We only need to take the struct_mutex if the object is pinned to the display engine and so requires checking for clflush. (The race with userspace pinning the object to a framebuffer is irrelevant.)
v2: Use access once for compiler hints (or not as it is a bitfield) v3: READ_ONCE, obj->pin_display is not a bitfield anymore v4: Don't be creative with goto. Signed-off-by: Chris Wilson <[email protected]> Cc: Daniel Vetter <[email protected]> Reviewed-by: Joonas Lahtinen <[email protected]> --- drivers/gpu/drm/i915/i915_gem.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index b99d64bfb7eb..063c56f5d6f8 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1518,26 +1518,23 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data, { struct drm_i915_gem_sw_finish *args = data; struct drm_i915_gem_object *obj; - int ret = 0; - - ret = i915_mutex_lock_interruptible(dev); - if (ret) - return ret; + int err = 0; obj = i915_gem_object_lookup(file, args->handle); - if (!obj) { - ret = -ENOENT; - goto unlock; - } + if (!obj) + return -ENOENT; /* Pinned buffers may be scanout, so flush the cache */ - if (obj->pin_display) - i915_gem_object_flush_cpu_write_domain(obj); + if (READ_ONCE(obj->pin_display)) { + err = i915_mutex_lock_interruptible(dev); + if (!err) { + i915_gem_object_flush_cpu_write_domain(obj); + mutex_unlock(&dev->struct_mutex); + } + } - i915_gem_object_put(obj); -unlock: - mutex_unlock(&dev->struct_mutex); - return ret; + i915_gem_object_put_unlocked(obj); + return err; } /** -- 2.8.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
