[src/trunk]: src/sys/external/bsd/drm2 Clarify ttm state transitions tt_unpop...

[maya <maya%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1075aed63081
branches:  trunk
changeset: 351993:1075aed63081
user:      maya <maya%NetBSD.org@localhost>
date:      Thu Mar 09 08:27:18 2017 +0000

description:
Clarify ttm state transitions tt_unpopulated<->tt_unbound<->tt_bound.
Assert it, too, and don't handle other cases.

We can add the assertion to ttm_agp_tt_unpopulate because it is called by
{nouveau,radeon}_ttm_tt_unpopulate, which is generically called
ttm_tt_unpopulate.

And the sole caller to ttm_tt_unpopulate (ttm_tt_destroy) only does so if the
state is unbound. the other caller is in a !NetBSD block.

We can add the assertion to ttm_agp_tt_populate and avoid handling the
!unpopulated case because the sole callers are {nouveau,radeon}_ttm_tt_populate
both of which return early in the !unpopulated case.

We can change the assertion on ttm_tt_wire because it is solely called by
ttm_bus_dma_populate, which already asserts that it is the unpopulated case.

from riastradh

diffstat:

 sys/external/bsd/drm2/dist/drm/ttm/ttm_tt.c |  11 +++++------
 sys/external/bsd/drm2/ttm/ttm_agp_backend.c |  13 ++++++++-----
 sys/external/bsd/drm2/ttm/ttm_bus_dma.c     |   8 ++++----
 3 files changed, 17 insertions(+), 15 deletions(-)

diffs (98 lines):

diff -r f6813de5c41f -r 1075aed63081 sys/external/bsd/drm2/dist/drm/ttm/ttm_tt.c
--- a/sys/external/bsd/drm2/dist/drm/ttm/ttm_tt.c       Thu Mar 09 08:05:21 2017 +0000
+++ b/sys/external/bsd/drm2/dist/drm/ttm/ttm_tt.c       Thu Mar 09 08:27:18 2017 +0000
@@ -360,9 +360,9 @@
  * ttm_tt_wire(ttm)
  *
  *     Wire the uvm pages of ttm and fill the ttm page array.  ttm
- *     must be unpopulated or unbound, and must be marked swapped.
- *     This does not change either state -- the caller is expected to
- *     include it among other operations for such a state transition.
+ *     must be unpopulated, and must be marked swapped.  This does not
+ *     change either state -- the caller is expected to include it
+ *     among other operations for such a state transition.
  */
 int
 ttm_tt_wire(struct ttm_tt *ttm)
@@ -372,9 +372,8 @@
        unsigned i;
        int error;
 
-       KASSERTMSG((ttm->state == tt_unpopulated || ttm->state == tt_unbound),
-           "ttm_tt %p must be unpopulated or unbound for wiring,"
-           " but state=%d",
+       KASSERTMSG((ttm->state == tt_unpopulated),
+           "ttm_tt %p must be unpopulated for wiring, but state=%d",
            ttm, (int)ttm->state);
        KASSERT(ISSET(ttm->page_flags, TTM_PAGE_FLAG_SWAPPED));
        KASSERT(uobj != NULL);
diff -r f6813de5c41f -r 1075aed63081 sys/external/bsd/drm2/ttm/ttm_agp_backend.c
--- a/sys/external/bsd/drm2/ttm/ttm_agp_backend.c       Thu Mar 09 08:05:21 2017 +0000
+++ b/sys/external/bsd/drm2/ttm/ttm_agp_backend.c       Thu Mar 09 08:27:18 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ttm_agp_backend.c,v 1.5 2015/10/17 21:05:57 jmcneill Exp $     */
+/*     $NetBSD: ttm_agp_backend.c,v 1.6 2017/03/09 08:27:18 maya Exp $ */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ttm_agp_backend.c,v 1.5 2015/10/17 21:05:57 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ttm_agp_backend.c,v 1.6 2017/03/09 08:27:18 maya Exp $");
 
 #include <sys/types.h>
 #include <sys/kmem.h>
@@ -78,9 +78,9 @@
 ttm_agp_tt_populate(struct ttm_tt *ttm)
 {
 
-       if (ttm->state != tt_unpopulated)
-               return 0;
-
+       KASSERTMSG((ttm->state == tt_unpopulated),
+           "ttm_agp_tt_populate: ttm %p state is not tt_unpopulated: %d",
+           ttm, (int)ttm->state);
        return ttm_bus_dma_populate(container_of(ttm, struct ttm_dma_tt, ttm));
 }
 
@@ -88,6 +88,9 @@
 ttm_agp_tt_unpopulate(struct ttm_tt *ttm)
 {
 
+       KASSERTMSG((ttm->state == tt_unbound),
+           "ttm_agp_tt_unpopulate: ttm %p state is not tt_unbound: %d",
+           ttm, (int)ttm->state);
        ttm_bus_dma_unpopulate(container_of(ttm, struct ttm_dma_tt, ttm));
 }
 
diff -r f6813de5c41f -r 1075aed63081 sys/external/bsd/drm2/ttm/ttm_bus_dma.c
--- a/sys/external/bsd/drm2/ttm/ttm_bus_dma.c   Thu Mar 09 08:05:21 2017 +0000
+++ b/sys/external/bsd/drm2/ttm/ttm_bus_dma.c   Thu Mar 09 08:27:18 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ttm_bus_dma.c,v 1.6 2017/03/09 08:05:21 maya Exp $     */
+/*     $NetBSD: ttm_bus_dma.c,v 1.7 2017/03/09 08:27:18 maya Exp $     */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ttm_bus_dma.c,v 1.6 2017/03/09 08:05:21 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ttm_bus_dma.c,v 1.7 2017/03/09 08:27:18 maya Exp $");
 
 #include <sys/bus.h>
 
@@ -47,8 +47,8 @@
  *     its DMA map.  The wiring and loading are stable as long as the
  *     associated bo is reserved.
  *
- *     Transitions from tt_unpopulated or tt_unbound to tt_unbound.
- *     Marks as wired, a.k.a. !swapped.
+ *     Transitions from tt_unpopulated to tt_unbound.  Marks as wired,
+ *     a.k.a. !swapped.
  */
 int
 ttm_bus_dma_populate(struct ttm_dma_tt *ttm_dma)