Index: head/sys/cam/cam_sim.c
===================================================================
--- head/sys/cam/cam_sim.c	(revision 365332)
+++ head/sys/cam/cam_sim.c	(revision 365333)
@@ -1,196 +1,195 @@
 /*-
  * Common functions for SCSI Interface Modules (SIMs).
  *
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (c) 1997 Justin T. Gibbs.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions, and the following disclaimer,
  *    without modification, immediately at the beginning of the file.
  * 2. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/bus.h>
 
 #include <cam/cam.h>
 #include <cam/cam_ccb.h>
 #include <cam/cam_sim.h>
 #include <cam/cam_queue.h>
 #include <cam/cam_xpt.h>
 
 #define CAM_PATH_ANY (u_int32_t)-1
 
 static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
 
 static struct mtx cam_sim_free_mtx;
 MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);
 
 struct cam_devq *
 cam_simq_alloc(u_int32_t max_sim_transactions)
 {
 	return (cam_devq_alloc(/*size*/0, max_sim_transactions));
 }
 
 void
 cam_simq_free(struct cam_devq *devq)
 {
 	cam_devq_free(devq);
 }
 
 struct cam_sim *
 cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
 	      const char *sim_name, void *softc, u_int32_t unit,
 	      struct mtx *mtx, int max_dev_transactions,
 	      int max_tagged_dev_transactions, struct cam_devq *queue)
 {
 	struct cam_sim *sim;
 
 	sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
 	    M_CAMSIM, M_ZERO | M_NOWAIT);
 
 	if (sim == NULL)
 		return (NULL);
 
 	sim->sim_action = sim_action;
 	sim->sim_poll = sim_poll;
 	sim->sim_name = sim_name;
 	sim->softc = softc;
 	sim->path_id = CAM_PATH_ANY;
 	sim->sim_dev = NULL;	/* set only by cam_sim_alloc_dev */
 	sim->unit_number = unit;
 	sim->bus_id = 0;	/* set in xpt_bus_register */
 	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
 	sim->max_dev_openings = max_dev_transactions;
 	sim->flags = 0;
 	sim->refcount = 1;
 	sim->devq = queue;
 	sim->mtx = mtx;
 	if (mtx == &Giant) {
 		sim->flags |= 0;
 		callout_init(&sim->callout, 0);
 	} else {
 		sim->flags |= CAM_SIM_MPSAFE;
 		callout_init(&sim->callout, 1);
 	}
 	return (sim);
 }
 
 struct cam_sim *
 cam_sim_alloc_dev(sim_action_func sim_action, sim_poll_func sim_poll,
 	      const char *sim_name, void *softc, device_t dev,
 	      struct mtx *mtx, int max_dev_transactions,
 	      int max_tagged_dev_transactions, struct cam_devq *queue)
 {
 	struct cam_sim *sim;
 
 	KASSERT(dev != NULL, ("%s: dev is null for sim_name %s softc %p\n",
 	    __func__, sim_name, softc));
 
 	sim = cam_sim_alloc(sim_action, sim_poll, sim_name, softc,
 	    device_get_unit(dev), mtx, max_dev_transactions,
 	    max_tagged_dev_transactions, queue);
 	if (sim != NULL)
 		sim->sim_dev = dev;
 	return (sim);
 }
 
 void
 cam_sim_free(struct cam_sim *sim, int free_devq)
 {
-	struct mtx *mtx = sim->mtx;
+	struct mtx *mtx;
 	int error;
 
-	if (mtx) {
-		mtx_assert(mtx, MA_OWNED);
-	} else {
+	if (sim->mtx == NULL) {
 		mtx = &cam_sim_free_mtx;
 		mtx_lock(mtx);
+	} else {
+		mtx = sim->mtx;
+		mtx_assert(mtx, MA_OWNED);
 	}
 	sim->refcount--;
 	if (sim->refcount > 0) {
 		error = msleep(sim, mtx, PRIBIO, "simfree", 0);
 		KASSERT(error == 0, ("invalid error value for msleep(9)"));
 	}
 	KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
-	if (sim->mtx == NULL)
+	if (mtx == &cam_sim_free_mtx)	/* sim->mtx == NULL */
 		mtx_unlock(mtx);
 
 	if (free_devq)
 		cam_simq_free(sim->devq);
 	free(sim, M_CAMSIM);
 }
 
 void
 cam_sim_release(struct cam_sim *sim)
 {
-	struct mtx *mtx = sim->mtx;
+	struct mtx *mtx;
 
-	if (mtx) {
-		if (!mtx_owned(mtx))
-			mtx_lock(mtx);
-		else
-			mtx = NULL;
-	} else {
+	if (sim->mtx == NULL)
 		mtx = &cam_sim_free_mtx;
+	else if (!mtx_owned(sim->mtx))
+		mtx = sim->mtx;
+	else
+		mtx = NULL;	/* We hold the lock. */
+	if (mtx)
 		mtx_lock(mtx);
-	}
 	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
 	sim->refcount--;
 	if (sim->refcount == 0)
 		wakeup(sim);
 	if (mtx)
 		mtx_unlock(mtx);
 }
 
 void
 cam_sim_hold(struct cam_sim *sim)
 {
-	struct mtx *mtx = sim->mtx;
+	struct mtx *mtx;
 
-	if (mtx) {
-		if (!mtx_owned(mtx))
-			mtx_lock(mtx);
-		else
-			mtx = NULL;
-	} else {
+	if (sim->mtx == NULL)
 		mtx = &cam_sim_free_mtx;
+	else if (!mtx_owned(sim->mtx))
+		mtx = sim->mtx;
+	else
+		mtx = NULL;	/* We hold the lock. */
+	if (mtx)
 		mtx_lock(mtx);
-	}
 	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
 	sim->refcount++;
 	if (mtx)
 		mtx_unlock(mtx);
 }
 
 void
 cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
 {
 	sim->path_id = path_id;
 }