sys/queue.h: Add {LIST,TAILQ}_REPLACE().

MFC after: 1 week
Obtained from: NetBSD
Sponsored by: Klara, Inc.
Reviewed by: cperciva, imp
Differential Revision: https://reviews.freebsd.org/D44679

sys/queue.h: Whitespace cleanup.

MFC after: 1 week
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D44678

sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

queue.h: Define {LIST,TAILQ}_REMOVE_HEAD

The LIST and TAILQ structures have fast _REMOVE macros (since each
element has a pointer to the previous element); we implement the
_REMOVE_HEAD macros for them by simply finding the first element and
then removing it.

Reviewed by: jhb, emaste
Sponsored by: https://www.patreon.com/cperciva
Differential Revision: https://reviews.freebsd.org/D41072

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

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

sys/queue.h: move trashing from SLIST_REMOVE to REMOVE_AFTER, REMOVE_HEAD

SLIST_REMOVE calls either REMOVE_AFTER or REMOVE_HEAD to do the job.
But those two macros can be used independently as well.

MFC after: 2 weeks

qeueue.h: Add {SLIST,STAILQ,LIST,TAILQ}_END()

We provide these for compat with other queue.h headers since some software
assumes it exists (e.g. the libevent contrib code), but we are not
encouraging their use (NULL should be used instead).

This fixes the following warning (which should arguable be an error since
it results in a function call to an undefined function):

.../contrib/libevent/buffer.c:495:16: warning: implicit declaration of function 'LIST_END' is invalid in C99 [-Wimplicit-function-declaration]
cbent != LIST_END(&buffer->callbacks);
^
.../contrib/libevent/buffer.c:495:13: warning: comparison between pointer and integer ('struct evbuffer_cb_entry *' and 'int') [-Wpointer-integer-compare]
cbent != LIST_END(&buffer->callbacks);
~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reviewed By: jhb
Differential Revision: https://reviews.freebsd.org/D27151

sys: clean up empty lines in .c and .h files

Trim trailing white space in comment

Approved by: cognet

Add wakeup_any(), cheaper wakeup_one() for taskqueue(9).

wakeup_one() and underlying sleepq_signal() spend additional time trying
to be fair, waking thread with highest priority, sleeping longest time.
But in case of taskqueue there are many absolutely identical threads, and
any fairness between them is quite pointless. It makes even worse, since
round-robin wakeups not only make previous CPU affinity in scheduler quite
useless, but also hide from user chance to see CPU bottlenecks, when
sequential workload with one request at a time looks evenly distributed
between multiple threads.

This change adds new SLEEPQ_UNFAIR flag to sleepq_signal(), making it wakeup
thread that went to sleep last, but no longer in context switch (to avoid
immediate spinning on the thread lock). On top of that new wakeup_any()
function is added, equivalent to wakeup_one(), but setting the flag.
On top of that taskqueue(9) is switchied to wakeup_any() to wakeup its
threads.

As result, on 72-core Xeon v4 machine sequential ZFS write to 12 ZVOLs
with 16KB block size spend 34% less time in wakeup_any() and descendants
then it was spending in wakeup_one(), and total write throughput increased
by ~10% with the same as before CPU usage.

Reviewed by: markj, mmacy
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D20669

Define QMD_SAVELINK() only for QUEUE_MACRO_DEBUG_TRASH case. Otherwise
with QUEUE_MACRO_DEBUG_TRACE compilation fails due to unused variable.

This commit brings in a new refactored TCP stack called Rack.
Rack includes the following features:
- A different SACK processing scheme (the old sack structures are not used).
- RACK (Recent acknowledgment) where counting dup-acks is no longer done
instead time is used to knwo when to retransmit. (see the I-D)
- TLP (Tail Loss Probe) where we will probe for tail-losses to attempt
to try not to take a retransmit time-out. (see the I-D)
- Burst mitigation using TCPHTPS
- PRR (partial rate reduction) see the RFC.

Once built into your kernel, you can select this stack by either
socket option with the name of the stack is "rack" or by setting
the global sysctl so the default is rack.

