25 files changed, 454 insertions, 236 deletions
diff --git a/share/man/man3/Makefile b/share/man/man3/Makefile
index b63ab812ea34..4e1592adf74a 100644
--- a/share/man/man3/Makefile
+++ b/share/man/man3/Makefile
@@ -49,7 +49,9 @@ MLINKS+=	bitstring.3 bit_alloc.3 \
 		bitstring.3 bit_clear.3 \
 		bitstring.3 bit_decl.3 \
 		bitstring.3 bit_ffc.3 \
+		bitstring.3 bit_ffc_at.3 \
 		bitstring.3 bit_ffs.3 \
+		bitstring.3 bit_ffs_at.3 \
 		bitstring.3 bit_nclear.3 \
 		bitstring.3 bit_nset.3 \
 		bitstring.3 bit_set.3 \
diff --git a/share/man/man3/pthread_getcpuclockid.3 b/share/man/man3/pthread_getcpuclockid.3
index de0e6bcfd5ef..c36be81e58dc 100644
--- a/share/man/man3/pthread_getcpuclockid.3
+++ b/share/man/man3/pthread_getcpuclockid.3
@@ -51,8 +51,8 @@
 The
 .Fn pthread_getcpuclockid
 returns the clock ID of the CPU-time clock of the thread specified by
-.Fa thread_id .
-If the thread described by
+.Fa thread_id ,
+if the thread described by
 .Fa thread_id
 exists.
 .Sh RETURN VALUES
@@ -61,7 +61,9 @@ Upon successful completion,
 returns zero; otherwise, an error number is returned to indicate the
 error.
 .Sh ERRORS
-The pthread_getcpuclockid() function will fail if:
+The
+.Fn pthread_getcpuclockid
+function will fail if:
 .Bl -tag -width Er
 .It Bq Er ESRCH
 The value specified by
diff --git a/share/man/man3/pthread_testcancel.3 b/share/man/man3/pthread_testcancel.3
index fc412de5b1ae..1dfc96483445 100644
--- a/share/man/man3/pthread_testcancel.3
+++ b/share/man/man3/pthread_testcancel.3
@@ -1,5 +1,5 @@
 .\" $FreeBSD$
-.Dd April 16, 2015
+.Dd August 16, 2016
 .Dt PTHREAD_TESTCANCEL 3
 .Os
 .Sh NAME
@@ -114,6 +114,7 @@ function is a cancellation point if
 .Fa cmd
 is
 .Dv F_SETLKW .
+.It Fn fdatasync
 .It Fn fsync
 .It Fn kevent
 The
diff --git a/share/man/man3/queue.3 b/share/man/man3/queue.3
index bde4687b0eb1..1023c65a5640 100644
--- a/share/man/man3/queue.3
+++ b/share/man/man3/queue.3
@@ -28,12 +28,13 @@
 .\"	@(#)queue.3	8.2 (Berkeley) 1/24/94
 .\" $FreeBSD$
 .\"
-.Dd June 24, 2015
+.Dd August 15, 2016
 .Dt QUEUE 3
 .Os
 .Sh NAME
 .Nm SLIST_CLASS_ENTRY ,
 .Nm SLIST_CLASS_HEAD ,
+.Nm SLIST_CONCAT ,
 .Nm SLIST_EMPTY ,
 .Nm SLIST_ENTRY ,
 .Nm SLIST_FIRST ,
@@ -75,6 +76,7 @@
 .Nm STAILQ_SWAP ,
 .Nm LIST_CLASS_ENTRY ,
 .Nm LIST_CLASS_HEAD ,
+.Nm LIST_CONCAT ,
 .Nm LIST_EMPTY ,
 .Nm LIST_ENTRY ,
 .Nm LIST_FIRST ,
@@ -125,6 +127,7 @@ lists and tail queues
 .\"
 .Fn SLIST_CLASS_ENTRY "CLASSTYPE"
 .Fn SLIST_CLASS_HEAD "HEADNAME" "CLASSTYPE"
+.Fn SLIST_CONCAT "SLIST_HEAD *head1" "SLIST_HEAD *head2" "TYPE" "SLIST_ENTRY NAME"
 .Fn SLIST_EMPTY "SLIST_HEAD *head"
 .Fn SLIST_ENTRY "TYPE"
 .Fn SLIST_FIRST "SLIST_HEAD *head"
@@ -141,7 +144,7 @@ lists and tail queues
 .Fn SLIST_REMOVE "SLIST_HEAD *head" "TYPE *elm" "TYPE" "SLIST_ENTRY NAME"
 .Fn SLIST_REMOVE_AFTER "TYPE *elm" "SLIST_ENTRY NAME"
 .Fn SLIST_REMOVE_HEAD "SLIST_HEAD *head" "SLIST_ENTRY NAME"
-.Fn SLIST_SWAP "SLIST_HEAD *head1" "SLIST_HEAD *head2" "SLIST_ENTRY NAME"
+.Fn SLIST_SWAP "SLIST_HEAD *head1" "SLIST_HEAD *head2" "TYPE"
 .\"
 .Fn STAILQ_CLASS_ENTRY "CLASSTYPE"
 .Fn STAILQ_CLASS_HEAD "HEADNAME" "CLASSTYPE"
@@ -164,10 +167,11 @@ lists and tail queues
 .Fn STAILQ_REMOVE "STAILQ_HEAD *head" "TYPE *elm" "TYPE" "STAILQ_ENTRY NAME"
 .Fn STAILQ_REMOVE_AFTER "STAILQ_HEAD *head" "TYPE *elm" "STAILQ_ENTRY NAME"
 .Fn STAILQ_REMOVE_HEAD "STAILQ_HEAD *head" "STAILQ_ENTRY NAME"
-.Fn STAILQ_SWAP "STAILQ_HEAD *head1" "STAILQ_HEAD *head2" "STAILQ_ENTRY NAME"
+.Fn STAILQ_SWAP "STAILQ_HEAD *head1" "STAILQ_HEAD *head2" "TYPE"
 .\"
 .Fn LIST_CLASS_ENTRY "CLASSTYPE"
 .Fn LIST_CLASS_HEAD "HEADNAME" "CLASSTYPE"
+.Fn LIST_CONCAT "LIST_HEAD *head1" "LIST_HEAD *head2" "TYPE" "LIST_ENTRY NAME"
 .Fn LIST_EMPTY "LIST_HEAD *head"
 .Fn LIST_ENTRY "TYPE"
 .Fn LIST_FIRST "LIST_HEAD *head"
@@ -249,6 +253,8 @@ Singly-linked lists add the following functionality:
 .Bl -enum -compact -offset indent
 .It
 O(n) removal of any entry in the list.
