Split iscsi(4) ctl frontend off of ctl(4) as cfiscsi(4)

The goal of this work is to remove the explicit dependency for ctl(4) on iscsi(4), so end-users without iscsi(4) support in the kernel can use ctl(4) for its other functions. This allows those without iscsi(4) support built into the kernel to use ctl(4) as a test mechanism. As a sidenote, this was possible around the 10.0-RELEASE period, but made impossible for end-users without iscsi(4) between 10.0-RELEASE and 11.0-RELEASE. Automatically load cfiscsi(4) from ctladm(8) and ctld(8) for backwards compatibility with previously releases. The automatic loading feature is compiled into the beforementioned tools if MK_ISCSI == yes when building world. Add a manpage for cfiscsi(4) and refer to it in ctl(4). Differential Revision: D10099 MFC after: 2 months Relnotes: yes Reviewed by: mav, trasz Sponsored by: Dell EMC Isilon
jakesfreeland · Mar 30, 2017 · 653e7d6 · 653e7d6
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diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
@@ -884,6 +884,7 @@ _dtrace_udp.4=	dtrace_udp.4
 .endif
 
 .if ${MK_ISCSI} != "no"
+MAN+=		cfiscsi.4
 MAN+=		iscsi.4
 MAN+=		iscsi_initiator.4
 MAN+=		iser.4

diff --git a/share/man/man4/cfiscsi.4 b/share/man/man4/cfiscsi.4
@@ -0,0 +1,104 @@
+.\" Copyright (c) 2013 Edward Tomasz Napierala
+.\" Copyright (c) 2015-2017 Alexander Motin <mav@FreeBSD.org>
+.\" Copyright (c) 2017 Ngie Cooper <ngie@FreeBSD.org>
+.\" 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 March 29, 2017
+.Dt CFISCSI 4
+.Os
+.Sh NAME
+.Nm cfiscsi
+.Nd CAM Target Layer iSCSI target frontend
+.Sh SYNOPSIS
+To compile this driver into the kernel,
+place the following lines in your
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device cfiscsi"
+.Cd "device ctl"
+.Cd "device iscsi"
+.Ed
+.Pp
+Alternatively, to load the driver as a
+module at boot time, place the following line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+cfiscsi_load="YES"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+subsystem provides iSCSI target device emulation via
+.Xr ctl 4
+and
+.Xr iscsi 4 .
+.Sh SYSCTL VARIABLES
+The following variables are available as both
+.Xr sysctl 8
+variables and
+.Xr loader 8
+tunables:
+.Bl -tag -width indent
+.It Va kern.cam.ctl.iscsi.debug
+Verbosity level for log messages from the kernel part of iSCSI target.
+Set to 0 to disable logging or 1 to warn about potential problems.
+Larger values enable debugging output.
+Defaults to 1.
+.It Va kern.cam.ctl.iscsi.maxtags
+The number of outstanding commands to advertise to each iSCSI initiator.
+Current implementation is not very accurate, so do not set this below 2.
+Defaults to 256.
+.It Va kern.cam.ctl.iscsi.ping_timeout
+The number of seconds to wait for the iSCSI initiator to respond to a NOP-In
+PDU.
+In the event that there is no response within that time the session gets
+forcibly terminated.
+Set to 0 to disable sending NOP-In PDUs.
+Defaults to 5.
+.El
+.Sh SEE ALSO
+.Xr ctl 4 ,
+.Xr iscsi 4
+.Sh HISTORY
+The
+.Nm
+subsystem first appeared in
+.Fx 10.0
+as part of the
+.Xr ctl 4
+driver.
+It was split off of
+.Xr ctl 4
+in
+.Fx 12.0 .
+.Sh AUTHORS
+.An -nosplit
+The
+.Nm
+subsystem was developed by
+.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
+under sponsorship from the FreeBSD Foundation.
+This manual page was written by
+.An Ngie Cooper Aq Mt ngie@FreeBSD.org .
diff --git a/share/man/man4/ctl.4 b/share/man/man4/ctl.4
@@ -24,18 +24,17 @@
 .\" SUCH DAMAGE.
 .\"
 .\" $FreeBSD$
-.Dd March 19, 2017
+.Dd March 29, 2017
 .Dt CTL 4
 .Os
 .Sh NAME
 .Nm ctl
-.Nd CAM Target Layer / iSCSI target subsystem
+.Nd CAM Target Layer
 .Sh SYNOPSIS
 To compile this driver into the kernel,
 place the following line in your
 kernel configuration file:
 .Bd -ragged -offset indent
-.Cd "device iscsi"
 .Cd "device ctl"
 .Ed
 .Pp
@@ -106,11 +105,8 @@ Provides access for local user-level applications via
 .Xr ioctl 2
 based API.
 .It iscsi
-Combined with
-.Xr iscsi 4
-and
-.Xr ctld 8 ,
-provides access for remote systems via iSCSI protocol.
+Provides access for remote systems via the iSCSI protocol using
+.Xr cfiscsi 4 .
 .It tpc
 Internal frontend used to receive requests from Third Party Copy engine,
 implementing copy offload operations.
@@ -194,24 +190,9 @@ the opposite change -- opens.
 If there is no primary node (both nodes are secondary, or secondary node has
 no connection to primary one), secondary node(s) report Transitioning state.
 State with two primary nodes is illegal (split brain condition).
-.It Va kern.cam.ctl.iscsi.debug
-Verbosity level for log messages from the kernel part of iSCSI target.
-Set to 0 to disable logging or 1 to warn about potential problems.
-Larger values enable debugging output.
-Defaults to 1.
-.It Va kern.cam.ctl.iscsi.maxtags
-The number of outstanding commands to advertise to each iSCSI initiator.
-Current implementation is not very accurate, so do not set this below 2.
-Defaults to 256.
-.It Va kern.cam.ctl.iscsi.ping_timeout
-The number of seconds to wait for the iSCSI initiator to respond to a NOP-In
-PDU.
-In the event that there is no response within that time the session gets
-forcibly terminated.
-Set to 0 to disable sending NOP-In PDUs.
-Defaults to 5.
 .El
 .Sh SEE ALSO
+.Xr cfiscsi 4 ,
 .Xr cfumass 4 ,
 .Xr ctladm 8 ,
 .Xr ctld 8 ,

