[src/trunk]: src/sys/external/bsd/drm2/linux Apparently one can reserve_share...

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

details:   https://anonhg.NetBSD.org/src/rev/9975b95160c4
branches:  trunk
changeset: 992908:9975b95160c4
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Aug 27 13:55:46 2018 +0000

description:
Apparently one can reserve_shared only once in a row.  Simplify.

diffstat:

 sys/external/bsd/drm2/include/linux/reservation.h |   3 +-
 sys/external/bsd/drm2/linux/linux_reservation.c   |  36 +++++++++++++---------
 2 files changed, 22 insertions(+), 17 deletions(-)

diffs (97 lines):

diff -r 75fb74a37a0d -r 9975b95160c4 sys/external/bsd/drm2/include/linux/reservation.h
--- a/sys/external/bsd/drm2/include/linux/reservation.h Mon Aug 27 13:55:35 2018 +0000
+++ b/sys/external/bsd/drm2/include/linux/reservation.h Mon Aug 27 13:55:46 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: reservation.h,v 1.5 2018/08/27 13:33:59 riastradh Exp $        */
+/*     $NetBSD: reservation.h,v 1.6 2018/08/27 13:55:46 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -44,7 +44,6 @@
        struct fence __rcu                      *robj_fence;
        struct reservation_object_list __rcu    *robj_list;
        struct reservation_object_list __rcu    *robj_prealloc;
-       uint32_t                                robj_nreserved;
 };
 
 struct reservation_object_list {
diff -r 75fb74a37a0d -r 9975b95160c4 sys/external/bsd/drm2/linux/linux_reservation.c
--- a/sys/external/bsd/drm2/linux/linux_reservation.c   Mon Aug 27 13:55:35 2018 +0000
+++ b/sys/external/bsd/drm2/linux/linux_reservation.c   Mon Aug 27 13:55:46 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_reservation.c,v 1.2 2018/08/27 13:35:35 riastradh Exp $  */
+/*     $NetBSD: linux_reservation.c,v 1.3 2018/08/27 13:55:46 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_reservation.c,v 1.2 2018/08/27 13:35:35 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_reservation.c,v 1.3 2018/08/27 13:55:46 riastradh Exp $");
 
 #include <linux/fence.h>
 #include <linux/reservation.h>
@@ -89,7 +89,6 @@
        robj->robj_fence = NULL;
        robj->robj_list = NULL;
        robj->robj_prealloc = NULL;
-       robj->robj_nreserved = 0;
 }
 
 /*
@@ -162,12 +161,13 @@
 /*
  * reservation_object_reserve_shared(robj)
  *
- *     Reserve space in robj to add a shared fence.
+ *     Reserve space in robj to add a shared fence.  To be used only
+ *     once before calling reservation_object_add_shared_fence.
  *
  *     Caller must have robj locked.
  *
- *     Internally, we start with room for four entries and double
- *     whenever we run out.  This is not guaranteed.
+ *     Internally, we start with room for four entries and double if
+ *     we don't have enough.  This is not guaranteed.
  */
 int
 reservation_object_reserve_shared(struct reservation_object *robj)
@@ -180,21 +180,27 @@
        list = robj->robj_list;
        prealloc = robj->robj_prealloc;
 
-       /* If there's too many objects reserved already, fail.  */
-       if (robj->robj_nreserved == UINT32_MAX)
-               return -ENOMEM;
+       /* If there's an existing list, check it for space.  */
+       if (list != NULL) {
+               /* If there's too many already, give up.  */
+               if (list->shared_count == UINT32_MAX)
+                       return -ENOMEM;
 
-       /* Bump the number of objects reserved.  */
-       n = ++robj->robj_nreserved;
+               /* Add one more. */
+               n = list->shared_count + 1;
 
-       /* If there's enough room in the existing list, stop here.  */
-       if (list != NULL && n < list->shared_max)
-               return 0;
+               /* If there's enough for one more, we're done.  */
+               if (n <= list->shared_max)
+                       return 0;
+       } else {
+               /* No list already.  We need space for 1.  */
+               n = 1;
+       }
 
        /* If not, maybe there's a preallocated list ready.  */
        if (prealloc != NULL) {
                /* If there's enough room in it, stop here.  */
-               if (n < prealloc->shared_max)
+               if (n <= prealloc->shared_max)
                        return 0;
 
                /* Try to double its capacity.  */