[SCSI] iscsi update: cleanup iscsi class interface

From:
michaelc@cs.wisc.edu
fujita.tomonori@lab.ntt.co.jp
da-x@monatomic.org

and err path fixup from:
ogerlitz@voltaire.com

This patch cleans up that interface by having the lld and class
pass a iscsi_cls_session or iscsi_cls_conn between each other when
the function is used by HW and SW iscsi llds. This way the lld
does not have to remember if it has to send a handle or pointer
and a handle or pointer to connection, session or host.

This also has the class verify the session handle that gets passed from
userspace instead of using the pointer passed into the kernel directly.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Alex Aizman <itn780@yahoo.com>
Signed-off-by: Dmitry Yusupov <dmitry_yus@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 112 insertions, 109 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 59a1c9d9d3bd..b61868587dca 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -164,9 +164,43 @@ static struct mempool_zone *z_reply;
 #define Z_MAX_ERROR     16
 #define Z_HIWAT_ERROR   12
 
+static LIST_HEAD(sesslist);
+static DEFINE_SPINLOCK(sesslock);
 static LIST_HEAD(connlist);
 static DEFINE_SPINLOCK(connlock);
 
+static struct iscsi_cls_session *iscsi_session_lookup(uint64_t handle)
+{
+        unsigned long flags;
+        struct iscsi_cls_session *sess;
+
+        spin_lock_irqsave(&sesslock, flags);
+        list_for_each_entry(sess, &sesslist, sess_list) {
+                if (sess == iscsi_ptr(handle)) {
+                        spin_unlock_irqrestore(&sesslock, flags);
+                        return sess;
+                }
+        }
+        spin_unlock_irqrestore(&sesslock, flags);
+        return NULL;
+}
+
+static struct iscsi_cls_conn *iscsi_conn_lookup(uint64_t handle)
+{
+        unsigned long flags;
+        struct iscsi_cls_conn *conn;
+
+        spin_lock_irqsave(&connlock, flags);
+        list_for_each_entry(conn, &connlist, conn_list) {
+                if (conn == iscsi_ptr(handle)) {
+                        spin_unlock_irqrestore(&connlock, flags);
+                        return conn;
+                }
+        }
+        spin_unlock_irqrestore(&connlock, flags);
+        return NULL;
+}
+
 /*
  * The following functions can be used by LLDs that allocate
  * their own scsi_hosts or by software iscsi LLDs
@@ -365,6 +399,7 @@ iscsi_transport_create_session(struct scsi_transport_template *scsit,
 {
         struct iscsi_cls_session *session;
         struct Scsi_Host *shost;
+        unsigned long flags;
 
         shost = scsi_host_alloc(transport->host_template,
                                 hostdata_privsize(transport));
@@ -389,6 +424,9 @@ iscsi_transport_create_session(struct scsi_transport_template *scsit,
                 goto remove_host;
 
         *(unsigned long*)shost->hostdata = (unsigned long)session;
+        spin_lock_irqsave(&sesslock, flags);
+        list_add(&session->sess_list, &sesslist);
+        spin_unlock_irqrestore(&sesslock, flags);
         return shost;
 
 remove_host:
@@ -410,9 +448,13 @@ EXPORT_SYMBOL_GPL(iscsi_transport_create_session);
 int iscsi_transport_destroy_session(struct Scsi_Host *shost)
 {
         struct iscsi_cls_session *session;
+        unsigned long flags;
 
         scsi_remove_host(shost);
         session = hostdata_session(shost->hostdata);
+        spin_lock_irqsave(&sesslock, flags);
+        list_del(&session->sess_list);
+        spin_unlock_irqrestore(&sesslock, flags);
         iscsi_destroy_session(session);
         /* ref from host alloc */
         scsi_host_put(shost);
@@ -424,22 +466,6 @@ EXPORT_SYMBOL_GPL(iscsi_transport_destroy_session);
 /*
  * iscsi interface functions
  */
-static struct iscsi_cls_conn*
-iscsi_if_find_conn(uint64_t key)
-{
-        unsigned long flags;
-        struct iscsi_cls_conn *conn;
-
-        spin_lock_irqsave(&connlock, flags);
-        list_for_each_entry(conn, &connlist, conn_list)
-                if (conn->connh == key) {
-                        spin_unlock_irqrestore(&connlock, flags);
-                        return conn;
-                }
-        spin_unlock_irqrestore(&connlock, flags);
-        return NULL;
-}
-
 static struct iscsi_internal *
 iscsi_if_transport_lookup(struct iscsi_transport *tt)
 {
@@ -559,25 +585,21 @@ iscsi_unicast_skb(struct mempool_zone *zone, struct sk_buff *skb)
         return 0;
 }
 