diff --git a/sys/cam/ctl/ctl_frontend_iscsi.c b/sys/cam/ctl/ctl_frontend_iscsi.c
@@ -184,8 +184,8 @@ static struct ctl_frontend cfiscsi_frontend =
 	.ioctl = cfiscsi_ioctl,
 	.shutdown = cfiscsi_shutdown,
 };
-CTL_FRONTEND_DECLARE(ctlcfiscsi, cfiscsi_frontend);
-MODULE_DEPEND(ctlcfiscsi, icl, 1, 1, 1);
+CTL_FRONTEND_DECLARE(cfiscsi, cfiscsi_frontend);
+MODULE_DEPEND(cfiscsi, icl, 1, 1, 1);
 
 static struct icl_pdu *
 cfiscsi_pdu_new_response(struct icl_pdu *request, int flags)

diff --git a/sys/conf/files b/sys/conf/files
@@ -102,7 +102,7 @@ cam/ctl/ctl_cmd_table.c		optional ctl
 cam/ctl/ctl_frontend.c		optional ctl
 cam/ctl/ctl_frontend_cam_sim.c	optional ctl
 cam/ctl/ctl_frontend_ioctl.c	optional ctl
-cam/ctl/ctl_frontend_iscsi.c	optional ctl
+cam/ctl/ctl_frontend_iscsi.c	optional ctl cfiscsi
 cam/ctl/ctl_ha.c		optional ctl
 cam/ctl/ctl_scsi_all.c		optional ctl
 cam/ctl/ctl_tpc.c		optional ctl
@@ -1783,10 +1783,10 @@ ipw_monitor.fw			optional ipwmonitorfw | ipwfw		\
 	compile-with	"${NORMAL_FW}"					\
 	no-obj no-implicit-rule						\
 	clean		"ipw_monitor.fw"
-dev/iscsi/icl.c			optional iscsi | ctl
-dev/iscsi/icl_conn_if.m		optional iscsi | ctl
-dev/iscsi/icl_soft.c		optional iscsi | ctl
-dev/iscsi/icl_soft_proxy.c	optional iscsi | ctl
+dev/iscsi/icl.c			optional iscsi
+dev/iscsi/icl_conn_if.m		optional cfiscsi | iscsi
+dev/iscsi/icl_soft.c		optional iscsi
+dev/iscsi/icl_soft_proxy.c	optional iscsi
 dev/iscsi/iscsi.c		optional iscsi scbus
 dev/iscsi_initiator/iscsi.c	optional iscsi_initiator scbus
 dev/iscsi_initiator/iscsi_subr.c	optional iscsi_initiator scbus

diff --git a/sys/modules/Makefile b/sys/modules/Makefile
@@ -471,6 +471,7 @@ _ipfilter=	ipfilter
 .endif
 
