[SCSI] iscsi: add async notification of session events

This patch adds or modifies the transport class functions
used to notify userspace of session state events.

We modify the session addition up event and add a destruction event
to notify userspace of session creation, relogin and destruction.

And we modify the conn error event to be sent by broadcast
since multiple listeners may want to listen for it.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 227 insertions, 82 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 7963c0538de5..7b9e8fa1a4e0 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -413,11 +413,59 @@ int iscsi_destroy_session(struct iscsi_cls_session *session)
 }
 EXPORT_SYMBOL_GPL(iscsi_destroy_session);
 
+static void mempool_zone_destroy(struct mempool_zone *zp)
+{
+        mempool_destroy(zp->pool);
+        kfree(zp);
+}
+
+static void*
+mempool_zone_alloc_skb(gfp_t gfp_mask, void *pool_data)
+{
+        struct mempool_zone *zone = pool_data;
+
+        return alloc_skb(zone->size, gfp_mask);
+}
+
+static void
+mempool_zone_free_skb(void *element, void *pool_data)
+{
+        kfree_skb(element);
+}
+
+static struct mempool_zone *
+mempool_zone_init(unsigned max, unsigned size, unsigned hiwat)
+{
+        struct mempool_zone *zp;
+
+        zp = kzalloc(sizeof(*zp), GFP_KERNEL);
+        if (!zp)
+                return NULL;
+
+        zp->size = size;
+        zp->hiwat = hiwat;
+        INIT_LIST_HEAD(&zp->freequeue);
+        spin_lock_init(&zp->freelock);
+        atomic_set(&zp->allocated, 0);
+
+        zp->pool = mempool_create(max, mempool_zone_alloc_skb,
+                                  mempool_zone_free_skb, zp);
+        if (!zp->pool) {
+                kfree(zp);
+                return NULL;
+        }
+
+        return zp;
+}
+
 static void iscsi_conn_release(struct device *dev)
 {
         struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev);
         struct device *parent = conn->dev.parent;
 
+        mempool_zone_destroy(conn->z_pdu);
+        mempool_zone_destroy(conn->z_error);
+
         kfree(conn);
         put_device(parent);
 }
@@ -427,6 +475,31 @@ static int iscsi_is_conn_dev(const struct device *dev)
         return dev->release == iscsi_conn_release;
 }
 
+static int iscsi_create_event_pools(struct iscsi_cls_conn *conn)
+{
+        conn->z_pdu = mempool_zone_init(Z_MAX_PDU,
+                        NLMSG_SPACE(sizeof(struct iscsi_uevent) +
+                                    sizeof(struct iscsi_hdr) +
+                                    DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH),
+                        Z_HIWAT_PDU);
+        if (!conn->z_pdu) {
+                dev_printk(KERN_ERR, &conn->dev, "iscsi: can not allocate "
+                           "pdu zone for new conn\n");
+                return -ENOMEM;
+        }
+
+        conn->z_error = mempool_zone_init(Z_MAX_ERROR,
+                        NLMSG_SPACE(sizeof(struct iscsi_uevent)),
+                        Z_HIWAT_ERROR);
+        if (!conn->z_error) {
+                dev_printk(KERN_ERR, &conn->dev, "iscsi: can not allocate "
+                           "error zone for new conn\n");
+                mempool_zone_destroy(conn->z_pdu);
+                return -ENOMEM;
+        }
+        return 0;
+}
+
 /**
  * iscsi_create_conn - create iscsi class connection
  * @session: iscsi cls session
@@ -459,9 +532,12 @@ iscsi_create_conn(struct iscsi_cls_session *session, uint32_t cid)
         conn->transport = transport;
         conn->cid = cid;
 
+        if (iscsi_create_event_pools(conn))
+                goto free_conn;
+
         /* this is released in the dev's release function */
         if (!get_device(&session->dev))
-                goto free_conn;
+                goto free_conn_pools;
 
         snprintf(conn->dev.bus_id, BUS_ID_SIZE, "connection%d:%u",
                  session->sid, cid);
@@ -478,6 +554,8 @@ iscsi_create_conn(struct iscsi_cls_session *session, uint32_t cid)
 
 release_parent_ref:
         put_device(&session->dev);
+free_conn_pools:
+
 free_conn:
         kfree(conn);
         return NULL;
@@ -525,20 +603,6 @@ static inline struct list_head *skb_to_lh(struct sk_buff *skb)
         return (struct list_head *)&skb->cb;
 }
 
-static void*
-mempool_zone_alloc_skb(gfp_t gfp_mask, void *pool_data)
-{
-        struct mempool_zone *zone = pool_data;
-
-        return alloc_skb(zone->size, gfp_mask);
-}
-
-static void
-mempool_zone_free_skb(void *element, void *pool_data)
-{
-        kfree_skb(element);
-}
-
 static void
 mempool_zone_complete(struct mempool_zone *zone)
 {
@@ -558,37 +622,6 @@ mempool_zone_complete(struct mempool_zone *zone)
         spin_unlock_irqrestore(&zone->freelock, flags);
 }
 
