sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Add flag to struct task to mark the task as requiring network epoch.

When processing a taskqueue and a task has associated epoch, then
enter for duration of the task. If consecutive tasks belong to the
same epoch, batch them. Now we are talking about the network epoch
only.

Shrink the ta_priority size to 8-bits. No current consumers use
a priority that won't fit into 8 bits. Also complexity of
taskqueue_enqueue() is a square of maximum value of priority, so
we unlikely ever want to go over UCHAR_MAX here.

Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D23518

Make taskqgroup_attach{,_cpu}(9) work across architectures

So far, intr_{g,s}etaffinity(9) take a single int for identifying
a device interrupt. This approach doesn't work on all architectures
supported, as a single int isn't sufficient to globally specify a
device interrupt. In particular, with multiple interrupt controllers
in one system as found on e. g. arm and arm64 machines, an interrupt
number as returned by rman_get_start(9) may be only unique relative
to the bus and, thus, interrupt controller, a certain device hangs
off from.
In turn, this makes taskqgroup_attach{,_cpu}(9) and - internal to
the gtaskqueue implementation - taskqgroup_attach_deferred{,_cpu}()
not work across architectures. Yet in turn, iflib(4) as gtaskqueue
consumer so far doesn't fit architectures where interrupt numbers
aren't globally unique.
However, at least for intr_setaffinity(..., CPU_WHICH_IRQ, ...) as
employed by the gtaskqueue implementation to bind an interrupt to a
particular CPU, using bus_bind_intr(9) instead is equivalent from
a functional point of view, with bus_bind_intr(9) taking the device
and interrupt resource arguments required for uniquely specifying a
device interrupt.
Thus, change the gtaskqueue implementation to employ bus_bind_intr(9)
instead and intr_{g,s}etaffinity(9) to take the device and interrupt
resource arguments required respectively. This change also moves
struct grouptask from <sys/_task.h> to <sys/gtaskqueue.h> and wraps
struct gtask along with the gtask_fn_t typedef into #ifdef _KERNEL
as userland likes to include <sys/_task.h> or indirectly drags it
in - for better or worse also with _KERNEL defined -, which with
device_t and struct resource dependencies otherwise is no longer
as easily possible now.
The userland inclusion problem probably can be improved a bit by
introducing a _WANT_TASK (as well as a _WANT_MOUNT) akin to the
existing _WANT_PRISON etc., which is orthogonal to this change,
though, and likely needs an exp-run.

While at it:
- Change the gt_cpu member in the grouptask structure to be of type
int as used elswhere for specifying CPUs (an int16_t may be too
narrow sooner or later),
- move the gtaskqueue_enqueue_fn typedef from <sys/gtaskqueue.h> to
the gtaskqueue implementation as it's only used and needed there,
- change the GTASK_INIT macro to use "gtask" rather than "task" as
argument given that it actually operates on a struct gtask rather
than a struct task, and
- let subr_gtaskqueue.c consistently use __func__ to print functions
names.

Reported by: mmel
Reviewed by: mmel
Differential Revision: https://reviews.freebsd.org/D19139

sys/sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Make struct grouptask gt_name member a char array

Previously, it was just a pointer which was copied, but
some callers pass in a stack variable which will go out of scope.
Add GROUPTASK_NAMELEN macro (32) and snprintf() the name into it,
using "grouptask" if name is NULL. We can now safely include
gtask->gt_name in console messages.

Reviewed by: sbruno
Approved by: sbruno (mentor)
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D12449

Update iflib to support more NIC designs

- Move group task queue into kern/subr_gtaskqueue.c
- Change intr_enable to return an int so it can be detected if it's not
implemented
- Allow different TX/RX queues per set to be different sizes
- Don't split up TX mbufs before transmit
- Allow a completion queue for TX as well as RX
- Pass the RX budget to isc_rxd_available() to allow an earlier return
and avoid multiple calls

Submitted by: shurd
Reviewed by: gallatin
Approved by: scottl
Differential Revision: https://reviews.freebsd.org/D7393

fix loss of taskqueue wakeups (introduced in r300113)

Submitted by: kmacy
Tested by: dchagin

Import the 'iflib' API library for network drivers. From the author:

"iflib is a library to eliminate the need for frequently duplicated device
independent logic propagated (poorly) across many network drivers."

