linux-kernel - [PATCH 4.9 51/93] scsi: ibmvscsis: Synchronize cmds at remove time

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Date:   Mon, 20 Mar 2017 18:51:26 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Michael Cyr <mikecyr@...ibm.com>,
        "Bryant G. Ly" <bryantly@...ux.vnet.ibm.com>,
        Steven Royer <seroyer@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 51/93] scsi: ibmvscsis: Synchronize cmds at remove time

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael Cyr <mikecyr@...ibm.com>

[ Upstream commit 8bf11557d44d00562360d370de8aa70ba89aa0d5 ]

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@...ibm.com>
Signed-off-by: Bryant G. Ly <bryantly@...ux.vnet.ibm.com>
Tested-by: Steven Royer <seroyer@...ux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c |   39 +++++++++++++++++++++++++++----
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h |    3 ++
 2 files changed, 37 insertions(+), 5 deletions(-)

--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -470,6 +470,18 @@ static void ibmvscsis_disconnect(struct
 
 	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:
@@ -482,6 +494,13 @@ static void ibmvscsis_disconnect(struct
 
 	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;
@@ -1187,6 +1206,15 @@ static void ibmvscsis_adapter_idle(struc
 		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);
@@ -3342,6 +3370,7 @@ static int ibmvscsis_probe(struct vio_de
 		     (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);
@@ -3397,10 +3426,11 @@ static int ibmvscsis_remove(struct vio_d
 
 	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);
@@ -3409,7 +3439,6 @@ static int ibmvscsis_remove(struct vio_d
 			 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);
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
+++ b/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;