Note that any connection that does not support SACK will be kicked
back to the "default" base FreeBSD stack (currently known as "default").

To build this into your kernel you will need to enable in your
kernel:
makeoptions WITH_EXTRA_TCP_STACKS=1
options TCPHPTS

Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D15525

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

queue.3: Document existing QMD_* macros

Feedback from: bapt, bdrewery, emaste
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D3983

queue(3): Enhance queue debugging macros

Split the QUEUE_MACRO_DEBUG into QUEUE_MACRO_DEBUG_TRACE and
QUEUE_MACRO_DEBUG_TRASH.

Add the debug macrso QMD_IS_TRASHED() and QMD_SLIST_CHECK_PREVPTR().

Document these in queue.3.

Reviewed by: emaste
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D3984

Add two new macros, SLIST_CONCAT and LIST_CONCAT. Note in both the
queue.h header file and in the queue.3 manual page that they are O(n)
so should be used only in low-usage paths with short lists (otherwise
an STAILQ or TAILQ should be used).

Reviewed by: kib

Make the system queue header file fully usable within C++ programs by
adding macros to define class lists.

This change is backwards compatible for all use within C and C++
programs. Only C++ programs will have added support to use the queue
macros within classes. Previously the queue macros could only be used
within structures.

The queue.3 manual page has been updated to describe the new
functionality and some alphabetic sorting has been done while
at it.

Differential Revision: https://reviews.freebsd.org/D2745
PR: 200827 (exp-run)
MFC after: 2 weeks

Pass macro arguments properly.

MFC after: 1 week

Fix order of arguments in the TRACEBUF_INITIALIZER macro so that we
can define QUEUE_MACRO_DEBUG to debug list problems.

MFC after: 1 week

Add new FOREACH_FROM variants of the queue(3) FOREACH macros which can
optionally start the traversal from a previously found element by passing the
element in as "var". Passing a NULL "var" retains the same semantics as the
regular FOREACH macros.

Kudos to phk for suggesting the "FROM" suffix instead of my original proposal.

Reviewed by: jhb (previous version), rpaulo
MFC after: 1 week

Fixes to QUEUE_MACRO_DEBUG support:
- Add const quilifiers to fields that store value of __FILE__.
- Use long type for fields that store value of __LINE__.
- Sort and style(9) debugging fields.
- Add initializer for debugging fields into TAILQ_INITIALIZER macro.

PR: 175759
Submitted by: Andrey Simonenko <simon comsys.ntu-kpi.kiev.ua>
Reviewed by: bde

Rename __member2struct() to __containerof().

Compared to __member2struct(), this macro has the following advantages:

- It ensures that the type of the pointer is compatible with the member
field of the structure (or a void pointer).
- It works properly in combination with volatile and const, though
unfortunately it drops these qualifiers from the returned value.

mdf@ proposed to add the container_of() macro, just like Linux has.
Eventually I decided against this, as <sys/param.h> is included all over
the place. It seems container_of() on Linux is specific to the kernel,
not userspace. I'd rather not pollute userspace with this.

I also thought about adding __container_of(), but this would have two
advantages. Xorg seems to already have a __container_of(), which is not
compatible with this version. Also, the underscore in the middle
conflicts with our existing macros (__offsetof, __rangeof, etc).

I'm changing member2struct() to use its old code, as the extra
strictness of this new macro conflicts with existing code (read: cxgb).

MFC after: 1 month

Correctness: use __member2struct() on the correct fields.

The prev-pointers point to the next-pointers of the previous element --
not the ENTRY structure. The next-pointers are stored in the ENTRY
structures first, so the code would already work correctly. Still, it is
more accurate to use the next-fields.

To prevent misuse of __member2struct() in the future, I've got a patch
that requires the pointer to be passed to this macro to be compatible
with the member of the structure. I'll commit this patch after I've
tested it properly.

MFC after: 1 month.

Implement LIST_PREV().