+.It
+O(n) concatenation of two lists.
 .El
 .Pp
 Singly-linked tail queues add the following functionality:
@@ -296,6 +302,8 @@ Linked lists are the simplest of the doubly linked data structures.
 They add the following functionality over the above:
 .Bl -enum -compact -offset indent
 .It
+O(n) concatenation of two lists.
+.It
 They may be traversed backwards.
 .El
 However:
@@ -401,6 +409,19 @@ evaluates to an initializer for the list
 .Fa head .
 .Pp
 The macro
+.Nm SLIST_CONCAT
+concatenates the list headed by
+.Fa head2
+onto the end of the one headed by
+.Fa head1
+removing all entries from the former.
+Use of this macro should be avoided as it traverses the entirety of the
+.Fa head1
+list.
+A singly-linked tail queue should be used if this macro is needed in
+high-usage code paths or to operate on long lists.
+.Pp
+The macro
 .Nm SLIST_EMPTY
 evaluates to true if there are no elements in the list.
 .Pp
@@ -508,6 +529,9 @@ The macro
 removes the element
 .Fa elm
 from the list.
+Use of this macro should be avoided as it traverses the entire list.
+A doubly-linked list should be used if this macro is needed in
+high-usage code paths or to operate on long lists.
 .Pp
 The macro
 .Nm SLIST_SWAP
@@ -724,6 +748,9 @@ The macro
 removes the element
 .Fa elm
 from the tail queue.
+Use of this macro should be avoided as it traverses the entire list.
+A doubly-linked tail queue should be used if this macro is needed in
+high-usage code paths or to operate on long tail queues.
 .Pp
 The macro
 .Nm STAILQ_SWAP
@@ -823,6 +850,19 @@ evaluates to an initializer for the list
 .Fa head .
 .Pp
 The macro
+.Nm LIST_CONCAT
+concatenates the list headed by
+.Fa head2
+onto the end of the one headed by
+.Fa head1
+removing all entries from the former.
+Use of this macro should be avoided as it traverses the entirety of the
+.Fa head1
+list.
+A tail queue should be used if this macro is needed in
+high-usage code paths or to operate on long lists.
+.Pp
+The macro
 .Nm LIST_EMPTY
 evaluates to true if there are no elements in the list.
 .Pp
diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index 1cd099b0b5a4..e85e531aa802 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -269,7 +269,6 @@ MAN=	aac.4 \
 	mac_stub.4 \
 	mac_test.4 \
 	malo.4 \
-	mcd.4 \
 	md.4 \
 	mdio.4 \
 	me.4 \
diff --git a/share/man/man4/gpioled.4 b/share/man/man4/gpioled.4
index 3e305959809f..3fb4c4d64e9d 100644
--- a/share/man/man4/gpioled.4
+++ b/share/man/man4/gpioled.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 14, 2014
+.Dd July 30, 2016
 .Dt GPIOLED 4
 .Os
 .Sh NAME
@@ -71,6 +71,8 @@ to create for
 Which pin on the GPIO interface to map to this instance.
 Please note that this mask should only ever have one bit set
 (any other bits - i.e., pins - will be ignored).
+.It Va hint.gpioled.%d.invert
+If set to 1, the pin will be set to 0 to light the LED, and 1 to clear it.
 .El
 .Pp
 On a
diff --git a/share/man/man4/if_ntb.4 b/share/man/man4/if_ntb.4
index 2f363dcc8efc..6f52d7774264 100644
--- a/share/man/man4/if_ntb.4
+++ b/share/man/man4/if_ntb.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 10, 2016
+.Dd July 29, 2016
 .Dt IF_NTB 4
 .Os
 .Sh NAME
@@ -49,7 +49,7 @@ The following tunables are settable from the
 .Bl -ohang
 .It Va hw.if_ntb.num_queues
 Number of transport queues to use per interface.
-Default is 1.
+Default is unlimited.
 .El
 .Sh DESCRIPTION
 The
@@ -84,3 +84,6 @@ Later improvements were done by
 .An Conrad E. Meyer Aq Mt cem@FreeBSD.org
 and
 .An Alexander Motin Aq Mt mav@FreeBSD.org .
