target_submit_cmd().

So instead of having iSCSI pass the start of its sense buffer into the
core and then later tell the core to skip the first 2 bytes, it seems
easier for iSCSI just to do the offset of 2 when it passes the sense
buffer into the core.  Then we can drop the se_tfo->set_fabric_sense_len()
everywhere, and just add a couple of lines of code to iSCSI to set the
sense data length to the beginning of the buffer right before it sends
it over the network.

(nab: Remove .set_fabric_sense_len usage from tcm_qla2xxx_npiv_ops +
      change transport_get_sense_buffer to follow v3.6-rc6 code w/o
      ->set_fabric_sense_len usage)
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

From Al Viro:

	BTW, speaking of struct file treatment related to sockets -
        there's this piece of code in iscsi:
        /*
         * The SCTP stack needs struct socket->file.
         */
        if ((np->np_network_transport == ISCSI_SCTP_TCP) ||
            (np->np_network_transport == ISCSI_SCTP_UDP)) {
                if (!new_sock->file) {
                        new_sock->file = kzalloc(
                                        sizeof(struct file), GFP_KERNEL);

For one thing, as far as I can see it'not true - sctp does *not* depend on
socket->file being non-NULL; it does, in one place, check socket->file->f_flags
for O_NONBLOCK, but there it treats NULL socket->file as "flag not set".
Which is the case here anyway - the fake struct file created in
__iscsi_target_login_thread() (and in iscsi_target_setup_login_socket(), with
the same excuse) do *not* get that flag set.

Moreover, it's a bloody serious violation of a bunch of asserts in VFS;
all struct file instances should come from filp_cachep, via get_empty_filp()
(or alloc_file(), which is a wrapper for it).  FWIW, I'm very tempted to
do this and be done with the entire mess:
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

All three callers of transport_generic_handle_data are from user context
and can use target_execute_cmd directly to handle the backend I/O submission
of WRITE I/O.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a bug in iscsit_allocate_iovecs() where iov_count was
incorrectly calculated using min(1UL, data_length / PAGE_SIZE) instead of
max(1UL, data_length / PAGE_SIZE), that ends up triggering an OOPs for
large block I/O when the SGL <-> iovec mapping exceeds the bogus iov_count
allocation size.

This is a regression introduced during the iscsi-target conversion back
to using core memory allocation here:

commit bfb79eac
Author: Andy Grover <agrover@redhat.com>
Date:   Tue Apr 3 15:51:29 2012 -0700

    target/iscsi: Go back to core allocating data buffer for cmd

Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We originally changed iscsi to allocate its own buffers just as an
intermediate step to clean up some core buffer allocation mechanisms. Now
we can put it back.

Also had to change allocate_iovecs to use data_length instead of
t_data_nents because iovecs are now allocated before the data buffer, thus
t_data_nents is not yet initialized.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Rename iscsit_build_pdu_and_seq_list to iscsit_do_build_pdu_and_seq_lists

Rename iscsit_do_build_list to iscsit_build_pdu_and_seq_lists

Move code from iscsit_decide_list_to_build into _seq_pdu_list.c, seems
a better fit.

Also update some comments in pdu/seq code for correctness and whitespace.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Redundant, just use iscsi_cmd->se_cmd.data_length once se_cmd is
initialized, or hdr->data_length before then.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

if we can get calls to init_se_cmd, get_sess_cmd, lookup_cmd_lun,
core_alua_check_nonop_delay, and handle_cdb_direct next to each other,
then we can just call target_submit_cmd. This is a step towards that
goal.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Trying to move a bunch of stuff around so iscsi can use target_submit_cmd
someday, and so stuff needs to be in that function directly instead of
hidden, so it can be reordered etc.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch renames a horribly misnamed function that no longer allocate
tasks to something more descriptive for it's modern use in target core.

(nab: Fix up ib_srpt to use this as well ahead of a target_submit_cmd
conversion)
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch includes the handful of squashed patches for target/iscsi from
Andy's original series into lio-core/master code:

*) Make iscsit_add_reject static
*) Remove unused data_offset_end from iscsi_datain_req
*) Remove "#if 0" stubs
*) Rename iscsi_datain_req to cmd_datain_node
*) Cleanups for built_r2ts_for_cmd()
*) Cleanups for Cleanup build_sendtargets_response()
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Immediate queue:

Consolidate down to one switch statement by moving send_tx_data and stuff
from second switch into the first switch, or the functions the first switch
calls.