Regular LISTs have been implemented in such a way that the prev-pointer
does not point to the previous element, but to the next-pointer stored
in the previous element. This is done to simplify LIST_REMOVE(). This
macro can be implemented without knowing the address of the list head.

Unfortunately this makes it harder to implement LIST_PREV(), which is
why this macro was never here. Still, it is possible to implement this
macro. If the prev-pointer points to the list head, we return NULL.
Otherwise we simply subtract the offset of the prev-pointer within the
structure.

It's not as efficient as traversing forward of course, but in practice
it shouldn't be that bad. In almost all use cases, people will want to
compare the value returned by LIST_PREV() against NULL, so an optimizing
compiler will not emit code that does more branching than TAILQs.

While there, make the code a bit more readable by introducing
__member2struct(). This makes STAILQ_LAST() far more readable.

MFC after: 1 month

Note that the _SWAP operation is supported for all list/queue types.
Also place STAILQ_REMOVE_HEAD in alphabetical order. Lastly, document
the _SWAP macros.

PR: kern/143033
MFC after: 1 week

Add SLIST_SWAP() macro.

MFC after: 1 week

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

MFC r204106:

Avoid corrupting the list or queue if _REMOVE is invoked with a
reference to the head.

PR: kern/119307

Avoid corrupting the list or queue if _REMOVE is invoked with a
reference to the head.

PR: kern/119307
MFC After: 1 week

Rename the queue macros I introduced last year.

Last year I added SLIST_REMOVE_NEXT and STAILQ_REMOVE_NEXT, to remove
entries behind an element in the list, using O(1) time. I recently
discovered NetBSD also has a similar macro, called SLIST_REMOVE_AFTER.
In my opinion this approach is a lot better:

- It doesn't have the unused first argument of the list pointer. I added
this, mainly because OpenBSD also had it.

- The _AFTER suffix makes a lot more sense, because it is related to
SLIST_INSERT_AFTER. _NEXT is only used to iterate through the list.

The reason why I want to rename this now, is to make sure we don't
release a major version with the badly named macros.

fail(9) support:

Add support for kernel fault injection using KFAIL_POINT_* macros and
fail_point_* infrastructure. Add example fail point in vfs_bio.c to
simulate VM buf pressure.

Approved by: dfr (mentor)

Remove the unused insque() and remque() functions.

We have no code in the tree that uses these anymore. New code should
just use the regular queue(3) macros.

This isn't needed...

prepare makefs for import to base

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

Introduce REMOVE_NEXT() macro's for SLIST and STAILQ.

Even though single linked lists allow items to be removed at constant time
(when the previous element is known), the queue macro's don't allow this.
Implement new REMOVE_NEXT() macro's. Because the REMOVE() macro's also
contain the same code, make it call REMOVE_NEXT().

The OpenBSD version of SLIST_REMOVE_NEXT() needs a reference to the list
head, even though it is unused. We'd better mimic this. The STAILQ version
also needs a reference to the list. This means the prototypes of both
macro's are the same.

Approved by: philip (mentor)
PR: kern/121117

Remove the non-standard and undocumented STAILQ_REMOVE_HEAD_UNTIL()
macro now that we no longer use it.

Add sanity checking for QUEUE(3) TAILQs under INVARIANTS (similar to
the LIST checks). Races may lead to list corruption, which can be
difficult to unravel in a post-mortem analysis. These checks verify
that the prev and next pointers are consistent when inserting or
removing elements, thus catching any corruption earlier.

QUEUE_MACRO_DEBUG is intended for userland code, so don't include checks
that call panic under it.

Cast the pointer to void * before casting it back to struct type * in
STAILQ_LAST. This quiets a warning from GCC about increased required
alignment for the cast.

Idea from: cognet

Userland applications may include queue.h and define INVARIANTS
but not provide a panic(9) implementation. Thus, enable the sanity
checks under INVARIANTS only if _KERNEL is also defined.

Submitted by: jmallett
Approved by: rwatson (mentor)

Add sanity checking for QUEUE(3) lists under INVARIANTS. Races may lead
to list corruption, which can be difficult to unravel in a post-mortem
analysis. These checks verify that prev and next pointers are consistent
when inserting or removing elements, thus catching any corruption earlier.

