Hi Danilo,
Apologies - I guess I should have submitted a patch to handle zero fences in your
locking functions with the final patch series.
On Sat, 2023-11-25 at 00:36 +0100, Danilo Krummrich wrote:
> *** CAUTION: This email originates from a source not known to Imagination Technologies. Think before you click a link or open an attachment ***
>
> Make use of GPUVM's drm_exec helper functions preventing direct access
> to GPUVM internal data structures, such as the external object list.
>
> This is especially important to ensure following the locking rules
> around the GPUVM external object list.
>
> Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
> Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> ---
> drivers/gpu/drm/imagination/pvr_vm.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/imagination/pvr_vm.c b/drivers/gpu/drm/imagination/pvr_vm.c
> index e0d74d9a6190..3f7888f5cc53 100644
> --- a/drivers/gpu/drm/imagination/pvr_vm.c
> +++ b/drivers/gpu/drm/imagination/pvr_vm.c
> @@ -337,27 +337,21 @@ static int
> pvr_vm_bind_op_lock_resvs(struct drm_exec *exec, struct pvr_vm_bind_op *bind_op)
> {
> drm_exec_until_all_locked(exec) {
> - struct drm_gem_object *r_obj = &bind_op->vm_ctx->dummy_gem;
> struct drm_gpuvm *gpuvm = &bind_op->vm_ctx->gpuvm_mgr;
> struct pvr_gem_object *pvr_obj = bind_op->pvr_obj;
> - struct drm_gpuvm_bo *gpuvm_bo;
>
> /* Acquire lock on the vm_context's reserve object. */
> - int err = drm_exec_lock_obj(exec, r_obj);
> + int err = drm_gpuvm_prepare_vm(gpuvm, exec, 0);
>
> drm_exec_retry_on_contention(exec);
> if (err)
> return err;
>
> /* Acquire lock on all BOs in the context. */
> - list_for_each_entry(gpuvm_bo, &gpuvm->extobj.list,
> - list.entry.extobj) {
> - err = drm_exec_lock_obj(exec, gpuvm_bo->obj);
> -
> - drm_exec_retry_on_contention(exec);
> - if (err)
> - return err;
> - }
> + err = drm_gpuvm_prepare_objects(gpuvm, exec, 0);
> + drm_exec_retry_on_contention(exec);
> + if (err)
> + return err;
Before I discovered the problem when not reserving fences, I was trying to use
drm_gpuvm_exec_lock() with vm_exec->extra.fn() for the part below. Is there
a reason not to do that now?
Many thanks,
Donald
>
> /* Unmap operations don't have an object to lock. */
> if (!pvr_obj)