+.Sh BUGS
+Linux supports only one queue per interface, so manual configuration
+may be required for compatibility.
diff --git a/share/man/man4/iwm.4 b/share/man/man4/iwm.4
index 45c0bf2c30cb..9b906d7c2d29 100644
--- a/share/man/man4/iwm.4
+++ b/share/man/man4/iwm.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 1, 2015
+.Dd July 26, 2016
 .Dt IWM 4
 .Os
 .Sh NAME
@@ -48,6 +48,7 @@ Choose one from:
 .Cd "device iwm3160fw"
 .Cd "device iwm7260fw"
 .Cd "device iwm7265fw"
+.Cd "device iwm8000Cfw"
 .Ed
 .Pp
 Or you can use
@@ -65,6 +66,7 @@ if_iwm_load="YES"
 iwm3160fw_load="YES"
 iwm7260fw_load="YES"
 iwm7265fw_load="YES"
+iwm8000Cfw_load="YES"
 .Ed
 .Sh DESCRIPTION
 The
@@ -73,8 +75,10 @@ driver provides support for:
 .Pp
 .Bl -tag -width Ds -offset indent -compact
 .It Intel Dual Band Wireless AC 3160
+.It Intel Dual Band Wireless AC 3165
 .It Intel Dual Band Wireless AC 7260
 .It Intel Dual Band Wireless AC 7265
+.It Intel Dual Band Wireless AC 8260
 .El
 .Pp
 .Nm
diff --git a/share/man/man4/iwmfw.4 b/share/man/man4/iwmfw.4
index 0e1832c1fedc..190f8061da32 100644
--- a/share/man/man4/iwmfw.4
+++ b/share/man/man4/iwmfw.4
@@ -22,7 +22,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 28, 2015
+.Dd July 26, 2016
 .Dt IWMFW 4
 .Os
 .Sh NAME
@@ -45,6 +45,7 @@ of the following:
 .Cd "device iwm3160fw"
 .Cd "device iwm7260fw"
 .Cd "device iwm7265fw"
+.Cd "device iwm8000Cfw"
 .Ed
 .Pp
 Alternatively, to load the driver as a
@@ -54,10 +55,11 @@ module at boot time, place the following line in
 iwm3160fw_load="YES"
 iwm7260fw_load="YES"
 iwm7265fw_load="YES"
+iwm8000Cfw_load="YES"
 .Ed
 .Sh DESCRIPTION
 This module provides access to firmware sets for the
-Intel Dual Band Wireless WiFi 3160, 7260 and 7265 series of
+Intel Dual Band Wireless WiFi 3160, 3165, 7260, 7265 and 8260 series of
 IEEE 802.11n/11ac adapters.
 It may be
 statically linked into the kernel, or loaded as a module.
diff --git a/share/man/man4/mcd.4 b/share/man/man4/mcd.4
deleted file mode 100644
index 3a79eee41799..000000000000
--- a/share/man/man4/mcd.4
+++ /dev/null
@@ -1,165 +0,0 @@
-.\"
-.\" Copyright (c) 1994 Keith E. Walker
-.\" All rights reserved.
-.\"
-.\" Redistribution and use in source and binary forms, with or without
-.\" modification, are permitted provided that the following conditions
-.\" are met:
-.\" 1. Redistributions of source code must retain the above copyright
-.\"    notice, this list of conditions and the following disclaimer.
-.\" 2. Redistributions in binary form must reproduce the above copyright
-.\"    notice, this list of conditions and the following disclaimer in the
-.\"    documentation and/or other materials provided with the distribution.
-.\" 3. The name of the author may not be used to endorse or promote products
-.\"    derived from this software without specific prior written permission
-.\"
-.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-.\"
-.\" $FreeBSD$
-.\"
-.Dd December 8, 1994
-.Dt MCD 4
-.Os
-.Sh NAME
-.Nm mcd
-.Nd Mitsumi CD-ROM driver
-.Sh SYNOPSIS
-.Cd "device mcd"
-.Pp
-In
-.Pa /boot/device.hints :
-.Cd hint.mcd.0.at="isa"
-.Cd hint.mcd.0.port="0x300"
-.Cd hint.mcd.0.irq="10"
-.Sh DESCRIPTION
-The
-.Nm
-driver provides a data and audio interface to the Mitsumi-brand CD-ROM
-player.
-The CD-ROM player must be interfaced to the ISA bus through
-one of the Mitsumi proprietary controller boards.
-The controller
-boards supported are the LU002S, LU005S, the FX001 and the quite
-common FX001D.
-.Pp
-The
-.Nm
-driver responds to disk-specific
-.Fn ioctl
-commands, namely the
-.Dv DIOCGPART
-command.
-Other disk-specific
-.Fn ioctl
-commands will return an error.
-.Pp
-The
-.Nm
-driver also responds to special CD-ROM
-.Fn ioctl
-commands.
-These commands
-control the CD-ROM player's audio features.
-The commands are:
-.Pp
-.Bl -tag -width CDIOCREADSUBCHANNEL -compact -offset indent
-.It CDIOCREADSUBCHANNEL
-get sub-channel information on current status of disc playing
-.It CDIOCREADTOCHEADER
-get table of contents header
-.It CDIOCREADTOCENTRYS
-gets all of the table of contents
-.It CDIOCPLAYTRACKS
-begins audio playing at location specified
-.It CDIOCPLAYBLOCKS
-fails with error
-.Er EINVAL
-.It CDIOCPLAYMSF
-begins audio playing at location specified
-.It CDIOCRESUME
-resumes playing a previously paused disc
-.It CDIOCPAUSE
-pauses a playing disc
-.It CDIOCSTART
-begins playing a disc
-.It CDIOCSTOP
-stops a previously playing disc
-.It CDIOCEJECT
-opens the disc tray (there is no support for a corresponding un-eject
-command).
-.It CDIOCRESET
-stops any play and resets the Mitsumi controller board
-.It CDIOCSETDEBUG
-cause the kernel to print debug messages to the console about the
-.Nm
-driver
-.It CDIOCCLRDEBUG
-cause the kernel to quit printing debug messages about the
-.Nm
-driver
-.El
-.Pp
-The
-.Fn ioctl
-commands defined above are the only ones that the
-.Nm
-driver supports.
-There are other CD-ROM related
-.Fn ioctl
-commands (such as
-.Dv CDIOCSETVOL
-and
-.Dv CDIOCSETSTERIO )
-which are available
-and may be supported by future versions of the driver.
