rusticl/icd: move refcnt() and get rid of needless atomic ops

The old impl used `get_arc` which internally calls into
`Arc::increment_strong_count` in order to protect against Arc::drop
deallocating our objects. We could also just not do that :)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27376>

src/gallium/frontends/rusticl/api/context.rs

@@ -34,7 +34,7 @@ impl CLInfo<cl_context_info> for cl_context {
             ),
             CL_CONTEXT_NUM_DEVICES => cl_prop::<cl_uint>(ctx.devs.len() as u32),
             CL_CONTEXT_PROPERTIES => cl_prop::<&Properties<cl_context_properties>>(&ctx.properties),
-            CL_CONTEXT_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_CONTEXT_REFERENCE_COUNT => cl_prop::<cl_uint>(Context::refcnt(*self)?),
             // CL_INVALID_VALUE if param_name is not one of the supported values
             _ => return Err(CL_INVALID_VALUE),
         })

src/gallium/frontends/rusticl/api/event.rs

@@ -32,7 +32,7 @@ impl CLInfo<cl_event_info> for cl_event {
                 };
                 cl_prop::<cl_command_queue>(cl_command_queue::from_ptr(ptr))
             }
-            CL_EVENT_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_EVENT_REFERENCE_COUNT => cl_prop::<cl_uint>(Event::refcnt(*self)?),
             CL_EVENT_COMMAND_TYPE => cl_prop::<cl_command_type>(event.cmd_type),
             _ => return Err(CL_INVALID_VALUE),
         })

src/gallium/frontends/rusticl/api/icd.rs

@@ -299,15 +299,21 @@ pub trait ReferenceCountedAPIPointer<T, const ERR: i32> {
             Ok(())
         }
     }
-
-    fn refcnt(&self) -> CLResult<u32> {
-        Ok((Arc::strong_count(&self.get_arc()?) - 1) as u32)
-    }
 }
 
 pub trait CLObject<'a, const ERR: i32, CL: ReferenceCountedAPIPointer<Self, ERR> + 'a>:
     Sized
 {
+    fn refcnt(ptr: CL) -> CLResult<u32> {
+        let ptr = ptr.get_ptr()?;
+        // SAFETY: `get_ptr` already checks if it's one of our pointers.
+        let arc = unsafe { Arc::from_raw(ptr) };
+        let res = Arc::strong_count(&arc);
+        // leak the arc again, so we don't reduce the refcount by dropping `arc`
+        let _ = Arc::into_raw(arc);
+        Ok(res as u32)
+    }
+
     fn refs_from_arr(objs: *const CL, count: u32) -> CLResult<Vec<&'a Self>> {
         // CL spec requires validation for obj arrays, both values have to make sense
         if objs.is_null() && count > 0 || !objs.is_null() && count == 0 {

src/gallium/frontends/rusticl/api/kernel.rs

@@ -33,7 +33,7 @@ impl CLInfo<cl_kernel_info> for cl_kernel {
                 let ptr = Arc::as_ptr(&kernel.prog);
                 cl_prop::<cl_program>(cl_program::from_ptr(ptr))
             }
-            CL_KERNEL_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_KERNEL_REFERENCE_COUNT => cl_prop::<cl_uint>(Kernel::refcnt(*self)?),
             // CL_INVALID_VALUE if param_name is not one of the supported values
             _ => return Err(CL_INVALID_VALUE),
         })

src/gallium/frontends/rusticl/api/memory.rs

@@ -235,7 +235,7 @@ impl CLInfo<cl_mem_info> for cl_mem {
             CL_MEM_HOST_PTR => cl_prop::<*mut c_void>(mem.host_ptr),
             CL_MEM_OFFSET => cl_prop::<usize>(mem.offset),
             CL_MEM_PROPERTIES => cl_prop::<&Vec<cl_mem_properties>>(&mem.props),
-            CL_MEM_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_MEM_REFERENCE_COUNT => cl_prop::<cl_uint>(Mem::refcnt(*self)?),
             CL_MEM_SIZE => cl_prop::<usize>(mem.size),
             CL_MEM_TYPE => cl_prop::<cl_mem_object_type>(mem.mem_type),
             CL_MEM_USES_SVM_POINTER | CL_MEM_USES_SVM_POINTER_ARM => {
@@ -908,7 +908,7 @@ impl CLInfo<cl_sampler_info> for cl_sampler {
             }
             CL_SAMPLER_FILTER_MODE => cl_prop::<cl_filter_mode>(sampler.filter_mode),
             CL_SAMPLER_NORMALIZED_COORDS => cl_prop::<bool>(sampler.normalized_coords),
-            CL_SAMPLER_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_SAMPLER_REFERENCE_COUNT => cl_prop::<cl_uint>(Sampler::refcnt(*self)?),
             CL_SAMPLER_PROPERTIES => {
                 cl_prop::<&Option<Properties<cl_sampler_properties>>>(&sampler.props)
             }

src/gallium/frontends/rusticl/api/program.rs

@@ -46,7 +46,7 @@ impl CLInfo<cl_program_info> for cl_program {
             CL_PROGRAM_KERNEL_NAMES => cl_prop::<&str>(&*prog.kernels().join(";")),
             CL_PROGRAM_NUM_DEVICES => cl_prop::<cl_uint>(prog.devs.len() as cl_uint),
             CL_PROGRAM_NUM_KERNELS => cl_prop::<usize>(prog.kernels().len()),
-            CL_PROGRAM_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_PROGRAM_REFERENCE_COUNT => cl_prop::<cl_uint>(Program::refcnt(*self)?),
             CL_PROGRAM_SCOPE_GLOBAL_CTORS_PRESENT => cl_prop::<cl_bool>(CL_FALSE),
             CL_PROGRAM_SCOPE_GLOBAL_DTORS_PRESENT => cl_prop::<cl_bool>(CL_FALSE),
             CL_PROGRAM_SOURCE => match &prog.src {

src/gallium/frontends/rusticl/api/queue.rs

@@ -30,7 +30,7 @@ impl CLInfo<cl_command_queue_info> for cl_command_queue {
             CL_QUEUE_PROPERTIES_ARRAY => {
                 cl_prop::<&Option<Properties<cl_queue_properties>>>(&queue.props_v2)
             }
-            CL_QUEUE_REFERENCE_COUNT => cl_prop::<cl_uint>(self.refcnt()?),
+            CL_QUEUE_REFERENCE_COUNT => cl_prop::<cl_uint>(Queue::refcnt(*self)?),
             // clGetCommandQueueInfo, passing CL_QUEUE_SIZE Returns CL_INVALID_COMMAND_QUEUE since
             // command_queue cannot be a valid device command-queue.
             CL_QUEUE_SIZE => return Err(CL_INVALID_COMMAND_QUEUE),