Turns an order-8 allocation into slab-sized ones, thereby preventing
allocation failures with memory fragmentation.

This likely saves memory as well, as the slab allocator can pack objects
more tightly than the buddy allocator.

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

Turns an order-10 allocation into slab-sized ones, thereby preventing
allocation failures with memory fragmentation.

This likely saves memory as well, as the slab allocator can pack objects
more tightly than the buddy allocator.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Bump core version to v4.1.0-rc2-ml, and for versions from the
following mainline fabric modules:

loopback: v2.1-rc2
tcm_fc: v0.4
iscsi-target: v4.1.0-rc2
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch drops the following unused legacy API callers from target_core_fabric.h:

*) TFO->fall_back_to_erl0()
*) TFO->stop_session()
*) TFO->sess_logged_in()
*) TFO->is_state_remove()

This patch also removes the stub usage in loopback, tcm_fc, iscsi_target,
and ib_srpt fabric modules.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch converts core_tpg_del_initiator_node_acl() shutdown from configfs
context to use se_node_acl->acl_kref and ->acl_free_comp in order to wait for
outstanding fabric callbacks to complete via transport_deregister_session()
callbacks before waking ->acl_free_comp from the last ->acl_kref put.

It also changes core_tpg_del_initiator_node_acl() to setup a local sess_list
with target_get_session() + acl->acl_stop = 1 for active sessions that will
be shutdown, and changes transport_deregister_session_configfs() to check
for ->acl_stop usage.

Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joern Engel <joern@logfs.org>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds se_node_acl->acl_kref for use with ->acl_free_comp
during explict se_node_acl release.  It adds kref_init() during
se_node_acl setup, kref_get() during __transport_register_session()
-> target_put_nacl() with existing transport_deregister_session()
fabric callback usage.

It also moves transport_free_session() to release *se_sess memory
after target_put_nacl() execution in transport_deregister_session()

Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joern Engel <joern@logfs.org>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add se_node_acl->acl_free_comp for NodeACL release path to wait for outstanding
fabric session shutdown to complete in transport_deregister_session() before
finishing NodeACL release from configfs process context.

Also make transport_deregister_session() clear the comp_nacl bit
to skip se_node_acl->acl_free_comp completion for dynamically generated
NodeACL during fabric session shutdown.

Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joern Engel <joern@logfs.org>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds basic se_session->sess_kref and get/put helpers for fabric
session reference counting.  It sets the initial kref in transport_init_session()
and adds a target_release_session() callback to invoke TFO->close_session()
for final session shutdown.

Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joern Engel <joern@logfs.org>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch allows target_submit_tmr() to pass gfp_t for se_cmd->se_tmr_req
allocation, and also set up se_cmd->se_tmr_req->ref_task_tag for passed
tag with TMR_ABORT_TASK.

Also update tcm_fc(fcoe) parameter usgae and add ref_task_tag FIXME
for TMR_ABORT_TASK usage,

Cc: Andy Grover <agrover@redhat.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Arun Easi <arun.easi@qlogic.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch makes target_submit_tmr() se_tmr_req allocation occur before
target_get_sess_cmd(), and changes target_submit_tmr() to return a failure
w/ non zero status to the fabric caller upon core_tmr_alloc_req() failure.

Cc: Andy Grover <agrover@redhat.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Arun Easi <arun.easi@qlogic.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

se_dev_attrib.max_sectors currently has two independent meanings:

 - It is reported in the block limits VPD page as the maximum transfer
   length, ie the largest IO that the front-end (fabric) can handle.
   Also the target core doesn't enforce this maximum transfer length.

 - It is used to hold the size of the largest IO that the back-end can
   handle, so we know when to split SCSI commands into multiple tasks.

Fix this by adding a new se_dev_attrib.fabric_max_sectors to hold the
maximum transfer length, and checking incoming IOs against that limit.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If the initiator sends us an INQUIRY command with an allocation length
that's shorter than what we want to return, we're simply supposed to
truncate our response and return what the initiator gave us space for,
without signaling any error.  Current target code has various tests that
don't fill out the full response if the buffer is too short and
sometimes return errors incorrectly.

Fix this up by allocating a bounce buffer for INQUIRY responses if we
need to, ie if we have cmd->data_length too small as well as
SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC set in cmd->se_cmd_flags -- for most
fabrics, we always allocate at least a full page, but for tcm_loop we
may have a small buffer coming directly from the SCSI stack.

This lets us delete a lot of cmd->data_length checking, and also makes
our INQUIRY handling correct per SPC in a lot more cases.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When TARGET_SCF_ACK_KREF is in use with target_submit_cmd() for
setting the extra acknowledgement reference to se_cmd->cmd_kref,
go ahead and set SCF_ACK_KREF in order to be used later by
abort task.
Reported-by: NRoland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

transport_generic_request_failure() is a wrapper around calling
transport_send_check_condition_and_sense() that is required once
an se_cmd->cmd_kref has been obtained via target_submit_cmd() ->
target_get_sess_cmd().

tcm_qla2xxx currently requires this, and since it's necessary for
other callers using target_submit_cmd() make it exportable now.
Reported-by: NRoland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Similar to target_submit_cmd, this function lets fabrics call one function
(albeit with a lot of parameters) instead of 3 or more.

(nab: Add missing return for transport_lookup_tmr_lun failure)
Signed-off-by: NAndy Grover <agrover@redhat.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Change the test for if a cmd is a tmr request to checking if
SCF_SCSI_TMR_CDB (a new flag) is set in cmd->se_cmd_flags.

