[SCSI] libfc: add hook for FC-4 provider registration

Allow FC-4 provider modules to hook into libfc, mostly for targets.
This should allow any FC-4 module to handle PRLI requests and maintain
process-association states.

Each provider registers its ops with libfc and then will be called for
any incoming PRLI for that FC-4 type on any instance.   The provider
can decide whether to handle that particular instance using any method
it likes, such as ACLs or other configuration information.

A count is kept of the number of successful PRLIs from the remote port.
Providers are called back with an implicit PRLO when the remote port
is about to be deleted or has been reset.

fc_lport_recv_req() now sends incoming FC-4 requests to FC-4 providers,
and there is a built-in provider always registered for handling
incoming ELS requests.

The call to provider recv() routines uses rcu_read_lock()
so that providers aren't removed during the call.  That lock is very
cheap and shouldn't affect any performance on ELS requests.
Providers can rely on the RCU lock to protect a session lookup as well.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 106 insertions, 27 deletions

diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index 309e3e713ea..a92954c1f42 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -257,6 +257,8 @@ static void fc_rport_work(struct work_struct *work)
 	struct fc_rport_operations *rport_ops;
 	struct fc_rport_identifiers ids;
 	struct fc_rport *rport;
+	struct fc4_prov *prov;
+	u8 type;
 
 	mutex_lock(&rdata->rp_mutex);
 	event = rdata->event;
@@ -306,6 +308,15 @@ static void fc_rport_work(struct work_struct *work)
 	case RPORT_EV_FAILED:
 	case RPORT_EV_LOGO:
 	case RPORT_EV_STOP:
+		if (rdata->prli_count) {
+			mutex_lock(&fc_prov_mutex);
+			for (type = 1; type < FC_FC4_PROV_SIZE; type++) {
+				prov = fc_passive_prov[type];
+				if (prov && prov->prlo)
+					prov->prlo(rdata);
+			}
+			mutex_unlock(&fc_prov_mutex);
+		}
 		port_id = rdata->ids.port_id;
 		mutex_unlock(&rdata->rp_mutex);
 
@@ -1643,9 +1654,9 @@ static void fc_rport_recv_prli_req(struct fc_rport_priv *rdata,
 	unsigned int len;
 	unsigned int plen;
 	enum fc_els_spp_resp resp;
+	enum fc_els_spp_resp passive;
 	struct fc_seq_els_data rjt_data;
-	u32 fcp_parm;
-	u32 roles = FC_RPORT_ROLE_UNKNOWN;
+	struct fc4_prov *prov;
 
 	FC_RPORT_DBG(rdata, "Received PRLI request while in state %s\n",
 		     fc_rport_state(rdata));
@@ -1679,46 +1690,41 @@ static void fc_rport_recv_prli_req(struct fc_rport_priv *rdata,
 	pp->prli.prli_len = htons(len);
 	len -= sizeof(struct fc_els_prli);
 
-	/* reinitialize remote port roles */
-	rdata->ids.roles = FC_RPORT_ROLE_UNKNOWN;
-
 	/*
 	 * Go through all the service parameter pages and build
 	 * response.  If plen indicates longer SPP than standard,
 	 * use that.  The entire response has been pre-cleared above.
 	 */
 	spp = &pp->spp;
+	mutex_lock(&fc_prov_mutex);
 	while (len >= plen) {
 		spp->spp_type = rspp->spp_type;
 		spp->spp_type_ext = rspp->spp_type_ext;
-		spp->spp_flags = rspp->spp_flags & FC_SPP_EST_IMG_PAIR;
-		resp = FC_SPP_RESP_ACK;
-
-		switch (rspp->spp_type) {
-		case 0:	/* common to all FC-4 types */
-			break;
-		case FC_TYPE_FCP:
-			fcp_parm = ntohl(rspp->spp_params);
-			if (fcp_parm & FCP_SPPF_RETRY)
-				rdata->flags |= FC_RP_FLAGS_RETRY;
-			rdata->supported_classes = FC_COS_CLASS3;
-			if (fcp_parm & FCP_SPPF_INIT_FCN)
-				roles |= FC_RPORT_ROLE_FCP_INITIATOR;
-			if (fcp_parm & FCP_SPPF_TARG_FCN)
-				roles |= FC_RPORT_ROLE_FCP_TARGET;
-			rdata->ids.roles = roles;
-
-			spp->spp_params = htonl(lport->service_params);
-			break;
-		default:
-			resp = FC_SPP_RESP_INVL;
-			break;
+		resp = 0;
+
+		if (rspp->spp_type < FC_FC4_PROV_SIZE) {
+			prov = fc_active_prov[rspp->spp_type];
+			if (prov)
+				resp = prov->prli(rdata, plen, rspp, spp);
+			prov = fc_passive_prov[rspp->spp_type];
+			if (prov) {
+				passive = prov->prli(rdata, plen, rspp, spp);
+				if (!resp || passive == FC_SPP_RESP_ACK)
+					resp = passive;
+			}
+		}
+		if (!resp) {
+			if (spp->spp_flags & FC_SPP_EST_IMG_PAIR)
+				resp |= FC_SPP_RESP_CONF;
+			else
+				resp |= FC_SPP_RESP_INVL;
 		}
 		spp->spp_flags |= resp;
 		len -= plen;
 		rspp = (struct fc_els_spp *)((char *)rspp + plen);
 		spp = (struct fc_els_spp *)((char *)spp + plen);
 	}
+	mutex_unlock(&fc_prov_mutex);
 
