Make it possible to set (via ctl.conf(5)) and query (via ctladm islist -v)

target iSCSI offload.  Add mechanism to query maximum receive data segment
size supported by chosen hardware offload module, and use it in ctld(8)
to determine the value to advertise to the other side.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation

2 files changed, 48 insertions, 7 deletions

diff --git a/sys/cam/ctl/ctl_frontend_iscsi.c b/sys/cam/ctl/ctl_frontend_iscsi.c
index 817f9ff..4b8b492 100644
--- a/sys/cam/ctl/ctl_frontend_iscsi.c
+++ b/sys/cam/ctl/ctl_frontend_iscsi.c
@@ -1222,7 +1222,7 @@ cfiscsi_session_unregister_initiator(struct cfiscsi_session *cs)
 }
 
 static struct cfiscsi_session *
-cfiscsi_session_new(struct cfiscsi_softc *softc)
+cfiscsi_session_new(struct cfiscsi_softc *softc, const char *offload)
 {
 	struct cfiscsi_session *cs;
 	int error;
@@ -1242,7 +1242,11 @@ cfiscsi_session_new(struct cfiscsi_softc *softc)
 	cv_init(&cs->cs_login_cv, "cfiscsi_login");
 #endif
 
-	cs->cs_conn = icl_new_conn(NULL, "cfiscsi", &cs->cs_lock);
+	cs->cs_conn = icl_new_conn(offload, "cfiscsi", &cs->cs_lock);
+	if (cs->cs_conn == NULL) {
+		free(cs, M_CFISCSI);
+		return (NULL);
+	}
 	cs->cs_conn->ic_receive = cfiscsi_receive_callback;
 	cs->cs_conn->ic_error = cfiscsi_error_callback;
 	cs->cs_conn->ic_prv0 = cs;
@@ -1325,7 +1329,7 @@ cfiscsi_accept(struct socket *so, struct sockaddr *sa, int portal_id)
 {
 	struct cfiscsi_session *cs;
 
-	cs = cfiscsi_session_new(&cfiscsi_softc);
+	cs = cfiscsi_session_new(&cfiscsi_softc, NULL);
 	if (cs == NULL) {
 		CFISCSI_WARN("failed to create session");
 		return;
@@ -1469,7 +1473,7 @@ cfiscsi_ioctl_handoff(struct ctl_iscsi *ci)
 		mtx_unlock(&cfiscsi_softc.lock);
 	} else {
 #endif
-		cs = cfiscsi_session_new(softc);
+		cs = cfiscsi_session_new(softc, cihp->offload);
 		if (cs == NULL) {
 			ci->status = CTL_ISCSI_ERROR;
 			snprintf(ci->error_str, sizeof(ci->error_str),
@@ -1620,6 +1624,7 @@ cfiscsi_ioctl_list(struct ctl_iscsi *ci)
 		    "<max_data_segment_length>%zd</max_data_segment_length>"
 		    "<immediate_data>%d</immediate_data>"
 		    "<iser>%d</iser>"
+		    "<offload>%s</offload>"
 		    "</connection>\n",
 		    cs->cs_id,
 		    cs->cs_initiator_name, cs->cs_initiator_addr, cs->cs_initiator_alias,
@@ -1629,7 +1634,8 @@ cfiscsi_ioctl_list(struct ctl_iscsi *ci)
 		    cs->cs_conn->ic_data_crc32c ? "CRC32C" : "None",
 		    cs->cs_max_data_segment_length,
 		    cs->cs_immediate_data,
-		    cs->cs_conn->ic_iser);
+		    cs->cs_conn->ic_iser,
+		    cs->cs_conn->ic_offload);
 		if (error != 0)
 			break;
 	}
@@ -1749,6 +1755,26 @@ cfiscsi_ioctl_logout(struct ctl_iscsi *ci)
 	ci->status = CTL_ISCSI_OK;
 }
 
