Since the block layer already contains functionality to assign
a tag to each request, use that functionality instead of
reimplementing that functionality in the SRP initiator driver.
This change makes the free_reqs list superfluous. Hence remove
that list.

[hch: updated to use .use_blk_tags instead scsi_activate_tcq]
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Changes in this patch:
- Move channel variables into a new structure (struct srp_rdma_ch).
- Add an srp_target_port pointer, 'lock' and 'comp_vector' members
  in struct srp_rdma_ch.
- Add code to initialize these three new member variables.
- Many boring "target->" into "ch->" changes.
- The cm_id and completion handler context pointers are now of type
  srp_rdma_ch * instead of srp_target_port *.
- Three kzalloc(a * b, f) calls have been changed into kcalloc(a, b, f)
  to avoid that this patch would trigger a checkpatch warning.
- Two casts from u64 into unsigned long long have been left out
  because these are superfluous. Since considerable time u64 is
  defined as unsigned long long for all architectures supported by
  the Linux kernel.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Introduce the srp_target_port member variables 'sgid' and 'pkey'.
Change the type of 'orig_dgid' from __be16[8] into union ib_gid.
This patch does not change any functionality but makes the
"Separate target and channel variables" patch easier to verify.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

If a cable is pulled during LUN scanning it can happen that the
SRP rport and the SCSI host have been created but no LUNs have been
added to the SCSI host. Since multipathd only sends SCSI commands
to a SCSI target if one or more SCSI devices are present and since
there is no keepalive mechanism for IB queue pairs this means that
after a LUN scan failed and after a reconnect has succeeded no
data will be sent over the QP and hence that a subsequent cable
pull will not be detected. Avoid this by not creating an rport or
SCSI host if a cable is pulled during a SCSI LUN scan.

Note: so far the above behavior has only been observed with the
kernel module parameter ch_count set to a value >= 2.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Attempting to connect three times may be insufficient after an
initiator system tries to relogin, especially if the relogin
attempt occurs before the SRP target service ID has been
registered. Since the srp_daemon retries a failed login attempt
anyway, remove the stale connection retry mechanism.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The patch that adds multichannel support into the SRP initiator
driver introduces an additional call to srp_free_ch_ib(). This
patch helps to keep that later patch simple.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth.  For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway.  The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

Most drivers use exactly the same implementation, so provide it as a
library function.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>

The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and
a slightly buggy strncasecmp.  The latter is the POSIX name, so strnicmp
was renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.

To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Roland Dreier <roland@kernel.org>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Expose more signature setting parameters. We modify the signature API
to allow usage of some new execution parameters relevant to data
integrity feature.

This patch modifies ib_sig_domain structure by:

- Deprecate DIF type in signature API (operation will
  be determined by the parameters alone, no DIF type awareness)
- Add APPTAG check bitmask (for input domain)
- Add REFTAG remap (increment) flag for each domain
- Add APPTAG/REFTAG escape options for each domain

The mlx5 driver is modified to follow the new parameters in HW
signature setup.

At the moment the callers (iser/isert) hard-code new parameters (by
DIF type). In the future, callers will retrieve them from the scsi
command structure.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Later there will be more parameters to set, so we want to do it in a
centralized place.

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

Later there will be more parameters to set, so we want to do it in a
centralized place.

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

In the future this will be a per-command parameter so we can lose it,
but in the mean time IP_CSUM is a lot lighter for SW layers to
compute, set it as default.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

We clear the struct before - no need to do 0 assignment.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Update the driver version and add Sagi Grimberg as maintainer
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

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>

- iser_hdr
- iser_data_buf
- iser_mem_reg
- iser_regd_buf
- iser_tx_desc
- iser_rx_desc
- iser_device
- iser_pi_context
- iser_conn
- ib_conn
- iser_comp
- iscsi_iser_task
- iser_global

While we're at it, change nit alignments in this file

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>

Change logging: "iser:XXXX" to "iser: XXXX"
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Match to the debug level of all functions in connect/disconnect flows.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Singal completion of every 32 scsi commands and suppress all the rest.
We don't do anything upon getting the completion so no need to "just
consume" it.  Cleanup of scsi command is done in cleanup_task callback.

