Hi Chris,
On Thu, Mar 26, 2020 at 02:27:27PM +0000, Chris Wilson wrote:
> Userptr causes lockdep to complain when we are using the aliasing-ppgtt
> (and ggtt, but for that it is rightfully so to complain about) in that
> when we revoke the userptr we take a mutex which we also use to revoke
> the mmaps. However, we only revoke mmaps for GGTT bindings and we never
> allow userptr to create a GGTT binding so the warning should be false
> and is simply caused by our conflation of the aliasing-ppgtt with the
> ggtt. So lets try treating the binding into the aliasing-ppgtt as a
> separate lockclass from the ggtt. The downside is that we are
> deliberately suppressing lockdep;s ability to warn us of cycles.
^^^^
typo
>
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/478
I'm not a big fan of links in commit messages, I think they would
be forbidden by law, but I'm not being picky on that.
I don't know, thogh, why your S-o-b is missing.
> ---
> drivers/gpu/drm/i915/i915_vma.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index 191577a98390..9f4a31cd54ac 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -914,7 +914,8 @@ int i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
> wakeref = intel_runtime_pm_get(&vma->vm->i915->runtime_pm);
>
> /* No more allocations allowed once we hold vm->mutex */
> - err = mutex_lock_interruptible(&vma->vm->mutex);
> + err = mutex_lock_interruptible_nested(&vma->vm->mutex,
> + !(flags & PIN_GLOBAL));
> if (err)
> goto err_fence;
>
> @@ -1320,7 +1321,7 @@ int i915_vma_unbind(struct i915_vma *vma)
> if (err)
> goto out_rpm;
>
> - err = mutex_lock_interruptible(&vm->mutex);
> + err = mutex_lock_interruptible_nested(&vma->vm->mutex, !wakeref);
looks reasonable to me. Thanks!
Are you planning to push it? You have my review for this.
Andi
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
