summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorThomas Hellström <thomas.hellstrom@linux.intel.com>2021-06-17 08:30:07 +0200
committerMatthew Auld <matthew.auld@intel.com>2021-06-17 14:22:58 +0100
commit1c4dbe056dab0b7c2a2f42f4d393cc7b9bdb98ad (patch)
treedff488e12d5c50d864b9a5c83dc56a7d4aa9091b
parenta6c5b891252143ee9bc02f649282905954d6705c (diff)
drm/i915: Reference objects on the ww object list
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 <thomas.hellstrom@linux.intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210617063018.92802-2-thomas.hellstrom@linux.intel.com
-rw-r--r--drivers/gpu/drm/i915/gem/i915_gem_object.h8
-rw-r--r--drivers/gpu/drm/i915/i915_gem.c4
2 files changed, 10 insertions, 2 deletions
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;
}
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 07aa80773a02..0a815e15ffc7 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1216,6 +1216,7 @@ static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) {
list_del(&obj->obj_link);
i915_gem_object_unlock(obj);
+ i915_gem_object_put(obj);
}
}
@@ -1223,6 +1224,7 @@ void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj)
{
list_del(&obj->obj_link);
i915_gem_object_unlock(obj);
+ i915_gem_object_put(obj);
}
void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
@@ -1247,6 +1249,8 @@ int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
if (!ret)
list_add_tail(&ww->contended->obj_link, &ww->obj_list);
+ else
+ i915_gem_object_put(ww->contended);
ww->contended = NULL;