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MFp4:

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Remove code that years ago was closing race between request submission
to SIM and device/SIM freeze. That race become impossible after moving from
spl to mutex locking, while this workaround causes some unexpected effects.
This commit is contained in:
Alexander Motin 2009-11-14 20:23:20 +00:00
parent d84c90a6cb
commit ec700f26b9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=199280
1 changed files with 3 additions and 37 deletions
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40
sys/cam/cam_xpt.c
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@ -3273,16 +3273,13 @@ xpt_run_dev_sendq(struct cam_eb *bus)
devq->send_queue.qfrozen_cnt++;
while ((devq->send_queue.entries > 0)
&& (devq->send_openings > 0)) {
&& (devq->send_openings > 0)
&& (devq->send_queue.qfrozen_cnt <= 1)) {
struct cam_ed_qinfo *qinfo;
struct cam_ed *device;
union ccb *work_ccb;
struct cam_sim *sim;
if (devq->send_queue.qfrozen_cnt > 1) {
break;
}
qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
CAMQ_HEAD);
device = qinfo->device;
@ -3330,9 +3327,7 @@ xpt_run_dev_sendq(struct cam_eb *bus)
}
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--;
@ -3370,8 +3365,6 @@ xpt_run_dev_sendq(struct cam_eb *bus)
*/
sim = work_ccb->ccb_h.path->bus->sim;
(*(sim->sim_action))(sim, work_ccb);
devq->active_dev = NULL;
}
devq->send_queue.qfrozen_cnt--;
}
@ -4102,45 +4095,18 @@ xpt_dev_async_default(u_int32_t async_code, struct cam_eb *bus,
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);
}