Also use TRASHIT to break LIST and SLIST link pointers on element removal,
from mlaier via -hackers.

Reviewed by: mlaier
Approved by: rwatson (mentor)

Fix typo so QUEUE_MACRO_DEBUG works again.

PR: 84654
Submitted by: Antoine.Pelisse@xloling.org (apelisse@gmail.com)

netchild's mega-patch to isolate compiler dependencies into a central
place.

This moves the dependency on GCC's and other compiler's features into
the central sys/cdefs.h file, while the individual source files can
then refer to #ifdef __COMPILER_FEATURE_FOO where they by now used to
refer to #if __GNUC__ > 3.1415 && __BARC__ <= 42.

By now, GCC and ICC (the Intel compiler) have been actively tested on
IA32 platforms by netchild. Extension to other compilers is supposed
to be possible, of course.

Submitted by: netchild
Reviewed by: various developers on arch@, some time ago

/* -> /*- for license, minor formatting changes

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

These are changes to allow to use the Intel C/C++ compiler (lang/icc)
to build the kernel. It doesn't affect the operation if gcc.

Most of the changes are just adding __INTEL_COMPILER to #ifdef's, as
icc v8 may define __GNUC__ some parts may look strange but are
necessary.

Additional changes:
- in_cksum.[ch]:
* use a generic C version instead of the assembly version in the !gcc
case (ASM code breaks with the optimizations icc does)
-> no bad checksums with an icc compiled kernel
Help from: andre, grehan, das
Stolen from: alpha version via ppc version
The entire checksum code should IMHO be replaced with the DragonFly
version (because it isn't guaranteed future revisions of gcc will
include similar optimizations) as in:
---snip---
Revision Changes Path
1.12 +1 -0 src/sys/conf/files.i386
1.4 +142 -558 src/sys/i386/i386/in_cksum.c
1.5 +33 -69 src/sys/i386/include/in_cksum.h
1.5 +2 -0 src/sys/netinet/igmp.c
1.6 +0 -1 src/sys/netinet/in.h
1.6 +2 -0 src/sys/netinet/ip_icmp.c

1.4 +3 -4 src/contrib/ipfilter/ip_compat.h
1.3 +1 -2 src/sbin/natd/icmp.c
1.4 +0 -1 src/sbin/natd/natd.c
1.48 +1 -0 src/sys/conf/files
1.2 +0 -1 src/sys/conf/files.amd64
1.13 +0 -1 src/sys/conf/files.i386
1.5 +0 -1 src/sys/conf/files.pc98
1.7 +1 -1 src/sys/contrib/ipfilter/netinet/fil.c
1.10 +2 -3 src/sys/contrib/ipfilter/netinet/ip_compat.h
1.10 +1 -1 src/sys/contrib/ipfilter/netinet/ip_fil.c
1.7 +1 -1 src/sys/dev/netif/txp/if_txp.c
1.7 +1 -1 src/sys/net/ip_mroute/ip_mroute.c
1.7 +1 -2 src/sys/net/ipfw/ip_fw2.c
1.6 +1 -2 src/sys/netinet/igmp.c
1.4 +158 -116 src/sys/netinet/in_cksum.c
1.6 +1 -1 src/sys/netinet/ip_gre.c
1.7 +1 -2 src/sys/netinet/ip_icmp.c
1.10 +1 -1 src/sys/netinet/ip_input.c
1.10 +1 -2 src/sys/netinet/ip_output.c
1.13 +1 -2 src/sys/netinet/tcp_input.c
1.9 +1 -2 src/sys/netinet/tcp_output.c
1.10 +1 -1 src/sys/netinet/tcp_subr.c
1.10 +1 -1 src/sys/netinet/tcp_syncache.c
1.9 +1 -2 src/sys/netinet/udp_usrreq.c

