scsi: target: iscsi: Rename iscsi_conn to iscsit_conn

The structure iscsi_conn naming is used by the iSCSI initiator
driver. Rename the target conn to iscsit_conn to have more readable code.

Link: https://lore.kernel.org/r/20220428092939.36768-2-mgurtovoy@nvidia.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: iscsi: Rename iscsi_cmd to iscsit_cmd

The structure iscsi_cmd naming is used by the iSCSI initiator driver.
Rename the target cmd to iscsit_cmd to have more readable code.

Link: https://lore.kernel.org/r/20220428092939.36768-1-mgurtovoy@nvidia.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

IB/isert: Align target max I/O size to initiator size

Since the Linux iser initiator default max I/O size set to 512KB and since
there is no handshake procedure for this size in iser protocol, set the
default max IO size of the target to 512KB as well.

For changing the default values, there is a module parameter for both
drivers.

Link: https://lore.kernel.org/r/20210524085215.29005-1-mgurtovoy@nvidia.com
Reviewed-by: Alaa Hleihel <alaa@nvidia.com>
Reviewed-by: Israel Rukshin <israelr@nvidia.com>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/isert: add module param to set sg_tablesize for IO cmd

Currently, iser target support max IO size of 16MiB by default. For some
adapters, allocating this amount of resources might reduce the total
number of possible connections that can be created. For those adapters,
it's preferred to reduce the max IO size to be able to create more
connections. Since there is no handshake procedure for max IO size in iser
protocol, set the default max IO size to 1MiB and add a module parameter
for enabling the option to control it for suitable adapters.

Fixes: 317000b926b0 ("IB/isert: allocate RW ctxs according to max IO size")
Link: https://lore.kernel.org/r/20201019094628.17202-1-mgurtovoy@nvidia.com
Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/isert: Fix unaligned immediate-data handling

Currently we allocate rx buffers in a single contiguous buffers for
headers (iser and iscsi) and data trailer. This means that most likely the
data starting offset is aligned to 76 bytes (size of both headers).

This worked fine for years, but at some point this broke, resulting in
data corruptions in isert when a command comes with immediate data and the
underlying backend device assumes 512 bytes buffer alignment.

We assume a hard-requirement for all direct I/O buffers to be 512 bytes
aligned. To fix this, we should avoid passing unaligned buffers for I/O.

Instead, we allocate our recv buffers with some extra space such that we
can have the data portion align to 512 byte boundary. This also means that
we cannot reference headers or data using structure but rather
accessors (as they may move based on alignment). Also, get rid of the
wrong __packed annotation from iser_rx_desc as this has only harmful
effects (not aligned to anything).

This affects the rx descriptors for iscsi login and data plane.

Fixes: 3d75ca0adef4 ("block: introduce multi-page bvec helpers")
Link: https://lore.kernel.org/r/20200904195039.31687-1-sagi@grimberg.me
Reported-by: Stephen Rust <srust@blockbridge.com>
Tested-by: Doug Dumitru <doug@dumitru.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/isert: use new shared CQ mechanism

Have the driver use shared CQs provided by the rdma core driver. Since
this provides similar functionality to iser_comp it has been removed.

Now there is no reason to allocate very large CQs when the driver is
loaded while gaining the advantage of shared CQs. Previously when a single
connection was opened a CQ was opened for every core with enough space for
eight connections, this is a very large overhead that in most cases will
not be utilized.

Link: https://lore.kernel.org/r/20200722135629.49467-2-maxg@mellanox.com
Signed-off-by: Yamin Friedman <yaminf@mellanox.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/isert: allocate RW ctxs according to max IO size

Current iSER target code allocates MR pool budget based on queue size.
Since there is no handshake between iSER initiator and target on max IO
size, we'll set the iSER target to support upto 16MiB IO operations and
allocate the correct number of RDMA ctxs according to the factor of MR's
per IO operation. This would guarantee sufficient size of the MR pool for
the required IO queue depth and IO size.

Link: https://lore.kernel.org/r/20200708091908.162263-1-maxg@mellanox.com
Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Tested-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

iser-target: avoid reinitializing rdma contexts for isert commands

isert commands that failed during isert_rdma_rw_ctx_post() are queued to
Queue-Full(QF) queue and are scheduled to be reposted during queue-full
queue processing. During this reposting, the rdma contexts are initialised
again in isert_rdma_rw_ctx_post(), which is leaking significant memory.