-int iscsi_recv_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr,
+int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
                    char *data, uint32_t data_size)
 {
         struct nlmsghdr *nlh;
         struct sk_buff *skb;
         struct iscsi_uevent *ev;
-        struct iscsi_cls_conn *conn;
         char *pdu;
         int len = NLMSG_SPACE(sizeof(*ev) + sizeof(struct iscsi_hdr) +
                               data_size);
 
-        conn = iscsi_if_find_conn(connh);
-        BUG_ON(!conn);
-
         mempool_zone_complete(conn->z_pdu);
 
         skb = mempool_zone_get_skb(conn->z_pdu);
         if (!skb) {
-                iscsi_conn_error(connh, ISCSI_ERR_CONN_FAILED);
+                iscsi_conn_error(conn, ISCSI_ERR_CONN_FAILED);
                 dev_printk(KERN_ERR, &conn->dev, "iscsi: can not deliver "
                            "control PDU: OOM\n");
                 return -ENOMEM;
@@ -590,7 +612,7 @@ int iscsi_recv_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr,
         ev->type = ISCSI_KEVENT_RECV_PDU;
         if (atomic_read(&conn->z_pdu->allocated) >= conn->z_pdu->hiwat)
                 ev->iferror = -ENOMEM;
-        ev->r.recv_req.conn_handle = connh;
+        ev->r.recv_req.conn_handle = iscsi_handle(conn);
         pdu = (char*)ev + sizeof(*ev);
         memcpy(pdu, hdr, sizeof(struct iscsi_hdr));
         memcpy(pdu + sizeof(struct iscsi_hdr), data, data_size);
@@ -599,17 +621,13 @@ int iscsi_recv_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr,
 }
 EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
 
-void iscsi_conn_error(iscsi_connh_t connh, enum iscsi_err error)
+void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
 {
         struct nlmsghdr *nlh;
         struct sk_buff  *skb;
         struct iscsi_uevent *ev;
-        struct iscsi_cls_conn *conn;
         int len = NLMSG_SPACE(sizeof(*ev));
 
-        conn = iscsi_if_find_conn(connh);
-        BUG_ON(!conn);
-
         mempool_zone_complete(conn->z_error);
 
         skb = mempool_zone_get_skb(conn->z_error);
@@ -626,7 +644,7 @@ void iscsi_conn_error(iscsi_connh_t connh, enum iscsi_err error)
         if (atomic_read(&conn->z_error->allocated) >= conn->z_error->hiwat)
                 ev->iferror = -ENOMEM;
         ev->r.connerror.error = error;
-        ev->r.connerror.conn_handle = connh;
+        ev->r.connerror.conn_handle = iscsi_handle(conn);
 
         iscsi_unicast_skb(conn->z_error, skb);
 
@@ -677,7 +695,7 @@ iscsi_if_get_stats(struct iscsi_transport *transport, struct sk_buff *skb,
                               ISCSI_STATS_CUSTOM_MAX);
         int err = 0;
 
-        conn = iscsi_if_find_conn(ev->u.get_stats.conn_handle);
+        conn = iscsi_conn_lookup(ev->u.get_stats.conn_handle);
         if (!conn)
                 return -EEXIST;
 
@@ -707,7 +725,7 @@ iscsi_if_get_stats(struct iscsi_transport *transport, struct sk_buff *skb,
                         ((char*)evstat + sizeof(*evstat));
                 memset(stats, 0, sizeof(*stats));
 
-                transport->get_stats(ev->u.get_stats.conn_handle, stats);
+                transport->get_stats(conn, stats);
                 actual_size = NLMSG_SPACE(sizeof(struct iscsi_uevent) +
                                           sizeof(struct iscsi_stats) +
                                           sizeof(struct iscsi_stats_custom) *
@@ -727,58 +745,34 @@ static int
 iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
 {
         struct iscsi_transport *transport = priv->iscsi_transport;
-        struct Scsi_Host *shost;
-
-        if (!transport->create_session)
-                return -EINVAL;
+        struct iscsi_cls_session *session;
+        uint32_t sid;
 
-        shost = transport->create_session(&priv->t,
-                                          ev->u.c_session.initial_cmdsn);
-        if (!shost)
+        session = transport->create_session(&priv->t,
+                                            ev->u.c_session.initial_cmdsn,
+                                            &sid);
+        if (!session)
                 return -ENOMEM;
 
