ensure CpuBufferPoolChunk::conflict_key is unique (#995)

vulkano/src/buffer/cpu_access.rs

@@ -328,8 +328,8 @@ unsafe impl<T: ?Sized, A> BufferAccess for CpuAccessibleBuffer<T, A>
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
-        self.inner.key()
+    fn conflict_key(&self) -> (u64, usize) {
+        (self.inner.key(), 0)
     }
 
     #[inline]

vulkano/src/buffer/cpu_pool.rs

@@ -618,8 +618,12 @@ unsafe impl<T, A> BufferAccess for CpuBufferPoolChunk<T, A>
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
-        self.buffer.inner.key() + self.index as u64
+    fn conflict_key(&self) -> (u64, usize) {
+        (
+            self.buffer.inner.key(),
+            // ensure the special cased empty buffers dont collide with a regular buffer starting at 0
+            if self.requested_len == 0 { usize::max_value() } else { self.index }
+        )
     }
 
     #[inline]
@@ -749,7 +753,7 @@ unsafe impl<T, A> BufferAccess for CpuBufferPoolSubbuffer<T, A>
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
+    fn conflict_key(&self) -> (u64, usize) {
         self.chunk.conflict_key()
     }
 

vulkano/src/buffer/device_local.rs

@@ -206,8 +206,8 @@ unsafe impl<T: ?Sized, A> BufferAccess for DeviceLocalBuffer<T, A>
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
-        self.inner.key()
+    fn conflict_key(&self) -> (u64, usize) {
+        (self.inner.key(), 0)
     }
 
     #[inline]

vulkano/src/buffer/immutable.rs

@@ -338,8 +338,8 @@ unsafe impl<T: ?Sized, A> BufferAccess for ImmutableBuffer<T, A> {
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
-        self.inner.key()
+    fn conflict_key(&self) -> (u64, usize) {
+        (self.inner.key(), 0)
     }
 
     #[inline]
@@ -404,8 +404,8 @@ unsafe impl<T: ?Sized, A> BufferAccess for ImmutableBufferInitialization<T, A> {
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
-        self.buffer.inner.key()
+    fn conflict_key(&self) -> (u64, usize) {
+        (self.buffer.inner.key(), 0)
     }
 
     #[inline]

vulkano/src/buffer/slice.rs

@@ -205,7 +205,7 @@ unsafe impl<T: ?Sized, B> BufferAccess for BufferSlice<T, B>
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
+    fn conflict_key(&self) -> (u64, usize) {
         self.resource.conflict_key()
     }
 

vulkano/src/buffer/traits.rs

@@ -108,7 +108,7 @@ pub unsafe trait BufferAccess: DeviceOwned {
     /// Since it is possible to accidentally return the same key for memory ranges that don't
     /// overlap, the `conflicts_buffer` or `conflicts_image` function should always be called to
     /// verify whether they actually overlap.
-    fn conflict_key(&self) -> u64;
+    fn conflict_key(&self) -> (u64, usize);
 
     /// Locks the resource for usage on the GPU. Returns an error if the lock can't be acquired.
     ///
@@ -173,7 +173,7 @@ unsafe impl<T> BufferAccess for T
     }
 
     #[inline]
-    fn conflict_key(&self) -> u64 {
+    fn conflict_key(&self) -> (u64, usize) {
         (**self).conflict_key()
     }
 

vulkano/src/command_buffer/synced/base.rs

@@ -318,13 +318,13 @@ impl<P> Hash for BuilderKey<P> {
         match self.resource_ty {
             KeyTy::Buffer => {
                 let c = &commands_lock.commands[self.command_id];
-                c.buffer(self.resource_index).conflict_key()
+                c.buffer(self.resource_index).conflict_key().hash(state)
             },
             KeyTy::Image => {
                 let c = &commands_lock.commands[self.command_id];
-                c.image(self.resource_index).conflict_key()
+                c.image(self.resource_index).conflict_key().hash(state)
             },
-        }.hash(state)
+        }
     }
 }
 
@@ -1064,6 +1064,8 @@ impl<P> SyncCommandBuffer<P> {
                     let cmd = &commands_lock[command_id];
                     let buf = cmd.buffer(resource_index);
 
+                    // Because try_gpu_lock needs to be called first,
+                    // this should never return Ok without first returning Err
                     let prev_err = match future.check_buffer_access(&buf, entry.exclusive, queue) {
                         Ok(_) => {
                             unsafe {