Previously we notified iscsi layer about the connection layer when
we consumed all of our flush errors. This was racy as there
was no guarentee that iscsi_conn wasn't terminated by then (which ends
up in an invalid memory access). In case we got a non FLUSH error
completion, we are guarenteed that iscsi_conn is still alive. We should
notify iSCSI layer with iscsi_conn_failure to initiate error handling.

While we are at it, add a nice kernel-doc style documentation.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

We no longer rely on iscsi connection teardown sequence, so no need to
give a grace period and continue cleanup if it expired. Have
iser_conn_release wait for full completion before freeing iser_conn.

ib_completion:
	Guaranteed to come when:
	    - Got DISCONNECTED/ADDR_CHANGE event or
	    - iSCSI called ep_disconnect/conn_stop
	Guaranteed to finish when:
	    - Got TIMEWAIT_EXIT/DEVICE_REMOVAL event
	    - All Flush errors are consumed
	    - IB related resources are destroyed

stop_completion:
	Guaranteed to come when:
	    - iSCSI calls conn_stop
	Guaranteed to finish when:
	    - All inflight tasks were cleaned up
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

iscsi daemon is in user-space, thus we can't rely on it to be invoked
at connection teardown (if not running or does not receive CPU time).

This patch addresses the issue by re-structuring iSER connection
teardown logic and CM events handling.

The CM events will dictate the RDMA resources destruction (ib_conn)
and iser_conn is kept around as long as iscsi_conn is left around
allowing iscsi/iser callbacks to continue after RDMA transport was
destroyed.

This patch introduces a separation in logic when handling CM events:

- DISCONNECTED_HANDLER, ADDR_CHANGED
  This events indicate the start of teardown process.
  Actions:
  1. Terminate the connection: rdma_disconnect (send DREQ/DREP)
  2. Notify iSCSI of connection failure
  3. Change state to TERMINATING
  4. Poll for all flush errors to be consumed

- TIMEWAIT_EXIT, DEVICE_REMOVAL
  These events indicate the final stage of termination process and
  we can free RDMA related resources.
  Actions:
  1. Call disconnected handler (we are not guaranteed that DISCONNECTED
     event was invoked in the past)
  2. Cleanup RDMA related resources
  3. For DEVICE_REMOVAL return non-zero rc from cma_handler to
     implicitly destroy the cm_id (Can't rely on user-space, make sure
     we have forward progress)

We replace flush_completion (indicate all flushes were consumed) with
ib_completion (rdma resources were cleaned up).

The iser_conn_release_work will wait for teardown completions:

- conn_stop was completed (tasks were cleaned-up) - stop_completion
- RDMA resources were destroyed - ib_completion

And then will continue to free iser connection representation (iser_conn).
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Put all connection IB related resources release in this routine.  One
exception is the cm_id which cannot be destroyed as the routine is
protected by the state mutex.  Also move its position to avoid forward
declaration.  While at it fix qp NULL assignment.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Structure that describes the RDMA relates connection objects.  Static
member of iser_conn.

This patch does not change any functionality
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Two reasons why we choose to do this:

1. No point today calling struct iser_conn by another name ib_conn
2. In the next patches we will restructure iser control plane representation
   - struct iser_conn: connection logical representation
   - struct ib_conn: connection RDMA layout representation

This patch does not change any functionality.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

When failing to allocate TX CQ we already allocated RX CQ, so we need to make
sure we release it. Also, when failing to register notification to the RX CQ
we currently leak both RX and TX CQs of the current index, fix that too.
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This is to prevent someone from thinking that this code section is
redundant.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Instead of waiting for events and condition changes of the iser
connection state, we wait for explicit completion of connection
establishment and teardown.

Separate connection establishment wait object from the teardown object
to avoid a situation where racing connection establishment and
teardown may concurrently wakeup each other.

ep_poll will wait for up_completion invoked by
iser_connected_handler() and iser release worker will wait for
flush_completion before releasing the connection.

Bound the completion wait with a 30 seconds timeout for cases where
iscsid (the user space iscsi daemon) is too slow or gone.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The iser connection state lookups and transitions are not fully protected.

Some transitions are protected with a spinlock, and in some cases the
state is accessed unprotected due to specific assumptions of the flow.

Introduce a new mutex to protect the connection state access. We use a
mutex since we need to also include a scheduling operations executed
under the state lock.

Each state transition/condition and its corresponding action will be
protected with the state mutex.

The rdma_cm events handler acquires the mutex when handling connection
events. Since iser connection state can transition to DOWN
concurrently during connection establishment, we bailout from
addr/route resolution events when the state is not PENDING.