unreferenced object 0xffff8830201d9640 (size 64):
comm "kworker/0:2", pid 195, jiffies 4295374851 (age 4528.436s)
hex dump (first 32 bytes):
00 60 8b cb 2e 00 00 00 00 10 00 00 00 00 00 00 .`..............
00 90 e3 cb 2e 00 00 00 00 10 00 00 00 00 00 00 ................
backtrace:
[<ffffffff8170711e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff811f8ba5>] __kmalloc+0x125/0x2b0
[<ffffffffa046b24f>] rdma_rw_ctx_init+0x15f/0x6f0 [ib_core]
[<ffffffffa07ab644>] isert_rdma_rw_ctx_post+0xc4/0x3c0 [ib_isert]
[<ffffffffa07ad972>] isert_put_datain+0x112/0x1c0 [ib_isert]
[<ffffffffa07dddce>] lio_queue_data_in+0x2e/0x30 [iscsi_target_mod]
[<ffffffffa076c322>] target_qf_do_work+0x2b2/0x4b0 [target_core_mod]
[<ffffffff81080c3b>] process_one_work+0x1db/0x5d0
[<ffffffff8108107d>] worker_thread+0x4d/0x3e0
[<ffffffff81088667>] kthread+0x117/0x150
[<ffffffff81713fa7>] ret_from_fork+0x27/0x40
[<ffffffffffffffff>] 0xffffffffffffffff

Here is patch to use the older rdma contexts while reposting
the isert commands intead of reinitialising them.

Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iser-target: avoid posting a recv buffer twice

We pre-allocate our send-queues and might overflow them
in case we have multi work-request operations which tend
to occur for large RDMA transfers over devices with limited
allowed sg elements. When we get to a queue-full condition
we might retry again later, so track our receive buffers
so we don't repost them for a retry case.

Reported-by: Potnuri Bharat Teja <bharat@chelsio.com>
Tested-by: Potnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Properly release resources on DEVICE_REMOVAL

When the low level driver exercises the hot unplug they would call
rdma_cm cma_remove_one which would fire DEVICE_REMOVAL event to all cma
consumers. Now, if consumer doesn't make sure they destroy all IB
objects created on that IB device instance prior to finalizing all
processing of DEVICE_REMOVAL callback, rdma_cm will let the lld to
de-register with IB core and destroy the IB device instance. And if the
consumer calls (say) ib_dereg_mr(), it will crash since that dev object
is NULL.

In the current implementation, iser-target just initiates the cleanup
and returns from DEVICE_REMOVAL callback. This deferred work creates a
race between iser-target cleaning IB objects(say MR) and lld destroying
IB device instance.

This patch includes the following fixes
-> make sure that consumer frees all IB objects associated with device
instance
-> return non-zero from the callback to destroy the rdma_cm id

Signed-off-by: Raju Rangoju <rajur@chelsio.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/isert: Remove an unused member variable

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Cc: Parav Pandit <pandit.parav@gmail.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/isert: convert to the generic RDMA READ/WRITE API

Replace the homegrown RDMA READ/WRITE code in isert with the generic API,
which also adds iWarp support to the I/O path as a side effect. Note
that full iWarp operation will need a few additional patches from Steve.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

iser-target: Use ib_drain_qp

Now the rdma core offers a QP draining service in v4.6-rc1,
use it instead of our own.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Kill the ->isert_cmd back pointer in struct iser_tx_desc

We only use the pointer when processing regular iSER commands, and it then
always points to the struct iser_cmd that contains the TX descriptor.

Remove it and rely on container_of to save a little space and avoid a
pointer that is updated multiple times per processed command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Kill struct isert_rdma_wr

There is exactly one instance per struct isert_cmd, so merge the two to
simplify everyones life.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Convert to new CQ API

Use the workqueue based CQ type similar to what isert was using previously,
and properly split up the completion handlers.

Note that this also takes special care to handle the magic login WRs
separately, and also renames the submission functions so that it's clear
that they are only to be used for the login buffers.

(Fix up isert_print_wc usage in isert_beacon_done - nab)

Signed-off-by: Christoph Hellwig <hch@lst.de>
[sagig: added iscsi conn reinstatement in non-flush
error completions and added error completion type print]
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Split and properly type the login buffer

The login receive buffer is used as a iser_rx_desc, so type it as such
in struct isert_conn and allocate the exactly right space for it. The
TX buffer is moved to a separate variable and properly sized as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove ISER_RECV_DATA_SEG_LEN

This is the same as ISCSI_DEF_MAX_RECV_SEG_LEN (and must be the same given
the structure layouts), so just use that constant instead. This also
allows removing ISER_RX_LOGIN_SIZE in favor of ISER_RX_PAYLOAD_SIZE.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove redundant wait in release_conn

With current termination flow we call release_conn after completion.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Rework connection termination

When we receive an event that triggers connection termination,
we have a a couple of things we may want to do:
1. In case we are already terminating, bailout early
2. In case we are connected but not bound, disconnect and schedule
a connection cleanup silently (don't reinstate)
3. In case we are connected and bound, disconnect and reinstate the connection

This rework fixes a bug that was detected against a mis-behaved
initiator which rejected our rdma_cm accept, in this stage the
isert_conn is no bound and reinstate caused a bogus dereference.

