PERFORCE change 170543 for review

[Alexander Motin-3]

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

Change 170543 by mav@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);
 }
 
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