First Push

NVIDIA-Linux-x86_64-535.161.07-grid/kernel/common/inc/nv-kref.h

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+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2017 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef __NV_KREF_H__
+#define __NV_KREF_H__
+
+#include <asm/atomic.h>
+
+typedef struct nv_kref
+{
+    atomic_t refcount;
+} nv_kref_t;
+
+static inline void nv_kref_init(nv_kref_t *nv_kref)
+{
+    atomic_set(&nv_kref->refcount, 1);
+}
+
+static inline void nv_kref_get(nv_kref_t *nv_kref)
+{
+    atomic_inc(&nv_kref->refcount);
+}
+
+static inline int nv_kref_put(nv_kref_t *nv_kref,
+                              void (*release)(nv_kref_t *nv_kref))
+{
+    if (atomic_dec_and_test(&nv_kref->refcount))
+    {
+	release(nv_kref);
+	return 1;
+    }
+
+    return 0;
+}
+
+static inline unsigned int nv_kref_read(const nv_kref_t *nv_kref)
+{
+    return atomic_read(&nv_kref->refcount);
+}
+
+#endif // __NV_KREF_H__