scsi: ibmvscsis: Synchronize cmds at remove time

This patch adds code to disconnect from the client, which will make sure
any outstanding commands have been completed, before continuing on with
the remove operation.
Signed-off-by: Michael Cyr <mikecyr@us.ibm.com>
Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Steven Royer <seroyer@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c

@@ -469,6 +469,18 @@ static void ibmvscsis_disconnect(struct work_struct *work)
 
 	case WAIT_ENABLED:
 		switch (new_state) {
+		case UNCONFIGURING:
+			vscsi->state = new_state;
+			vscsi->flags |= RESPONSE_Q_DOWN;
+			vscsi->flags &= ~(SCHEDULE_DISCONNECT |
+					  DISCONNECT_SCHEDULED);
+			dma_rmb();
+			if (vscsi->flags & CFG_SLEEPING) {
+				vscsi->flags &= ~CFG_SLEEPING;
+				complete(&vscsi->unconfig);
+			}
+			break;
+
 		/* should never happen */
 		case ERR_DISCONNECT:
 		case ERR_DISCONNECT_RECONNECT:
@@ -481,6 +493,13 @@ static void ibmvscsis_disconnect(struct work_struct *work)
 
 	case WAIT_IDLE:
 		switch (new_state) {
+		case UNCONFIGURING:
+			vscsi->flags |= RESPONSE_Q_DOWN;
+			vscsi->state = new_state;
+			vscsi->flags &= ~(SCHEDULE_DISCONNECT |
+					  DISCONNECT_SCHEDULED);
+			ibmvscsis_free_command_q(vscsi);
+			break;
 		case ERR_DISCONNECT:
 		case ERR_DISCONNECT_RECONNECT:
 			vscsi->state = new_state;
@@ -1186,6 +1205,15 @@ static void ibmvscsis_adapter_idle(struct scsi_info *vscsi)
 		free_qs = true;
 
 	switch (vscsi->state) {
+	case UNCONFIGURING:
+		ibmvscsis_free_command_q(vscsi);
+		dma_rmb();
+		isync();
+		if (vscsi->flags & CFG_SLEEPING) {
+			vscsi->flags &= ~CFG_SLEEPING;
+			complete(&vscsi->unconfig);
+		}
+		break;
 	case ERR_DISCONNECT_RECONNECT:
 		ibmvscsis_reset_queue(vscsi);
 		pr_debug("adapter_idle, disc_rec: flags 0x%x\n", vscsi->flags);
@@ -3338,6 +3366,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
 		     (unsigned long)vscsi);
 
 	init_completion(&vscsi->wait_idle);
+	init_completion(&vscsi->unconfig);
 
 	snprintf(wq_name, 24, "ibmvscsis%s", dev_name(&vdev->dev));
 	vscsi->work_q = create_workqueue(wq_name);
@@ -3393,10 +3422,11 @@ static int ibmvscsis_remove(struct vio_dev *vdev)
 
 	pr_debug("remove (%s)\n", dev_name(&vscsi->dma_dev->dev));
 
-	/*
-	 * TBD: Need to handle if there are commands on the waiting_rsp q
-	 *      Actually, can there still be cmds outstanding to tcm?
-	 */
+	spin_lock_bh(&vscsi->intr_lock);
+	ibmvscsis_post_disconnect(vscsi, UNCONFIGURING, 0);
+	vscsi->flags |= CFG_SLEEPING;
+	spin_unlock_bh(&vscsi->intr_lock);
+	wait_for_completion(&vscsi->unconfig);
 
 	vio_disable_interrupts(vdev);
 	free_irq(vdev->irq, vscsi);
@@ -3405,7 +3435,6 @@ static int ibmvscsis_remove(struct vio_dev *vdev)
 			 DMA_BIDIRECTIONAL);
 	kfree(vscsi->map_buf);
 	tasklet_kill(&vscsi->work_task);
-	ibmvscsis_unregister_command_q(vscsi);
 	ibmvscsis_destroy_command_q(vscsi);
 	ibmvscsis_freetimer(vscsi);
 	ibmvscsis_free_cmds(vscsi);

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h

@@ -257,6 +257,8 @@ struct scsi_info {
 #define SCHEDULE_DISCONNECT           0x00400
 	/* disconnect handler is scheduled */
 #define DISCONNECT_SCHEDULED          0x00800
+	/* remove function is sleeping */
+#define CFG_SLEEPING                  0x01000
 	u32 flags;
 	/* adapter lock */
 	spinlock_t intr_lock;
@@ -285,6 +287,7 @@ struct scsi_info {
 
 	struct workqueue_struct *work_q;
 	struct completion wait_idle;
+	struct completion unconfig;
 	struct device dev;
 	struct vio_dev *dma_dev;
 	struct srp_target target;