Participation is purely optional. The IFLIB kernel config option is
provided for drivers that want to transition between legacy and iflib
modes of operation. ixl and ixgbe driver conversions will be committed
shortly. We hope to see participation from the Broadcom and maybe
Chelsio drivers in the near future.

Submitted by: mmacy@nextbsd.org
Reviewed by: gallatin
Differential Revision: D5211

Revert r256587.

Requested by: zec

For VIMAGE kernels store vnet in the struct task, and set vnet context
during task processing.

Reported & tested by: mm

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Use a safer mechanism for determining if a task is currently running,
that does not rely on the lifetime of pointers being the same. This also
restores the task KBI.

Suggested by: jhb
MFC after: 1 month

Fix taskqueue_drain(9) to not have false negatives. For threaded
taskqueues, more than one task can be running simultaneously.

Also make taskqueue_run(9) static to the file, since there are no
consumers in the base kernel and the function signature needs to change
with this fix.

Remove mention of taskqueue_run(9) and taskqueue_run_fast(9) from the
taskqueue(9) man page.

Reviewed by: jhb
Approved by: zml (mentor)

Revert taskqueue(9) related commits until mdf@ is approved and can
resolve issues.

This reverts commits r207439, r208623, r208624

Revert r207439 and solve the problem differently. The task handler
ta_func may free the task structure, so no references to its members
are valid after the handler has been called. Using a per-queue member
and having waits longer than strictly necessary was suggested by jhb.

Submitted by: Matthew Fleming <matthew.fleming@isilon.com>
Reviewed by: zml, jhb

Handle taskqueue_drain(9) correctly on a threaded taskqueue:

taskqueue_drain(9) will not correctly detect whether a task is
currently running. The check is against a field in the taskqueue
struct, but for a threaded queue with more than one thread, multiple
threads can simultaneously be running a task, thus stomping over the
tq_running field.

Submitted by: Matthew Fleming <matthew.fleming@isilon.com>
Reviewed by: jhb
Approved by: dfr (mentor)

- Import the HEAD csup code which is the basis for the cvsmode work.

revert changes accidentally included in last commit

import vendor fixes to cxgb

o eliminate modification of task structures after their run to avoid
modify-after-free races when the task structure is malloc'd
o shrink task structure by removing ta_flags (no longer needed with
avoid fix) and combining ta_pending and ta_priority

Reviewed by: dwhite, dfr
MFC after: 4 days

Add taskqueue_drain. This waits for the specified task to finish, if
running, or returns. The calling program is responsible for making sure
that nothing new is enqueued.

# man page coming soon.

Remove (at least temporarily) the check that prevents us from including
this file from userland. Since we export struct ifnet to userland, and
that struct ifnet now contains a struct task, userland needs to know
what struct task looks like.

We need to consider having a pointer to a struct task here instead and
forward declare struct task in the !_KERNEL case.

Defer the vrele() on a jail's root vnode reference from prison_free()
to a new prison_complete() task run by a task queue. This removes
a requirement for grabbing Giant in crfree(). Embed the 'struct task'
in 'struct prison' so that we don't have to allocate memory from
prison_free() (which means we also defer the FREE()).

With this change, I believe grabbing Giant from crfree() can now be
removed, but need to check the uidinfo code paths.

To avoid header pollution, move the definition of 'struct task'
to _task.h, and recursively include from taskqueue.h and jail.h; much
preferably to all files including jail.h picking up a requirement to
include taskqueue.h.

Bumped into by: sam
Reviewed by: bde, tjr