Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add mechanism for choosing iSER-capable ICL modules.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Provide a way for ICL modules to declare they support PIM_UNMAPPED.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Pass maxtags value to the ICL module. iSER needs it.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Rename icl_proxy.c to icl_soft_proxy.c, to make it clear it's a part
of software ICL backend.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add icl_conn_connect() ICL method, required for iSER.

Obtained from: Mellanox Technologies (earlier version)
MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Make ICL_KERNEL_PROXY compilable.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Make it possible to set (via iscsi.conf(5)) and query (via iscsictl -v)
initiator iSCSI offload. Pass maximum data segment size supported by
chosen offload module to iscsid(8), and make iscsid(8) not try to negotiate
anything larger than that.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add kobj interface between ICL and the rest of the iSCSI stack.
Review note - icl.c was moved to icl_soft.c.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

s/icl_pdu_new_bhs/icl_pdu_new/; no functional changes, just a little
nicer code.

Sponsored by: The FreeBSD Foundation

Make iSCSI connection close somewhat less aggressive.

It allows to push out some final data from the send queue to the socket
before its close. In particular, it increases chances for logout response
to be delivered to the initiator.

Properly pass the initiator address when running in proxy mode.

Sponsored by: The FreeBSD Foundation

Properly identify target portal when running in proxy mode. While here,
remove CTL_ISCSI_CLOSE, it wasn't used or implemented anyway.

Sponsored by: The FreeBSD Foundation

Rework the iSCSI PDU transmit code to avoid lock contention and coalesce
PDUs before sending.

Sponsored by: The FreeBSD Foundation

We don't need TAILQ for iSCSI PDUs; STAILQ is enough.

Sponsored by: The FreeBSD Foundation

Instead of "icltx" and "iclrx", use thread names with prefix from upper
layer, so that one can see which side of the stack the threads are for.

Sponsored by: The FreeBSD Foundation

Get rid of ICL lock; use upper-layer (initiator or target) lock instead.
This avoids extra locking in icl_pdu_queue(); the upper layer needs to call
it while holding its own lock anyway, to avoid sending PDUs out of order.

Sponsored by: The FreeBSD Foundation

Move the ic_outstanding_count under #ifdef DIAGNOSTIC.

Sponsored by: The FreeBSD Foundation

Bring in the new iSCSI target and initiator.

Reviewed by: ken (parts)
Approved by: re (delphij)
Sponsored by: FreeBSD Foundation