 .if ${MK_ISCSI} != "no" || defined(ALL_MODULES)
+SUBDIR+=	cfiscsi
 SUBDIR+=	iscsi
 SUBDIR+=	iscsi_initiator
 .endif

diff --git a/sys/modules/cfiscsi/Makefile b/sys/modules/cfiscsi/Makefile
@@ -0,0 +1,12 @@
+# $FreeBSD$
+
+.PATH: ${SRCTOP}/sys/cam/ctl
+
+KMOD=	cfiscsi
+
+#CFLAGS+=-DICL_KERNEL_PROXY
+
+MFILES=	dev/iscsi/icl_conn_if.m
+SRCS=	ctl_frontend_iscsi.c icl_conn_if.h
+
+.include <bsd.kmod.mk>
diff --git a/sys/modules/ctl/Makefile b/sys/modules/ctl/Makefile
@@ -12,7 +12,6 @@ SRCS+=	ctl_cmd_table.c
 SRCS+=	ctl_frontend.c
 SRCS+=	ctl_frontend_cam_sim.c
 SRCS+=	ctl_frontend_ioctl.c
-SRCS+=	ctl_frontend_iscsi.c
 SRCS+=	ctl_ha.c
 SRCS+=	ctl_scsi_all.c
 SRCS+=	ctl_tpc.c
@@ -23,11 +22,10 @@ SRCS+=	scsi_ctl.c
 SRCS+=	bus_if.h
 SRCS+=	device_if.h
 SRCS+=	vnode_if.h
-SRCS+=	icl_conn_if.h
 SRCS+=	opt_cam.h
 
 #CFLAGS+=-DICL_KERNEL_PROXY
 
-MFILES=	kern/bus_if.m kern/device_if.m dev/iscsi/icl_conn_if.m
+MFILES=	kern/bus_if.m kern/device_if.m
 
 .include <bsd.kmod.mk>
diff --git a/usr.sbin/ctladm/Makefile b/usr.sbin/ctladm/Makefile
@@ -1,5 +1,7 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 PROG=		ctladm
 SRCS=		ctladm.c util.c ctl_util.c ctl_scsi_all.c
 .PATH:		${SRCTOP}/sys/cam/ctl
@@ -17,4 +19,8 @@ WARNS?= 3
 LIBADD=		cam sbuf bsdxml util
 MAN=		ctladm.8
 
+.if ${MK_ISCSI} != "no"
+CFLAGS+=	-DWANT_ISCSI
+.endif
+
 .include <bsd.prog.mk>
diff --git a/usr.sbin/ctladm/ctladm.c b/usr.sbin/ctladm/ctladm.c
@@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/callout.h>
 #include <sys/ioctl.h>
 #include <sys/linker.h>
+#include <sys/module.h>
 #include <sys/queue.h>
 #include <sys/sbuf.h>
 #include <sys/stat.h>
@@ -4152,6 +4153,13 @@ main(int argc, char **argv)
 			retval = 1;
 			goto bailout;
 		}
+#ifdef	WANT_ISCSI
+		else {
+			if (modfind("cfiscsi") == -1 &&
+			    kldload("cfiscsi") == -1)
+				warn("couldn't load cfiscsi");
+		}
+#endif
 	} else if ((command != CTLADM_CMD_HELP)
 		&& ((cmdargs & CTLADM_ARG_DEVICE) == 0)) {
 		fprintf(stderr, "%s: you must specify a device with the "

diff --git a/usr.sbin/ctld/Makefile b/usr.sbin/ctld/Makefile
@@ -1,5 +1,7 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 CFLAGS+=-I${SRCTOP}/contrib/libucl/include
 .PATH:  ${SRCTOP}/contrib/libucl/include
 
@@ -21,4 +23,8 @@ CLEANFILES=	y.tab.c y.tab.h y.output
 WARNS?=		6
 NO_WMISSING_VARIABLE_DECLARATIONS=
 
+.if ${MK_ISCSI} != "no"
+CFLAGS+=	-DWANT_ISCSI
+.endif
+
 .include <bsd.prog.mk>
diff --git a/usr.sbin/ctld/kernel.c b/usr.sbin/ctld/kernel.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/callout.h>
 #include <sys/ioctl.h>
 #include <sys/linker.h>
+#include <sys/module.h>
 #include <sys/queue.h>
 #include <sys/sbuf.h>
 #include <sys/stat.h>
@@ -90,6 +91,14 @@ kernel_init(void)
 	}
 	if (ctl_fd < 0)
 		log_err(1, "failed to open %s", CTL_DEFAULT_DEV);
+#ifdef	WANT_ISCSI
+	else {
+		saved_errno = errno;
+		if (modfind("cfiscsi") == -1 && kldload("cfiscsi") == -1)
+			log_warn("couldn't load cfiscsi");
+		errno = saved_errno;
+	}
+#endif
 }
 
 /*