SCSI fixes on 20201030

Four driver fixes and one core fix.  The core fix closes a race window
 where we could kick off a second asynchronous scan because the test
 and set of the variable preventing it isn't atomic.
 
 Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "Four driver fixes and one core fix.

  The core fix closes a race window where we could kick off a second
  asynchronous scan because the test and set of the variable preventing
  it isn't atomic"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: hisi_sas: Stop using queue #0 always for v2 hw
  scsi: ibmvscsi: Fix potential race after loss of transport
  scsi: mptfusion: Fix null pointer dereferences in mptscsih_remove()
  scsi: qla2xxx: Return EBUSY on fcport deletion
  scsi: core: Don't start concurrent async scan on same host

drivers/message/fusion/mptscsih.c

@@ -1176,8 +1176,10 @@ mptscsih_remove(struct pci_dev *pdev)
 	MPT_SCSI_HOST		*hd;
 	int sz1;
 
-	if((hd = shost_priv(host)) == NULL)
-		return;
+	if (host == NULL)
+		hd = NULL;
+	else
+		hd = shost_priv(host);
 
 	mptscsih_shutdown(pdev);
 
@@ -1193,14 +1195,15 @@ mptscsih_remove(struct pci_dev *pdev)
 	    "Free'd ScsiLookup (%d) memory\n",
 	    ioc->name, sz1));
 
-	kfree(hd->info_kbuf);
+	if (hd)
+		kfree(hd->info_kbuf);
 
 	/* NULL the Scsi_Host pointer
 	 */
 	ioc->sh = NULL;
 
-	scsi_host_put(host);
-
+	if (host)
+		scsi_host_put(host);
 	mpt_detach(pdev);
 
 }

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -445,7 +445,7 @@ static int hisi_sas_task_prep(struct sas_task *task,
 		}
 	}
 
-	if (scmd) {
+	if (scmd && hisi_hba->shost->nr_hw_queues) {
 		unsigned int dq_index;
 		u32 blk_tag;
 

drivers/scsi/ibmvscsi/ibmvscsi.c

@@ -806,6 +806,22 @@ static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
 	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 }
 
+/**
+ * ibmvscsi_set_request_limit - Set the adapter request_limit in response to
+ * an adapter failure, reset, or SRP Login. Done under host lock to prevent
+ * race with SCSI command submission.
+ * @hostdata:	adapter to adjust
+ * @limit:	new request limit
+ */
+static void ibmvscsi_set_request_limit(struct ibmvscsi_host_data *hostdata, int limit)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(hostdata->host->host_lock, flags);
+	atomic_set(&hostdata->request_limit, limit);
+	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+}
+
 /**
  * ibmvscsi_reset_host - Reset the connection to the server
  * @hostdata:	struct ibmvscsi_host_data to reset
@@ -813,7 +829,7 @@ static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
 static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
 {
 	scsi_block_requests(hostdata->host);
-	atomic_set(&hostdata->request_limit, 0);
+	ibmvscsi_set_request_limit(hostdata, 0);
 
 	purge_requests(hostdata, DID_ERROR);
 	hostdata->action = IBMVSCSI_HOST_ACTION_RESET;
@@ -1146,13 +1162,13 @@ static void login_rsp(struct srp_event_struct *evt_struct)
 		dev_info(hostdata->dev, "SRP_LOGIN_REJ reason %u\n",
 			 evt_struct->xfer_iu->srp.login_rej.reason);
 		/* Login failed.  */
-		atomic_set(&hostdata->request_limit, -1);
+		ibmvscsi_set_request_limit(hostdata, -1);
 		return;
 	default:
 		dev_err(hostdata->dev, "Invalid login response typecode 0x%02x!\n",
 			evt_struct->xfer_iu->srp.login_rsp.opcode);
 		/* Login failed.  */
-		atomic_set(&hostdata->request_limit, -1);
+		ibmvscsi_set_request_limit(hostdata, -1);
 		return;
 	}
 
