[SCSI] iscsi class: add async scan helper
authorMike Christie <michaelc@cs.wisc.edu>
Thu, 31 Jan 2008 19:36:48 +0000 (13:36 -0600)
committerJames Bottomley <James.Bottomley@HansenPartnership.com>
Fri, 8 Feb 2008 00:02:35 +0000 (18:02 -0600)
In qla4xxx's probe it will call the iscsi session setup functions
for session that got setup on the initial start. This then makes
it easy for the iscsi class to export a helper which indicates
when those scans are done.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
drivers/scsi/scsi_transport_iscsi.c
include/scsi/scsi_transport_iscsi.h

index af88955d0ec1edec9b04b38cbe5f0f92b415ab24..af1799723e7b52bc7265c36a7513110a182bd22e 100644 (file)
@@ -127,6 +127,7 @@ static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
        memset(ihost, 0, sizeof(*ihost));
        INIT_LIST_HEAD(&ihost->sessions);
        mutex_init(&ihost->mutex);
+       atomic_set(&ihost->nr_scans, 0);
 
        snprintf(ihost->scan_workq_name, KOBJ_NAME_LEN, "iscsi_scan_%d",
                shost->host_no);
@@ -284,6 +285,25 @@ static int iscsi_is_session_dev(const struct device *dev)
        return dev->release == iscsi_session_release;
 }
 
+/**
+ * iscsi_scan_finished - helper to report when running scans are done
+ * @shost: scsi host
+ * @time: scan run time
+ *
+ * This function can be used by drives like qla4xxx to report to the scsi
+ * layer when the scans it kicked off at module load time are done.
+ */
+int iscsi_scan_finished(struct Scsi_Host *shost, unsigned long time)
+{
+       struct iscsi_host *ihost = shost->shost_data;
+       /*
+        * qla4xxx will have kicked off some session unblocks before calling
+        * scsi_scan_host, so just wait for them to complete.
+        */
+       return !atomic_read(&ihost->nr_scans);
+}
+EXPORT_SYMBOL_GPL(iscsi_scan_finished);
+
 static int iscsi_user_scan(struct Scsi_Host *shost, uint channel,
                           uint id, uint lun)
 {
@@ -306,17 +326,21 @@ static void iscsi_scan_session(struct work_struct *work)
 {
        struct iscsi_cls_session *session =
                        container_of(work, struct iscsi_cls_session, scan_work);
+       struct Scsi_Host *shost = iscsi_session_to_shost(session);
+       struct iscsi_host *ihost = shost->shost_data;
        unsigned long flags;
 
        spin_lock_irqsave(&session->lock, flags);
        if (session->state != ISCSI_SESSION_LOGGED_IN) {
                spin_unlock_irqrestore(&session->lock, flags);
-               return;
+               goto done;
        }
        spin_unlock_irqrestore(&session->lock, flags);
 
        scsi_scan_target(&session->dev, 0, session->target_id,
                         SCAN_WILD_CARD, 1);
+done:
+       atomic_dec(&ihost->nr_scans);
 }
 
 static void session_recovery_timedout(struct work_struct *work)
@@ -366,7 +390,15 @@ void iscsi_unblock_session(struct iscsi_cls_session *session)
        spin_unlock_irqrestore(&session->lock, flags);
 
        __iscsi_unblock_session(session);
-       queue_work(ihost->scan_workq, &session->scan_work);
+       /*
+        * Only do kernel scanning if the driver is properly hooked into
+        * the async scanning code (drivers like iscsi_tcp do login and
+        * scanning from userspace).
+        */
+       if (shost->hostt->scan_finished) {
+               if (queue_work(ihost->scan_workq, &session->scan_work))
+                       atomic_inc(&ihost->nr_scans);
+       }
 }
 EXPORT_SYMBOL_GPL(iscsi_unblock_session);
 
@@ -550,7 +582,7 @@ void iscsi_remove_session(struct iscsi_cls_session *session)
        session->state = ISCSI_SESSION_FREE;
        spin_unlock_irqrestore(&session->lock, flags);
        __iscsi_unblock_session(session);
-       iscsi_unbind_session(session);
+       __iscsi_unbind_session(&session->unbind_work);
 
        /* flush running scans */
        flush_workqueue(ihost->scan_workq);
index 1f0ec46b4f876fab2803c88d00599bd026a67163..83693ba09c29db7fa5c0bb5f9a7585c76845c170 100644 (file)
@@ -203,6 +203,7 @@ struct iscsi_cls_session {
 
 struct iscsi_host {
        struct list_head sessions;
+       atomic_t nr_scans;
        struct mutex mutex;
        struct workqueue_struct *scan_workq;
        char scan_workq_name[KOBJ_NAME_LEN];
@@ -229,6 +230,6 @@ extern struct iscsi_cls_conn *iscsi_create_conn(struct iscsi_cls_session *sess,
 extern int iscsi_destroy_conn(struct iscsi_cls_conn *conn);
 extern void iscsi_unblock_session(struct iscsi_cls_session *session);
 extern void iscsi_block_session(struct iscsi_cls_session *session);
-
+extern int iscsi_scan_finished(struct Scsi_Host *shost, unsigned long time);
 
 #endif