svn commit: r333180 - head/sys/dev/nvme

[Alexander Motin]

Author: mav
Date: Wed May  2 20:13:03 2018
New Revision: 333180
URL: https://svnweb.freebsd.org/changeset/base/333180

Log:
  Fix LOR between controller and queue locks.
  
  Admin pass-through requests took controller lock before the queue lock,
  but in case of request submission to a failed controller controller lock
  was taken after the queue lock.  Fix that by reducing the lock scopes and
  switching to mtx_pool locks to track pass-through request completion.
  
  Sponsored by:	iXsystems, Inc.

Modified:
  head/sys/dev/nvme/nvme_ctrlr.c

Modified: head/sys/dev/nvme/nvme_ctrlr.c
==============================================================================
--- head/sys/dev/nvme/nvme_ctrlr.c	Wed May  2 20:10:27 2018	(r333179)
+++ head/sys/dev/nvme/nvme_ctrlr.c	Wed May  2 20:13:03 2018	(r333180)
@@ -233,11 +233,12 @@ nvme_ctrlr_fail_req_task(void *arg, int pending)
 	struct nvme_request	*req;
 
 	mtx_lock(&ctrlr->lock);
-	while (!STAILQ_EMPTY(&ctrlr->fail_req)) {
-		req = STAILQ_FIRST(&ctrlr->fail_req);
+	while ((req = STAILQ_FIRST(&ctrlr->fail_req)) != NULL) {
 		STAILQ_REMOVE_HEAD(&ctrlr->fail_req, stailq);
+		mtx_unlock(&ctrlr->lock);
 		nvme_qpair_manual_complete_request(req->qpair, req,
 		    NVME_SCT_GENERIC, NVME_SC_ABORTED_BY_REQUEST, TRUE);
+		mtx_lock(&ctrlr->lock);
 	}
 	mtx_unlock(&ctrlr->lock);
 }
@@ -978,6 +979,7 @@ static void
 nvme_pt_done(void *arg, const struct nvme_completion *cpl)
 {
 	struct nvme_pt_command *pt = arg;
+	struct mtx *mtx = pt->driver_lock;
 	uint16_t status;
 
 	bzero(&pt->cpl, sizeof(pt->cpl));
@@ -987,9 +989,10 @@ nvme_pt_done(void *arg, const struct nvme_completion *
 	status &= ~NVME_STATUS_P_MASK;
 	pt->cpl.status = status;
 
-	mtx_lock(pt->driver_lock);
+	mtx_lock(mtx);
+	pt->driver_lock = NULL;
 	wakeup(pt);
-	mtx_unlock(pt->driver_lock);
+	mtx_unlock(mtx);
 }
 
 int
@@ -1058,15 +1061,7 @@ nvme_ctrlr_passthrough_cmd(struct nvme_controller *ctr
 
 	req->cmd.nsid = htole32(nsid);
 
-	if (is_admin_cmd)
-		mtx = &ctrlr->lock;
-	else {
-		KASSERT((nsid-1) >= 0 && (nsid-1) < NVME_MAX_NAMESPACES,
-		    ("%s: invalid namespace ID %d\n", __func__, nsid));
-		mtx = &ctrlr->ns[nsid-1].lock;
-	}
-
-	mtx_lock(mtx);
+	mtx = mtx_pool_find(mtxpool_sleep, pt);
 	pt->driver_lock = mtx;
 
 	if (is_admin_cmd)
@@ -1074,10 +1069,10 @@ nvme_ctrlr_passthrough_cmd(struct nvme_controller *ctr
 	else
 		nvme_ctrlr_submit_io_request(ctrlr, req);
 
-	mtx_sleep(pt, mtx, PRIBIO, "nvme_pt", 0);
+	mtx_lock(mtx);
+	while (pt->driver_lock != NULL)
+		mtx_sleep(pt, mtx, PRIBIO, "nvme_pt", 0);
 	mtx_unlock(mtx);
-
-	pt->driver_lock = NULL;
 
 err:
 	if (buf != NULL) {