[SCSI] iscsi_transport: Add support to display CHAP list and delete CHAP entry

For offload iSCSI like qla4xxx CHAP entries are stored in FLASH.
This patch adds support to list CHAP entries stored in FLASH and
delete specified CHAP entry from FLASH using iscsi tools.

Signed-off-by: Nilesh Javali <nilesh.javali@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index a20f181..7bf0dec 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -727,10 +727,11 @@
 	kfree(session);
 }
 
-static int iscsi_is_session_dev(const struct device *dev)
+int iscsi_is_session_dev(const struct device *dev)
 {
 	return dev->release == iscsi_session_release;
 }
+EXPORT_SYMBOL_GPL(iscsi_is_session_dev);
 
 static int iscsi_iter_session_fn(struct device *dev, void *data)
 {
@@ -2002,6 +2003,96 @@
 }
 
 static int
+iscsi_get_chap(struct iscsi_transport *transport, struct nlmsghdr *nlh)
+{
+	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
+	struct Scsi_Host *shost = NULL;
+	struct iscsi_chap_rec *chap_rec;
+	struct iscsi_internal *priv;
+	struct sk_buff *skbchap;
+	struct nlmsghdr *nlhchap;
+	struct iscsi_uevent *evchap;
+	uint32_t chap_buf_size;
+	int len, err = 0;
+	char *buf;
+
+	if (!transport->get_chap)
+		return -EINVAL;
+
+	priv = iscsi_if_transport_lookup(transport);
+	if (!priv)
+		return -EINVAL;
+
+	chap_buf_size = (ev->u.get_chap.num_entries * sizeof(*chap_rec));
+	len = NLMSG_SPACE(sizeof(*ev) + chap_buf_size);
+
+	shost = scsi_host_lookup(ev->u.get_chap.host_no);
+	if (!shost) {
+		printk(KERN_ERR "%s: failed. Cound not find host no %u\n",
+		       __func__, ev->u.get_chap.host_no);
+		return -ENODEV;
+	}
+
+	do {
+		int actual_size;
+
+		skbchap = alloc_skb(len, GFP_KERNEL);
+		if (!skbchap) {
+			printk(KERN_ERR "can not deliver chap: OOM\n");
+			err = -ENOMEM;
+			goto exit_get_chap;
+		}
+
+		nlhchap = __nlmsg_put(skbchap, 0, 0, 0,
+				      (len - sizeof(*nlhchap)), 0);
+		evchap = NLMSG_DATA(nlhchap);
+		memset(evchap, 0, sizeof(*evchap));
+		evchap->transport_handle = iscsi_handle(transport);
+		evchap->type = nlh->nlmsg_type;
+		evchap->u.get_chap.host_no = ev->u.get_chap.host_no;
+		evchap->u.get_chap.chap_tbl_idx = ev->u.get_chap.chap_tbl_idx;
+		evchap->u.get_chap.num_entries = ev->u.get_chap.num_entries;
+		buf = (char *) ((char *)evchap + sizeof(*evchap));
+		memset(buf, 0, chap_buf_size);
+
+		err = transport->get_chap(shost, ev->u.get_chap.chap_tbl_idx,
+				    &evchap->u.get_chap.num_entries, buf);
+
+		actual_size = NLMSG_SPACE(sizeof(*ev) + chap_buf_size);
+		skb_trim(skbchap, NLMSG_ALIGN(actual_size));
+		nlhchap->nlmsg_len = actual_size;
+
+		err = iscsi_multicast_skb(skbchap, ISCSI_NL_GRP_ISCSID,
+					  GFP_KERNEL);
+	} while (err < 0 && err != -ECONNREFUSED);
+
+exit_get_chap:
+	scsi_host_put(shost);
+	return err;
+}
+
+static int iscsi_delete_chap(struct iscsi_transport *transport,
+			     struct iscsi_uevent *ev)
+{
+	struct Scsi_Host *shost;
+	int err = 0;
+
+	if (!transport->delete_chap)
+		return -ENOSYS;
+
+	shost = scsi_host_lookup(ev->u.delete_chap.host_no);
+	if (!shost) {
+		printk(KERN_ERR "%s could not find host no %u\n",
+		       __func__, ev->u.delete_chap.host_no);
+		return -ENODEV;
+	}
+
+	err = transport->delete_chap(shost, ev->u.delete_chap.chap_tbl_idx);
+	scsi_host_put(shost);
+	return err;
+}
+
+static int
 iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
 {
 	int err = 0;
@@ -2149,6 +2240,12 @@
 	case ISCSI_UEVENT_PING:
 		err = iscsi_send_ping(transport, ev);
 		break;
+	case ISCSI_UEVENT_GET_CHAP:
+		err = iscsi_get_chap(transport, nlh);
+		break;
+	case ISCSI_UEVENT_DELETE_CHAP:
+		err = iscsi_delete_chap(transport, ev);
+		break;
 	default:
 		err = -ENOSYS;
 		break;
@@ -2198,6 +2295,8 @@
 			 */
 			if (ev->type == ISCSI_UEVENT_GET_STATS && !err)
 				break;
+			if (ev->type == ISCSI_UEVENT_GET_CHAP && !err)
+				break;
 			err = iscsi_if_send_reply(group, nlh->nlmsg_seq,
 				nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
 		} while (err < 0 && err != -ECONNREFUSED && err != -ESRCH);