Hello Stefan Schake,
Commit 766cc6b1f7fc ("drm/vc4: Add CTM support") from Apr 20, 2018
(linux-next), leads to the following Smatch static checker warning:
drivers/gpu/drm/vc4/vc4_kms.c:555 vc4_ctm_atomic_check()
warn: reusing outside iterator: 'i'
drivers/gpu/drm/vc4/vc4_kms.c
504 static int
505 vc4_ctm_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
506 {
507 struct vc4_dev *vc4 = to_vc4_dev(dev);
508 struct vc4_ctm_state *ctm_state = NULL;
509 struct drm_crtc *crtc;
510 struct drm_crtc_state *old_crtc_state, *new_crtc_state;
511 struct drm_color_ctm *ctm;
512 int i;
513
514 for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
515 /* CTM is being disabled. */
516 if (!new_crtc_state->ctm && old_crtc_state->ctm) {
517 ctm_state = vc4_get_ctm_state(state, &vc4->ctm_manager);
518 if (IS_ERR(ctm_state))
519 return PTR_ERR(ctm_state);
520 ctm_state->fifo = 0;
521 }
522 }
523
524 for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
^
This loops from zero to state->dev->mode_config.num_crtc - 1.
525 if (new_crtc_state->ctm == old_crtc_state->ctm)
526 continue;
527
528 if (!ctm_state) {
529 ctm_state = vc4_get_ctm_state(state, &vc4->ctm_manager);
530 if (IS_ERR(ctm_state))
531 return PTR_ERR(ctm_state);
532 }
533
534 /* CTM is being enabled or the matrix changed. */
535 if (new_crtc_state->ctm) {
536 struct vc4_crtc_state *vc4_crtc_state =
537 to_vc4_crtc_state(new_crtc_state);
538
539 /* fifo is 1-based since 0 disables CTM. */
540 int fifo = vc4_crtc_state->assigned_channel + 1;
541
542 /* Check userland isn't trying to turn on CTM for more
543 * than one CRTC at a time.
544 */
545 if (ctm_state->fifo && ctm_state->fifo != fifo) {
546 DRM_DEBUG_DRIVER("Too many CTM configured\n");
547 return -EINVAL;
548 }
549
550 /* Check we can approximate the specified CTM.
551 * We disallow scalars |c| > 1.0 since the HW has
552 * no integer bits.
553 */
554 ctm = new_crtc_state->ctm->data;
--> 555 for (i = 0; i < ARRAY_SIZE(ctm->matrix); i++) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This uses the same iterator and restarts the loop.
556 u64 val = ctm->matrix[i];
557
558 val &= ~BIT_ULL(63);
559 if (val > BIT_ULL(32))
560 return -EINVAL;
561 }
562
563 ctm_state->fifo = fifo;
564 ctm_state->ctm = ctm;
565 }
566 }
567
568 return 0;
569 }
regards,
dan carpenter
