[SCSI] libiscsi: Support drivers initiating session removal
authorMike Christie <michaelc@cs.wisc.edu>
Wed, 24 Sep 2008 16:46:10 +0000 (11:46 -0500)
committerJames Bottomley <James.Bottomley@HansenPartnership.com>
Mon, 13 Oct 2008 13:28:59 +0000 (09:28 -0400)
If the driver knows when hardware is removed like with cxgb3i,
bnx2i, qla4xxx and iser then we will want to remove the sessions/devices
that are bound to that device before removing the host.

cxgb3i and in the future bnx2i will remove the host and that will
remove all the sessions on the hba. iser can call iscsi_kill_session
when it gets an event that indicates that a hca is removed.
And when qla4xxx is hooked in to the lib (it is only hooked into
the class right now) it can call iscsi remove host like the
partial offload card drivers.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
drivers/infiniband/ulp/iser/iscsi_iser.c
drivers/scsi/iscsi_tcp.c
drivers/scsi/libiscsi.c
drivers/scsi/qla4xxx/ql4_os.c
drivers/scsi/scsi_transport_iscsi.c
include/scsi/iscsi_if.h
include/scsi/libiscsi.h
include/scsi/scsi_transport_iscsi.h

index 5a1cf2580e16a3dd45517d9484986709e75bafeb..0474da173eb18bdb08e13726d3083ad4885b3451 100644 (file)
@@ -378,6 +378,7 @@ static void iscsi_iser_session_destroy(struct iscsi_cls_session *cls_session)
 {
        struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 
+       iscsi_session_teardown(cls_session);
        iscsi_host_remove(shost);
        iscsi_host_free(shost);
 }
index e960f00da93aac8a3de8f4ecee6ca70bfba162e7..752f42884cc1a0887f6705e325f2d0c054f0addc 100644 (file)
@@ -1885,6 +1885,7 @@ static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
        struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 
        iscsi_r2tpool_free(cls_session->dd_data);
+       iscsi_session_teardown(cls_session);
 
        iscsi_host_remove(shost);
        iscsi_host_free(shost);
index f9539af28f028cc68996265aedf051dc0eafe84e..390781894be996ea36b4a0953626d33511866dfe 100644 (file)
@@ -983,6 +983,38 @@ struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
 }
 EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);
 
+void iscsi_session_failure(struct iscsi_cls_session *cls_session,
+                          enum iscsi_err err)
+{
+       struct iscsi_session *session = cls_session->dd_data;
+       struct iscsi_conn *conn;
+       struct device *dev;
+       unsigned long flags;
+
+       spin_lock_irqsave(&session->lock, flags);
+       conn = session->leadconn;
+       if (session->state == ISCSI_STATE_TERMINATE || !conn) {
+               spin_unlock_irqrestore(&session->lock, flags);
+               return;
+       }
+
+       dev = get_device(&conn->cls_conn->dev);
+       spin_unlock_irqrestore(&session->lock, flags);
+       if (!dev)
+               return;
+       /*
+        * if the host is being removed bypass the connection
+        * recovery initialization because we are going to kill
+        * the session.
+        */
+       if (err == ISCSI_ERR_INVALID_HOST)
+               iscsi_conn_error_event(conn->cls_conn, err);
+       else
+               iscsi_conn_failure(conn, err);
+       put_device(dev);
+}
+EXPORT_SYMBOL_GPL(iscsi_session_failure);
+
 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
 {
        struct iscsi_session *session = conn->session;
@@ -997,9 +1029,10 @@ void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
        if (conn->stop_stage == 0)
                session->state = ISCSI_STATE_FAILED;
        spin_unlock_irqrestore(&session->lock, flags);
+
        set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
        set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
-       iscsi_conn_error(conn->cls_conn, err);
+       iscsi_conn_error_event(conn->cls_conn, err);
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
 
@@ -1905,6 +1938,7 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
                                   int dd_data_size, uint16_t qdepth)
 {
        struct Scsi_Host *shost;
+       struct iscsi_host *ihost;
 
        shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
        if (!shost)
@@ -1919,22 +1953,43 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
                qdepth = ISCSI_DEF_CMD_PER_LUN;
        }
        shost->cmd_per_lun = qdepth;
+
+       ihost = shost_priv(shost);
+       spin_lock_init(&ihost->lock);
+       ihost->state = ISCSI_HOST_SETUP;
+       ihost->num_sessions = 0;
+       init_waitqueue_head(&ihost->session_removal_wq);
        return shost;
 }
 EXPORT_SYMBOL_GPL(iscsi_host_alloc);
 