Still keep dataout and control send completions as we may need to
cleanup there. This helps reducing the amount of interrupts/completions
in the IO path.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Poll in batch of 16. Since we don't want it on the stack, keep under
iser completion context (iser_comp).
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Avoid post_send counting (atomic) in the IO path just to keep track of
how many completions we need to consume.  Use a beacon post to indicate
that all prior posts completed.
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 will solve a possible condition where we might miss TX completion
(flush error) during session teardown.  Since we are using a single
CQ, we don't need to actively drain the TX CQ, instead just wait for
flush_completion (when counters reach zero) and remove iser_poll_for_flush_errors().

This patch might introduce a minor performance regression on its own,
but the next patches will enhance performance using a single CQ for RX
and TX.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

We need a way to guarentee that we don't stay in soft-IRQ context for
too long.  We might starve other pending CQ tasklets or worse lock
against application trying to issue IO on the running CPU.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoi Dayan <roid@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>

Introduce iser_comp which centralizes all iser completion related
items and is referenced by iser_device and each ib_conn.
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 iscsid was violently killed (SIGKILL) during its error
recovery stage, we may never get a connection teardown sequence for
some of the old connections.  No harm done, but when we try to unload
the module we will need to cleanup all these connections.  So we
actually may end-up here - so it's not a BUG_ON(), just give a relaxed
warning that this happened and continue with normal unload.  BUG_ON()
will cause segfault on module_exit and we don't want that.
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>

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>

Bailout in case a task cleanup (iscsi_iser_cleanup_task) is called
after the IB device was removed (DEVICE_REMOVAL CM event).  We also
call iscsi_conn_stop with a lock taken to prevent DEVICE_REMOVAL and
tasks cleanup from racing.
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>

Previously we didn't need to unbind the iser_conn and iscsi_conn since
we always relied on iscsi daemon to teardown the connection and never
let it finish before we cleanup all that is needed in iser.  This is
not the case anymore (for DEVICE_REMOVAL event).  So avoid any possible
chance we cause iscsi_conn dereference after iscsi_conn was freed.

We also call iser_conn_terminate (safe to call multiple times) just
for the corner case of iscsi daemon stopping an old connection before
invoking endpoint removal (might happen if it was violently killed).

Notice we are unbinding under a lock - which is required.
Signed-off-by: NAriel Nahum <arieln@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@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>

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>

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>

Testing xmit_more support with netperf and connected UDP sockets,
I found strange dst refcount false sharing.

Current handling of IFF_XMIT_DST_RELEASE is not optimal.

Dropping dst in validate_xmit_skb() is certainly too late in case
packet was queued by cpu X but dequeued by cpu Y

The logical point to take care of drop/force is in __dev_queue_xmit()
before even taking qdisc lock.

As Julian Anastasov pointed out, need for skb_dst() might come from some
packet schedulers or classifiers.

This patch adds new helper to cleanly express needs of various drivers
or qdiscs/classifiers.

Drivers that need skb_dst() in their ndo_start_xmit() should call
following helper in their setup instead of the prior :

	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
->
	netif_keep_dst(dev);

Instead of using a single bit, we use two bits, one being
eventually rebuilt in bonding/team drivers.

The other one, is permanent and blocks IFF_XMIT_DST_RELEASE being
rebuilt in bonding/team. Eventually, we could add something
smarter later.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch explicitly disables TX completion interrupt coalescing logic
in isert_put_response() and isert_put_datain() that was originally added
as an efficiency optimization in commit 95b60f07.

It has been reported that this change can trigger ABORT_TASK timeouts
under certain small block workloads, where disabling coalescing was
required for stability.  According to Sagi, this doesn't impact
overall performance, so go ahead and disable it for now.
Reported-by: NMoussa Ba <moussaba@micron.com>
Reported-by: NSagi Grimberg <sagig@dev.mellanox.co.il>
Cc: <stable@vger.kernel.org> # 3.13+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Unused return value from down_interruptible
Reported-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

To catch future errors sooner.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>