Response queue:

Do not lock istate_lock except directly around i_state modifications.

Put entire ISTATE_SEND_DATAIN path within first switch statement, in prep
for further refactoring.

All other cases set use_misc = 1 and will not be using sendpage, so just
use send_tx_data for these and set use_misc param to 1.

map_sg, sent_status, use_misc, and se_cmd vars no longer needed.

Then put immediate and response handling in separate functions in order
to get iscsi_target_tx_thread down to where it fits on a page.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When processing immediate queue, we're switching on a local variable
so it's not necessary to lock around it. However, we are modifying
cmd->i_state in two spots, so lock around those parts only.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

*) Use decoded cmd->immediate_cmd for conditional instead of
   re-examining hdr->opcode
*) Make iscist_dataout_post_crc_passed more legible
*) use max() to reduce code in build_r2ts_for_cmd()
*) Remove CONFIG_SMP and if 0 ifdefs
*) Replace if/goto with a while loop
*) Remove unused conn->tx_immediate_queue and tx_response_queue
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The name change makes it clear this list_head is so the cmd can be an
item in the connection's conn_cmd_list.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Get rid of a bunch of write-only variables.  In a number of cases I
suspect actual bugs to be present, so I left all of those for a second
look.

(nab: fix lio-core patch fuzz)
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch addresses a iscsi-target specific bug related to reservation conflict
handling in iscsit_handle_scsi_cmd() that has been causing reservation conflicts
to complete and not fail as expected due to incorrect errno checking.  The problem
occured with the change to return -EBUSY from transport_generic_cmd_sequencer() ->
transport_generic_allocate_tasks() failures, that broke iscsit_handle_scsi_cmd()
checking for -EINVAL in order to invoke a non GOOD status response.

This was manifesting itself as data corruption with legacy SPC-2 reservations,
but also effects iscsi-target LUNs with SPC-3 persistent reservations.

This bug was originally introduced in lio-core commit:

commit 03e98c9e
Author: Nicholas Bellinger <nab@linux-iscsi.org>
Date:   Fri Nov 4 02:36:16 2011 -0700

    target: Address legacy PYX_TRANSPORT_* return code breakage
Reported-by: NMartin Svec <martin.svec@zoner.cz>
Cc: Martin Svec <martin.svec@zoner.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch converts iscsi-target session code to use se_sess->sess_kref
counting for iscsi session shutdown.  The following cases include:

*) last iscsit_close_connection() shutdown path to invoke close session
*) iscsit_logout_post_handler_closesession() for explict logout
*) iscsit_free_session() caller for explict shutdown

It also moves iscsit_stop_session() call from lio_tpg_close_session()
into lio_tpg_shutdown_session() TFO callbacks to invoke an explict
shutdown, and also changes iscsi_check_for_session_reinstatement()
login code to use se_sess->sess_kref.

(v2: Make iscsit_handle_time2retain_timeout() use target_put_session)

Cc: Andy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Make iscsit_alloc_buffs() failure case for page_alloc_failed use correct
__free_page() SGL pointer, and return -ENOMEM for iscsit_allocate_iovecs
failure to push se_cmd->t_mem_sg release into iscsit_release_cmd()
callback during iscsit_add_reject_from_cmd() connection reset.

Also drop cmd->t_mem_sg = NULL assignment from page_alloc_failed
failure case.
Reported-by: NRoland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

iscsit_get_lun_for_{cmd,tmr} are unnecessary.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Replace various atomic_ts used as flags in struct se_cmd with a single
transport_state bitmap that requires t_state_lock to be held for modifications.

In the target core that assumption generally is true, but some recently added
code in the SRP target had to grow new lock calls.  I can't say I like the way
how it messes with the command state directly, but let's leave that for later.

(Re-add missing ib_srpt.c changes that nab dropped..)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Trim security.h
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJames Morris <jmorris@namei.org>