This addresses a scenario where ep_poll retries expire during CMA
connection establishment. In this case ep_disconnect is invoked while
CMA events keep coming (address/route resolution, connected, etc...).
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Make it void.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

iser connection needs asynchronous cleanup completions which are
triggered in ep_disconnect.  As a result we are keeping the
corresponding iscsi_endpoint structure hanging for no good reason. In
order to avoid that, we seperate iser_conn from iscsi_endpoint storage
space to have their destruction being independent.

iscsi_endpoint will be destroyed at ep_disconnect stage, while the
iser connection will wait for asynchronous completions to be released
in an orderly fashion.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The iser initiator is the RDMA responder so it should publish to the
target the max inflight rdma read requests its local HCA can handle in
responder_resources (max_qp_rd_atom).

The iser target should take the min of that and its local HCA max
inflight oustanding rdma read requests (max_qp_init_rd_atom).

We keep initiator_depth set to 1 in order to compat with old targets.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

In case the DISCONNECTED event is not delivered after rdma_disconnect
is called, the CM waits TIMEWAIT seconds and delivers the
TIMEWAIT_EXIT local event. We use this as the notification needed to
continue in the teardown and release sequence.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Replace struct sockaddr_in with struct sockaddr which supports both
IPv4 and IPv6, and print using the %pIS format directive.
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

In some circumstances (multiple targets), RDMA_CM ESTABLISHED event
and ep_disconnect may race. In this case, the iser connection state
may transition to UP (after ep_disconnect transitioned it to
TERMINATING), while the connection is being torn down.

Upon RDMA_CM event ESTABLISHED we allow iser connection state to
transition to UP only from PENDING. We also make sure to protect this
state change (done under the connection lock).
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

iSER relies on refcounting to manage iser connections establishment
and teardown.

Following commit 39ff05db ("IB/iser: Enhance disconnection logic
for multi-pathing"), iser connection maintain 3 references:

 - iscsi_endpoint (at creation stage)
 - cma_id (at connection request stage)
 - iscsi_conn (at bind stage)

We can avoid taking explicit refcounts by correctly serializing iser
teardown flows (graceful and non-graceful).

Our approach is to trigger a scheduled work to handle ordered teardown
by gracefully waiting for 2 cleanup stages to complete:

 1. Cleanup of live pending tasks indicated by iscsi_conn_stop completion
 2. Flush errors processing

Each completed stage will notify a waiting worker thread when it is
done to allow teardwon continuation.

Since iSCSI connection establishment may trigger endpoint disconnect
without a successful endpoint connect, we rely on the iscsi <-> iser
binding (.conn_bind) to learn about the teardown policy we should take
wrt cleanup stages.

Since all cleanup worker threads are scheduled (release_wq) in
.ep_disconnect it is safe to assume that when module_exit is called,
all cleanup workers are already scheduled. Thus proper module unload
shall flush all scheduled works before allowing safe exit, to
guarantee no resources got left behind.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NRoi Dayan <roid@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Update Mellanox copyrights for 2014 on the iser initiator driver.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Add an iser info print with the local/remote QP information carried
out when the connection is established.  While here, fix a little
leftover from the T10 work and set a debug print to be carried in
debug and not info level.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The iscsi stack has existing mechanisms to link back and forth between
the iscsi connection and the iscsi transport (e.g iser/tcp) connection.

This is done through a dd_data pointer field in struct iscsi_conn
which can be set to point to the transport connection, etc.

The iscsi_iser_conn structure was used to get this linking done in
another way, which is uneeded and adds extra complication to the iser
code, so we just remove it.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The iser disconnection flow isn't done before all the inflight
recv/send buffers posted to the QP are either flushed or normally
completed to the CQ that serves this connection.  The condition check
is done in iser_handle_comp_error().

Currently, it's possible for the send buffer completion that makes the
posted send buffers counter reach zero to be polled in the drain tx
call, which is after the rx cq is fully drained.  Since this
completion might be not an error one (for example, it might be a
completion of the logout request iSCSI PDU) we will skip
iser_handle_comp_error().  So the connection will never terminate from
the iscsi stack point of view, and we hang.

To resolve this race, do the draining of the tx cq before the loop on
the rx cq.
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Fix pr_err (printk) format warning:

    drivers/infiniband/ulp/iser/iser_verbs.c:1181:4: warning: format '%lx' expects argument of type 'long unsigned int', but argument 3 has type 'sector_t' [-Wformat]
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Once the iSCSI transaction is completed we must implement
check_protection in order to notify on DIF errors that may have
occured.

The routine boils down to calling ib_check_mr_status to get the
signature status of the transaction.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

During connection establishment we also initialize T10-PI resources
(QP, PI contexts) in order to support SCSI's protection operations.
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Use modparams to activate protection information support.

pi_enable bool: Based on this parameter iSER will know if it should
support T10-PI.  We don't want to do this by default as it requires to
allocate and initialize extra resources.  In case pi_enable=N, iSER
won't publish to SCSI midlayer any DIF capabilities.

pi_guard int: Based on this parameter iSER will publish DIX guard type
support to SCSI midlayer.  0 means CRC is allowed to be passed in DIX
buffers, 1 (or non-zero) means IP-CSUM is allowed to be passed in DIX
buffers.  Note that over the wire, only CRC is allowed.