+static void
+cfiscsi_ioctl_limits(struct ctl_iscsi *ci)
+{
+	struct ctl_iscsi_limits_params *cilp;
+	int error;
+
+	cilp = (struct ctl_iscsi_limits_params *)&(ci->data);
+
+	error = icl_limits(cilp->offload, &cilp->data_segment_limit);
+	if (error != 0) {
+		ci->status = CTL_ISCSI_ERROR;
+		snprintf(ci->error_str, sizeof(ci->error_str),
+			"%s: icl_limits failed with error %d",
+			__func__, error);
+		return;
+	}
+
+	ci->status = CTL_ISCSI_OK;
+}
+
 #ifdef ICL_KERNEL_PROXY
 static void
 cfiscsi_ioctl_listen(struct ctl_iscsi *ci)
@@ -2176,6 +2202,9 @@ cfiscsi_ioctl(struct cdev *dev,
 	case CTL_ISCSI_LOGOUT:
 		cfiscsi_ioctl_logout(ci);
 		break;
+	case CTL_ISCSI_LIMITS:
+		cfiscsi_ioctl_limits(ci);
+		break;
 #ifdef ICL_KERNEL_PROXY
 	case CTL_ISCSI_LISTEN:
 		cfiscsi_ioctl_listen(ci);
diff --git a/sys/cam/ctl/ctl_ioctl.h b/sys/cam/ctl/ctl_ioctl.h
index 532953f..c7a3c29 100644
--- a/sys/cam/ctl/ctl_ioctl.h
+++ b/sys/cam/ctl/ctl_ioctl.h
@@ -657,6 +657,7 @@ typedef enum {
 	CTL_ISCSI_LIST,
 	CTL_ISCSI_LOGOUT,
 	CTL_ISCSI_TERMINATE,
+	CTL_ISCSI_LIMITS,
 #if defined(ICL_KERNEL_PROXY) || 1
 	/*
 	 * We actually need those in all cases, but leave the ICL_KERNEL_PROXY,
@@ -677,6 +678,7 @@ typedef enum {
 #define	CTL_ISCSI_NAME_LEN	224	/* 223 bytes, by RFC 3720, + '\0' */
 #define	CTL_ISCSI_ADDR_LEN	47	/* INET6_ADDRSTRLEN + '\0' */
 #define	CTL_ISCSI_ALIAS_LEN	128	/* Arbitrary. */
+#define	CTL_ISCSI_OFFLOAD_LEN	8	/* Arbitrary. */
 
 struct ctl_iscsi_handoff_params {
 	char			initiator_name[CTL_ISCSI_NAME_LEN];
@@ -698,11 +700,12 @@ struct ctl_iscsi_handoff_params {
 	uint32_t		max_burst_length;
 	uint32_t		first_burst_length;
 	uint32_t		immediate_data;
+	char			offload[CTL_ISCSI_OFFLOAD_LEN];
 #ifdef ICL_KERNEL_PROXY
 	int			connection_id;
-	int			spare[3];
+	int			spare[1];
 #else
-	int			spare[4];
+	int			spare[2];
 #endif
 };
 
@@ -733,6 +736,14 @@ struct ctl_iscsi_terminate_params {
 	int			spare[4];
 };
 
+struct ctl_iscsi_limits_params {
+	char			offload[CTL_ISCSI_OFFLOAD_LEN];
+						/* passed to kernel */
+	size_t			data_segment_limit;
+						/* passed to userland */
+	int			spare[4];
+};
+
 #ifdef ICL_KERNEL_PROXY
 struct ctl_iscsi_listen_params {
 	int				iser;
@@ -780,6 +791,7 @@ union ctl_iscsi_data {
 	struct ctl_iscsi_list_params		list;
 	struct ctl_iscsi_logout_params		logout;
 	struct ctl_iscsi_terminate_params	terminate;
+	struct ctl_iscsi_limits_params		limits;
 #ifdef ICL_KERNEL_PROXY
 	struct ctl_iscsi_listen_params		listen;
 	struct ctl_iscsi_accept_params		accept;