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drm/amdkfd: Fix a circular lock dependency

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Fix a circular lock dependency exposed under userptr memory pressure.
The DQM lock is the only one taken inside the MMU notifier. We need
to make sure that no reclaim is done under this lock, and that
no other locks are taken under which reclaim is possible.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Felix Kuehling 2019-04-23 23:32:56 -04:00 committed by Alex Deucher
parent 16631afff2
commit 32cce8bc86
1 changed files with 29 additions and 4 deletions
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33
drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
View file

@ -794,10 +794,14 @@ static int register_process(struct device_queue_manager *dqm,
retval = dqm->asic_ops.update_qpd(dqm, qpd);
dqm->processes_count++;
kfd_inc_compute_active(dqm->dev);
dqm_unlock(dqm);
/* Outside the DQM lock because under the DQM lock we can't do
* reclaim or take other locks that others hold while reclaiming.
*/
kfd_inc_compute_active(dqm->dev);
return retval;
}
@ -818,7 +822,6 @@ static int unregister_process(struct device_queue_manager *dqm,
list_del(&cur->list);
kfree(cur);
dqm->processes_count--;
kfd_dec_compute_active(dqm->dev);
goto out;
}
}
@ -826,6 +829,13 @@ static int unregister_process(struct device_queue_manager *dqm,
retval = 1;
out:
dqm_unlock(dqm);
/* Outside the DQM lock because under the DQM lock we can't do
* reclaim or take other locks that others hold while reclaiming.
*/
if (!retval)
kfd_dec_compute_active(dqm->dev);
return retval;
}
@ -1519,6 +1529,7 @@ static int process_termination_nocpsch(struct device_queue_manager *dqm,
struct queue *q, *next;
struct device_process_node *cur, *next_dpn;
int retval = 0;
bool found = false;
dqm_lock(dqm);
@ -1537,12 +1548,19 @@ static int process_termination_nocpsch(struct device_queue_manager *dqm,
list_del(&cur->list);
kfree(cur);
dqm->processes_count--;
kfd_dec_compute_active(dqm->dev);
found = true;
break;
}
}
dqm_unlock(dqm);
/* Outside the DQM lock because under the DQM lock we can't do
* reclaim or take other locks that others hold while reclaiming.
*/
if (found)
kfd_dec_compute_active(dqm->dev);
return retval;
}
@ -1588,6 +1606,7 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
struct device_process_node *cur, *next_dpn;
enum kfd_unmap_queues_filter filter =
KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES;
bool found = false;
retval = 0;
@ -1624,7 +1643,7 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
list_del(&cur->list);
kfree(cur);
dqm->processes_count--;
kfd_dec_compute_active(dqm->dev);
found = true;
break;
}
}
@ -1638,6 +1657,12 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
dqm_unlock(dqm);
/* Outside the DQM lock because under the DQM lock we can't do
* reclaim or take other locks that others hold while reclaiming.
*/
if (found)
kfd_dec_compute_active(dqm->dev);
/* Lastly, free mqd resources.
* Do uninit_mqd() after dqm_unlock to avoid circular locking.
*/