What's great about this is that we don't need the
post_recv_buf_count anymore, so get rid of it.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Add new state ISER_CONN_BOUND to isert_conn

We need an indication that isert_conn->iscsi_conn binding has
happened so we'll know not to invoke a connection reinstatement
on an unbound connection which will lead to a bogus isert_conn->conn
dereferece.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Support the remote invalidation exception

We'll use remote invalidate, according to negotiation result
during connection establishment. If the initiator declared that
it supports the remote invalidate exception and the local HCA
supports IB_DEVICE_MEM_MGT_EXTENSIONS then the target will
use IB_WR_SEND_WITH_INV with the correct rkey for the response.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/isert: Remove unused file iser_proto.h

We don't need iser_proto.h anymore, remove it and
move (non-protocol) declarations to ib_isert.h

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/iser,isert: Create and use new shared header

The iser RDMA_CM negotiation protocol is shared by
the initiator and the target, so have a shared header
for the defines and structure. Move relevant items from
the initiator and target headers.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/ulps: Avoid calling ib_query_device

Instead, use the cached copy of the attributes present on the device.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

iser-target: Port to new memory registration API

Remove fastreg page list allocation as the page vector
is now private to the provider. Instead of constructing
the page list and fast_req work request, call ib_map_mr_sg
and construct ib_reg_wr.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB: split struct ib_send_wr

This patch split up struct ib_send_wr so that all non-trivial verbs
use their own structure which embedds struct ib_send_wr. This dramaticly
shrinks the size of a WR for most common operations:

sizeof(struct ib_send_wr) (old): 96

sizeof(struct ib_send_wr): 48
sizeof(struct ib_rdma_wr): 64
sizeof(struct ib_atomic_wr): 96
sizeof(struct ib_ud_wr): 88
sizeof(struct ib_fast_reg_wr): 88
sizeof(struct ib_bind_mw_wr): 96
sizeof(struct ib_sig_handover_wr): 80

And with Sagi's pending MR rework the fast registration WR will also be
down to a reasonable size:

sizeof(struct ib_fastreg_wr): 64

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> [srp, srpt]
Reviewed-by: Chuck Lever <chuck.lever@oracle.com> [sunrpc]
Tested-by: Haggai Eran <haggaie@mellanox.com>
Tested-by: Sagi Grimberg <sagig@mellanox.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>

iser-target: Skip data copy if all the command data comes as immediate

Given that supporting zcopy immediate data for all IOs requires
iser driver to use its own buffer allocations, we settle with
avoiding data copy for IOs with data length of up to 8K (which
is more latency sensitive anyway).

This trims IO write latency by up to 3us and increase IOPs
by up to 40% by saving CPU time doing sg_copy_from_buffer
(8K IO size is the obvious winner here).

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Change the recv buffers posting logic

iser target batches post recv operations to avoid
the overhead of acquiring the recv queue lock and
posting a HW doorbell for each command.

We change it to be per command in order to support
zcopy immediate data for IOs that fits in the 8K
transfer boundary (in the next patch).

(Fix minor patch fuzz due to ib_mr removal - nab)

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix pending connections handling in target stack shutdown sequnce

Instead of handing a connection to the iscsi stack
for processing right after accepting (rdma_accept) we only hand
the connection to the iscsi core after we reached to a connected
state (ESTABLISHED CM event). This will prevent two error scenrios:

1. race between rdma connection teardown and iscsi login sequence
reported by Nic in: (ce9a9fc20a78a "iser-target: Fix REJECT CM event
use-after-free OOPs")

2. target stack shutdown sequence race with constant login attempts by
multiple initiators.

We address this by maintaining two queues at the isert_np level:
- accepted: connections that were accepted but have not reached
connected state (might get rejected, unreachable or error).
- pending: connections in connected state, but have yet to handed
to the iscsi core for login processing. iser connections are promoted
to the pending queue only from the accepted queue.

