drm/i915: Skip the sanity checks if the current relocation is valid

If the presumed_offset as feed to userspace and returned to the kernel
from a previous execbuffer is still valid, then we do not need to rewrite
the relocation entry and may skip the offset sanity checks.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 47 insertions, 45 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c60ca32f65d2..dea9ac069851 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3128,6 +3128,21 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                 }
                 target_obj_priv = target_obj->driver_private;
 
+#if WATCH_RELOC
+                DRM_INFO("%s: obj %p offset %08x target %d "
+                         "read %08x write %08x gtt %08x "
+                         "presumed %08x delta %08x\n",
+                         __func__,
+                         obj,
+                         (int) reloc->offset,
+                         (int) reloc->target_handle,
+                         (int) reloc->read_domains,
+                         (int) reloc->write_domain,
+                         (int) target_obj_priv->gtt_offset,
+                         (int) reloc->presumed_offset,
+                         reloc->delta);
+#endif
+
                 /* The target buffer should have appeared before us in the
                  * exec_object list, so it should have a GTT space bound by now.
                  */
@@ -3139,35 +3154,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         return -EINVAL;
                 }
 
-                if (reloc->offset > obj->size - 4) {
-                        DRM_ERROR("Relocation beyond object bounds: "
-                                  "obj %p target %d offset %d size %d.\n",
-                                  obj, reloc->target_handle,
-                                  (int) reloc->offset, (int) obj->size);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
-                }
-                if (reloc->offset & 3) {
-                        DRM_ERROR("Relocation not 4-byte aligned: "
-                                  "obj %p target %d offset %d.\n",
-                                  obj, reloc->target_handle,
-                                  (int) reloc->offset);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
-                }
-
-                if (reloc->delta >= target_obj->size) {
-                        DRM_ERROR("Relocation beyond target object bounds: "
-                                  "obj %p target %d delta %d size %d.\n",
-                                  obj, reloc->target_handle,
-                                  (int) reloc->delta, (int) target_obj->size);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
-                }
-
+                /* Validate that the target is in a valid r/w GPU domain */
                 if (reloc->write_domain & I915_GEM_DOMAIN_CPU ||
                     reloc->read_domains & I915_GEM_DOMAIN_CPU) {
                         DRM_ERROR("reloc with read/write CPU domains: "
@@ -3181,7 +3168,6 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         i915_gem_object_unpin(obj);
                         return -EINVAL;
                 }
-
                 if (reloc->write_domain && target_obj->pending_write_domain &&
                     reloc->write_domain != target_obj->pending_write_domain) {
                         DRM_ERROR("Write domain conflict: "
@@ -3196,21 +3182,6 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         return -EINVAL;
                 }
 
-#if WATCH_RELOC
-                DRM_INFO("%s: obj %p offset %08x target %d "
-                         "read %08x write %08x gtt %08x "
-                         "presumed %08x delta %08x\n",
-                         __func__,
-                         obj,
-                         (int) reloc->offset,
-                         (int) reloc->target_handle,
-                         (int) reloc->read_domains,
-                         (int) reloc->write_domain,
-                         (int) target_obj_priv->gtt_offset,
-                         (int) reloc->presumed_offset,
-                         reloc->delta);
-#endif
-
                 target_obj->pending_read_domains |= reloc->read_domains;
                 target_obj->pending_write_domain |= reloc->write_domain;
 
@@ -3222,6 +3193,37 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         continue;
                 }
 
+                /* Check that the relocation address is valid... */
+                if (reloc->offset > obj->size - 4) {
+                        DRM_ERROR("Relocation beyond object bounds: "
+                                  "obj %p target %d offset %d size %d.\n",
+                                  obj, reloc->target_handle,
+                                  (int) reloc->offset, (int) obj->size);
+                        drm_gem_object_unreference(target_obj);
+                        i915_gem_object_unpin(obj);
+                        return -EINVAL;
+                }
+                if (reloc->offset & 3) {
+                        DRM_ERROR("Relocation not 4-byte aligned: "
+                                  "obj %p target %d offset %d.\n",
+                                  obj, reloc->target_handle,
+                                  (int) reloc->offset);
+                        drm_gem_object_unreference(target_obj);
+                        i915_gem_object_unpin(obj);
+                        return -EINVAL;
+                }
+
+                /* and points to somewhere within the target object. */
+                if (reloc->delta >= target_obj->size) {
+                        DRM_ERROR("Relocation beyond target object bounds: "
+                                  "obj %p target %d delta %d size %d.\n",
+                                  obj, reloc->target_handle,
+                                  (int) reloc->delta, (int) target_obj->size);
+                        drm_gem_object_unreference(target_obj);
+                        i915_gem_object_unpin(obj);
+                        return -EINVAL;
+                }
+
                 ret = i915_gem_object_set_to_gtt_domain(obj, 1);
                 if (ret != 0) {
                         drm_gem_object_unreference(target_obj);