-        ev->r.c_session_ret.session_handle = iscsi_handle(iscsi_hostdata(shost->hostdata));
-        ev->r.c_session_ret.sid = shost->host_no;
+        ev->r.c_session_ret.session_handle = iscsi_handle(session);
+        ev->r.c_session_ret.sid = sid;
         return 0;
 }
 
 static int
-iscsi_if_destroy_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
+iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
 {
-        struct iscsi_transport *transport = priv->iscsi_transport;
-
-        struct Scsi_Host *shost;
-
-        if (!transport->destroy_session)
-                return -EINVAL;
-
-        shost = scsi_host_lookup(ev->u.d_session.sid);
-        if (shost == ERR_PTR(-ENXIO))
-                return -EEXIST;
-
-        if (transport->destroy_session)
-                transport->destroy_session(shost);
-        /* ref from host lookup */
-        scsi_host_put(shost);
-        return 0;
-}
-
-static int
-iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev){
-        struct Scsi_Host *shost;
         struct iscsi_cls_conn *conn;
+        struct iscsi_cls_session *session;
         unsigned long flags;
 
-        if (!transport->create_conn)
+        session = iscsi_session_lookup(ev->u.c_conn.session_handle);
+        if (!session)
                 return -EINVAL;
 
-        shost = scsi_host_lookup(ev->u.c_conn.sid);
-        if (shost == ERR_PTR(-ENXIO))
-                return -EEXIST;
-
-        conn = transport->create_conn(shost, ev->u.c_conn.cid);
+        conn = transport->create_conn(session, ev->u.c_conn.cid);
         if (!conn)
-                goto release_ref;
+                return -ENOMEM;
 
         conn->z_pdu = mempool_zone_init(Z_MAX_PDU,
                         NLMSG_SPACE(sizeof(struct iscsi_uevent) +
@@ -800,14 +794,13 @@ iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
                 goto free_pdu_pool;
         }
 
-        ev->r.handle = conn->connh = iscsi_handle(conn->dd_data);
+        ev->r.handle = iscsi_handle(conn);
 
         spin_lock_irqsave(&connlock, flags);
         list_add(&conn->conn_list, &connlist);
         conn->active = 1;
         spin_unlock_irqrestore(&connlock, flags);
 
-        scsi_host_put(shost);
         return 0;
 
 free_pdu_pool:
@@ -815,8 +808,6 @@ free_pdu_pool:
 destroy_conn:
         if (transport->destroy_conn)
                 transport->destroy_conn(conn->dd_data);
-release_ref:
-        scsi_host_put(shost);
         return -ENOMEM;
 }
 
@@ -827,13 +818,9 @@ iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev
         struct iscsi_cls_conn *conn;
         struct mempool_zone *z_error, *z_pdu;
 
-        conn = iscsi_if_find_conn(ev->u.d_conn.conn_handle);
+        conn = iscsi_conn_lookup(ev->u.d_conn.conn_handle);
         if (!conn)
-                return -EEXIST;
-
-        if (!transport->destroy_conn)
                 return -EINVAL;
-
         spin_lock_irqsave(&connlock, flags);
         conn->active = 0;
         list_del(&conn->conn_list);
@@ -858,6 +845,8 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
         struct iscsi_uevent *ev = NLMSG_DATA(nlh);
         struct iscsi_transport *transport = NULL;
         struct iscsi_internal *priv;
+        struct iscsi_cls_session *session;
+        struct iscsi_cls_conn *conn;
 
         if (NETLINK_CREDS(skb)->uid)
                 return -EPERM;
@@ -867,6 +856,9 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 return -EINVAL;
         transport = priv->iscsi_transport;
 
+        if (!try_module_get(transport->owner))
+                return -EINVAL;
+
         daemon_pid = NETLINK_CREDS(skb)->pid;
 