@@ -1163,7 +1179,7 @@ static void login_rsp(struct srp_event_struct *evt_struct)
 	 * This value is set rather than added to request_limit because
 	 * request_limit could have been set to -1 by this client.
 	 */
-	atomic_set(&hostdata->request_limit,
+	ibmvscsi_set_request_limit(hostdata,
 		   be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta));
 
 	/* If we had any pending I/Os, kick them */
@@ -1195,13 +1211,13 @@ static int send_srp_login(struct ibmvscsi_host_data *hostdata)
 	login->req_buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
 					 SRP_BUF_FORMAT_INDIRECT);
 
-	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	/* Start out with a request limit of 0, since this is negotiated in
 	 * the login request we are just sending and login requests always
 	 * get sent by the driver regardless of request_limit.
 	 */
-	atomic_set(&hostdata->request_limit, 0);
+	ibmvscsi_set_request_limit(hostdata, 0);
 
+	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	rc = ibmvscsi_send_srp_event(evt_struct, hostdata, login_timeout * 2);
 	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 	dev_info(hostdata->dev, "sent SRP login\n");
@@ -1781,7 +1797,7 @@ static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
 		return;
 	case VIOSRP_CRQ_XPORT_EVENT:	/* Hypervisor telling us the connection is closed */
 		scsi_block_requests(hostdata->host);
-		atomic_set(&hostdata->request_limit, 0);
+		ibmvscsi_set_request_limit(hostdata, 0);
 		if (crq->format == 0x06) {
 			/* We need to re-setup the interpartition connection */
 			dev_info(hostdata->dev, "Re-enabling adapter!\n");
@@ -2137,12 +2153,12 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 	}
 
 	hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
+	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
 	if (rc) {
-		atomic_set(&hostdata->request_limit, -1);
+		ibmvscsi_set_request_limit(hostdata, -1);
 		dev_err(hostdata->dev, "error after %s\n", action);
 	}
-	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
 	scsi_unblock_requests(hostdata->host);
 }
@@ -2226,7 +2242,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 	init_waitqueue_head(&hostdata->work_wait_q);
 	hostdata->host = host;
 	hostdata->dev = dev;
-	atomic_set(&hostdata->request_limit, -1);
+	ibmvscsi_set_request_limit(hostdata, -1);
 	hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
 
 	if (map_persist_bufs(hostdata)) {

drivers/scsi/qla2xxx/qla_nvme.c

@@ -554,10 +554,12 @@ static int qla_nvme_post_cmd(struct nvme_fc_local_port *lport,
 
 	fcport = qla_rport->fcport;
 
-	if (!qpair || !fcport || (qpair && !qpair->fw_started) ||
-	    (fcport && fcport->deleted))
+	if (!qpair || !fcport)
 		return -ENODEV;
 
+	if (!qpair->fw_started || fcport->deleted)
+		return -EBUSY;
+
 	vha = fcport->vha;
 
 	if (!(fcport->nvme_flag & NVME_FLAG_REGISTERED))

drivers/scsi/scsi_scan.c

@@ -1714,15 +1714,16 @@ static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
  */
 static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
 {
-	struct async_scan_data *data;
+	struct async_scan_data *data = NULL;
 	unsigned long flags;
 
 	if (strncmp(scsi_scan_type, "sync", 4) == 0)
 		return NULL;
 
+	mutex_lock(&shost->scan_mutex);
 	if (shost->async_scan) {
 		shost_printk(KERN_DEBUG, shost, "%s called twice\n", __func__);
-		return NULL;
+		goto err;
 	}
 
 	data = kmalloc(sizeof(*data), GFP_KERNEL);
@@ -1733,7 +1734,6 @@ static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
 		goto err;
 	init_completion(&data->prev_finished);
 
-	mutex_lock(&shost->scan_mutex);
 	spin_lock_irqsave(shost->host_lock, flags);
 	shost->async_scan = 1;
 	spin_unlock_irqrestore(shost->host_lock, flags);
@@ -1748,6 +1748,7 @@ static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
 	return data;
 
  err:
+	mutex_unlock(&shost->scan_mutex);
 	kfree(data);
 	return NULL;
 }