+static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
+{
+       iscsi_session_failure(cls_session, ISCSI_ERR_INVALID_HOST);
+}
+
 /**
  * iscsi_host_remove - remove host and sessions
  * @shost: scsi host
  *
- * This will also remove any sessions attached to the host, but if userspace
- * is managing the session at the same time this will break. TODO: add
- * refcounting to the netlink iscsi interface so a rmmod or host hot unplug
- * does not remove the memory from under us.
+ * If there are any sessions left, this will initiate the removal and wait
+ * for the completion.
  */
 void iscsi_host_remove(struct Scsi_Host *shost)
 {
-       iscsi_host_for_each_session(shost, iscsi_session_teardown);
+       struct iscsi_host *ihost = shost_priv(shost);
+       unsigned long flags;
+
+       spin_lock_irqsave(&ihost->lock, flags);
+       ihost->state = ISCSI_HOST_REMOVED;
+       spin_unlock_irqrestore(&ihost->lock, flags);
+
+       iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
+       wait_event_interruptible(ihost->session_removal_wq,
+                                ihost->num_sessions == 0);
+       if (signal_pending(current))
+               flush_signals(current);
+
        scsi_remove_host(shost);
 }
 EXPORT_SYMBOL_GPL(iscsi_host_remove);
@@ -1950,6 +2005,27 @@ void iscsi_host_free(struct Scsi_Host *shost)
 }
 EXPORT_SYMBOL_GPL(iscsi_host_free);
 
+static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
+{
+       struct iscsi_host *ihost = shost_priv(shost);
+       unsigned long flags;
+
+       shost = scsi_host_get(shost);
+       if (!shost) {
+               printk(KERN_ERR "Invalid state. Cannot notify host removal "
+                     "of session teardown event because host already "
+                     "removed.\n");
+               return;
+       }
+
+       spin_lock_irqsave(&ihost->lock, flags);
+       ihost->num_sessions--;
+       if (ihost->num_sessions == 0)
+               wake_up(&ihost->session_removal_wq);
+       spin_unlock_irqrestore(&ihost->lock, flags);
+       scsi_host_put(shost);
+}
+
 /**
  * iscsi_session_setup - create iscsi cls session and host and session
  * @iscsit: iscsi transport template
@@ -1970,9 +2046,19 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
                    uint16_t cmds_max, int cmd_task_size,
                    uint32_t initial_cmdsn, unsigned int id)
 {
+       struct iscsi_host *ihost = shost_priv(shost);
        struct iscsi_session *session;
        struct iscsi_cls_session *cls_session;
        int cmd_i, scsi_cmds, total_cmds = cmds_max;
+       unsigned long flags;
+
+       spin_lock_irqsave(&ihost->lock, flags);
+       if (ihost->state == ISCSI_HOST_REMOVED) {
+               spin_unlock_irqrestore(&ihost->lock, flags);
+               return NULL;
+       }
+       ihost->num_sessions++;
+       spin_unlock_irqrestore(&ihost->lock, flags);
 
        if (!total_cmds)
                total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
@@ -1985,7 +2071,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
                printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
                       "must be a power of two that is at least %d.\n",
                       total_cmds, ISCSI_TOTAL_CMDS_MIN);
-               return NULL;
+               goto dec_session_count;
        }
 
        if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
@@ -2009,7 +2095,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
        cls_session = iscsi_alloc_session(shost, iscsit,
                                          sizeof(struct iscsi_session));
        if (!cls_session)
-               return NULL;
+               goto dec_session_count;
        session = cls_session->dd_data;
        session->cls_session = cls_session;
        session->host = shost;
@@ -2048,6 +2134,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
 
        if (iscsi_add_session(cls_session, id))
                goto cls_session_fail;
+
        return cls_session;
 
 cls_session_fail:
@@ -2056,6 +2143,8 @@ module_get_fail:
        iscsi_pool_free(&session->cmdpool);
 cmdpool_alloc_fail:
        iscsi_free_session(cls_session);
+dec_session_count:
+       iscsi_host_dec_session_cnt(shost);
        return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_session_setup);
@@ -2071,6 +2160,7 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
 {
        struct iscsi_session *session = cls_session->dd_data;
        struct module *owner = cls_session->transport->owner;
+       struct Scsi_Host *shost = session->host;
 
        iscsi_pool_free(&session->cmdpool);
 
