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drm/amdkfd: unbind only existing processes

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When unbinding a process from a device (initiated by amd_iommu_v2), the
driver needs to make sure that process still exists in the process table.
There is a possibility that amdkfd's own notifier handler -
kfd_process_notifier_release() - was called before the unbind function
and it already removed the process from the process table.

v2:
Because there can be only one process with the specified pasid, and
because *p can't be NULL inside the hash_for_each_rcu macro, it is more
reasonable to just put the whole code inside the if statement that
compares the pasid value. That way, when we exit hash_for_each_rcu, we
simply exit the function as well.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
CC: Stable <stable@vger.kernel.org>
This commit is contained in:
Oded Gabbay 2016-05-26 08:41:08 +03:00
parent ab3ab68493
commit 121b78e679
1 changed files with 43 additions and 33 deletions
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76
drivers/gpu/drm/amd/amdkfd/kfd_process.c
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@ -404,42 +404,52 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
idx = srcu_read_lock(&kfd_processes_srcu);
/*
* Look for the process that matches the pasid. If there is no such
* process, we either released it in amdkfd's own notifier, or there
* is a bug. Unfortunately, there is no way to tell...
*/
hash_for_each_rcu(kfd_processes_table, i, p, kfd_processes)
if (p->pasid == pasid)
break;
if (p->pasid == pasid) {
srcu_read_unlock(&kfd_processes_srcu, idx);
pr_debug("Unbinding process %d from IOMMU\n", pasid);
mutex_lock(&p->mutex);
if ((dev->dbgmgr) && (dev->dbgmgr->pasid == p->pasid))
kfd_dbgmgr_destroy(dev->dbgmgr);
pqm_uninit(&p->pqm);
pdd = kfd_get_process_device_data(dev, p);
if (!pdd) {
mutex_unlock(&p->mutex);
return;
}
if (pdd->reset_wavefronts) {
dbgdev_wave_reset_wavefronts(pdd->dev, p);
pdd->reset_wavefronts = false;
}
/*
* Just mark pdd as unbound, because we still need it
* to call amd_iommu_unbind_pasid() in when the
* process exits.
* We don't call amd_iommu_unbind_pasid() here
* because the IOMMU called us.
*/
pdd->bound = false;
mutex_unlock(&p->mutex);
return;
}
srcu_read_unlock(&kfd_processes_srcu, idx);
BUG_ON(p->pasid != pasid);
mutex_lock(&p->mutex);
if ((dev->dbgmgr) && (dev->dbgmgr->pasid == p->pasid))
kfd_dbgmgr_destroy(dev->dbgmgr);
pqm_uninit(&p->pqm);
pdd = kfd_get_process_device_data(dev, p);
if (!pdd) {
mutex_unlock(&p->mutex);
return;
}
if (pdd->reset_wavefronts) {
dbgdev_wave_reset_wavefronts(pdd->dev, p);
pdd->reset_wavefronts = false;
}
/*
* Just mark pdd as unbound, because we still need it to call
* amd_iommu_unbind_pasid() in when the process exits.
* We don't call amd_iommu_unbind_pasid() here
* because the IOMMU called us.
*/
pdd->bound = false;
mutex_unlock(&p->mutex);
}
struct kfd_process_device *kfd_get_first_process_device_data(struct kfd_process *p)