1.5 +1 -2 src/sys/netinet6/ipsec.c
1.5 +1 -2 src/sys/netproto/ipsec/ipsec.c
1.5 +1 -1 src/sys/netproto/ipsec/ipsec_input.c
1.4 +1 -2 src/sys/netproto/ipsec/ipsec_output.c

and finally remove
sys/i386/i386 in_cksum.c
sys/i386/include in_cksum.h
---snip---
- endian.h:
* DTRT in C++ mode
- quad.h:
* we don't use gcc v1 anymore, remove support for it
Suggested by: bde (long ago)
- assym.h:
* avoid zero-length arrays (remove dependency on a gcc specific
feature)
This change changes the contents of the object file, but as it's
only used to generate some values for a header, and the generator
knows how to handle this, there's no impact in the gcc case.
Explained by: bde
Submitted by: Marius Strobl <marius@alchemy.franken.de>
- aicasm.c:
* minor change to teach it about the way icc spells "-nostdinc"
Not approved by: gibbs (no reply to my mail)
- bump __FreeBSD_version (lang/icc needs to know about the changes)

Incarnations of this patch survive gcc compiles since a loooong time,
I use it on my desktop. An icc compiled kernel works since Nov. 2003
(exceptions: snd_* if used as modules), it survives a build of the
entire ports collection with icc.

Parts of this commit contains suggestions or submissions from
Marius Strobl <marius@alchemy.franken.de>.

Reviewed by: -arch
Submitted by: netchild

Add safe _FOREACH iterators to the rest of the queue.h types.

Add LIST_FOREACH_SAFE, which is like LIST_FOREACH but allows you
to walk the list and remove the current item and destroy/free it.

Alexander Kabaev will likely do the equivalent for the other list
types, but I just happened to have this one sitting in a local
non-FreeBSD tree already.

Add a macro for SLIST traversal 'SLIST_FOREACH_PREVPTR',
this macro keeps a pointer to the previous element's next
pointer to allow for search and O(1) removal.

Move __offsetof() macro from <machine/ansi.h> to <sys/cdefs.h>. It's
hardly MD, since all our platforms share the same macro. It's not
really compiler dependent either, but this helps in reducing
<machine/ansi.h> to only type definitions.

check in the version if this that compiles, not the one that doesn't

Make some more debugging code go away when debugging is not turned on.

Oops, that was a heck of a lot more debugging left onthan I intended..
turn it off!

I don't know if people think that these debugging macros are worth keeping
or not but I'll keep them for a short while, while the danger of
queue stuffups in the (rather complicated) run queue code exists.

Part 1 of KSE-III

The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)

NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..

Parenthesize some macro arguments.

PR: 20024
Submitted by: Tony Finch <dot@dotat.at>

Add macros for concatenating tailqs and stailqs.

PR: 20024
Submitted by: Tony Finch <dot@dotat.at> (TAILQ_CONCAT)

Remove __P

Correct a comment that should have been updated in rev 1.43, when
CIRCLEQ was removed.

PR: kern/32688
Submitted by: Jordan DeLong <fracture@allusion.net>

namei.h: move "struct componentname" definition outside "struct nameidata",
and provide a valid STDC/C++ definition for function NDINIT

queue.h libkern.h: put explicit casts from void * in insque, remque and memset

(for the records, these changes are necessary to let the files
compile with g++, which is used to build a FreeBSD module
for "Click" -- see www.pdos.lcs.mit.edu/click/ .
Given that they have zero impact on our code, it is worthwhile
to have them in.

MFC after: 3 days

CIRCLEQs are a disgrace to everything Knuth taught us in Volume 1 Chapter 2.

Retire them before anybody starts to use them again.

Use TAILQ instead, it provides the same functionality.

Convert all users of fldoff() to offsetof(). fldoff() is bad
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.

Define __offsetof() in <machine/ansi.h>

Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>

Remove myriad of local offsetof() definitions.

Remove includes of <stddef.h> in kernel code.

NB: Kernelcode should *never* include from /usr/include !

Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.

Deprecate <struct.h> with a warning. The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.

