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

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+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2020-22 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_HASH_H__
+#define __NV_HASH_H__
+
+#include "conftest.h"
+#include "nv-list-helpers.h"
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/hash.h>
+
+#if defined(NV_LINUX_STRINGHASH_H_PRESENT)
+#include <linux/stringhash.h>       /* full_name_hash() */
+#else
+#include <linux/dcache.h>
+#endif
+
+#if (NV_FULL_NAME_HASH_ARGUMENT_COUNT == 3)
+#define nv_string_hash(_str) full_name_hash(NULL, _str, strlen(_str))
+#else
+#define nv_string_hash(_str) full_name_hash(_str, strlen(_str))
+#endif
+
+/**
+ * This naive hashtable was introduced by commit d9b482c8ba19 (v3.7, 2012-10-31).
+ * To support older kernels import necessary functionality from
+ * <linux/hashtable.h>.
+ */
+
+#define NV_HASH_SIZE(name) (ARRAY_SIZE(name))
+#define NV_HASH_BITS(name) ilog2(NV_HASH_SIZE(name))
+
+/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
+#define NV_HASH_MIN(val, bits) \
+    (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
+
+#define NV_DECLARE_HASHTABLE(name, bits) \
+    struct hlist_head name[1 << (bits)]
+
+static inline void _nv_hash_init(struct hlist_head *ht, unsigned int sz)
+{
+    unsigned int i;
+
+    for (i = 0; i < sz; i++)
+    {
+        INIT_HLIST_HEAD(&ht[i]);
+    }
+}
+
+/**
+ * nv_hash_init - initialize a hash table
+ * @hashtable: hashtable to be initialized
+ */
+#define nv_hash_init(hashtable) _nv_hash_init(hashtable, NV_HASH_SIZE(hashtable))
+
+/**
+ * nv_hash_add - add an object to a hashtable
+ * @hashtable: hashtable to add to
+ * @node: the &struct hlist_node of the object to be added
+ * @key: the key of the object to be added
+ */
+#define nv_hash_add(hashtable, node, key) \
+    hlist_add_head(node, &hashtable[NV_HASH_MIN(key, NV_HASH_BITS(hashtable))])
+
+/**
+ * nv_hash_for_each_possible - iterate over all possible objects hashing to the
+ * same bucket
+ * @name: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @member: the name of the hlist_node within the struct
+ * @key: the key of the objects to iterate over
+ */
+#define nv_hash_for_each_possible(name, obj, member, key) \
+    hlist_for_each_entry(obj, &name[NV_HASH_MIN(key, NV_HASH_BITS(name))], member)
+
+#endif // __NV_HASH_H__