svn commit: r351588 - stable/11/sys/dev/nvme

[Alexander Motin]

Author: mav
Date: Wed Aug 28 21:13:28 2019
New Revision: 351588
URL: https://svnweb.freebsd.org/changeset/base/351588

Log:
  MFC r351352: Improve NVMe hot unplug handling.
  
  If device is unplugged from the system (CSTS register reads return
  0xffffffff), it makes no sense to send any more recovery requests or
  expect any responses back.  If there is a detach call in such state,
  just stop all activity and free resources.  If there is no detach
  call (hot-plug is not supported), rely on normal timeout handling,
  but when it trigger controller reset, do not wait for impossible and
  quickly report failure.
  
  Sponsored by:	iXsystems, Inc.

Modified:
  stable/11/sys/dev/nvme/nvme_ctrlr.c
  stable/11/sys/dev/nvme/nvme_qpair.c

Modified: stable/11/sys/dev/nvme/nvme_ctrlr.c
==============================================================================
--- stable/11/sys/dev/nvme/nvme_ctrlr.c	Wed Aug 28 21:01:51 2019	(r351587)
+++ stable/11/sys/dev/nvme/nvme_ctrlr.c	Wed Aug 28 21:13:28 2019	(r351588)
@@ -202,10 +202,13 @@ nvme_ctrlr_fail(struct nvme_controller *ctrlr)
 	int i;
 
 	ctrlr->is_failed = TRUE;
+	nvme_admin_qpair_disable(&ctrlr->adminq);
 	nvme_qpair_fail(&ctrlr->adminq);
 	if (ctrlr->ioq != NULL) {
-		for (i = 0; i < ctrlr->num_io_queues; i++)
+		for (i = 0; i < ctrlr->num_io_queues; i++) {
+			nvme_io_qpair_disable(&ctrlr->ioq[i]);
 			nvme_qpair_fail(&ctrlr->ioq[i]);
+		}
 	}
 	nvme_notify_fail_consumers(ctrlr);
 }
@@ -244,17 +247,19 @@ nvme_ctrlr_wait_for_ready(struct nvme_controller *ctrl
 	int ms_waited;
 	union csts_register csts;
 
-	csts.raw = nvme_mmio_read_4(ctrlr, csts);
-
 	ms_waited = 0;
-	while (csts.bits.rdy != desired_val) {
+	while (1) {
+		csts.raw = nvme_mmio_read_4(ctrlr, csts);
+		if (csts.raw == 0xffffffff)		/* Hot unplug. */
+			return (ENXIO);
+		if (csts.bits.rdy == desired_val)
+			break;
 		if (ms_waited++ > ctrlr->ready_timeout_in_ms) {
 			nvme_printf(ctrlr, "controller ready did not become %d "
 			    "within %d ms\n", desired_val, ctrlr->ready_timeout_in_ms);
 			return (ENXIO);
 		}
 		DELAY(1000);
-		csts.raw = nvme_mmio_read_4(ctrlr, csts);
 	}
 
 	return (0);
@@ -1229,12 +1234,20 @@ nvme_ctrlr_construct(struct nvme_controller *ctrlr, de
 void
 nvme_ctrlr_destruct(struct nvme_controller *ctrlr, device_t dev)
 {
-	int				i;
+	int	gone, i;
 
 	if (ctrlr->resource == NULL)
 		goto nores;
 
-	nvme_notify_fail_consumers(ctrlr);
+	/*
+	 * Check whether it is a hot unplug or a clean driver detach.
+	 * If device is not there any more, skip any shutdown commands.
+	 */
+	gone = (nvme_mmio_read_4(ctrlr, csts) == 0xffffffff);
+	if (gone)
+		nvme_ctrlr_fail(ctrlr);
+	else
+		nvme_notify_fail_consumers(ctrlr);
 
 	for (i = 0; i < NVME_MAX_NAMESPACES; i++)
 		nvme_ns_destruct(&ctrlr->ns[i]);
@@ -1243,11 +1256,11 @@ nvme_ctrlr_destruct(struct nvme_controller *ctrlr, dev
 		destroy_dev(ctrlr->cdev);
 
 	for (i = 0; i < ctrlr->num_io_queues; i++) {
-		nvme_ctrlr_destroy_qpair(ctrlr, &ctrlr->ioq[i]);
+		if (!gone)
+			nvme_ctrlr_destroy_qpair(ctrlr, &ctrlr->ioq[i]);
 		nvme_io_qpair_destroy(&ctrlr->ioq[i]);
 	}
 	free(ctrlr->ioq, M_NVME);
-
 	nvme_admin_qpair_destroy(&ctrlr->adminq);
 
 	/*
@@ -1257,9 +1270,11 @@ nvme_ctrlr_destruct(struct nvme_controller *ctrlr, dev
 	 *   shutdown notification in case the system is shutdown before
 	 *   reloading the driver.
 	 */
-	nvme_ctrlr_shutdown(ctrlr);
+	if (!gone)
+		nvme_ctrlr_shutdown(ctrlr);
 
-	nvme_ctrlr_disable(ctrlr);
+	if (!gone)
+		nvme_ctrlr_disable(ctrlr);
 
 	if (ctrlr->taskqueue)
 		taskqueue_free(ctrlr->taskqueue);
@@ -1296,14 +1311,19 @@ nvme_ctrlr_shutdown(struct nvme_controller *ctrlr)
 	cc.raw = nvme_mmio_read_4(ctrlr, cc);
 	cc.bits.shn = NVME_SHN_NORMAL;
 	nvme_mmio_write_4(ctrlr, cc, cc.raw);
-	csts.raw = nvme_mmio_read_4(ctrlr, csts);
-	while ((csts.bits.shst != NVME_SHST_COMPLETE) && (ticks++ < 5*hz)) {
-		pause("nvme shn", 1);
+	while (1) {
 		csts.raw = nvme_mmio_read_4(ctrlr, csts);
+		if (csts.raw == 0xffffffff)		/* Hot unplug. */
+			break;
+		if (csts.bits.shst == NVME_SHST_COMPLETE)
+			break;
+		if (ticks++ > 5*hz) {
+			nvme_printf(ctrlr, "did not complete shutdown within"
+			    " 5 seconds of notification\n");
+			break;
+		}
+		pause("nvme shn", 1);
 	}
-	if (csts.bits.shst != NVME_SHST_COMPLETE)
-		nvme_printf(ctrlr, "did not complete shutdown within 5 seconds "
-		    "of notification\n");
 }
 
 void

Modified: stable/11/sys/dev/nvme/nvme_qpair.c
==============================================================================
--- stable/11/sys/dev/nvme/nvme_qpair.c	Wed Aug 28 21:01:51 2019	(r351587)
+++ stable/11/sys/dev/nvme/nvme_qpair.c	Wed Aug 28 21:13:28 2019	(r351588)
@@ -788,7 +788,8 @@ nvme_timeout(void *arg)
 		    nvme_abort_complete, tr);
 	} else {
 		nvme_printf(ctrlr, "Resetting controller due to a timeout%s.\n",
-		    csts.bits.cfs ? " and fatal error status" : "");
+		    (csts.raw == 0xffffffff) ? " and possible hot unplug" :
+		    (csts.bits.cfs ? " and fatal error status" : ""));
 		nvme_ctrlr_reset(ctrlr);
 	}
 }