@@ -2083,6 +2173,7 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
        kfree(session->ifacename);
 
        iscsi_destroy_session(cls_session);
+       iscsi_host_dec_session_cnt(shost);
        module_put(owner);
 }
 EXPORT_SYMBOL_GPL(iscsi_session_teardown);
index 4255b36ff968ca26d7f98d991b45852fb6e7a7d8..db7ea3bb4e833afb50884b92c74f1b98c4b5d6ec 100644 (file)
@@ -353,7 +353,7 @@ void qla4xxx_mark_device_missing(struct scsi_qla_host *ha,
                      ha->host_no, ddb_entry->bus, ddb_entry->target,
                      ddb_entry->fw_ddb_index));
        iscsi_block_session(ddb_entry->sess);
-       iscsi_conn_error(ddb_entry->conn, ISCSI_ERR_CONN_FAILED);
+       iscsi_conn_error_event(ddb_entry->conn, ISCSI_ERR_CONN_FAILED);
 }
 
 static struct srb* qla4xxx_get_new_srb(struct scsi_qla_host *ha,
index cbaae48f47ed9e1fb800dd71b019f637c1201f3e..f9e45f83e467266812408610726c865aa66d82d1 100644 (file)
@@ -1010,7 +1010,7 @@ int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
 
        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
-               iscsi_conn_error(conn, ISCSI_ERR_CONN_FAILED);
+               iscsi_conn_error_event(conn, ISCSI_ERR_CONN_FAILED);
                iscsi_cls_conn_printk(KERN_ERR, conn, "can not deliver "
                                      "control PDU: OOM\n");
                return -ENOMEM;
@@ -1031,7 +1031,7 @@ int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
 }
 EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
 
-void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
+void iscsi_conn_error_event(struct iscsi_cls_conn *conn, enum iscsi_err error)
 {
        struct nlmsghdr *nlh;
        struct sk_buff  *skb;
@@ -1063,7 +1063,7 @@ void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
        iscsi_cls_conn_printk(KERN_INFO, conn, "detected conn error (%d)\n",
                              error);
 }
-EXPORT_SYMBOL_GPL(iscsi_conn_error);
+EXPORT_SYMBOL_GPL(iscsi_conn_error_event);
 
 static int
 iscsi_if_send_reply(int pid, int seq, int type, int done, int multi,
index 16be12f1cbe8cabe0ace86dafbb6e1760cf82505..f274d248a91f4e3cf600ea1404779b9411b849c9 100644 (file)
@@ -213,6 +213,7 @@ enum iscsi_err {
        ISCSI_ERR_DATA_DGST             = ISCSI_ERR_BASE + 15,
        ISCSI_ERR_PARAM_NOT_FOUND       = ISCSI_ERR_BASE + 16,
        ISCSI_ERR_NO_SCSI_CMD           = ISCSI_ERR_BASE + 17,
+       ISCSI_ERR_INVALID_HOST          = ISCSI_ERR_BASE + 18,
 };
 
 /*
index 5e75bb7f311c5b57fbca77fe801ce504dd019d3f..7d8cd159f5925f610a693a2a5383aa44e9a3a01c 100644 (file)
@@ -287,6 +287,11 @@ struct iscsi_session {
        struct iscsi_pool       cmdpool;        /* PDU's pool */
 };
 
+enum {
+       ISCSI_HOST_SETUP,
+       ISCSI_HOST_REMOVED,
+};
+
 struct iscsi_host {
        char                    *initiatorname;
        /* hw address or netdev iscsi connection is bound to */
@@ -295,6 +300,12 @@ struct iscsi_host {
        /* local address */
        int                     local_port;
        char                    local_address[ISCSI_ADDRESS_BUF_LEN];
+
+       wait_queue_head_t       session_removal_wq;
+       /* protects sessions and state */
+       spinlock_t              lock;
+       int                     num_sessions;
+       int                     state;
 };
 
 /*
@@ -351,6 +362,8 @@ extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
 extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
                           int);
 extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);
+extern void iscsi_session_failure(struct iscsi_cls_session *cls_session,
+                                 enum iscsi_err err);
 extern int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
                                enum iscsi_param param, char *buf);
 extern void iscsi_suspend_tx(struct iscsi_conn *conn);
index 8b6c91df4c7a9057c08aa23569838ac7358ddc89..8749d4d8e24444a5da188c7825e71360e6c94a1f 100644 (file)
@@ -135,7 +135,8 @@ extern int iscsi_unregister_transport(struct iscsi_transport *tt);
 /*
  * control plane upcalls
  */
-extern void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error);
+extern void iscsi_conn_error_event(struct iscsi_cls_conn *conn,
+                                  enum iscsi_err error);
 extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
                          char *data, uint32_t data_size);
 
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