Paritials reviews by: various.
Significant brucifications by: bde

Don't bogusly include <struct.h>

Bogusly define our own versions of strbase() and fldoff() until we
have sorted out where they live in the kernel.

Make check for empty list in STAILQ_LAST() more readable.

Restore STAILQ_LAST() semantics to match that of TAILQ_LAST()
and CIRCLEQ_LAST(). Return the last element instead of a pointer
to the next field of the last element.

Reviewed by: dfr

Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by: msmith and others

Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by: phk
Reviewed by: phk
Approved by: mdodd

Major style cleanup; make ordering and internal use of the macros consistent.
Hopefully enforce KNF conformance. Add a missing _HEAD_INITIALIZER.

Reviewed by: archie, phk, bde
(bde did not like all of it)
Approved by: mdodd

Add TAILQ_FOREACH_REVERSE() macro.

Submitted by: Jake Burkholder <jburkhol@home.com>

Add a new macro CIRCLEQ_FOREACH_REVERSE for traversing through a
circle queue in the reverse direction (from tail to head).

Fix spelling, slingly -> singly.

Submitted by: nrahlstr

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

Macro needed for NEWCARD kernel and STAILQ emulation.

Pointed out by Richard Wackerbar

Add SLIST_HEAD_INITIALIZER for static initialisation of SLISTs.

Add STAILQ_FOREACH.

$Id$ -> $FreeBSD$

Backout the previous change. Claimed to break compatibility with
NetBSD.

Requested-By: John Polstra

Remove bogus argument to LIST_HEAD_INITIALIZER

Remove feature creep: STAILQ_REMOVE_HEAD_UNTIL added it for convenience
but we can do without it.

Name change suggested by Justin (QUEUE->UNTIL)

Copied STAILQ_HEAD_INITIALIZER and LIST_HEAD_INITIALIZER from NetBSD, and
added STAILQ_REMOVE_HEAD_QUEUE to emulate NetBSD's SIMPLEQ_REMOVE_HEAD (that
removes not only the first element but a queue of elements).

When some functions were added to sys/queue.h (1.15, 1.16),
the queue diagram (in comment, showing member functions)
update were slipped.

PR: 7048
Submitted by: SAWADA Mizuki <miz@qb3.so-net.ne.jp>

Fix the termination test in CIRCLEQ_FOREACH.

Prompted by: Julian Assange <proff@iq.org>

Add the 'do/while hack' to all the queue macros
to allow them to be more generally used.

Submitted by: Kirk McKusick (from some of his trees)
(possibly some cleanups to follow)

Correct the definition of CIRCLEQ_EMPTY. It would give a false positive
if the queue contained only one element.

Submitted by: Greg Ansley <gja@ansley.com>

buf.h:
Change the definition of a buffer queue so that bufqdisksort can
properly deal with bordered writes.

Add inline functions for accessing buffer queues. This should be
considered an opaque data structure by clients.

callout.h:
New callout implementation.

device.h:
Add support for CAM interrupts.

disk.h:
disklabel.h:
tqdisksort->bufqdisksort

kernel.h:
Add new configuration entries for configuration hooks and calling
cpu_rootconf and cpu_dumpconf.

param.h:
Add a priority for sleeping waiting on config hooks.

proc.h:
Update for new callout implementation.

queue.h:
Add TAILQ_HEAD_INITIALIZER from NetBSD.

systm.h:
Add prototypes for cpu_root/dumpconf, splcam, splsoftcam, etc..

Add SLIST_FOREACH

Add accessors for STAILQ.

Reviewed by: phk

Add some more "member functions" to these. Still not complete.

Add LIST_FIRST, LIST_FOREACH and LIST_NEXT

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Add
SLIST_EMPTY(head)
SLIST_FIRST(head)
SLIST_NEXT(elm, field)

Which do the obvious things while hiding implementation details.