 	/*
 	 * Send LS_ACC.	 If this fails, the originator should retry.
@@ -1888,6 +1894,79 @@ int fc_rport_init(struct fc_lport *lport)
 EXPORT_SYMBOL(fc_rport_init);
 
 /**
+ * fc_rport_fcp_prli() - Handle incoming PRLI for the FCP initiator.
+ * @rdata: remote port private
+ * @spp_len: service parameter page length
+ * @rspp: received service parameter page
+ * @spp: response service parameter page
+ *
+ * Returns the value for the response code to be placed in spp_flags;
+ * Returns 0 if not an initiator.
+ */
+static int fc_rport_fcp_prli(struct fc_rport_priv *rdata, u32 spp_len,
+			     const struct fc_els_spp *rspp,
+			     struct fc_els_spp *spp)
+{
+	struct fc_lport *lport = rdata->local_port;
+	u32 fcp_parm;
+
+	fcp_parm = ntohl(rspp->spp_params);
+	rdata->ids.roles = FC_RPORT_ROLE_UNKNOWN;
+	if (fcp_parm & FCP_SPPF_INIT_FCN)
+		rdata->ids.roles |= FC_RPORT_ROLE_FCP_INITIATOR;
+	if (fcp_parm & FCP_SPPF_TARG_FCN)
+		rdata->ids.roles |= FC_RPORT_ROLE_FCP_TARGET;
+	if (fcp_parm & FCP_SPPF_RETRY)
+		rdata->flags |= FC_RP_FLAGS_RETRY;
+	rdata->supported_classes = FC_COS_CLASS3;
+
+	if (!(lport->service_params & FC_RPORT_ROLE_FCP_INITIATOR))
+		return 0;
+
+	spp->spp_flags |= rspp->spp_flags & FC_SPP_EST_IMG_PAIR;
+
+	/*
+	 * OR in our service parameters with other providers (target), if any.
+	 */
+	fcp_parm = ntohl(spp->spp_params);
+	spp->spp_params = htonl(fcp_parm | lport->service_params);
+	return FC_SPP_RESP_ACK;
+}
+
+/*
+ * FC-4 provider ops for FCP initiator.
+ */
+struct fc4_prov fc_rport_fcp_init = {
+	.prli = fc_rport_fcp_prli,
+};
+
+/**
+ * fc_rport_t0_prli() - Handle incoming PRLI parameters for type 0
+ * @rdata: remote port private
+ * @spp_len: service parameter page length
+ * @rspp: received service parameter page
+ * @spp: response service parameter page
+ */
+static int fc_rport_t0_prli(struct fc_rport_priv *rdata, u32 spp_len,
+			    const struct fc_els_spp *rspp,
+			    struct fc_els_spp *spp)
+{
+	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR)
+		return FC_SPP_RESP_INVL;
+	return FC_SPP_RESP_ACK;
+}
+
+/*
+ * FC-4 provider ops for type 0 service parameters.
+ *
+ * This handles the special case of type 0 which is always successful
+ * but doesn't do anything otherwise.
+ */
+struct fc4_prov fc_rport_t0_prov = {
+	.prli = fc_rport_t0_prli,
+};
+
+/**
  * fc_setup_rport() - Initialize the rport_event_queue
  */
 int fc_setup_rport(void)