-.Sh FILES
-.Bl -tag -width /dev/(r)mcd0a -compact
-.It Pa /dev/(r)mcd0a
-accesses
-.Bx
-partition on the disc.
-Normally, there is only
-one file system on a CD-ROM disc.
-.It Pa /dev/(r)mcd0c
-accesses raw device.
-.El
-.Sh NOTES
-The character-mode devices for the
-.Nm
-driver should only be used for accessing the audio features of the
-CD-ROM player as the performance on data is abysmal.
-.Pp
-The current version of the driver uses neither the DMA or IRQ
-features of the interface board, although it has an interrupt handler
-for any IRQ requests that are generated.
-Until the DMA features are
-supported, the only interrupts that the board generates are those that
-are not supported by the driver anyway.
-.Sh SEE ALSO
-.In sys/cdio.h
-.Sh HISTORY
-An
-.Nm
-driver appeared in
-.Fx 1.0 .
-.Sh AUTHORS
-.An -nosplit
-The driver was written by
-.An Holger Veit
-(data part) and
-.An Brian Moore
-(audio part).
-Changes were provided by
-.An Gary Clark II ,
-.An Andrew A. Chernov ,
-and
-.An Jordan K. Hubbard .
diff --git a/share/man/man4/ng_checksum.4 b/share/man/man4/ng_checksum.4
new file mode 100644
index 000000000000..5ede910b7997
--- /dev/null
+++ b/share/man/man4/ng_checksum.4
@@ -0,0 +1,141 @@
+.\" Copyright (c) 2015 Dmitry Vagin <daemon.hammer@ya.ru>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd October 29, 2015
+.Dt NG_CHECKSUM 4
+.Os
+.Sh NAME
+.Nm ng_checksum
+.Nd IP checksum node type
+.Sh SYNOPSIS
+.In netgraph/ng_checksum.h
+.Sh DESCRIPTION
+The
+.Nm checksum
+node can calculate and prepare for calculation in hardware
+IPv4 header, TCP, UDP checksum.
+.Sh HOOKS
+This node type has two hooks:
+.Bl -tag -width ".Va out"
+.It Va in
+Packets received on this hook are processed according to settings specified
+in config and then forwarded to
+.Ar out
+hook, if it exists and connected. Otherwise they are reflected back to the
+.Ar in
+hook.
+.It Va out
+Packets received on this hook are forwarded to
+.Ar in
+hook without any changes.
+.El
+.Sh CONTROL MESSAGES
+This node type supports the generic control messages, plus the following:
+.Bl -tag -width foo
+.It Dv NGM_CHECKSUM_SETDLT Pq Ic setdlt
+Sets data link type on the
+.Va in
+hook. Currently, supported types are
+.Cm DLT_RAW
+(raw IP datagrams) and
+.Cm DLT_EN10MB
+(Ethernet). DLT_ definitions can be found in
+.In net/bpf.h
+header. Currently used values are
+.Cm DLT_EN10MB
+= 1 and
+.Cm DLT_RAW
+= 12.
+.It Dv NGM_CHECKSUM_GETDLT Pq Ic getdlt
+This control message obtains data link type on the
+.Va in
+hook.
+.It Dv NGM_CHECKSUM_SETCONFIG Pq Ic setconfig
+Sets node configuration. The following
+.Vt "struct ng_checksum_config"
+must be supplied as an argument:
+.Bd -literal -offset 4n
+struct ng_checksum_config {
+	uint64_t	csum_flags;
+	uint64_t	csum_offload;
+};
+.Ed
+.Pp
+The
+.Va csum_flags
+can be set to any combination of CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6
+(other values are ignored) for instructing node need calculate the corresponding checksum.
+.Pp
+The
+.Va csum_offload
+can be set to any combination of CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6
+(other values are ignored) for instructing node what checksum can calculate in hardware.
+.Pp
+Also processed any combination of CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6 sets before on mbuf.
+.It Dv NGM_CHECKSUM_GETCONFIG Pq Ic getconfig
+This control message obtains current node configuration,
+returned as
+.Vt "struct ng_checksum_config" .
+.It Dv NGM_CHECKSUM_GET_STATS Pq Ic getstats
+Returns node statistics as a
+.Vt "struct ng_checksum_stats" .
+.It Dv NGM_CHECKSUM_CLR_STATS Pq Ic clrstats
+Clear node statistics.
+.It Dv NGM_CHECKSUM_GETCLR_STATS Pq Ic getclrstats
+This command is identical to
+.Dv NGM_CHECKSUM_GET_STATS ,
+except that the statistics are also atomically cleared.
+.El
+.Sh SHUTDOWN
+This node shuts down upon receipt of a
+.Dv NGM_SHUTDOWN
+control message, or when all hooks have been disconnected.
+.Sh EXAMPLES
+.Xr ngctl 8
+script:
+.Bd -literal -offset 4n
+/usr/sbin/ngctl -f- <<-SEQ
+	msg checksum-1: "setdlt 1"
+	ngctl msg checksum-1: "setconfig { csum_flags=0 csum_offload=6 }"
+.Ed
+.Pp
+Set data link type to
+.Cm DLT_EN10MB
+(Ethernet), not set additional checksum flags, set hardware
+can calculate CSUM_IP_UDP|CSUM_IP_TCP.
+.Sh SEE ALSO
+.Xr netgraph 4 ,
+.Xr ng_patch 4 ,
+.Xr ngctl 8
+.Sh HISTORY
+The
+.Nm
+node type was implemented in
+.Fx 10.2 
+and first submitted in 
+.Fx 12.0 .
