drm/asahi: slotalloc: Allow initializing empty slots

These slots can never be used.

Signed-off-by: Asahi Lina <[email protected]>

Author: hoshinolina

drivers/gpu/drm/asahi/buffer.rs

@@ -734,7 +734,7 @@ impl BufferManager::ver {
         Ok(BufferManager::ver(slotalloc::SlotAllocator::new(
             NUM_BUFFERS,
             BufferManagerInner::ver { owners },
-            |_inner, _slot| BufferSlotInner::ver(),
+            |_inner, _slot| Some(BufferSlotInner::ver()),
             c_str!("BufferManager::SlotAllocator"),
             static_lock_class!(),
             static_lock_class!(),

drivers/gpu/drm/asahi/event.rs

@@ -154,10 +154,12 @@ impl EventManager {
             alloc: slotalloc::SlotAllocator::new(
                 NUM_EVENTS,
                 inner,
-                |inner: &mut EventManagerInner, slot| EventInner {
-                    stamp: &inner.stamps[slot as usize].0,
-                    gpu_stamp: inner.stamps.weak_item_pointer(slot as usize),
-                    gpu_fw_stamp: inner.fw_stamps.weak_item_pointer(slot as usize),
+                |inner: &mut EventManagerInner, slot| {
+                    Some(EventInner {
+                        stamp: &inner.stamps[slot as usize].0,
+                        gpu_stamp: inner.stamps.weak_item_pointer(slot as usize),
+                        gpu_fw_stamp: inner.fw_stamps.weak_item_pointer(slot as usize),
+                    })
                 },
                 c_str!("EventManager::SlotAllocator"),
                 static_lock_class!(),

drivers/gpu/drm/asahi/mmu.rs

@@ -1203,7 +1203,7 @@ impl Uat {
             slots: slotalloc::SlotAllocator::new(
                 UAT_USER_CTX as u32,
                 (),
-                |_inner, _slot| SlotInner(),
+                |_inner, _slot| Some(SlotInner()),
                 c_str!("Uat::SlotAllocator"),
                 static_lock_class!(),
                 static_lock_class!(),

drivers/gpu/drm/asahi/slotalloc.rs

@@ -130,7 +130,7 @@ impl<T: SlotItem> SlotAllocator<T> {
     pub(crate) fn new(
         num_slots: u32,
         mut data: T::Data,
-        mut constructor: impl FnMut(&mut T::Data, u32) -> T,
+        mut constructor: impl FnMut(&mut T::Data, u32) -> Option<T>,
         name: &'static CStr,
         lock_key1: LockClassKey,
         lock_key2: LockClassKey,
@@ -139,8 +139,8 @@ impl<T: SlotItem> SlotAllocator<T> {
 
         for i in 0..num_slots {
             slots
-                .try_push(Some(Entry {
-                    item: constructor(&mut data, i),
+                .try_push(constructor(&mut data, i).map(|item| Entry {
+                    item,
                     get_time: 0,
                     drop_time: 0,
                 }))