drm/i915: Use vma->exec_entry as our double-entry placeholder

This has the benefit of not requiring us to manipulate the
vma->exec_link list when tearing down the execbuffer, and is a
marginally cheaper test to detect the user error.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170615081435.17699-2-chris@chris-wilson.co.uk

3 files changed, 44 insertions, 51 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 51e365f70464..891247d79299 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -59,9 +59,6 @@ mark_free(struct drm_mm_scan *scan,
         if (i915_vma_is_pinned(vma))
                 return false;
 
-        if (WARN_ON(!list_empty(&vma->exec_list)))
-                return false;
-
         if (flags & PIN_NONFAULT && !list_empty(&vma->obj->userfault_link))
                 return false;
 
@@ -160,8 +157,6 @@ search_again:
         list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
                 ret = drm_mm_scan_remove_block(&scan, &vma->node);
                 BUG_ON(ret);
-
-                INIT_LIST_HEAD(&vma->exec_list);
         }
 
         /* Can we unpin some objects such as idle hw contents,
@@ -209,17 +204,12 @@ found:
                 if (drm_mm_scan_remove_block(&scan, &vma->node))
                         __i915_vma_pin(vma);
                 else
-                        list_del_init(&vma->exec_list);
+                        list_del(&vma->exec_list);
         }
 
         /* Unbinding will emit any required flushes */
         ret = 0;
-        while (!list_empty(&eviction_list)) {
-                vma = list_first_entry(&eviction_list,
-                                       struct i915_vma,
-                                       exec_list);
-
-                list_del_init(&vma->exec_list);
+        list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
                 __i915_vma_unpin(vma);
                 if (ret == 0)
                         ret = i915_vma_unbind(vma);
@@ -315,7 +305,7 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
                 }
 
                 /* Overlap of objects in the same batch? */
-                if (i915_vma_is_pinned(vma) || !list_empty(&vma->exec_list)) {
+                if (i915_vma_is_pinned(vma)) {
                         ret = -ENOSPC;
                         if (vma->exec_entry &&
                             vma->exec_entry->flags & EXEC_OBJECT_PINNED)
@@ -336,7 +326,6 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
         }
 
         list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
-                list_del_init(&vma->exec_list);
                 __i915_vma_unpin(vma);
                 if (ret == 0)
                         ret = i915_vma_unbind(vma);
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 1c5a6a63a767..a7aa21dcc553 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -108,13 +108,40 @@ static int eb_create(struct i915_execbuffer *eb)
                 eb->and = -eb->args->buffer_count;
         }
 
-        INIT_LIST_HEAD(&eb->vmas);
         return 0;
 }
 
+static inline void
+__eb_unreserve_vma(struct i915_vma *vma,
+                   const struct drm_i915_gem_exec_object2 *entry)
+{
+        if (unlikely(entry->flags & __EXEC_OBJECT_HAS_FENCE))
+                i915_vma_unpin_fence(vma);
+
+        if (entry->flags & __EXEC_OBJECT_HAS_PIN)
+                __i915_vma_unpin(vma);
+}
+
+static void
+eb_unreserve_vma(struct i915_vma *vma)
+{
+        struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;
+
+        __eb_unreserve_vma(vma, entry);
+        entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
+}
+
 static void
 eb_reset(struct i915_execbuffer *eb)
 {
+        struct i915_vma *vma;
+
+        list_for_each_entry(vma, &eb->vmas, exec_list) {
+                eb_unreserve_vma(vma);
+                i915_vma_put(vma);
+                vma->exec_entry = NULL;
+        }
+
         if (eb->and >= 0)
                 memset(eb->buckets, 0, (eb->and+1)*sizeof(struct hlist_head));
 }
@@ -146,6 +173,8 @@ eb_lookup_vmas(struct i915_execbuffer *eb)
         struct list_head objects;
         int i, ret;
 
+        INIT_LIST_HEAD(&eb->vmas);
+
         INIT_LIST_HEAD(&objects);
         spin_lock(&eb->file->table_lock);
         /* Grab a reference to the object and release the lock so we can lookup
@@ -252,40 +281,23 @@ static struct i915_vma *eb_get_vma(struct i915_execbuffer *eb, unsigned long han
         }
 }
 
-static void
-eb_unreserve_vma(struct i915_vma *vma)
-{
-        struct drm_i915_gem_exec_object2 *entry;
-
-        if (!drm_mm_node_allocated(&vma->node))
-                return;
-
-        entry = vma->exec_entry;
-
-        if (entry->flags & __EXEC_OBJECT_HAS_FENCE)
-                i915_vma_unpin_fence(vma);
-
-        if (entry->flags & __EXEC_OBJECT_HAS_PIN)
-                __i915_vma_unpin(vma);
-
-        entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
-}
-
 static void eb_destroy(struct i915_execbuffer *eb)
 {
-        i915_gem_context_put(eb->ctx);
+        struct i915_vma *vma;
 
-        while (!list_empty(&eb->vmas)) {
-                struct i915_vma *vma;
+        list_for_each_entry(vma, &eb->vmas, exec_list) {
+                if (!vma->exec_entry)
+                        continue;
 
-                vma = list_first_entry(&eb->vmas,
-                                       struct i915_vma,
-                                       exec_list);
-                list_del_init(&vma->exec_list);
-                eb_unreserve_vma(vma);
+                __eb_unreserve_vma(vma, vma->exec_entry);
                 vma->exec_entry = NULL;
                 i915_vma_put(vma);
         }
+
+        i915_gem_context_put(eb->ctx);
+
+        if (eb->buckets)
+                kfree(eb->buckets);
 }
 
 static inline int use_cpu_reloc(struct drm_i915_gem_object *obj)
@@ -985,13 +997,7 @@ eb_relocate_slow(struct i915_execbuffer *eb)
         int i, total, ret;
 
         /* We may process another execbuffer during the unlock... */
-        while (!list_empty(&eb->vmas)) {
-                vma = list_first_entry(&eb->vmas, struct i915_vma, exec_list);
-                list_del_init(&vma->exec_list);
-                eb_unreserve_vma(vma);
-                i915_vma_put(vma);
-        }
-
+        eb_reset(eb);
         mutex_unlock(&dev->struct_mutex);
 
         total = 0;
@@ -1052,7 +1058,6 @@ eb_relocate_slow(struct i915_execbuffer *eb)
         }
 
         /* reacquire the objects */
-        eb_reset(eb);
         ret = eb_lookup_vmas(eb);
         if (ret)
                 goto err;
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 1aba47024656..6cf32da682ec 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -85,7 +85,6 @@ vma_create(struct drm_i915_gem_object *obj,
         if (vma == NULL)
                 return ERR_PTR(-ENOMEM);
 
-        INIT_LIST_HEAD(&vma->exec_list);
         for (i = 0; i < ARRAY_SIZE(vma->last_read); i++)
                 init_request_active(&vma->last_read[i], i915_vma_retire);
         init_request_active(&vma->last_fence, NULL);