MFC r271588: Update CAM CCB accounting for the new status quo.

devq_openings counter lost its meaning after allocation queues has gone.
held counter is still meaningful, but problematic to update due to separate
locking of CCB allocation and queuing.

To fix that replace devq_openings counter with allocated counter.  held is
now calculated on request as difference between number of allocated, queued
and active CCBs.

5 files changed, 19 insertions, 22 deletions

diff --git a/sbin/camcontrol/camcontrol.c b/sbin/camcontrol/camcontrol.c
index 12a0e5c..4129cf4 100644
--- a/sbin/camcontrol/camcontrol.c
+++ b/sbin/camcontrol/camcontrol.c
@@ -4469,9 +4469,9 @@ tagcontrol(struct cam_device *device, int argc, char **argv,
 		fprintf(stdout, "%s", pathstr);
 		fprintf(stdout, "dev_active    %d\n", ccb->cgds.dev_active);
 		fprintf(stdout, "%s", pathstr);
-		fprintf(stdout, "devq_openings %d\n", ccb->cgds.devq_openings);
+		fprintf(stdout, "allocated     %d\n", ccb->cgds.allocated);
 		fprintf(stdout, "%s", pathstr);
-		fprintf(stdout, "devq_queued   %d\n", ccb->cgds.devq_queued);
+		fprintf(stdout, "queued        %d\n", ccb->cgds.queued);
 		fprintf(stdout, "%s", pathstr);
 		fprintf(stdout, "held          %d\n", ccb->cgds.held);
 		fprintf(stdout, "%s", pathstr);
diff --git a/sys/cam/cam_ccb.h b/sys/cam/cam_ccb.h
index 139bd50..c2f6c46 100644
--- a/sys/cam/cam_ccb.h
+++ b/sys/cam/cam_ccb.h
@@ -352,8 +352,8 @@ struct ccb_getdevstats {
 	struct	ccb_hdr	ccb_h;
 	int	dev_openings;	/* Space left for more work on device*/	
 	int	dev_active;	/* Transactions running on the device */
-	int	devq_openings;	/* Space left for more queued work */
-	int	devq_queued;	/* Transactions queued to be sent */
+	int	allocated;	/* CCBs allocated for the device */
+	int	queued;		/* CCBs queued to be sent to the device */
 	int	held;		/*
 				 * CCBs held by peripheral drivers
 				 * for this device
diff --git a/sys/cam/cam_queue.c b/sys/cam/cam_queue.c
index f6624f3..b67f687 100644
--- a/sys/cam/cam_queue.c
+++ b/sys/cam/cam_queue.c
@@ -290,7 +290,6 @@ cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
 
 	delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
 	ccbq->total_openings += delta;
-	ccbq->devq_openings += delta;
 	ccbq->dev_openings += delta;
 
 	new_size = imax(64, 1 << fls(new_size + new_size / 2));
@@ -308,7 +307,6 @@ cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
 	    imax(64, 1 << fls(openings + openings / 2))) != 0)
 		return (1);
 	ccbq->total_openings = openings;
-	ccbq->devq_openings = openings;
 	ccbq->dev_openings = openings;
 	return (0);
 }
diff --git a/sys/cam/cam_queue.h b/sys/cam/cam_queue.h
index 0f74e82..33f6b1d 100644
--- a/sys/cam/cam_queue.h
+++ b/sys/cam/cam_queue.h
@@ -62,10 +62,9 @@ struct cam_ccbq {
 	struct ccb_hdr_tailq	queue_extra_head;
 	int	queue_extra_entries;
 	int	total_openings;
-	int	devq_openings;
+	int	allocated;
 	int	dev_openings;
 	int	dev_active;
-	int	held;
 };
 
 struct cam_ed;
@@ -188,8 +187,8 @@ cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
 static __inline void
 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
 {
-	ccbq->devq_openings--;
-	ccbq->held++;
+
+	ccbq->allocated++;
 }
 
 static __inline void
@@ -198,8 +197,6 @@ cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
 	struct ccb_hdr *old_ccb;
 	struct camq *queue = &ccbq->queue;
 
-	ccbq->held--;
-
 	/*
 	 * If queue is already full, try to resize.
 	 * If resize fail, push CCB with lowest priority out to the TAILQ.
@@ -264,7 +261,7 @@ cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
 
 	send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
 	ccbq->dev_active++;
-	ccbq->dev_openings--;		
+	ccbq->dev_openings--;
 }
 
 static __inline void
@@ -272,15 +269,14 @@ cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
 {
 
 	ccbq->dev_active--;
-	ccbq->dev_openings++;	
-	ccbq->held++;
+	ccbq->dev_openings++;
 }
 
 static __inline void
 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
 {
-	ccbq->held--;
-	ccbq->devq_openings++;
+
+	ccbq->allocated--;
 }
 
 #endif /* _KERNEL */
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index 79d3023..a5ff305 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -2652,20 +2652,25 @@ call_sim:
 			struct ccb_getdevstats *cgds;
 			struct cam_eb *bus;
 			struct cam_et *tar;
+			struct cam_devq *devq;
 
 			cgds = &start_ccb->cgds;
 			bus = path->bus;
 			tar = path->target;
+			devq = bus->sim->devq;
+			mtx_lock(&devq->send_mtx);
 			cgds->dev_openings = dev->ccbq.dev_openings;
 			cgds->dev_active = dev->ccbq.dev_active;
-			cgds->devq_openings = dev->ccbq.devq_openings;
-			cgds->devq_queued = cam_ccbq_pending_ccb_count(&dev->ccbq);
-			cgds->held = dev->ccbq.held;
+			cgds->allocated = dev->ccbq.allocated;
+			cgds->queued = cam_ccbq_pending_ccb_count(&dev->ccbq);
+			cgds->held = cgds->allocated - cgds->dev_active -
+			    cgds->queued;
 			cgds->last_reset = tar->last_reset;
 			cgds->maxtags = dev->maxtags;
 			cgds->mintags = dev->mintags;
 			if (timevalcmp(&tar->last_reset, &bus->last_reset, <))
 				cgds->last_reset = bus->last_reset;
+			mtx_unlock(&devq->send_mtx);
 			cgds->ccb_h.status = CAM_REQ_CMP;
 		}
 		break;
@@ -3008,7 +3013,6 @@ xpt_polled_action(union ccb *start_ccb)
 	 * can get it before us while we simulate interrupts.
 	 */
 	mtx_lock(&devq->send_mtx);
-	dev->ccbq.devq_openings--;
 	dev->ccbq.dev_openings--;
 	while((devq->send_openings <= 0 || dev->ccbq.dev_openings < 0) &&
 	    (--timeout > 0)) {
@@ -3020,7 +3024,6 @@ xpt_polled_action(union ccb *start_ccb)
 		camisr_runqueue();
 		mtx_lock(&devq->send_mtx);
 	}
-	dev->ccbq.devq_openings++;
 	dev->ccbq.dev_openings++;
 	mtx_unlock(&devq->send_mtx);