drm: Add reference counting to drm_atomic_state
drm_atomic_state has a complicated single owner model that tracks the
single reference from allocation through to destruction on another
thread - or perhaps on a local error path. We can simplify this tracking
by using reference counting (at a cost of a few more atomics). This is
even more beneficial when the lifetime of the state becomes more
convoluted than being passed to a single worker thread for the commit.
v2: Double check !intel atomic_commit functions for missing gets
v3: Update kerneldocs
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161014121833.439-27-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 36f83fe..07b432f 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1208,7 +1208,7 @@
drm_atomic_helper_commit_cleanup_done(state);
- drm_atomic_state_free(state);
+ drm_atomic_state_put(state);
}
static void commit_work(struct work_struct *work)
@@ -1290,6 +1290,7 @@
* make sure work items don't artifically stall on each another.
*/
+ drm_atomic_state_get(state);
if (nonblock)
queue_work(system_unbound_wq, &state->commit_work);
else
@@ -1591,7 +1592,7 @@
*
* This signals completion of the atomic update @state, including any cleanup
* work. If used, it must be called right before calling
- * drm_atomic_state_free().
+ * drm_atomic_state_put().
*
* This is part of the atomic helper support for nonblocking commits, see
* drm_atomic_helper_setup_commit() for an overview.
@@ -2114,18 +2115,13 @@
state->legacy_cursor_update = true;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2187,18 +2183,13 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2327,18 +2318,13 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2480,11 +2466,8 @@
}
err = drm_atomic_commit(state);
-
free:
- if (err < 0)
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return err;
}
EXPORT_SYMBOL(drm_atomic_helper_disable_all);
@@ -2535,7 +2518,7 @@
err = drm_atomic_helper_disable_all(dev, &ctx);
if (err < 0) {
- drm_atomic_state_free(state);
+ drm_atomic_state_put(state);
state = ERR_PTR(err);
goto unlock;
}
@@ -2624,18 +2607,13 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2684,18 +2662,13 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2744,18 +2717,13 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2828,18 +2796,13 @@
}
ret = drm_atomic_nonblocking_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -2915,19 +2878,14 @@
crtc_state->active = active;
ret = drm_atomic_commit(state);
- if (ret != 0)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
connector->dpms = old_mode;
- drm_atomic_state_free(state);
-
+ drm_atomic_state_put(state);
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);
@@ -3334,7 +3292,7 @@
free:
if (err < 0) {
- drm_atomic_state_free(state);
+ drm_atomic_state_put(state);
state = ERR_PTR(err);
}
@@ -3449,22 +3407,14 @@
goto fail;
ret = drm_atomic_commit(state);
- if (ret)
- goto fail;
-
- /* Driver takes ownership of state on successful commit. */
-
- drm_property_unreference_blob(blob);
-
- return 0;
fail:
if (ret == -EDEADLK)
goto backoff;
- drm_atomic_state_free(state);
+ drm_atomic_state_put(state);
drm_property_unreference_blob(blob);
-
return ret;
+
backoff:
drm_atomic_state_clear(state);
drm_atomic_legacy_backoff(state);