PERFORCE change 170543 for review

[Alexander Motin]

http://p4web.freebsd.org/chv.cgi?CH=170543

Change 170543 by mav at mav_mavbook on 2009/11/12 13:37:13

	Remove code that 10 years ago was closing race between sim_action()
	and device/SIM freeze. It just impossible with present CAM locking,
	but caused some unexpected side effects.

Affected files ...

.. //depot/projects/scottl-camlock/src/sys/cam/cam_queue.c#6 edit
.. //depot/projects/scottl-camlock/src/sys/cam/cam_queue.h#5 edit
.. //depot/projects/scottl-camlock/src/sys/cam/cam_xpt.c#127 edit

Differences ...

==== //depot/projects/scottl-camlock/src/sys/cam/cam_queue.c#6 (text+ko) ====

@@ -334,7 +334,6 @@
 	}
 	ccbq->devq_openings = openings;
 	ccbq->dev_openings = openings;	
-	TAILQ_INIT(&ccbq->active_ccbs);
 	return (0);
 }
 

==== //depot/projects/scottl-camlock/src/sys/cam/cam_queue.h#5 (text+ko) ====

@@ -60,7 +60,6 @@
 	int	dev_openings;	
 	int	dev_active;
 	int	held;
-	struct	ccb_hdr_tailq active_ccbs;
 };
 
 struct cam_ed;
@@ -209,9 +208,6 @@
 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
 {
 
-	TAILQ_INSERT_TAIL(&ccbq->active_ccbs,
-			  &(send_ccb->ccb_h),
-			  xpt_links.tqe);
 	send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
 	ccbq->dev_active++;
 	ccbq->dev_openings--;		
@@ -220,8 +216,7 @@
 static __inline void
 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
 {
-	TAILQ_REMOVE(&ccbq->active_ccbs, &done_ccb->ccb_h,
-		     xpt_links.tqe);
+
 	ccbq->dev_active--;
 	ccbq->dev_openings++;	
 	ccbq->held++;

==== //depot/projects/scottl-camlock/src/sys/cam/cam_xpt.c#127 (text+ko) ====

@@ -3327,9 +3327,7 @@
 			}
 			mtx_unlock(&xsoftc.xpt_lock);
 		}
-		devq->active_dev = device;
 		cam_ccbq_remove_ccb(&device->ccbq, work_ccb);
-
 		cam_ccbq_send_ccb(&device->ccbq, work_ccb);
 
 		devq->send_openings--;
@@ -3367,8 +3365,6 @@
 		 */
 		sim = work_ccb->ccb_h.path->bus->sim;
 		(*(sim->sim_action))(sim, work_ccb);
-
-		devq->active_dev = NULL;
 	}
 	devq->send_queue.qfrozen_cnt--;
 }
@@ -4099,45 +4095,18 @@
 u_int32_t
 xpt_freeze_devq(struct cam_path *path, u_int count)
 {
-	struct ccb_hdr *ccbh;
 
 	mtx_assert(path->bus->sim->mtx, MA_OWNED);
-
 	path->device->ccbq.queue.qfrozen_cnt += count;
-
-	/*
-	 * Mark the last CCB in the queue as needing
-	 * to be requeued if the driver hasn't
-	 * changed it's state yet.  This fixes a race
-	 * where a ccb is just about to be queued to
-	 * a controller driver when it's interrupt routine
-	 * freezes the queue.  To completly close the
-	 * hole, controller drives must check to see
-	 * if a ccb's status is still CAM_REQ_INPROG
-	 * just before they queue
-	 * the CCB.  See ahc_action/ahc_freeze_devq for
-	 * an example.
-	 */
-	ccbh = TAILQ_LAST(&path->device->ccbq.active_ccbs, ccb_hdr_tailq);
-	if (ccbh && ccbh->status == CAM_REQ_INPROG)
-		ccbh->status = CAM_REQUEUE_REQ;
 	return (path->device->ccbq.queue.qfrozen_cnt);
 }
 
 u_int32_t
 xpt_freeze_simq(struct cam_sim *sim, u_int count)
 {
+
 	mtx_assert(sim->mtx, MA_OWNED);
-
 	sim->devq->send_queue.qfrozen_cnt += count;
-	if (sim->devq->active_dev != NULL) {
-		struct ccb_hdr *ccbh;
-
-		ccbh = TAILQ_LAST(&sim->devq->active_dev->ccbq.active_ccbs,
-				  ccb_hdr_tailq);
-		if (ccbh && ccbh->status == CAM_REQ_INPROG)
-			ccbh->status = CAM_REQUEUE_REQ;
-	}
 	return (sim->devq->send_queue.qfrozen_cnt);
 }