+.Sh AUTHORS
+.An "Dmitry Vagin" Aq daemon.hammer@ya.ru .
diff --git a/share/man/man4/ntb_hw.4 b/share/man/man4/ntb_hw.4
index 901ee73d2783..b6dffce166de 100644
--- a/share/man/man4/ntb_hw.4
+++ b/share/man/man4/ntb_hw.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 10, 2016
+.Dd July 28, 2016
 .Dt NTB_HW 4
 .Os
 .Sh NAME
@@ -51,6 +51,20 @@ The following tunables are settable from the
 .It Va hw.ntb.debug_level
 Driver debug level.
 The default value is 0, higher means more verbose.
+.It Va hint.ntb_hw. Ns Ar X Ns Va .config
+Configures NTB resources split between several consumer devices.
+Configuration of multiple consumer devices separated by commas.
+Each device can be configured as: "<name>[:<mw>[:<spad>[:<db>]]]", where:
+.Va name
+is a name of the driver which should attach the device (empty means any),
+.Va mw
+is a number of memory windows to allocate (empty means all available),
+.Va spad
+is a number of scratchpad registers to allocate (empty means all available),
+.Va db
+is a number of doorbells to allocate (empty means all available).
+The default configuration is empty string, which means single device
+with all available resources allowing any driver attachment.
 .El
 .Sh DESCRIPTION
 The NTB allows you to connect two computer systems using a PCIe link if they
@@ -69,7 +83,7 @@ The hardware provides 2-3 memory windows to the other system's memory,
 On Xeon processors one of memory windows is typically consumed by the driver
 to workaround multiple hardware erratas.
 .Sh CONFIGURATION
-Tne NTB configuration should be set by BIOS.
+The NTB configuration should be set by BIOS.
 It includes enabling NTB, choosing between NTB-to-NTB or NTB-to-Root Port mode,
 enabling split BAR mode (one of two 64-bit BARs can be split into two 32-bit
 ones) and configuring BAR sizes in bits (from 12 to 29/39) for both NTB sides.
diff --git a/share/man/man4/ntb_transport.4 b/share/man/man4/ntb_transport.4
index 33800c40fafb..43b412cd8f5f 100644
--- a/share/man/man4/ntb_transport.4
+++ b/share/man/man4/ntb_transport.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 10, 2016
+.Dd July 29, 2016
 .Dt NTB_TRANSPORT 4
 .Os
 .Sh NAME
@@ -44,10 +44,15 @@ The following tunables are settable from the
 .It Va hw.ntb_transport.debug_level
 Driver debug level.
 The default value is 0, higher means more verbose.
-.It Va hw.ntb_transport.max_num_clients
-Number of bidirectional queues to setup.
-The default value is 0, that means one queue per available memory window.
-Maximal number is limited by number of doorbells.
+.It Va hint.ntb_transport. Ns Ar X Ns Va .config
+Configures queues allocation for consumer devices, separated by commas.
+Each device can be configured as: "<name>[:<queues>]", where:
+.Va name
+is a name of the driver which should attach the device (empty means any),
+.Va queues
+is a number of queues to allocate (empty means automatic),
+The default configuration is empty string, which means single device
+with one queue per memory window allowing any driver attachment.
 .El
 .Sh DESCRIPTION
 The
diff --git a/share/man/man4/pci.4 b/share/man/man4/pci.4
index b1a056b970a7..68aaa4454592 100644
--- a/share/man/man4/pci.4
+++ b/share/man/man4/pci.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 3, 2008
+.Dd August 9, 2016
 .Dt PCI 4
 .Os
 .Sh NAME
@@ -229,7 +229,8 @@ The status tells the user the disposition of his request for a device list.
 The possible status values are:
 .Bl -ohang
 .It PCI_GETCONF_LAST_DEVICE
-This means that there are no more devices in the PCI device list after the
+This means that there are no more devices in the PCI device list matching
+the specified criteria after the
 ones returned in the
 .Va matches
 buffer.
@@ -245,9 +246,7 @@ and
 to zero to start over at the beginning of the list.
 .It PCI_GETCONF_MORE_DEVS
 This tells the user that his buffer was not large enough to hold all of the
-remaining devices in the device list that possibly match his criteria.
-It is possible for this status to be returned, even when none of the remaining
-devices in the list would match the user's criteria.
+remaining devices in the device list that match his criteria.
 .It PCI_GETCONF_ERROR
 This indicates a general error while servicing the user's request.
 If the
diff --git a/share/man/man4/syscons.4 b/share/man/man4/syscons.4
index 4d5acbcadc43..6b9f6873626d 100644
--- a/share/man/man4/syscons.4
+++ b/share/man/man4/syscons.4
@@ -468,10 +468,11 @@ be selected by setting this variable to
 .Ql sc
 or
 .Ql vt .
-If not set, the default console in the
+The
 .Pa GENERIC
-kernel is
-.Xr vt 4 .
+kernel uses
+.Xr vt 4
+when this value is not set.
 .El
 .Sh FILES
 .Bl -tag -width /usr/share/syscons/xxxxyyyyzzz -compact
diff --git a/share/man/man4/tcp.4 b/share/man/man4/tcp.4
index f275a4da45f9..54f503f5c2c8 100644
--- a/share/man/man4/tcp.4
+++ b/share/man/man4/tcp.4
@@ -633,7 +633,8 @@ when trying to use a TCP function block that is not available;
 .Xr mod_cc 4 ,
 .Xr siftr 4 ,
 .Xr syncache 4 ,
-.Xr setkey 8
+.Xr setkey 8 ,
+.Xr tcp_functions 9
 .Rs
 .%A "V. Jacobson"
 .%A "R. Braden"
diff --git a/share/man/man4/vt.4 b/share/man/man4/vt.4
index adf6ecc1ee21..400d5d188cc0 100644
--- a/share/man/man4/vt.4
+++ b/share/man/man4/vt.4
@@ -201,10 +201,11 @@ Set this value to
 or
 .Ql sc
 to choose a specific system console, overriding the default.
