net/smc: Introduce a specific sysctl for TEST_LINK time

SMC-R tests the viability of link by sending out TEST_LINK LLC
messages over RoCE fabric when connections on link have been
idle for a time longer than keepalive interval (testlink time).

But using tcp_keepalive_time as testlink time maybe not quite
suitable because it is default no less than two hours[1], which
is too long for single link to find peer dead. The active host
will still use peer-dead link (QP) sending messages, and can't
find out until get IB_WC_RETRY_EXC_ERR error CQEs, which takes
more time than TEST_LINK timeout (SMC_LLC_WAIT_TIME) normally.

So this patch introduces a independent sysctl for SMC-R to set
link keepalive time, in order to detect link down in time. The
default value is 30 seconds.

[1] https://www.rfc-editor.org/rfc/rfc1122#page-101

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net/smc: extend LLC layer for SMC-Rv2

Add support for large v2 LLC control messages in smc_llc.c.
The new large work request buffer allows to combine control
messages into one packet that had to be spread over several
packets before.
Add handling of the new v2 LLC messages.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: move add link processing for new device into llc layer

When a new ib device is up smc will send an add link invitation to the
peer if needed. This is currently done with rudimentary flow control.
Under high workload these add link invitations can disturb other llc
flows because they arrive unexpected. Fix this by integrating the
invitations into the normal llc event flow and handle them as a flow.
While at it, check for already assigned requests in the flow before
the new add link request is assigned.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 1f90a05d9ff9 ("net/smc: add smcr_port_add() and smcr_link_up() processing")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: log important pnetid and state change events

Print to system log when SMC links are available or go down, link group
state changes or pnetids are applied to and removed from devices.
The log entries are triggered by either user configuration actions or
adapter activation/deactivation events and are not expected to happen
often. The entries help SMC users to keep track of the SMC link group
status and to detect when actions are needed (like to add replacements
for failed adapters).

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: save SMC-R peer link_uid

During SMC-R link establishment the peers exchange the link_uid that
is used for debugging purposes. Save the peer link_uid in smc_link so it
can be retrieved by the smc_diag netlink interface.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: create improved SMC-R link_uid

The link_uid of an SMC-R link is exchanged between SMC peers and its
value can be used for debugging purposes. Create a unique link_uid
during link initialization and use it in communication with SMC-R peers.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add termination reason and handle LLC protocol violation

Allow to set the reason code for the link group termination, and set
meaningful values before termination processing is triggered. This
reason code is sent to the peer in the final delete link message.
When the LLC request or response layer receives a message type that was
not handled, drop a warning and terminate the link group.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: send DELETE_LINK, ALL message and wait for send to complete

Add smc_llc_send_message_wait() which uses smc_wr_tx_send_wait() to send
an LLC message and waits for the message send to complete.
smc_llc_send_link_delete_all() calls the new function to send an
DELETE_LINK,ALL LLC message. The RFC states that the sender of this type
of message needs to wait for the completion event of the message
transmission and can terminate the link afterwards.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: enqueue local LLC messages

As SMC server, when a second link was deleted, trigger the setup of an
asymmetric link. Do this by enqueueing a local ADD_LINK message which
is processed by the LLC layer as if it were received from peer. Do the
same when a new IB port became active and a new link could be created.
smc_llc_srv_add_link_local() enqueues a local ADD_LINK message.
And smc_llc_srv_delete_link_local() is used the same way to enqueue a
local DELETE_LINK message. This is used when an IB port is no longer
active.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: first part of add link processing as SMC server

First set of functions to process an ADD_LINK LLC request as an SMC
server. Find an alternate IB device, determine the new link group type
and get the index for the new link. Then initialize the link and send
the ADD_LINK LLC message to the peer. Save the contents of the response,
ready the link, map all used buffers and register the buffers with the
IB device. If any error occurs, stop the processing and clear the link.
And call smc_llc_srv_add_link() in af_smc.c to start second link
establishment after the initial link of a link group was created.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: final part of add link processing as SMC client

This patch finalizes the ADD_LINK processing of new links. Receive the
CONFIRM_LINK request from peer, complete the link initialization,
register all used buffers with the IB device and finally send the
CONFIRM_LINK response, which completes the ADD_LINK processing.
And activate smc_llc_cli_add_link() in af_smc.c.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: rkey processing for a new link as SMC client

Part of the SMC client new link establishment process is the exchange of
rkeys for all used buffers.
Add new LLC message type ADD_LINK_CONTINUE which is used to exchange
rkeys of all current RMB buffers. Add functions to iterate over all
used RMB buffers of the link group, and implement the ADD_LINK_CONTINUE
processing.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add smcr_port_err() and smcr_link_down() processing

Call smcr_port_err() when an IB event reports an inactive IB device.
smcr_port_err() calls smcr_link_down() for all affected links.
smcr_link_down() either triggers the local DELETE_LINK processing, or
sends an DELETE_LINK LLC message to the SMC server to initiate the
processing.
The old handler function smc_port_terminate() is removed.
Add helper smcr_link_down_cond() to take a link down conditionally, and
smcr_link_down_cond_sched() to schedule the link_down processing to a
work.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: extend smc_llc_send_add_link() and smc_llc_send_delete_link()