This way the iscsi core now will only handle functional iser connections
and once we shutdown the target stack, we look for any stales that
got left behind so we can safely release them.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove np_ prefix from isert_np members

These are always referenced from np-> so no need
for the prefix.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove unused variables

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove ib_get_dma_mr calls

The pd now has a local_dma_lkey member which completely replaces
ib_get_dma_mr, use it instead.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

iser-target: Remove conn_ prefix from struct isert_conn members

These variables are always accessed via struct isert_conn so
no need to have a "conn_" prefix for them.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove un-needed rdma_listen backlog

iser target can handle as many connect request as
the fabric sends to it. This backlog should not set as
a back-pressure mechanism (which is not very useful).

isert does need a back-pressure mechanism, but it should
be added in isert by monitoring the number of pending
established connections (will be added in a later stage).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Use a single DMA MR and PD per device

This is to favor the HCA cache hit rate using less MRs
and PDs. This commit partially reverts commit:
"eb6ab13 IB/isert: separate connection protection domains and dma MRs"

At the time I thought this would be needed.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Use debug_level parameter to control logging level

Personal preference, easier control of the log level with
a single modparam which can be changed dynamically. Allows
better saparation of control and IO plains.

Replaced throughout ib_isert.c:
s/pr_debug/isert_dbg/g
s/pr_info/isert_info/g
s/pr_warn/isert_warn/g
s/pr_err/isert_err/g

Plus nit checkpatch warning change.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix logout sequence

We don't want to wait for conn_logout_comp from isert_comp_wq
context as this blocks further completions from being processed.
Instead we wait for it conditionally (if logout response was
actually posted) in wait_conn. This wait should normally happen
immediately as it occurs after we consumed all the completions
(including flush errors) and conn_logout_comp should have been
completed.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Reduce CQ lock contention by batch polling

In order to reduce the contention on CQ locking (present
in some LLDDs) we poll in batches of 16 work completion items.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove an atomic operation from the IO path

In order to know that we consumed all the connection completions
we maintain atomic post_send_buf_count for each IO post send. But
we can know that if we post a "beacon" (zero length RECV work request)
after we move the QP into error state and the target does not serve
any new IO. When we consume it, we know we finished all the connection
completion and we can go ahead and destroy stuff.

In error completion handler we now just need to check for ISERT_BEACON_WRID
to arrive and then wait for session commands to cleanup and complete
conn_wait_comp_err.

We reserve another CQ and QP entries to fit the zero length post recv.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Use single CQ for TX and RX

Using TX and RX CQs attached to the same vector might
create a throttling effect coming from the serial processing
of a work-queue. Use one CQ instead, it will do better in interrupt
processing and it provides a simpler code. Also, We get rid of
redundant isert_rx_wq.

Next we can remove the atomic post_send_buf_count from the IO path.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Centralize completion elements to a context

A pre-step before going to a single CQ.
Also this makes the code a little more simple to
read.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Remove interrupt coalescing

It is disabled at the moment, we will get that back
in once the target is more stable.

This reverts commit 95b60f0
"Add support for completion interrupt coalescing"

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iscsi,iser-target: Expose supported protection ops according to t10_pi

iSER will report supported protection operations based on
the tpg attribute t10_pi settings and HCA PI offload capabilities.
If the HCA does not support PI offload or tpg attribute t10_pi is
not set, we fall to SW PI mode.

In order to do that, we move iscsit_get_sup_prot_ops after connection
tpg assignment.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Allocate PI contexts dynamically

This patch converts to allocate PI contexts dynamically in order
avoid a potentially bogus np->tpg_np and associated NULL pointer
dereference in isert_connect_request() during iser-target endpoint
shutdown with multiple network portals.

Also, there is really no need to allocate these at connection
establishment since it is not guaranteed that all the IOs on
that connection will be to a PI formatted device.

We can do it in a lazy fashion so the initial burst will have a
transient slow down, but very fast all IOs will allocate a PI
context.

Squashed:

iser-target: Centralize PI context handling code

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix implicit termination of connections

In situations such as bond failover, The new session establishment
implicitly invokes the termination of the old connection.

So, we don't want to wait for the old connection wait_conn to completely
terminate before we accept the new connection and post a login response.

The solution is to deffer the comp_wait completion and the conn_put to
a work so wait_conn will effectively be non-blocking (flush errors are
assumed to come very fast).

We allocate isert_release_wq with WQ_UNBOUND and WQ_UNBOUND_MAX_ACTIVE
to spread the concurrency of release works.

Reported-by: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Handle ADDR_CHANGE event for listener cm_id

The np listener cm_id will also get ADDR_CHANGE event
upcall (in case it is bound to a specific IP). Handle
it correctly by creating a new cm_id and implicitly
destroy the old one.

Since this is the second event a listener np cm_id may
encounter, we move the np cm_id event handling to a
routine.

Squashed:

iser-target: Move cma_id setup to a function

Reported-by: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Parallelize CM connection establishment

There is no point in accepting a new CM request only
when we are completely done with the last iscsi login.
Instead we accept immediately, this will also cause the
CM connection to reach connected state and the initiator
is allowed to send the first login. We mark that we got
the initial login and let iscsi layer pick it up when it
gets there.

