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drm/amdkfd: Use mmu_notifier_get

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We use mmu_notifier_put to free the MMU notifier. That needs to be
paired with mmu_notifier_get to work correctly. Othewrise the next patch
would cause a kernel oops.

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 2021-02-12 01:36:47 -05:00 committed by Alex Deucher
parent 263a4febd1
commit 3248b6d3cb
1 changed files with 28 additions and 7 deletions
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35
drivers/gpu/drm/amd/amdkfd/kfd_process.c
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@ -1011,6 +1011,16 @@ static void kfd_process_ref_release(struct kref *ref)
queue_work(kfd_process_wq, &p->release_work);
}
static struct mmu_notifier *kfd_process_alloc_notifier(struct mm_struct *mm)
{
int idx = srcu_read_lock(&kfd_processes_srcu);
struct kfd_process *p = find_process_by_mm(mm);
srcu_read_unlock(&kfd_processes_srcu, idx);
return p ? &p->mmu_notifier : ERR_PTR(-ESRCH);
}
static void kfd_process_free_notifier(struct mmu_notifier *mn)
{
kfd_unref_process(container_of(mn, struct kfd_process, mmu_notifier));
@ -1075,6 +1085,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
.release = kfd_process_notifier_release,
.alloc_notifier = kfd_process_alloc_notifier,
.free_notifier = kfd_process_free_notifier,
};
@ -1152,6 +1163,7 @@ static int kfd_process_device_init_cwsr_dgpu(struct kfd_process_device *pdd)
static struct kfd_process *create_process(const struct task_struct *thread)
{
struct kfd_process *process;
struct mmu_notifier *mn;
int err = -ENOMEM;
process = kzalloc(sizeof(*process), GFP_KERNEL);
@ -1182,19 +1194,28 @@ static struct kfd_process *create_process(const struct task_struct *thread)
if (err != 0)
goto err_init_apertures;
/* Must be last, have to use release destruction after this */
process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;
err = mmu_notifier_register(&process->mmu_notifier, process->mm);
if (err)
goto err_register_notifier;
get_task_struct(process->lead_thread);
/* alloc_notifier needs to find the process in the hash table */
hash_add_rcu(kfd_processes_table, &process->kfd_processes,
(uintptr_t)process->mm);
/* MMU notifier registration must be the last call that can fail
* because after this point we cannot unwind the process creation.
* After this point, mmu_notifier_put will trigger the cleanup by
* dropping the last process reference in the free_notifier.
*/
mn = mmu_notifier_get(&kfd_process_mmu_notifier_ops, process->mm);
if (IS_ERR(mn)) {
err = PTR_ERR(mn);
goto err_register_notifier;
}
BUG_ON(mn != &process->mmu_notifier);
get_task_struct(process->lead_thread);
return process;
err_register_notifier:
hash_del_rcu(&process->kfd_processes);
kfd_process_free_outstanding_kfd_bos(process);
kfd_process_destroy_pdds(process);
err_init_apertures: