IB/srp: Enable multiple connections to the same target

Enable multiple concurrent connections to the same SRP target:

1) Use port GUID instead of node GUID in the initiator port
   identifier.  This allows connections to be made from multiple HCA
   ports at the same time.
2) Let the user specify the identifier extention when adding the
   device.  This allows userspace to make multiple connections even
   from the same port, if it wants too.

Without this, only one connection can be made from any given HCA, even
if it has multiple ports, because we don't use multi-channel mode, so
targets will only allow one connection from a given initiator port ID.
Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -343,29 +343,32 @@ static int srp_send_req(struct srp_target_port *target)
 	 */
 	if (target->io_class == SRP_REV10_IB_IO_CLASS) {
 		memcpy(req->priv.initiator_port_id,
-		       target->srp_host->initiator_port_id + 8, 8);
+		       &target->path.sgid.global.interface_id, 8);
 		memcpy(req->priv.initiator_port_id + 8,
-		       target->srp_host->initiator_port_id, 8);
+		       &target->initiator_ext, 8);
 		memcpy(req->priv.target_port_id,     &target->ioc_guid, 8);
 		memcpy(req->priv.target_port_id + 8, &target->id_ext, 8);
 	} else {
 		memcpy(req->priv.initiator_port_id,
-		       target->srp_host->initiator_port_id, 16);
+		       &target->initiator_ext, 8);
+		memcpy(req->priv.initiator_port_id + 8,
+		       &target->path.sgid.global.interface_id, 8);
 		memcpy(req->priv.target_port_id,     &target->id_ext, 8);
 		memcpy(req->priv.target_port_id + 8, &target->ioc_guid, 8);
 	}
 
 	/*
 	 * Topspin/Cisco SRP targets will reject our login unless we
-	 * zero out the first 8 bytes of our initiator port ID.  The
-	 * second 8 bytes must be our local node GUID, but we always
-	 * use that anyway.
+	 * zero out the first 8 bytes of our initiator port ID and set
+	 * the second 8 bytes to the local node GUID.
 	 */
 	if (topspin_workarounds && !memcmp(&target->ioc_guid, topspin_oui, 3)) {
 		printk(KERN_DEBUG PFX "Topspin/Cisco initiator port ID workaround "
 		       "activated for target GUID %016llx\n",
 		       (unsigned long long) be64_to_cpu(target->ioc_guid));
 		memset(req->priv.initiator_port_id, 0, 8);
+		memcpy(req->priv.initiator_port_id + 8,
+		       &target->srp_host->dev->dev->node_guid, 8);
 	}
 
 	status = ib_send_cm_req(target->cm_id, &req->param);
@@ -1553,6 +1556,7 @@ enum {
 	SRP_OPT_MAX_SECT	= 1 << 5,
 	SRP_OPT_MAX_CMD_PER_LUN	= 1 << 6,
 	SRP_OPT_IO_CLASS	= 1 << 7,
+	SRP_OPT_INITIATOR_EXT	= 1 << 8,
 	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
 				   SRP_OPT_IOC_GUID	|
 				   SRP_OPT_DGID		|
@@ -1569,6 +1573,7 @@ static match_table_t srp_opt_tokens = {
 	{ SRP_OPT_MAX_SECT,		"max_sect=%d" 		},
 	{ SRP_OPT_MAX_CMD_PER_LUN,	"max_cmd_per_lun=%d" 	},
 	{ SRP_OPT_IO_CLASS,		"io_class=%x"		},
+	{ SRP_OPT_INITIATOR_EXT,	"initiator_ext=%s"	},
 	{ SRP_OPT_ERR,			NULL 			}
 };
 
@@ -1668,6 +1673,12 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
 			target->io_class = token;
 			break;
 
+		case SRP_OPT_INITIATOR_EXT:
+			p = match_strdup(args);
+			target->initiator_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
+			kfree(p);
+			break;
+
 		default:
 			printk(KERN_WARNING PFX "unknown parameter or missing value "
 			       "'%s' in target creation request\n", p);
@@ -1814,9 +1825,6 @@ static struct srp_host *srp_add_port(struct srp_device *device, u8 port)
 	host->dev  = device;
 	host->port = port;
 
-	host->initiator_port_id[7] = port;
-	memcpy(host->initiator_port_id + 8, &device->dev->node_guid, 8);
-
 	host->class_dev.class = &srp_class;
 	host->class_dev.dev   = device->dev->dma_device;
 	snprintf(host->class_dev.class_id, BUS_ID_SIZE, "srp-%s-%d",

drivers/infiniband/ulp/srp/ib_srp.h

@@ -91,7 +91,6 @@ struct srp_device {
 };
 
 struct srp_host {
-	u8			initiator_port_id[16];
 	struct srp_device      *dev;
 	u8			port;
 	struct class_device	class_dev;
@@ -122,6 +121,7 @@ struct srp_target_port {
 	__be64			id_ext;
 	__be64			ioc_guid;
 	__be64			service_id;
+	__be64			initiator_ext;
 	u16			io_class;
 	struct srp_host	       *srp_host;
 	struct Scsi_Host       *scsi_host;