This reduces the parallel login sequence by a factor of
more then 4 (and more for multi-login) and also prevents
the initiator (who does all logins in parallel) from
giving up on login timeout expiration.

In order to support multiple login requests sequence (CHAP)
we call isert_rx_login_req from isert_rx_completion insead
of letting isert_get_login_rx call it.

Squashed:

iser-target: Use kref_get_unless_zero in connected_handler
iser-target: Acquire conn_mutex when changing connection state
iser-target: Reject connect request in failure path

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix flush + disconnect completion handling

ISER_CONN_UP state is not sufficient to know if
we should wait for completion of flush errors and
disconnected_handler event.

Instead, split it to 2 states:
- ISER_CONN_UP: Got to CM connected phase, This state
indicates that we need to wait for a CM disconnect
event before going to teardown.

- ISER_CONN_FULL_FEATURE: Got to full feature phase
after we posted login response, This state indicates
that we posted recv buffers and we need to wait for
flush completions before going to teardown.

Also avoid deffering disconnected handler to a work,
and handle it within disconnected handler.
More work here is needed to handle DEVICE_REMOVAL event
correctly (cleanup all resources).

Squashed:

iser-target: Don't deffer disconnected handler to a work

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iscsi,iser-target: Initiate termination only once

Since commit 0fc4ea701fcf ("Target/iser: Don't put isert_conn inside
disconnected handler") we put the conn kref in isert_wait_conn, so we
need .wait_conn to be invoked also in the error path.

Introduce call to isert_conn_terminate (called under lock)
which transitions the connection state to TERMINATING and calls
rdma_disconnect. If the state is already teminating, just bail
out back (temination started).

Also, make sure to destroy the connection when getting a connect
error event if didn't get to connected (state UP). Same for the
handling of REJECTED and UNREACHABLE cma events.

Squashed:

iscsi-target: Add call to wait_conn in establishment error flow

Reported-by: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Target/iser: Improve cm events handling

There are 4 RDMA_CM events that all basically mean that
the user should teardown the IB connection:
- DISCONNECTED
- ADDR_CHANGE
- DEVICE_REMOVAL
- TIMEWAIT_EXIT

Only in DISCONNECTED/ADDR_CHANGE it makes sense to
call rdma_disconnect (send DREQ/DREP to our initiator).
So we keep the same teardown handler for all of them
but only indicate calling rdma_disconnect for the relevant
events.

This patch also removes redundant debug prints for each single
event.

v2 changes:
- Call isert_disconnected_handler() for DEVICE_REMOVAL (Or + Sag)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Target/iser: Fix hangs in connection teardown

In ungraceful teardowns isert close flows seem racy such that
isert_wait_conn hangs as RDMA_CM_EVENT_DISCONNECTED never
gets invoked (no one called rdma_disconnect).

Both graceful and ungraceful teardowns will have rx flush errors
(isert posts a batch once connection is established). Once all
flush errors are consumed we invoke isert_wait_conn and it will
be responsible for calling rdma_disconnect. This way it can be
sure that rdma_disconnect was called and it won't wait forever.

This patch also removes the logout_posted indicator. either the
logout completion was consumed and no problem decrementing the
post_send_buf_count, or it was consumed as a flush error. no point
of keeping it for isert_wait_conn as there is no danger that
isert_conn will be accidentally removed while it is running.

(Drop unnecessary sleep_on_conn_wait_comp check in
isert_cq_rx_comp_err - nab)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Target/iser: Fix iscsit_accept_np and rdma_cm racy flow

RDMA CM and iSCSI target flows are asynchronous and completely
uncorrelated. Relying on the fact that iscsi_accept_np will be called
after CM connection request event and will wait for it is a mistake.

When attempting to login to a few targets this flow is racy and
unpredictable, but for parallel login to dozens of targets will
race and hang every time.

The correct synchronizing mechanism in this case is pending on
a semaphore rather than a wait_for_event. We keep the pending
interruptible for iscsi_np cleanup stage.