-If not set, the default in the
+The
 .Pa GENERIC
-kernel is
-.Nm .
+kernel uses
+.Nm
+when this value is not set.
 .It Va kern.vt.fb.default_mode
 Set this value to a graphic mode to override the default mode picked by the
 .Nm
diff --git a/share/man/man5/src.conf.5 b/share/man/man5/src.conf.5
index 07baddb2aff3..61a73e5b0787 100644
--- a/share/man/man5/src.conf.5
+++ b/share/man/man5/src.conf.5
@@ -1,7 +1,7 @@
 .\" DO NOT EDIT-- this file is automatically generated.
 .\" from FreeBSD: head/tools/build/options/makeman 292283 2015-12-15 18:42:30Z bdrewery
 .\" $FreeBSD$
-.Dd June 28, 2016
+.Dd July 28, 2016
 .Dt SRC.CONF 5
 .Os
 .Sh NAME
@@ -1002,13 +1002,13 @@ amd64/amd64 and arm64/aarch64.
 Set to use GCC's stack unwinder (instead of LLVM's libunwind).
 .Pp
 It is a default setting on
-amd64/amd64, arm/arm, arm/armeb, arm/armv6, i386/i386, mips/mipsel, mips/mips, mips/mips64el, mips/mips64, mips/mipsn32, pc98/i386, powerpc/powerpc, powerpc/powerpc64 and sparc64/sparc64.
+arm/arm, arm/armeb, arm/armv6, mips/mipsel, mips/mips, mips/mips64el, mips/mips64, mips/mipsn32, powerpc/powerpc, powerpc/powerpc64 and sparc64/sparc64.
 .It Va WITH_LLVM_LIBUNWIND
 .\" from FreeBSD: head/tools/build/options/WITH_LLVM_LIBUNWIND 293450 2016-01-09 00:42:07Z emaste
 Set to use LLVM's libunwind stack unwinder (instead of GCC's unwinder).
 .Pp
 It is a default setting on
-arm64/aarch64.
+amd64/amd64, arm64/aarch64, i386/i386 and pc98/i386.
 .It Va WITHOUT_LOCALES
 .\" from FreeBSD: head/tools/build/options/WITHOUT_LOCALES 156932 2006-03-21 07:50:50Z ru
 Set to not build localization files; see
diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index f519e0f20f28..aff86cf9e8ad 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1015,7 +1015,6 @@ MLINKS+=lock.9 lockdestroy.9 \
 	lock.9 lockmgr_printinfo.9 \
 	lock.9 lockmgr_recursed.9 \
 	lock.9 lockmgr_rw.9 \
-	lock.9 lockmgr_waiters.9 \
 	lock.9 lockstatus.9
 MLINKS+=LOCK_PROFILING.9 MUTEX_PROFILING.9
 MLINKS+=make_dev.9 destroy_dev.9 \
@@ -1303,6 +1302,7 @@ MLINKS+=pci.9 pci_alloc_msi.9 \
 	pci.9 pci_get_vpd_ident.9 \
 	pci.9 pci_get_vpd_readonly.9 \
 	pci.9 pci_iov_attach.9 \
+	pci.9 pci_iov_attach_name.9 \
 	pci.9 pci_iov_detach.9 \
 	pci.9 pci_msi_count.9 \
 	pci.9 pci_msix_count.9 \
@@ -1766,6 +1766,7 @@ MLINKS+=timeout.9 callout.9 \
 	timeout.9 callout_schedule_sbt_curcpu.9 \
 	timeout.9 callout_schedule_sbt_on.9 \
 	timeout.9 callout_stop.9 \
+	timeout.9 callout_when.9 \
 	timeout.9 untimeout.9
 MLINKS+=ucred.9 cred_update_thread.9 \
 	ucred.9 crcopy.9 \
diff --git a/share/man/man9/bitset.9 b/share/man/man9/bitset.9
index 19f53a2a029c..ef5511503333 100644
--- a/share/man/man9/bitset.9
+++ b/share/man/man9/bitset.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 20, 2015
+.Dd July 29, 2016
 .Dt BITSET 9
 .Os
 .Sh NAME
@@ -77,9 +77,9 @@
 .Fn BIT_EMPTY "const SETSIZE" "struct STRUCTNAME *bitset"
 .Ft bool
 .Fn BIT_ISFULLSET "const SETSIZE" "struct STRUCTNAME *bitset"
-.Ft size_t
+.Ft int
 .Fn BIT_FFS "const SETSIZE" "struct STRUCTNAME *bitset"
-.Ft size_t
+.Ft int
 .Fn BIT_COUNT "const SETSIZE" "struct STRUCTNAME *bitset"
 .\"
 .Ft bool
diff --git a/share/man/man9/cpuset.9 b/share/man/man9/cpuset.9
index fb0a9fcd95b1..1d778ad940d3 100644
--- a/share/man/man9/cpuset.9
+++ b/share/man/man9/cpuset.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 20, 2015
+.Dd July 29, 2016
 .Dt CPUSET 9
 .Os
 .Sh NAME
@@ -75,9 +75,9 @@
 .Fn CPU_EMPTY "cpuset_t *cpuset"
 .Ft bool
 .Fn CPU_ISFULLSET "cpuset_t *cpuset"
-.Ft size_t
+.Ft int
 .Fn CPU_FFS "cpuset_t *cpuset"
-.Ft size_t
+.Ft int
 .Fn CPU_COUNT "cpuset_t *cpuset"
 .\"
 .Ft bool
diff --git a/share/man/man9/lock.9 b/share/man/man9/lock.9
index db99cad4abaa..001c5f182120 100644
--- a/share/man/man9/lock.9
+++ b/share/man/man9/lock.9
@@ -39,7 +39,6 @@
 .Nm lockmgr_printinfo ,
 .Nm lockmgr_recursed ,
 .Nm lockmgr_rw ,
-.Nm lockmgr_waiters ,
 .Nm lockstatus ,
 .Nm lockmgr_assert
 .Nd "lockmgr family of functions"
@@ -66,8 +65,6 @@
 .Ft int
 .Fn lockmgr_rw "struct lock *lkp" "u_int flags" "struct rwlock *ilk"
 .Ft int
-.Fn lockmgr_waiters "const struct lock *lkp"
-.Ft int
 .Fn lockstatus "const struct lock *lkp"
 .Pp
 .Cd "options INVARIANTS"
@@ -279,10 +276,6 @@ function returns true if the lock is recursed, 0
 otherwise.
