[SCSI] iscsi_transport: wait on session in error handler path

wait for session to come online in eh_device_reset_handler
and eh_target_reset_handler

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: Ravi Anand <ravi.anand@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index d4b96623aa59..e84026def1f4 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -30,6 +30,7 @@
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_transport_iscsi.h>
 #include <scsi/iscsi_if.h>
+#include <scsi/scsi_cmnd.h>
 
 #define ISCSI_SESSION_ATTRS 23
 #define ISCSI_CONN_ATTRS 13
@@ -534,6 +535,37 @@ static void iscsi_scan_session(struct work_struct *work)
         atomic_dec(&ihost->nr_scans);
 }
 
+/**
+ * iscsi_block_scsi_eh - block scsi eh until session state has transistioned
+ * cmd: scsi cmd passed to scsi eh handler
+ *
+ * If the session is down this function will wait for the recovery
+ * timer to fire or for the session to be logged back in. If the
+ * recovery timer fires then FAST_IO_FAIL is returned. The caller
+ * should pass this error value to the scsi eh.
+ */
+int iscsi_block_scsi_eh(struct scsi_cmnd *cmd)
+{
+        struct iscsi_cls_session *session =
+                        starget_to_session(scsi_target(cmd->device));
+        unsigned long flags;
+        int ret = 0;
+
+        spin_lock_irqsave(&session->lock, flags);
+        while (session->state != ISCSI_SESSION_LOGGED_IN) {
+                if (session->state == ISCSI_SESSION_FREE) {
+                        ret = FAST_IO_FAIL;
+                        break;
+                }
+                spin_unlock_irqrestore(&session->lock, flags);
+                msleep(1000);
+                spin_lock_irqsave(&session->lock, flags);
+        }
+        spin_unlock_irqrestore(&session->lock, flags);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(iscsi_block_scsi_eh);
+
 static void session_recovery_timedout(struct work_struct *work)
 {
         struct iscsi_cls_session *session =