Also remove se_tmr_req_cache usage in favor of kzalloc usage,
and make core_tmr_alloc_req() return int + setup se_cmd->se_tmr_req
directly and fix up various fabric module usages

Cc: Andy Grover <agrover@redhat.com>
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>

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

There is no reason to have a flag telling if a command is on the per-lun list,
we can simply do a list_empty check before removing it as long as we're careful
to always use list_del_init.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
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>

Retval not very useful, and may even be harmful. Once submitted, fabrics
should expect a sense error if anything goes wrong. All fabrics checking
of this retval are useless or broken:

fc checks it just to emit more debug output.
ib_srpt trickles retval up, then it is ignored.
qla2xxx trickles it up, which then causes a bug because the abort goto
in qla_target.c thinks cmd hasn't been sent to target.

Just returning nothing is best.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We need to handle >1 page control cdbs, so extend the code to do a vmap
if bigger than 1 page. It seems like kmap() is still preferable if just
a page, fewer TLB shootdowns(?), so keep using that when possible.

Rename function pair for their new scope.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The target code was not setting the additional sense length field in the
sense data it returned, which meant that at least the Linux stack
ignored the ASC/ASCQ fields.  For example, without this patch, on a
tcm_loop device:

    # sg_raw -v /dev/sda 2 0 0 0 0 0

gives

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
      Raw sense data (in hex):
            70 00 05 00 00 00 00 00

while after the patch we correctly get the following (which matches what
a regular disk returns):

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
     Additional sense: Invalid command operation code
     Raw sense data (in hex):
            70 00 05 00 00 00 00 0a  00 00 00 00 20 00 00 00
            00 00
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch makes __transport_execute_tasks() perform the addition of
tasks to dev->execute_task_list via __transport_add_tasks_from_cmd()
while holding dev->execute_task_lock during normal I/O fast path
submission.

It effectively removes the unnecessary re-acquire of dev->execute_task_lock
during transport_execute_tasks() -> transport_add_tasks_from_cmd() ahead
of calling  __transport_execute_tasks() to queue tasks for the passed
*se_cmd descriptor.

(v2: Re-add goto check_depth usage for multi-task submission for now..)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Historically, pSCSI devices have been the ones that required target-core
to enforce a per se_device->depth_left.  This patch changes target-core
to no longer (by default) enforce a per se_device->depth_left or sleep in
transport_tcq_window_closed() when we out of queue slots for all backend
export cases.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove the now unused target_core_fabric_ops->check_release_cmd() as
target_core handles this directly for se_cmd->cmd_kref objects now.

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

This patch adds a target_submit_cmd() caller that can be used by fabrics
to submit an uninitialized se_cmd descriptor to an struct se_session +
unpacked_lun from workqueue process context.  This call will invoke the
following steps:

- transport_init_se_cmd() to setup se_cmd specific pointers
- Obtain se_cmd->cmd_kref references with target_get_sess_cmd()
- set se_cmd->t_tasks_bidi
- transport_lookup_cmd_lun() to setup struct se_cmd->se_lun from
  the passed unpacked_lun
- transport_generic_allocate_tasks() to setup the passed *cdb, and
- transport_handle_cdb_direct() handle READ dispatch or WRITE
  ready-to-transfer callback to fabric

v2 changes from hch feedback:

*) Add target_sc_flags_table for target_submit_cmd flags
*) Rename bidi parameter to flags, add TARGET_SCF_BIDI_OP
*) Convert checks to BUG_ON
*) Add out_check_cond for transport_send_check_condition_and_sense
   usage

v3 changes:

*) Add TARGET_SCF_ACK_KREF for target_submit_cmd into
   target_get_sess_cmd to determine when the fabric caller is expecting
   a second kref_put() from fabric packet acknowledgement.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch moves target_put_sess_cmd() to use a se_cmd->cmd_kref
callback target_release_cmd_kref when performing driver release of
fabric->se_cmd descriptor memory.  It sets the default cmd_kref
count value to '2' within target_get_sess_cmd() setup, and
currently assumes TFO->check_stop_free() usage.

It drops se_tfo->check_release_cmd() usage in the main
transport_release_cmd codepath.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If we want dynamically allocated objects to be cacheline aligned we need
to tell that to the slab allocator by using the proper flags and not
by liberally sprinkling annotations onto all structures.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is no need to make task_state_active an atomic_t given that it is
always set under the execute_task_lock so we can make it a simple bool.
Also rename it to t_state_active to be closer to the list it guards,
and make sure all checks before the list addion/removal actually happen
under execute_task_lock.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We only reach transport_complete_task once per task, so the test and set on
task_error_status is never going to have an effect.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This reorganized the headers under include/target into:

 - target_core_base.h stays as is with all target-wide data stuctures and defines
 - target_core_backend.h contains the whole interface to I/O backends
 - target_core_fabric.h contains the whole interface to fabric modules

Except for those only the various configfs macro headers stay around.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Create a new headers, drivers/target/target_core_internal.h that is supposed
to hold all target_core-internal prototypes.  Move all non-exported includes
from include/target to it, and merge the smaller prototype-only includes
inside drivers/target into it as well.  Mark functions that were found to
not be called outside their implementation file static.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Some are never used, some are set but never read, dev_hoq_count is
incremented and decremented, but never read.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

And use a SCF_BIDI flag instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

And use a SCF_FUA flag instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We never walk ordered_cmd_list in the se_device, so remove all code related
to supporting it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>