From 1c4dbe056dab0b7c2a2f42f4d393cc7b9bdb98ad Mon Sep 17 00:00:00 2001 From: Thomas Hellström Date: Thu, 17 Jun 2021 08:30:07 +0200 Subject: drm/i915: Reference objects on the ww object list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since the ww transaction endpoint easily end up far out-of-scope of the objects on the ww object list, particularly for contending lock objects, make sure we reference objects on the list so they don't disappear under us. This comes with a performance penalty so it's been debated whether this is really needed. But I think this is motivated by the fact that locking is typically difficult to get right, and whatever we can do to make it simpler for developers moving forward should be done, unless the performance impact is far too high. Signed-off-by: Thomas Hellström Reviewed-by: Matthew Auld Signed-off-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20210617063018.92802-2-thomas.hellstrom@linux.intel.com --- drivers/gpu/drm/i915/gem/i915_gem_object.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/gem/i915_gem_object.h') diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h index d66aa00d023a..241666931945 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h @@ -169,13 +169,17 @@ static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj, else ret = dma_resv_lock(obj->base.resv, ww ? &ww->ctx : NULL); - if (!ret && ww) + if (!ret && ww) { + i915_gem_object_get(obj); list_add_tail(&obj->obj_link, &ww->obj_list); + } if (ret == -EALREADY) ret = 0; - if (ret == -EDEADLK) + if (ret == -EDEADLK) { + i915_gem_object_get(obj); ww->contended = obj; + } return ret; } -- cgit