[PATCH 1/1] drm/amdgpu: Use spinlock_irqsave for pasid_lock

[Christian König]

Am 15.06.21 um 00:07 schrieb Felix Kuehling:
> This should fix a kernel LOCKDEP warning on Vega10:
> [  149.416604] ================================
> [  149.420877] WARNING: inconsistent lock state
> [  149.425152] 5.11.0-kfd-fkuehlin #517 Not tainted
> [  149.429770] --------------------------------
> [  149.434053] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
> [  149.440059] swapper/3/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
> [  149.445198] ffff9ac80e005d68 (&adev->vm_manager.pasid_lock){?.+.}-{2:2}, at: amdgpu_vm_get_task_info+0x25/0x90 [amdgpu]
> [  149.456252] {HARDIRQ-ON-W} state was registered at:
> [  149.461136]   lock_acquire+0x242/0x390
> [  149.464895]   _raw_spin_lock+0x2c/0x40
> [  149.468647]   amdgpu_vm_handle_fault+0x44/0x380 [amdgpu]
> [  149.474187]   gmc_v9_0_process_interrupt+0xa8/0x410 [amdgpu]

This is actually a false postive, but the patch is ok since it's the 
easiest way to fix this :)

> ...
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 3b6c0b48d0b1..0b63686fc31a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -3394,11 +3394,12 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
>   {
>   	bool is_compute_context = false;
>   	struct amdgpu_bo *root;
> +	unsigned long irqflags;
>   	uint64_t value, flags;
>   	struct amdgpu_vm *vm;
>   	int r;
>   
> -	spin_lock(&adev->vm_manager.pasid_lock);
> +	spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>   	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>   	if (vm) {
>   		root = amdgpu_bo_ref(vm->root.base.bo);
> @@ -3406,7 +3407,7 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
>   	} else {
>   		root = NULL;
>   	}
> -	spin_unlock(&adev->vm_manager.pasid_lock);
> +	spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>   
>   	if (!root)
>   		return false;
> @@ -3424,11 +3425,11 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
>   		goto error_unref;
>   
>   	/* Double check that the VM still exists */
> -	spin_lock(&adev->vm_manager.pasid_lock);
> +	spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>   	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>   	if (vm && vm->root.base.bo != root)
>   		vm = NULL;
> -	spin_unlock(&adev->vm_manager.pasid_lock);
> +	spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>   	if (!vm)
>   		goto error_unlock;
>