-static struct mempool_zone *
-mempool_zone_init(unsigned max, unsigned size, unsigned hiwat)
-{
-        struct mempool_zone *zp;
-
-        zp = kzalloc(sizeof(*zp), GFP_KERNEL);
-        if (!zp)
-                return NULL;
-
-        zp->size = size;
-        zp->hiwat = hiwat;
-        INIT_LIST_HEAD(&zp->freequeue);
-        spin_lock_init(&zp->freelock);
-        atomic_set(&zp->allocated, 0);
-
-        zp->pool = mempool_create(max, mempool_zone_alloc_skb,
-                                  mempool_zone_free_skb, zp);
-        if (!zp->pool) {
-                kfree(zp);
-                return NULL;
-        }
-
-        return zp;
-}
-
-static void mempool_zone_destroy(struct mempool_zone *zp)
-{
-        mempool_destroy(zp->pool);
-        kfree(zp);
-}
-
 static struct sk_buff*
 mempool_zone_get_skb(struct mempool_zone *zone)
 {
@@ -601,6 +634,27 @@ mempool_zone_get_skb(struct mempool_zone *zone)
 }
 
 static int
+iscsi_broadcast_skb(struct mempool_zone *zone, struct sk_buff *skb)
+{
+        unsigned long flags;
+        int rc;
+
+        skb_get(skb);
+        rc = netlink_broadcast(nls, skb, 0, 1, GFP_KERNEL);
+        if (rc < 0) {
+                mempool_free(skb, zone->pool);
+                printk(KERN_ERR "iscsi: can not broadcast skb (%d)\n", rc);
+                return rc;
+        }
+
+        spin_lock_irqsave(&zone->freelock, flags);
+        INIT_LIST_HEAD(skb_to_lh(skb));
+        list_add(skb_to_lh(skb), &zone->freequeue);
+        spin_unlock_irqrestore(&zone->freelock, flags);
+        return 0;
+}
+
+static int
 iscsi_unicast_skb(struct mempool_zone *zone, struct sk_buff *skb, int pid)
 {
         unsigned long flags;
@@ -695,7 +749,7 @@ void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
         ev->r.connerror.cid = conn->cid;
         ev->r.connerror.sid = iscsi_conn_get_sid(conn);
 
-        iscsi_unicast_skb(conn->z_error, skb, priv->daemon_pid);
+        iscsi_broadcast_skb(conn->z_error, skb);
 
         dev_printk(KERN_INFO, &conn->dev, "iscsi: detected conn error (%d)\n",
                    error);
@@ -796,6 +850,131 @@ iscsi_if_get_stats(struct iscsi_transport *transport, struct nlmsghdr *nlh)
         return err;
 }
 
+/**
+ * iscsi_if_destroy_session_done - send session destr. completion event
+ * @conn: last connection for session
+ *
+ * This is called by HW iscsi LLDs to notify userpsace that its HW has
+ * removed a session.
+ **/
+int iscsi_if_destroy_session_done(struct iscsi_cls_conn *conn)
+{
+        struct iscsi_internal *priv;
+        struct iscsi_cls_session *session;
+        struct Scsi_Host *shost;
+        struct iscsi_uevent *ev;
+        struct sk_buff  *skb;
+        struct nlmsghdr *nlh;
+        unsigned long flags;
+        int rc, len = NLMSG_SPACE(sizeof(*ev));
+
+        priv = iscsi_if_transport_lookup(conn->transport);
+        if (!priv)
+                return -EINVAL;
+
+        session = iscsi_dev_to_session(conn->dev.parent);
+        shost = iscsi_session_to_shost(session);
+
+        mempool_zone_complete(conn->z_pdu);
+
+        skb = mempool_zone_get_skb(conn->z_pdu);
+        if (!skb) {
+                dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
+                          "session creation event\n");
+                return -ENOMEM;
+        }
+
+        nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
+        ev = NLMSG_DATA(nlh);
+        ev->transport_handle = iscsi_handle(conn->transport);
+        ev->type = ISCSI_KEVENT_DESTROY_SESSION;
+        ev->r.d_session.host_no = shost->host_no;
+        ev->r.d_session.sid = session->sid;
+
+        /*
+         * this will occur if the daemon is not up, so we just warn
+         * the user and when the daemon is restarted it will handle it
+         */
+        rc = iscsi_broadcast_skb(conn->z_pdu, skb);
+        if (rc < 0)
+                dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
+                          "session destruction event. Check iscsi daemon\n");
+
+        spin_lock_irqsave(&sesslock, flags);
+        list_del(&session->sess_list);
+        spin_unlock_irqrestore(&sesslock, flags);
+
+        spin_lock_irqsave(&connlock, flags);
+        conn->active = 0;
+        list_del(&conn->conn_list);
+        spin_unlock_irqrestore(&connlock, flags);
+
+        return rc;
+}
+EXPORT_SYMBOL_GPL(iscsi_if_destroy_session_done);
+
+/**
+ * iscsi_if_create_session_done - send session creation completion event
+ * @conn: leading connection for session
+ *
+ * This is called by HW iscsi LLDs to notify userpsace that its HW has
+ * created a session or a existing session is back in the logged in state.
+ **/
+int iscsi_if_create_session_done(struct iscsi_cls_conn *conn)
+{
+        struct iscsi_internal *priv;
+        struct iscsi_cls_session *session;
+        struct Scsi_Host *shost;
+        struct iscsi_uevent *ev;
+        struct sk_buff  *skb;
+        struct nlmsghdr *nlh;
+        unsigned long flags;
+        int rc, len = NLMSG_SPACE(sizeof(*ev));
+
+        priv = iscsi_if_transport_lookup(conn->transport);
+        if (!priv)
+                return -EINVAL;
+
+        session = iscsi_dev_to_session(conn->dev.parent);
+        shost = iscsi_session_to_shost(session);
+
+        mempool_zone_complete(conn->z_pdu);
+
+        skb = mempool_zone_get_skb(conn->z_pdu);
+        if (!skb) {
+                dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
+                          "session creation event\n");
+                return -ENOMEM;
+        }
+
+        nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
+        ev = NLMSG_DATA(nlh);
+        ev->transport_handle = iscsi_handle(conn->transport);
+        ev->type = ISCSI_UEVENT_CREATE_SESSION;
+        ev->r.c_session_ret.host_no = shost->host_no;
+        ev->r.c_session_ret.sid = session->sid;
+
+        /*
+         * this will occur if the daemon is not up, so we just warn
+         * the user and when the daemon is restarted it will handle it
+         */
+        rc = iscsi_broadcast_skb(conn->z_pdu, skb);
+        if (rc < 0)
+                dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
+                          "session creation event. Check iscsi daemon\n");
+
+        spin_lock_irqsave(&sesslock, flags);
+        list_add(&session->sess_list, &sesslist);
+        spin_unlock_irqrestore(&sesslock, flags);
+
+        spin_lock_irqsave(&connlock, flags);
+        list_add(&conn->conn_list, &connlist);
+        conn->active = 1;
+        spin_unlock_irqrestore(&connlock, flags);
+        return rc;
+}
+EXPORT_SYMBOL_GPL(iscsi_if_create_session_done);
+
 static int
 iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
 {
@@ -841,26 +1020,6 @@ iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
                 return -ENOMEM;
         }
 
-        conn->z_pdu = mempool_zone_init(Z_MAX_PDU,
-                        NLMSG_SPACE(sizeof(struct iscsi_uevent) +
-                                    sizeof(struct iscsi_hdr) +
-                                    DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH),
-                        Z_HIWAT_PDU);
-        if (!conn->z_pdu) {
-                dev_printk(KERN_ERR, &conn->dev, "iscsi: can not allocate "
-                           "pdu zone for new conn\n");
-                goto destroy_conn;
-        }
-
-        conn->z_error = mempool_zone_init(Z_MAX_ERROR,
-                        NLMSG_SPACE(sizeof(struct iscsi_uevent)),
-                        Z_HIWAT_ERROR);
-        if (!conn->z_error) {
-                dev_printk(KERN_ERR, &conn->dev, "iscsi: can not allocate "
-                           "error zone for new conn\n");
-                goto free_pdu_pool;
-        }
-
         ev->r.c_conn_ret.sid = session->sid;
         ev->r.c_conn_ret.cid = conn->cid;
 
@@ -870,13 +1029,6 @@ iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
         spin_unlock_irqrestore(&connlock, flags);
 
         return 0;
-
-free_pdu_pool:
-        mempool_zone_destroy(conn->z_pdu);
-destroy_conn:
-        if (transport->destroy_conn)
-                transport->destroy_conn(conn->dd_data);
-        return -ENOMEM;
 }
 
 static int
@@ -884,7 +1036,6 @@ iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev
 {
         unsigned long flags;
         struct iscsi_cls_conn *conn;
-        struct mempool_zone *z_error, *z_pdu;
 
         conn = iscsi_conn_lookup(ev->u.d_conn.sid, ev->u.d_conn.cid);
         if (!conn)
@@ -894,15 +1045,8 @@ iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev
         list_del(&conn->conn_list);
         spin_unlock_irqrestore(&connlock, flags);
 
-        z_pdu = conn->z_pdu;
-        z_error = conn->z_error;
-
         if (transport->destroy_conn)
                 transport->destroy_conn(conn);
-
-        mempool_zone_destroy(z_pdu);
-        mempool_zone_destroy(z_error);
-
         return 0;
 }
 
@@ -1331,6 +1475,7 @@ iscsi_register_transport(struct iscsi_transport *tt)
         if (!priv)
                 return NULL;
         INIT_LIST_HEAD(&priv->list);
+        priv->daemon_pid = -1;
         priv->iscsi_transport = tt;
         priv->t.user_scan = iscsi_user_scan;