(Squash patch to remove dead code into parent - nab)

Reported-by: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Support T10-PI protected transactions

In case the Target core passed transport T10 protection
operation:

1. Register data buffer (data memory region)
2. Register protection buffer if exsists (prot memory region)
3. Register signature region (signature memory region)
- use work request IB_WR_REG_SIG_MR
4. Execute RDMA
5. Upon RDMA completion check the signature status
- if succeeded send good SCSI response
- if failed send SCSI bad response with appropriate sense buffer

(Fix up compile error in isert_reg_sig_mr, and fix up incorrect
se_cmd->prot_type -> TARGET_PROT_NORMAL comparision - nab)
(Fix failed sector assignment in isert_completion_rdma_* - Sagi + nab)
(Fix enum assignements for protection type - Sagi)
(Fix devision on 32-bit in isert_completion_rdma_* - Sagi + Fengguang)
(Fix context change for v3.14-rc6 code - nab)
(Fix iscsit_build_rsp_pdu inc_statsn flag usage - nab)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Initialize T10-PI resources

Introduce pi_context to hold relevant RDMA protection resources.
We eliminate data_key_valid boolean and replace it with indicators
container to indicate:
- Is the descriptor protected (registered via signature MR)
- Is the data_mr key valid (can spare LOCAL_INV WR)
- Is the prot_mr key valid (can spare LOCAL_INV WR)
- Is the sig_mr key valid (can spare LOCAL_INV WR)

Upon connection establishment check if network portal is T10-PI
enabled and allocate T10-PI resources if necessary, allocate
signature enabled memory regions and mark connection queue-pair
as signature enabled.

(Fix context change for v3.14-rc6 code - nab)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Introduce isert_map/unmap_data_buf

export map/unmap data buffer to a routine that may
be used in various places in the code and keep the
mapping data in a designated descriptor. Also, let
isert_fast_reg_mr to decide weather to use global
MR or do fast registration.

This commit does not change any functionality.

(Fix context change for v3.14-rc6 code - nab)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix command leak for tx_desc->comp_llnode_batch

This patch addresses a number of active I/O shutdown issues
related to isert_cmd descriptors being leaked that are part
of a completion interrupt coalescing batch.

This includes adding logic in isert_cq_tx_comp_err() to
drain any associated tx_desc->comp_llnode_batch, as well
as isert_cq_drain_comp_llist() to drain any associated
isert_conn->conn_comp_llist.

Also, set tx_desc->llnode_active in isert_init_send_wr()
in order to determine when work requests need to be skipped
in isert_cq_tx_work() exception path code.

Finally, update isert_init_send_wr() to only allow interrupt
coalescing when ISER_CONN_UP.

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.13+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Ignore completions for FRWRs in isert_cq_tx_work

This patch changes IB_WR_FAST_REG_MR + IB_WR_LOCAL_INV related
work requests to include a ISER_FRWR_LI_WRID value in order to
signal isert_cq_tx_work() that these requests should be ignored.

This is necessary because even though IB_SEND_SIGNALED is not
set for either work request, during a QP failure event the work
requests will be returned with exception status from the TX
completion queue.

v2 changes:
- Rename ISER_FRWR_LI_WRID -> ISER_FASTREG_LI_WRID (Sagi)

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iscsi/iser-target: Fix isert_conn->state hung shutdown issues

This patch addresses a couple of different hug shutdown issues
related to wait_event() + isert_conn->state. First, it changes
isert_conn->conn_wait + isert_conn->conn_wait_comp_err from
waitqueues to completions, and sets ISER_CONN_TERMINATING from
within isert_disconnect_work().

Second, it splits isert_free_conn() into isert_wait_conn() that
is called earlier in iscsit_close_connection() to ensure that
all outstanding commands have completed before continuing.

Finally, it breaks isert_cq_comp_err() into seperate TX / RX
related code, and adds logic in isert_cq_rx_comp_err() to wait
for outstanding commands to complete before setting ISER_CONN_DOWN
and calling complete(&isert_conn->conn_wait_comp_err).

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: Avoid frwr notation, user fastreg

Use fast registration lingo. fast registration will
also incorporate signature/DIF registration.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

IB/isert: seperate connection protection domains and dma MRs

It is more correct to seperate connections protection domains
and dma_mr handles. protection information support requires to
do so.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

ib_isert: Add support for completion interrupt coalescing

This patch adds support for completion interrupt coalescing that
allows only every ISERT_COMP_BATCH_COUNT (8) to set IB_SEND_SIGNALED,
thus avoiding completion interrupts for every posted iser_tx_desc.

The batch processing is done using a per isert_conn llist that once
IB_SEND_SIGNALED has been set is saved to tx_desc->comp_llnode_batch,
and completion processing of previously posted iser_tx_descs is done
in a single shot from within isert_send_completion() code.

Note this is only done for response PDUs from ISCSI_OP_SCSI_CMD, and
all other control type of PDU responses will force an implicit batch
drain to occur.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: introduce fast memory registration mode (FRWR)

This model was introduced in 00f7ec36c "RDMA/core: Add memory
management extensions support" and works when the IB device
supports the IB_DEVICE_MEM_MGT_EXTENSIONS capability.

