scsi: hisi_sas: Run I_T nexus resets in parallel for clear nexus reset

For a clear nexus reset operation, the I_T nexus resets are executed
serially for each device. For devices attached through an expander, this
may take 2s per device; so, in total, could take a long time.

Reduce the total time by running the I_T nexus resets in parallel through
async operations.

Link: https://lore.kernel.org/r/1623058179-80434-3-git-send-email-john.garry@huawei.comSigned-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -8,6 +8,7 @@
 #define _HISI_SAS_H_
 
 #include <linux/acpi.h>
+#include <linux/async.h>
 #include <linux/blk-mq.h>
 #include <linux/blk-mq-pci.h>
 #include <linux/clk.h>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -1886,12 +1886,24 @@ static int hisi_sas_lu_reset(struct domain_device *device, u8 *lun)
 	return rc;
 }
 
+static void hisi_sas_async_I_T_nexus_reset(void *data, async_cookie_t cookie)
+{
+	struct domain_device *device = data;
+	struct hisi_hba *hisi_hba = dev_to_hisi_hba(device);
+	int rc;
+
+	rc = hisi_sas_debug_I_T_nexus_reset(device);
+	if (rc != TMF_RESP_FUNC_COMPLETE)
+		dev_info(hisi_hba->dev, "I_T_nexus reset fail for dev:%016llx rc=%d\n",
+			 SAS_ADDR(device->sas_addr), rc);
+}
+
 static int hisi_sas_clear_nexus_ha(struct sas_ha_struct *sas_ha)
 {
 	struct hisi_hba *hisi_hba = sas_ha->lldd_ha;
-	struct device *dev = hisi_hba->dev;
 	HISI_SAS_DECLARE_RST_WORK_ON_STACK(r);
-	int rc, i;
+	ASYNC_DOMAIN_EXCLUSIVE(async);
+	int i;
 
 	queue_work(hisi_hba->wq, &r.work);
 	wait_for_completion(r.completion);
@@ -1906,12 +1918,11 @@ static int hisi_sas_clear_nexus_ha(struct sas_ha_struct *sas_ha)
 		    dev_is_expander(device->dev_type))
 			continue;
 
-		rc = hisi_sas_debug_I_T_nexus_reset(device);
-		if (rc != TMF_RESP_FUNC_COMPLETE)
-			dev_info(dev, "clear nexus ha: for device[%d] rc=%d\n",
-				 sas_dev->device_id, rc);
+		async_schedule_domain(hisi_sas_async_I_T_nexus_reset,
+				      device, &async);
 	}
 
+	async_synchronize_full_domain(&async);
 	hisi_sas_release_tasks(hisi_hba);
 
 	return TMF_RESP_FUNC_COMPLETE;