This set of commits to the VM system does the following, and contain
contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

More usage of the TAILQ macros. Additional minor fix to queue.h.
Performance enhancements to the pageout daemon.
Addition of a wait in the case that the pageout daemon
has to run immediately.
Slightly modify the pageout algorithm.
Significant revamp of the pmap/fork code:
1) PTE's and UPAGES's are NO LONGER in the process's map.
2) PTE's and UPAGES's reside in their own objects.
3) TOTAL elimination of recursive page table pagefaults.
4) The page directory now resides in the PTE object.
5) Implemented pmap_copy, thereby speeding up fork time.
6) Changed the pv entries so that the head is a pointer
and not an entire entry.
7) Significant cleanup of pmap_protect, and pmap_remove.
8) Removed significant amounts of machine dependent
fork code from vm_glue. Pushed much of that code into
the machine dependent pmap module.
9) Support more completely the reuse of already zeroed
pages (Page table pages and page directories) as being
already zeroed.
Performance and code cleanups in vm_map:
1) Improved and simplified allocation of map entries.
2) Improved vm_map_copy code.
3) Corrected some minor problems in the simplify code.
Implemented splvm (combo of splbio and splimp.) The VM code now
seldom uses splhigh.
Improved the speed of and simplified kmem_malloc.
Minor mod to vm_fault to avoid using pre-zeroed pages in the case
of objects with backing objects along with the already
existant condition of having a vnode. (If there is a backing
object, there will likely be a COW... With a COW, it isn't
necessary to start with a pre-zeroed page.)
Minor reorg of source to perhaps improve locality of ref.

Add five macros to TAILQ family to improve readability.

Implement the SLIST and the STAILQ macros. This gives a program all the
aesthetics of using the 4.4 queue macros without paying undo space or time
in scenartios where a singly-linked list works fine.

From queue.h:
/*
* A singly-linked list is headed by a single forward pointer. The elements
* are singly linked for minimum space and pointer manipulation overhead at
* the expense of O(n) removal for arbitrary elements. New elements can be
* added to the list after an existing element or at the head of the list.
* Elements being removed from the head of the list should use the explicit
* macro for this purpose for optimum efficiency. A singly-linked list may
* only be traversed in the forward direction. Singly-linked lists are ideal
* for applications with large datasets and few or no removals or for
* implementing a LIFO queue.
*
* A singly-linked tail queue is headed by a pair of pointers, one to the
* head of the list and the other to the tail of the list. The elements are
* singly linked for minimum space and pointer manipulation overhead at the
* expense of O(n) removal for arbitrary elements. New elements can be added
* to the list after an existing element, at the head of the list, or at the
* end of the list. Elements being removed from the head of the tail queue
* should use the explicit macro for this purpose for optimum efficiency.
* A singly-linked tail queue may only be traversed in the forward direction.
* Singly-linked tail queues are ideal for applications with large datasets
* and few or no removals or for implementing a FIFO queue.
*/

Import 4.4BSD-Lite2 onto the vendor branch, note that in the kernel, all
files are off the vendor branch, so this should not change anything.

A "U" marker generally means that the file was not changed in between
the 4.4Lite and Lite-2 releases, and does not need a merge. "C" generally
means that there was a change.
[new sys/syscallargs.h file, to be "cvs rm"ed]

Merge in Lite2: fix comment
optimize TAILQ_INSERT_HEAD
Reviewed by: davidg & bde

4.4Lite2 implemented the LIST_INSERT_BEFORE and TAILQ_INSERT_BEFORE
exactly as I did (should have checked there first I guess) except my
macro for TAILQ_INSERT_BEFORE took an unneeded arg. We now match 4.4Lite2.

Suggested by: Jeffrey Hsu <hsu@FreeBSD.org>

Add LIST_INSERT_BEFORE and TAILQ_INSERT_BEFORE. These are used by the
new eisaconf code.

Moved inline functions for insque() and remque() to <sys/queue.h>.
Protected them with `#ifdef KERNEL' so that <sys/queue.h> is valid C++.
Added the necessary #includes of <sys/queue.h>.

These functions are bogus and should be replaced by the queue macros.

Remove trailing whitespace.

Added $Id$

BSD 4.4 Lite Kernel Sources