All LLC sends are done from worker context only, so remove the prep
functions which were used to build the message before it was sent, and
add the function content into the respective send function
smc_llc_send_add_link() and smc_llc_send_delete_link().
Extend smc_llc_send_add_link() to include the qp_mtu value in the LLC
message, which is needed to establish a link after the initial link was
created. Extend smc_llc_send_delete_link() to contain a link_id and a
reason code for the link deletion in the LLC message, which is needed
when a specific link should be deleted.
And add the list of existing DELETE_LINK reason codes.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: remove obsolete link state DELETING

The connection layer in af_smc.c is now using the new LLC flow
framework, which made the link state DELETING obsolete. Remove the state
and the respective helpers.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: multiple link support and LLC flow for smc_llc_do_delete_rkey

Adapt smc_llc_do_delete_rkey() to use the LLC flow and support multiple
links when deleting the rkeys for rmb buffers at the peer.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: multiple link support and LLC flow for smc_llc_do_confirm_rkey

Adapt smc_llc_do_confirm_rkey() to use the LLC flow and support the
rkeys of multiple links when the CONFIRM_RKEY LLC message is build.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add logic to evaluate CONFIRM_LINK messages to LLC layer

Introduce smc_llc_eval_conf_link() to evaluate the CONFIRM_LINK message
contents. This implements this logic at the LLC layer. The function will
be used by af_smc.c to process the received LLC layer messages.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add event-based llc_flow framework

The new framework allows to start specific types of LLC control flows,
protects active flows and makes it possible to wait for flows to finish
before starting a new flow.
This mechanism is used for the LLC control layer to model flows like
'add link' or 'delete link' which need to send/receive several LLC
messages and are not allowed to get interrupted by the wrong type of
messages.
'Add link' or 'Delete link' messages arriving in the middle of a flow
are delayed and processed when the current flow finished.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: move llc layer related init and clear into smc_llc.c

Introduce smc_llc_lgr_init() and smc_llc_lgr_clear() to implement all
llc layer specific initialization and cleanup in module smc_llc.c.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: use worker to process incoming llc messages

Incoming llc messages are processed in irq tasklet context, and
a worker is used to send outgoing messages. The worker is needed
because getting a send buffer could result in a wait for a free buffer.

To make sure all incoming llc messages are processed in a serialized way
introduce an event queue and create a new queue entry for each message
which is queued to this event queue. A new worker processes the event
queue entries in order.
And remove the use of a separate worker to send outgoing llc messages
because the messages are processed in worker context already.
With this event queue the serialized llc_wq work queue is obsolete,
remove it.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: simplify link deactivation

Cancel the testlink worker during link clear processing and remove the
extra function smc_llc_link_inactive().

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add new link state and related helpers

Before a link can be reused it must have been cleared. Lowest current
link state is INACTIVE, which does not mean that the link is already
cleared.
Add a new state UNUSED that is set when the link is cleared and can be
reused.
Add helper smc_llc_usable_link() to find an active link in a link group,
and smc_link_usable() to determine if a link is usable.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add infrastructure to send delete rkey messages

Add the infrastructure to send LLC messages of type DELETE RKEY to
unregister a shared memory region at the peer.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: improve delete link processing

Send an orderly DELETE LINK request before termination of a link group,
add support for client triggered DELETE LINK processing. And send a
disorderly DELETE LINK before module is unloaded.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: use correct vlan gid of RoCE device

SMC code uses the base gid for VLAN traffic. The gids exchanged in
the CLC handshake and the gid index used for the QP have to switch
from the base gid to the appropriate vlan gid.

When searching for a matching IB device port for a certain vlan
device, it does not make sense to return an IB device port, which
is not enabled for the used vlan_id. Add another check whether a
vlan gid exists for a certain IB device port.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: fewer parameters for smc_llc_send_confirm_link()

Link confirmation will always be sent across the new link being
confirmed. This allows to shrink the parameter list.
No functional change.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: use a workqueue to defer llc send

SMC handles deferred work in tasklets. As tasklets cannot sleep this
can result in rare EBUSY conditions, so defer this work in a work queue.
The high level api functions do not defer work because they can sleep
until the llc send is actually completed.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: move link llc initialization to llc layer

Move the llc layer specific initialization and cleanup out of smc_core.c
into smc_llc.c (smc_llc_link_init and smc_llc_link_clear). Move all
initialization of a link into the new init function.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: simplify test_link function usage

Make smc_llc_send_test_link() static and remove it from the header file.
And to send a test_link response set the response flag and send the
message back as-is, without using smc_llc_send_test_link(). And because
smc_llc_send_test_link() must no longer send responses, remove the
response flag handling from the function.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: register new rmbs with the peer

Register new rmb buffers with the remote peer by exchanging a
confirm_rkey llc message.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: periodic testlink support

Add periodic LLC testlink support to ensure the link is still active.
The interval time is initialized using the value of
sysctl_tcp_keepalive_time.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: process add/delete link messages

Add initial support for the LLC messages ADD LINK and DELETE LINK.
Introduce a link state field. Extend the initial LLC handshake with
ADD LINK processing.

Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: process confirm/delete rkey messages

Process and respond to CONFIRM RKEY and DELETE RKEY messages.

Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: respond to test link messages

Add TEST LINK message responses, which also serves as preparation for
support of sockopt TCP_KEEPALIVE.

Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: cleanup smc_llc.h and smc_clc.h headers

Remove structures used internal only from headers.
And remove an extra function parameter.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

smc: link layer control (LLC)

send and receive LLC messages CONFIRM_LINK (via IB message send and CQE)

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>