In the next phase, it is worth considering passing these parameters
from iscsid via nlmsg.  This will allow these parameters to be
connection based rather than global.
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

In T10-PI support we will have memory keys for protection buffers and
signature transactions.  We prefer to compact indicators rather than
keeping multiple bools.

This commit does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

For T10-PI offload support, we will need to know the device signature
offload capability upon every connection establishment.

This patch does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

fastreg descriptor will include protection information context.  In
order to place the logic in one place we introduce iser_create_fr_desc
function.

This patch does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

FRWR stands for "fast registration work request". We want to avoid
calling the fastreg pool with that name, instead we name it fastreg
which stands for "fast registration".

This pool will include more elements in the future, so it is a good
idea to generalize the name.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

In case iSER uses fast registration method, it should not request for
successful completions on fast registration nor local invalidate
requests.  We color wr_id with ISER_FRWR_LI_WRID in order to correctly
consume error completions.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Fix a possible NULL pointer dereference in disconnection flow. This
can happen if the target disconnected/rejected the connection request,
e.g before the binding stage between iscsi connection to the transport
connection.
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Fix leak where desc is not being freed in error flows.
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Newer HCAs and Virtual functions may not support FMRs but rather a fast
registration model, which we call FRWR - "Fast Registration Work Requests".

This model was introduced in 00f7ec36 ("RDMA/core: Add memory management
extensions support") and works when the IB device supports the
IB_DEVICE_MEM_MGT_EXTENSIONS capability.

Upon creating the iser device iser will test whether the HCA supports
FMRs.  If no support for FMRs, check if IB_DEVICE_MEM_MGT_EXTENSIONS
is supported and assign function pointers that handle fast
registration and allocation of appropriate resources (fast_reg
descriptors).

Registration is done using posting IB_WR_FAST_REG_MR to the QP and
invalidations using posting IB_WR_LOCAL_INV.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This is preparation step for other memory registration methods to be
added.  In addition, change reg/unreg routines signature to indicate
they use FMRs.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Currently the driver uses FMRs as the only means to register the
memory pointed by SG provided by the SCSI mid-layer with the RDMA
device.

As preparation step for adding more methods for fast path memory
registration, make the alloc/free and reg/unreg calls function
pointers, which are for now just set to the existing FMR ones.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Use cmds_max passed from user space to be the number of PDUs to be
supported for the session instead of hard-coded ISCSI_DEF_XMIT_CMDS_MAX.
This allow controlling the max number of SCSI commands for the session.
Also don't ignore the qdepth passed from user space.

Derive from session->cmds_max the actual number of RX buffers and FMR
pool size to allocate during the connection bind phase.

Since the iser transport connection is established before the iscsi
session/connection are created and bound, we still use one hard-coded
quantity ISER_DEF_XMIT_CMDS_MAX to compute the maximum number of
work-requests to be supported by the RC QP used for the connection.

The above quantity is made to be a power of two between ISCSI_TOTAL_CMDS_MIN
(16) and ISER_DEF_XMIT_CMDS_MAX (512) inclusive.
Signed-off-by: NShlomo Pongratz <shlomop@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This is a preparation step to a patch that accepts the number of max
SCSI commands to be supported a session from user space iSCSI tools.

Move the allocation of the login buffer, FMR pool and its associated
page vector from iser_create_ib_conn_res() (which is called prior when
we actually know how many commands should be supported) to
iser_alloc_rx_descriptors() (which is called during the iscsi
connection bind step where this quantity is known).

Also do small refactoring around the deallocation to make that path
similar to the allocation one.
Signed-off-by: NShlomo Pongratz <shlomop@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Add Mellanox copyright to the iser initiator source code which I maintain.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Change the code to destroy the "last opened" rdma_cm id after making
sure we released all other objects (QP, CQs, PD, etc) associated with
the IB device.

Since iser accesses the IB device using the rdma_cm id, we need to
free any objects that are related to the device that is associated
with the rdma_cm id prior to destroying that id.  When this isn't
done, the low level driver that created this device can be unloaded
before iser has a chance to free all the objects and a such a call may
invoke code segment which isn't valid any more and crash.

Cc: Sean Hefty <sean.hefty@intel.com
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Annex A12 of the IBTA spec defines additional information that needs
to be provided through the CM exchange relating to usage of ZBVA (Zero
Based VAs) and Send With Invalidate over an iSER connection.

Currently, the initiator sets both to not supported, but does provide
the header so that existing iSER targets can be patched to start
looking on the private data carried by the CM.

This is a preparation step to enable iSER with HW drivers for which
FMRs are not supported, such as mlx4 VF instances or new HW devices
which might support only FRWR (Fast Registration Work-Requests) along
the details of the IB_DEVICE_MEM_MGT_EXTENSIONS device capability.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>