 .Pp
 The
-.Fn lockmgr_waiters
-function returns true if the lock has waiters, 0 otherwise.
-.Pp
-The
 .Fn lockstatus
 function returns the status of the lock in relation to the current thread.
 .Pp
diff --git a/share/man/man9/pci.9 b/share/man/man9/pci.9
index a53f971ad0bb..161f9aa13292 100644
--- a/share/man/man9/pci.9
+++ b/share/man/man9/pci.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 24, 2016
+.Dd August 3, 2016
 .Dt PCI 9
 .Os
 .Sh NAME
@@ -50,6 +50,7 @@
 .Nm pci_get_vpd_ident ,
 .Nm pci_get_vpd_readonly ,
 .Nm pci_iov_attach ,
+.Nm pci_iov_attach_name ,
 .Nm pci_iov_detach ,
 .Nm pci_msi_count ,
 .Nm pci_msix_count ,
@@ -152,6 +153,14 @@
 .Ft int
 .Fn pci_iov_attach "device_t dev" "nvlist_t *pf_schema" "nvlist_t *vf_schema"
 .Ft int
+.Fo pci_iov_attach_name
+.Fa "device_t dev"
+.Fa "nvlist_t *pf_schema"
+.Fa "nvlist_t *vf_schema"
+.Fa "const char *fmt"
+.Fa "..."
+.Fc
+.Ft int
 .Fn pci_iov_detach "device_t dev"
 .Sh DESCRIPTION
 The
@@ -595,6 +604,20 @@ and is responsible for freeing them.
 The driver must never free the schemas itself.
 .Pp
 The
+.Fn pci_iov_attach_name
+function is a variant of
+.Fn pci_iov_attach
+that allows the name of the associated character device in
+.Pa /dev/iov
+to be specified by
+.Fa fmt .
+The
+.Fn pci_iov_attach
+function uses the name of
+.Fa dev
+as the device name.
+.Pp
+The
 .Fn pci_iov_detach
 function is used to advise the SR-IOV infrastructure that the driver for the
 given device is attempting to detach and that all SR-IOV resources for the
diff --git a/share/man/man9/tcp_functions.9 b/share/man/man9/tcp_functions.9
index 06c42ff0fa60..b998dd0dd7df 100644
--- a/share/man/man9/tcp_functions.9
+++ b/share/man/man9/tcp_functions.9
@@ -114,14 +114,17 @@ struct tcp_function_block {
 			    struct inpcb *inp, struct tcpcb *tp);
 	/* Optional memory allocation/free routine */
 	void	(*tfb_tcp_fb_init)(struct tcpcb *);
-	void	(*tfb_tcp_fb_fini)(struct tcpcb *);
+	void	(*tfb_tcp_fb_fini)(struct tcpcb *, int);
 	/* Optional timers, must define all if you define one */
 	int	(*tfb_tcp_timer_stop_all)(struct tcpcb *);
 	void	(*tfb_tcp_timer_activate)(struct tcpcb *,
 			    uint32_t, u_int);
 	int	(*tfb_tcp_timer_active)(struct tcpcb *, uint32_t);
 	void	(*tfb_tcp_timer_stop)(struct tcpcb *, uint32_t);
+	/* Optional functions */
 	void	(*tfb_tcp_rexmit_tmr)(struct tcpcb *);
+	void	(*tfb_tcp_handoff_ok)(struct tcpcb *);
+	/* System use */
 	volatile uint32_t tfb_refcnt;
 	uint32_t  tfb_flags;
 };
@@ -157,6 +160,16 @@ in the
 .Va tfb_tcp_fb_fini
 field.
 .Pp
+If the
+.Va tfb_tcp_fb_fini
+argument is non-NULL, the function to which it points is called when the
+kernel is destroying the TCP control block or when the socket is transitioning
+to use a different TCP stack.
+The function is called with arguments of the TCP control block and an integer
+flag.
+The flag will be zero if the socket is transitioning to use another TCP stack
+or one if the TCP control block is being destroyed.
+.Pp
 If the TCP stack implements additional timers, the TCP stack should set a
 non-NULL pointer in the
 .Va tfb_tcp_timer_stop_all ,
@@ -193,6 +206,37 @@ However, care must be taken to ensure the retransmit timer leaves the
 TCP control block in a valid state for the remainder of the retransmit
 timer logic.
 .Pp
+A user may select a new TCP stack before calling
+.Xr connect 2
+or
+.Xr listen 2 .
+Optionally, a TCP stack may also allow a user to begin using the TCP stack for
+a connection that is in a later state by setting a non-NULL function pointer in
+the
+.Va tfb_tcp_handoff_ok
+field.
+If this field is non-NULL and a user attempts to select that TCP stack after
+calling
+.Xr connect 2
+or
+.Xr listen 2
+for that socket, the kernel will call the function pointed to by the
+.Va tfb_tcp_handoff_ok
+field.
