On Fri, Jun 03, 2016 at 05:55:44PM +0100, Chris Wilson wrote: > Since we are not concerned with userspace racing itself with set-tiling > (the order is indeterminant even if we take a lock), then we can safely > read back the single obj->tiling_mode and do the static lookup of > swizzle mode without having to take a lock. > > get-tiling is reasonably frequent due to the back-channel passing around > of tiling parameters in DRI2/DRI3. > > Signed-off-by: Chris Wilson <[email protected]> > --- > drivers/gpu/drm/i915/i915_gem_tiling.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c > b/drivers/gpu/drm/i915/i915_gem_tiling.c > index 326de7eae101..d6acd0a27c06 100644 > --- a/drivers/gpu/drm/i915/i915_gem_tiling.c > +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c > @@ -302,10 +302,8 @@ i915_gem_get_tiling(struct drm_device *dev, void *data, > if (!obj) > return -ENOENT; > > - mutex_lock(&dev->struct_mutex); > - > args->tiling_mode = obj->tiling_mode;
READ_ONCE here. With that Reviewed-by: Daniel Vetter <[email protected]> > - switch (obj->tiling_mode) { > + switch (args->tiling_mode) { > case I915_TILING_X: > args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x; > break; > @@ -329,8 +327,6 @@ i915_gem_get_tiling(struct drm_device *dev, void *data, > if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17) > args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10; > > - i915_gem_object_put(obj); > - mutex_unlock(&dev->struct_mutex); > - > + i915_gem_object_put_unlocked(obj); > return 0; > } > -- > 2.8.1 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
