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 <chris@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
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
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