+The function should return 0 if the user is allowed to switch the socket to use
+the TCP stack. Otherwise, the function should return an error code, which will
+be returned to the user.
+If the
+.Va tfb_tcp_handoff_ok
+field is
+.Dv NULL
+and a user attempts to select the TCP stack after calling
+.Xr connect 2
+or
+.Xr listen 2
+for that socket, the operation will fail and the kernel will return
+.Er EINVAL .
+.Pp
 The
 .Va tfb_refcnt
 and
@@ -269,8 +313,10 @@ The
 .Fa blk
 argument references a function block that is not currently registered.
 .Sh SEE ALSO
-.Xr malloc 9 ,
-.Xr tcp 4
+.Xr connect 2 ,
+.Xr listen 2 ,
+.Xr tcp 4 ,
+.Xr malloc 9
 .Sh HISTORY
 This framework first appeared in
 .Fx 11.0 .
diff --git a/share/man/man9/timeout.9 b/share/man/man9/timeout.9
index 73925b2947d7..54b63d22272d 100644
--- a/share/man/man9/timeout.9
+++ b/share/man/man9/timeout.9
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 4, 2016
+.Dd July 27, 2016
 .Dt TIMEOUT 9
 .Os
 .Sh NAME
@@ -56,6 +56,7 @@
 .Nm callout_schedule_sbt_curcpu ,
 .Nm callout_schedule_sbt_on ,
 .Nm callout_stop ,
+.Nm callout_when ,
 .Nm timeout ,
 .Nm untimeout
 .Nd execute a function after a specified length of time
@@ -91,20 +92,48 @@ struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle);
 .Ft int
 .Fn callout_reset "struct callout *c" "int ticks" "timeout_t *func" "void *arg"
 .Ft int
-.Fn callout_reset_curcpu "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg"
+.Fo callout_reset_curcpu
+.Fa "struct callout *c"
+.Fa "int ticks"
+.Fa "timeout_t *func"
+.Fa "void *arg"
+.Fc
 .Ft int
-.Fn callout_reset_on "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg" "int cpu"
+.Fo callout_reset_on
+.Fa "struct callout *c"
+.Fa "int ticks"
+.Fa "timeout_t *func"
+.Fa "void *arg"
+.Fa "int cpu"
+.Fc
 .Ft int
-.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
+.Fo callout_reset_sbt
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "timeout_t *func"
+.Fa "void *arg"
+.Fa "int flags"
+.Fc
 .Ft int
-.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
+.Fo callout_reset_sbt_curcpu
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "timeout_t *func"
+.Fa "void *arg"
+.Fa "int flags"
+.Fc
 .Ft int
-.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int cpu" "int flags"
+.Fo callout_reset_sbt_on
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "timeout_t *func"
+.Fa "void *arg"
+.Fa "int cpu"
+.Fa "int flags"
+.Fc
 .Ft int
 .Fn callout_schedule "struct callout *c" "int ticks"
 .Ft int
@@ -112,16 +141,37 @@ struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle);
 .Ft int
 .Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu"
 .Ft int
-.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
+.Fo callout_schedule_sbt
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "int flags"
+.Fc
 .Ft int
-.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
+.Fo callout_schedule_sbt_curcpu
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "int flags"
+.Fc
 .Ft int
-.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int cpu" "int flags"
+.Fo callout_schedule_sbt_on
+.Fa "struct callout *c"
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t pr"
+.Fa "int cpu"
+.Fa "int flags"
+.Fc
 .Ft int
 .Fn callout_stop "struct callout *c"
+.Ft sbintime_t
+.Fo callout_when
+.Fa "sbintime_t sbt"
+.Fa "sbintime_t precision"
+.Fa "int flags"
+.Fa "sbintime_t *sbt_res"
+.Fa "sbintime_t *precision_res"
+.Fc
 .Ft struct callout_handle
 .Fn timeout "timeout_t *func" "void *arg" "int ticks"
 .Ft void
@@ -387,6 +437,26 @@ or this value is used as the length of the time window.
 Smaller values
 .Pq which result in larger time intervals
 allow the callout subsystem to aggregate more events in one timer interrupt.
+.It Dv C_PRECALC
+The
+.Fa sbt
+argument specifies the absolute time at which the callout should be run,
+and the
+.Fa pr
+argument specifies the requested precision, which will not be
+adjusted during the scheduling process.
+The
+.Fa sbt
+and
+.Fa pr
+values should be calculated by an earlier call to
+.Fn callout_when
+which uses the user-supplied
+.Fa sbt ,
+.Fa pr ,
+and
+.Fa flags
+values.
 .It Dv C_HARDCLOCK
 Align the timeouts to
 .Fn hardclock
@@ -503,6 +573,39 @@ but it
 .Em does not
 clear it when a callout expires normally via the execution of the
 callout function.
+.Pp
+The
+.Fn callout_when
+function may be used to pre-calculate the absolute time at which the
+timeout should be run and the precision of the scheduled run time
+according to the required time
+.Fa sbt ,
+precision
+.Fa precision ,
+and additional adjustments requested by the
+.Fa flags
+argument.
+Flags accepted by the
+.Fn callout_when
+function are the same as flags for the
+.Fn callout_reset
+function.
+The resulting time is assigned to the variable pointed to by the
+.Fa sbt_res
+argument, and the resulting precision is assigned to
+.Fa *precision_res .
+When passing the results to
+.Fa callout_reset ,
+add the
+.Va C_PRECALC
+flag to
+.Fa flags ,
+to avoid incorrect re-adjustment.
+The function is intended for situations where precise time of the callout
+run should be known in advance, since
+trying to read this time from the callout structure itself after a
+.Fn callout_reset
+call is racy.
 .Ss "Avoiding Race Conditions"
 The callout subsystem invokes callout functions from its own thread
 context.