         switch (nlh->nlmsg_type) {
@@ -874,7 +866,11 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 err = iscsi_if_create_session(priv, ev);
                 break;
         case ISCSI_UEVENT_DESTROY_SESSION:
-                err = iscsi_if_destroy_session(priv, ev);
+                session = iscsi_session_lookup(ev->u.d_session.session_handle);
+                if (session)
+                        transport->destroy_session(session);
+                else
+                        err = -EINVAL;
                 break;
         case ISCSI_UEVENT_CREATE_CONN:
                 err = iscsi_if_create_conn(transport, ev);
@@ -883,41 +879,48 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 err = iscsi_if_destroy_conn(transport, ev);
                 break;
         case ISCSI_UEVENT_BIND_CONN:
-                if (!iscsi_if_find_conn(ev->u.b_conn.conn_handle))
-                        return -EEXIST;
-                ev->r.retcode = transport->bind_conn(
-                        ev->u.b_conn.session_handle,
-                        ev->u.b_conn.conn_handle,
-                        ev->u.b_conn.transport_fd,
-                        ev->u.b_conn.is_leading);
+                session = iscsi_session_lookup(ev->u.b_conn.session_handle);
+                conn = iscsi_conn_lookup(ev->u.b_conn.conn_handle);
+
+                if (session && conn)
+                        ev->r.retcode = transport->bind_conn(session, conn,
+                                        ev->u.b_conn.transport_fd,
+                                        ev->u.b_conn.is_leading);
+                else
+                        err = -EINVAL;
                 break;
         case ISCSI_UEVENT_SET_PARAM:
-                if (!iscsi_if_find_conn(ev->u.set_param.conn_handle))
-                        return -EEXIST;
-                ev->r.retcode = transport->set_param(
-                        ev->u.set_param.conn_handle,
-                        ev->u.set_param.param, ev->u.set_param.value);
+                conn = iscsi_conn_lookup(ev->u.set_param.conn_handle);
+                if (conn)
+                        ev->r.retcode = transport->set_param(conn,
+                                ev->u.set_param.param, ev->u.set_param.value);
+                else
+                        err = -EINVAL;
                 break;
         case ISCSI_UEVENT_START_CONN:
-                if (!iscsi_if_find_conn(ev->u.start_conn.conn_handle))
-                        return -EEXIST;
-                ev->r.retcode = transport->start_conn(
-                        ev->u.start_conn.conn_handle);
+                conn = iscsi_conn_lookup(ev->u.start_conn.conn_handle);
+                if (conn)
+                        ev->r.retcode = transport->start_conn(conn);
+                else
+                        err = -EINVAL;
+
                 break;
         case ISCSI_UEVENT_STOP_CONN:
-                if (!iscsi_if_find_conn(ev->u.stop_conn.conn_handle))
-                        return -EEXIST;
-                transport->stop_conn(ev->u.stop_conn.conn_handle,
-                        ev->u.stop_conn.flag);
+                conn = iscsi_conn_lookup(ev->u.stop_conn.conn_handle);
+                if (conn)
+                        transport->stop_conn(conn, ev->u.stop_conn.flag);
+                else
+                        err = -EINVAL;
                 break;
         case ISCSI_UEVENT_SEND_PDU:
-                if (!iscsi_if_find_conn(ev->u.send_pdu.conn_handle))
-                        return -EEXIST;
-                ev->r.retcode = transport->send_pdu(
-                       ev->u.send_pdu.conn_handle,
-                       (struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
-                       (char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
-                        ev->u.send_pdu.data_size);
+                conn = iscsi_conn_lookup(ev->u.send_pdu.conn_handle);
+                if (conn)
+                        ev->r.retcode = transport->send_pdu(conn,
+                                (struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
+                                (char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
+                                ev->u.send_pdu.data_size);
+                else
+                        err = -EINVAL;
                 break;
         case ISCSI_UEVENT_GET_STATS:
                 err = iscsi_if_get_stats(transport, skb, nlh);
@@ -927,6 +930,7 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 break;
         }
 
+        module_put(transport->owner);
         return err;
 }
 
@@ -997,7 +1001,7 @@ show_conn_int_param_##param(struct class_device *cdev, char *buf)	\
         struct iscsi_cls_conn *conn = iscsi_cdev_to_conn(cdev);         \
         struct iscsi_transport *t = conn->transport;                    \
                                                                         \
-        t->get_conn_param(conn->dd_data, param, &value);                \
+        t->get_conn_param(conn, param, &value);                         \
         return snprintf(buf, 20, format"\n", value);                    \
 }
 
@@ -1024,10 +1028,9 @@ show_session_int_param_##param(struct class_device *cdev, char *buf)	\
 {                                                                       \
         uint32_t value = 0;                                             \
         struct iscsi_cls_session *session = iscsi_cdev_to_session(cdev);        \
-        struct Scsi_Host *shost = iscsi_session_to_shost(session);      \
         struct iscsi_transport *t = session->transport;                 \
                                                                         \
-        t->get_session_param(shost, param, &value);                     \
+        t->get_session_param(session, param, &value);                   \
         return snprintf(buf, 20, format"\n", value);                    \
 }