Upon creating the isert device, ib_isert will test whether the HCA
supports FRWR. If supported then set the flag and assign
function pointers that handle fast registration and deregistration
of appropriate resources (fast_reg descriptors).

When new connection coming in, ib_isert will check frwr flag and
create frwr resouces, if fail to do it will switch back to
old model of using global dma key and turn off the frwr support.

Registration is done using posting IB_WR_FAST_REG_MR to the QP and
invalidations using posting IB_WR_LOCAL_INV.

Signed-off-by: Vu Pham <vu@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: generalize rdma memory registration and cleanup

Current driver uses global dma key to register the memory pointed
by sg list provided by the target core.

This is the preparation step for adding more methods like fast
path memory registration, make the reg/unreg calls be function
pointers.

Signed-off-by: Vu Pham <vu@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: move rdma wr processing to a shared function

isert_put_datain() and isert_get_dataout() share a lot of code
in rdma wr processing, move this common code to a shared function.

Use isert_unmap_cmd to cleanup for RDMA_READ completion.
Remove duplicate field in isert_cmd and isert_rdma_wr structs
Change misc debug messages to track isert_cmd

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Vu Pham <vu@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iscsi/iser-target: Convert to command priv_size usage

This command converts iscsi/isert-target to use allocations based on
iscsit_transport->priv_size within iscsit_allocate_cmd(), instead of
using an embedded isert_cmd->iscsi_cmd.

This includes removing iscsit_transport->alloc_cmd() usage, along
with updating isert-target code to use iscsit_priv_cmd().

Also, remove left-over iscsit_transport->release_cmd() usage for
direct calls to iscsit_release_cmd(), and drop the now unused
lio_cmd_cache and isert_cmd_cache.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

iser-target: Rename sense_buf_[dma,len] to pdu_[dma,len]

Now that these two variables are used for REJECT payloads as well
as SCSI response sense payloads, rename them to something that
makes more sense.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED

This patch addresses a bug where RDMA_CM_EVENT_DISCONNECTED may occur
before the connection shutdown has been completed by rx/tx threads,
that causes isert_free_conn() to wait indefinately on ->conn_wait.

This patch allows isert_disconnect_work code to invoke rdma_disconnect
when isert_disconnect_work() process context is started by client
session reset before isert_free_conn() code has been reached.

It also adds isert_conn->conn_mutex protection for ->state within
isert_disconnect_work(), isert_cq_comp_err() and isert_free_conn()
code, along with isert_check_state() for wait_event usage.

(v2: Add explicit iscsit_cause_connection_reinstatement call
during isert_disconnect_work() to force conn reset)

Cc: stable@vger.kernel.org # 3.10+
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iser-target: Add iSCSI Extensions for RDMA (iSER) target driver

This patch adds support for iSCSI Extensions for RDMA target mode,
and includes CQ pooling per isert_device context distributed across
multiple active iser target sessions.

It also uses cmwq process context for RX / TX ib_post_cq() polling
via isert_cq_desc->cq_[rx,tx]_work invoked by isert_cq_[rx,tx]_callback()
hardIRQ context callbacks.

v5 changes:

- Use ISER_RECV_DATA_SEG_LEN instead of hardcoded value in ISER_RX_PAD_SIZE (Or)
- Fix make W=1 warnings (Or)
- Add missing depends on NET && INFINIBAND_ADDR_TRANS in Kconfig (Randy + Or)
- Make isert_device_find_by_ib_dev() return proper ERR_PTR (Wei Yongjun)
- Properly setup iscsi_np->np_sockaddr in isert_setup_np() (Shlomi + nab)
- Add special case for early ISCSI_OP_SCSI_CMD exception handling (nab)

v4 changes:
- Mark isert_cq_rx_work as static (Or)
- Drop unnecessary ib_dma_sync_single_for_cpu + ib_dma_sync_single_for_device
calls for isert_cmd->sense_buf_dma from isert_put_response (Or)
- Use 12288 for ISER_RX_PAD_SIZE base to save extra page per
struct iser_rx_desc (Or + nab)
- Drop now unnecessary isert_rx_desc usage, and convert RX users to
iser_rx_desc (Or + nab)
- Move isert_[alloc,free]_rx_descriptors() ahead of
isert_create_device_ib_res() usage (nab)
- Mark isert_cq_[rx,tx]_callback() + prototypes as static
- Fix 'warning: 'ret' may be used uninitialized' warning for
isert_create_device_ib_res on powerpc allmodconfig (fengguang + nab)
- Fix 'warning: 'ret' may be used uninitialized' warning for
isert_connect_request on i386 allyesconfig (fengguang + nab)
- Fix pr_debug conversion specification in isert_rx_completion()
(fengguang + nab)
- Drop unnecessary isert_conn->conn_cm_id != NULL check in
isert_connect_release causing the build warning:
"variable dereferenced before check 'isert_conn->conn_cm_id'"
- Fix isert_lid + isert_np leak in isert_setup_np failure path
- Add isert_conn->conn_wait_comp_err usage in isert_free_conn()
for isert_cq_comp_err completion path
- Add isert_conn->logout_posted bit to determine decrement of
isert_conn->post_send_buf_count from logout response completion
- Always set ISER_CONN_DOWN from isert_disconnect_work() callback

v3 changes:

- Convert to use per isert_cq_desc->cq_[rx,tx]_work + drop tasklets (Or + nab)
- Move IB_EVENT_QP_LAST_WQE_REACHED warn into correct
isert_qp_event_callback (Or)
- Drop unnecessary IB_ACCESS_REMOTE_* access flag usage in
isert_create_device_ib_res (Or)
- Add common isert_init_send_wr(), and convert isert_put_* calls (Or)
- Move to verbs+core logic to single ib_isert.[c,h] (Or + nab)
- Add kmem_cache isert_cmd_cache usage for descriptor allocation (nab)
- Move common ib_post_send() logic used by isert_put_*() to
isert_post_response() (nab)
- Add isert_put_reject call in isert_response_queue() for posting
ISCSI_REJECT response. (nab)
- Add ISTATE_SEND_REJECT checking in isert_do_control_comp. (nab)

v2 changes:

- Drop unused ISERT_ADDR_ROUTE_TIMEOUT define
- Add rdma_notify() call for IB_EVENT_COMM_EST in isert_qp_event_callback()
- Make isert_query_device() less verbose
- Drop unused RDMA_CM_EVENT_ADDR_ERROR and RDMA_CM_EVENT_ROUTE_ERROR
cases from isert_cma_handler()
- Drop unused rdma/ib_fmr_pool.h include
- Update isert_conn_setup_qp() to assign cq based upon least used
- Add isert_create_device_ib_res() to setup PD, CQs and MRs for each
underlying struct ib_device, instead of using per isert_conn resources.
- Add isert_free_device_ib_res() to release PD, CQs and MRs for each
underlying struct ib_device.
- Add isert_device_find_by_ib_dev()
- Change isert_connect_request() to drop PD, CQs and MRs allocation,
and use isert_device_find_by_ib_dev() instead.
- Add isert_device_try_release()
- Change isert_connect_release() to decrement cq_active_qps, and drop
PD, CQs and MRs resource release.
- Update isert_connect_release() to call isert_device_try_release()
- Make isert_create_device_ib_res() determine device->cqs_used based
upon num_online_cpus()
- Drop misleading isert_dump_ib_wc() usage
- Drop unused rdma/ib_fmr_pool.h include
- Use proper xfer_len for login PDUs in isert_rx_completion()
- Add isert_release_cmd() usage
- Change isert_alloc_cmd() to setup iscsi_cmd.release_cmd() pointer
- Change isert_put_cmd() to perform per iscsi_opcode specific release
logic
- Add isert_unmap_cmd() call for ISCSI_OP_SCSI_CMD from isert_put_cmd()
- Change isert_send_completion() to call
atomic_dec(&isert_conn->post_send_buf_count)
based upon per iscsi_opcode logic
- Drop ISTATE_REMOVE processing from isert_immediate_queue()
- Drop ISTATE_SEND_DATAIN processing from isert_response_queue()
- Drop ISTATE_SEND_STATUS processing from isert_response_queue()
- Drop iscsit_transport->iscsit_unmap_cmd() and ->iscsit_free_cmd()
- Convert iser_cq_tx_tasklet() to use struct isert_cq_desc pooling logic
- Convert isert_cq_tx_callback() to use struct isert_cq_desc pooling
logic
- Convert iser_cq_rx_tasklet() to use struct isert_cq_desc pooling logic
- Convert isert_cq_rx_callback() to use struct isert_cq_desc pooling
logic
- Add explict iscsit_stop_dataout_timer() call to
isert_do_rdma_read_comp()
- Use isert_get_dataout() for iscsit_transport->iscsit_get_dataout()
caller
- Drop ISTATE_SEND_R2T processing from isert_immediate_queue()
- Drop unused rdma/ib_fmr_pool.h include
- Drop isert_cmd->cmd_kref in favor of se_cmd->cmd_kref usage
- Add struct isert_device in order to support multiple EQs + CQ pooling
- Add struct isert_cq_desc
- Drop tasklets and cqs from isert_conn
- Bump ISERT_MAX_CQ to 64
- Various minor checkpatch fixes

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>