[PATCH libdrm 7/9] amdgpu: Use normal integers for device / core BO reference counting

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

The dev_mutex / dev->bo_table_mutex is always locked when accessing the
reference counts, so no need for atomic operations.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 amdgpu/amdgpu_bo.c       |  6 +++---
 amdgpu/amdgpu_device.c   | 18 ++++++++++--------
 amdgpu/amdgpu_internal.h |  6 +++---
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c
index 8d42db90..f40df484 100644
--- a/amdgpu/amdgpu_bo.c
+++ b/amdgpu/amdgpu_bo.c
@@ -65,7 +65,7 @@ static int amdgpu_core_bo_create(struct amdgpu_core_device *dev,
 		return r;
 	}
 
-	atomic_set(&bo->refcount, 1);
+	bo->refcount = 1;
 	bo->alloc_size = size;
 	bo->handle = handle;
 	pthread_mutex_init(&bo->cpu_access_mutex, NULL);
@@ -95,7 +95,7 @@ static int amdgpu_bo_create(amdgpu_device_handle user_dev,
 				goto out;
 			}
 		}
-		atomic_inc(&bo->refcount);
+		bo->refcount++;
 	} else {
 		r = amdgpu_core_bo_create(dev, size, handle, &bo);
 		if (r)
@@ -467,7 +467,7 @@ static void amdgpu_core_bo_free(struct amdgpu_bo *user_bo)
 	struct amdgpu_core_device *dev = user_bo->dev->core;
 	struct amdgpu_core_bo *bo = user_bo->core;
 
-	if (update_references(&bo->refcount, NULL)) {
+	if (--bo->refcount == 0) {
 		/* Remove the buffer from the hash tables. */
 		handle_table_remove(&dev->bo_handles, bo->handle);
 
diff --git a/amdgpu/amdgpu_device.c b/amdgpu/amdgpu_device.c
index 8d9a85c2..8a99b8bb 100644
--- a/amdgpu/amdgpu_device.c
+++ b/amdgpu/amdgpu_device.c
@@ -72,6 +72,9 @@ static int fd_compare(int fd1, int fd2)
 
 static void amdgpu_device_free(struct amdgpu_core_device *dev)
 {
+	if (--dev->refcount > 0)
+		return;
+
 	close(dev->fd);
 
 	amdgpu_vamgr_deinit(&dev->vamgr_32);
@@ -112,7 +115,7 @@ static int amdgpu_device_init(amdgpu_device_handle user_dev)
 			break;
 
 	if (dev_iter) {
-		atomic_inc(&dev_iter->core->refcount);
+		dev_iter->core->refcount++;
 		user_dev->core = dev_iter->core;
 		return 0;
 	}
@@ -123,7 +126,7 @@ static int amdgpu_device_init(amdgpu_device_handle user_dev)
 		return -ENOMEM;
 	}
 
-	atomic_set(&dev->refcount, 1);
+	dev->refcount = 1;
 	pthread_mutex_init(&dev->bo_table_mutex, NULL);
 
 	dev->fd = user_dev->user_fd;
@@ -199,7 +202,7 @@ drm_public int amdgpu_device_initialize(int fd,
 
 	for (user_dev = dev_list; user_dev; user_dev = user_dev->next) {
 		if (same_file_description(user_dev->user_fd, fd)) {
-			atomic_inc(&user_dev->refcount);
+			user_dev->refcount++;
 			goto out;
 		}
 	}
@@ -233,7 +236,7 @@ drm_public int amdgpu_device_initialize(int fd,
 		goto cleanup;
 	}
 
-	atomic_set(&user_dev->refcount, 1);
+	user_dev->refcount = 1;
 	user_dev->next = dev_list;
 	dev_list = user_dev;
 
@@ -248,7 +251,7 @@ out:
 cleanup:
 	if (!user_dev->core || user_dev->user_fd != user_dev->core->fd)
 		close(user_dev->user_fd);
-	if (user_dev->core && update_references(&user_dev->core->refcount, NULL))
+	if (user_dev->core)
 		amdgpu_device_free(user_dev->core);
 	free(user_dev);
 	pthread_mutex_unlock(&dev_mutex);
@@ -261,7 +264,7 @@ drm_public int amdgpu_device_deinitialize(amdgpu_device_handle user_dev)
 
 	pthread_mutex_lock(&dev_mutex);
 
-	if (update_references(&user_dev->refcount, NULL)) {
+	if (--user_dev->refcount == 0) {
 		struct amdgpu_device **node = &dev_list;
 
 		while (*node != user_dev && (*node)->next)
@@ -271,8 +274,7 @@ drm_public int amdgpu_device_deinitialize(amdgpu_device_handle user_dev)
 		if (user_dev->user_fd != dev->fd)
 			close(user_dev->user_fd);
 
-		if (update_references(&dev->refcount, NULL))
-			amdgpu_device_free(dev);
+		amdgpu_device_free(dev);
 
 		free(user_dev);
 	}
diff --git a/amdgpu/amdgpu_internal.h b/amdgpu/amdgpu_internal.h
index 686d50ec..70566f98 100644
--- a/amdgpu/amdgpu_internal.h
+++ b/amdgpu/amdgpu_internal.h
@@ -65,7 +65,7 @@ struct amdgpu_va {
 };
 
 struct amdgpu_core_device {
-	atomic_t refcount;
+	int refcount;
 	int fd;
 	unsigned major_version;
 	unsigned minor_version;
@@ -90,14 +90,14 @@ struct amdgpu_core_device {
 };
 
 struct amdgpu_device {
-	atomic_t refcount;
+	int refcount;
 	int user_fd;
 	struct amdgpu_core_device *core;
 	struct amdgpu_device *next;
 };
 
 struct amdgpu_core_bo {
-	atomic_t refcount;
+	int refcount;
 	amdgpu_bo_handle user_bos;
 
 	uint64_t alloc_size;
-- 
2.20.1