[src/trunk]: src/sys/external/bsd/drm2/dist/drm/i915 i915: Abuse abstractions...

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

details:   https://anonhg.NetBSD.org/src/rev/6e11b2de9044
branches:  trunk
changeset: 1028842:6e11b2de9044
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 12:11:14 2021 +0000

description:
i915: Abuse abstractions gruesomely but with less lock screwitude.

diffstat:

 sys/external/bsd/drm2/dist/drm/i915/i915_active.c |  43 +++++++++++++---------
 1 files changed, 26 insertions(+), 17 deletions(-)

diffs (104 lines):

diff -r a18d60274863 -r 6e11b2de9044 sys/external/bsd/drm2/dist/drm/i915/i915_active.c
--- a/sys/external/bsd/drm2/dist/drm/i915/i915_active.c Sun Dec 19 12:11:05 2021 +0000
+++ b/sys/external/bsd/drm2/dist/drm/i915/i915_active.c Sun Dec 19 12:11:14 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: i915_active.c,v 1.7 2021/12/19 11:59:04 riastradh Exp $        */
+/*     $NetBSD: i915_active.c,v 1.8 2021/12/19 12:11:14 riastradh Exp $        */
 
 /*
  * SPDX-License-Identifier: MIT
@@ -7,7 +7,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: i915_active.c,v 1.7 2021/12/19 11:59:04 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: i915_active.c,v 1.8 2021/12/19 12:11:14 riastradh Exp $");
 
 #include <linux/debugobjects.h>
 
@@ -285,6 +285,7 @@
        prealloc = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
        if (!prealloc)
                return NULL;
+       memset(prealloc, 0, sizeof(*prealloc));
 
        spin_lock_irq(&ref->tree_lock);
        GEM_BUG_ON(i915_active_is_idle(ref));
@@ -724,6 +725,7 @@
                                goto unwind;
                        }
 
+                       memset(node, 0, sizeof(*node));
                        RCU_INIT_POINTER(node->base.fence, NULL);
                        node->base.cb.func = node_retire;
                        node->timeline = idx;
@@ -852,16 +854,20 @@
                /* serialise with reuse_idle_barrier */
                smp_store_mb(*ll_to_fence_slot(node), &rq->fence);
 #ifdef __NetBSD__
-               spin_unlock(&rq->lock);
+               /* XXX ugh bletch */
                struct i915_active_fence *active =
                    container_of(node, struct i915_active_fence, llist);
                /* XXX something bad went wrong in making this code */
                KASSERT(active->cb.func == node_retire ||
                    active->cb.func == excl_retire ||
                    active->cb.func == i915_active_noop);
-               (void)dma_fence_add_callback(active->fence, &active->cb,
-                   active->cb.func);
-               spin_lock(&rq->lock);
+               KASSERTMSG(active->fence == &rq->fence,
+                   "active=%p fence=%p; rq=%p fence=%p",
+                   active, active->fence, rq, &rq->fence);
+               KASSERTMSG(!active->cb.fcb_onqueue, "active=%p", active);
+               active->cb.fcb_onqueue = true;
+               TAILQ_INSERT_TAIL(&rq->fence.f_callbacks, &active->cb,
+                   fcb_entry);
 #else
                list_add_tail((struct list_head *)node, &rq->fence.cb_list);
 #endif
@@ -917,30 +923,33 @@
        prev = xchg(__active_fence_slot(active), fence);
        if (prev) {
                GEM_BUG_ON(prev == fence);
+               spin_lock_nested(prev->lock, SINGLE_DEPTH_NESTING);
 #ifdef __NetBSD__
+               /* XXX ugh bletch */
                KASSERT(active->cb.func == node_retire ||
                    active->cb.func == excl_retire ||
                    active->cb.func == i915_active_noop);
-               (void)dma_fence_remove_callback(prev, &active->cb);
+               if (active->cb.fcb_onqueue) {
+                       TAILQ_REMOVE(&prev->f_callbacks, &active->cb,
+                           fcb_entry);
+                       active->cb.fcb_onqueue = false;
+               }
 #else
-               spin_lock_nested(prev->lock, SINGLE_DEPTH_NESTING);
                __list_del_entry(&active->cb.node);
+#endif
                spin_unlock(prev->lock); /* serialise with prev->cb_list */
-#endif
        }
        GEM_BUG_ON(rcu_access_pointer(active->fence) != fence);
-#ifndef __NetBSD__
+#ifdef __NetBSD__
+       /* XXX ugh bletch */
+       KASSERT(!active->cb.fcb_onqueue);
+       active->cb.fcb_onqueue = true;
+       TAILQ_INSERT_TAIL(&fence->f_callbacks, &active->cb, fcb_entry);
+#else
        list_add_tail(&active->cb.node, &fence->cb_list);
 #endif
        spin_unlock_irqrestore(fence->lock, flags);
 
-#ifdef __NetBSD__
-       KASSERT(active->cb.func == node_retire ||
-           active->cb.func == excl_retire ||
-           active->cb.func == i915_active_noop);
-       dma_fence_add_callback(fence, &active->cb, active->cb.func);
-#endif
-
        return prev;
 }