Per-cpu refcounters

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Signed-off-by: Jan Musial <jan.musial@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
Signed-off-by: Rafal Stefanowski <rafal.stefanowski@huawei.com>

env/posix/ocf_env_refcnt.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright(c) 2019-2021 Intel Corporation
+ * Copyright(c) 2024 Huawei Technologies
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "ocf_env_refcnt.h"
+
+int env_refcnt_init(struct env_refcnt *rc, const char *name, size_t name_len)
+{
+	env_atomic_set(&rc->counter, 0);
+	env_atomic_set(&rc->freeze, 0);
+	env_atomic_set(&rc->callback, 0);
+	rc->cb = NULL;
+
+	return 0;
+}
+
+void env_refcnt_deinit(struct env_refcnt *rc)
+{
+
+}
+
+void env_refcnt_dec(struct env_refcnt *rc)
+{
+	int val = env_atomic_dec_return(&rc->counter);
+	ENV_BUG_ON(val < 0);
+
+	if (!val && env_atomic_cmpxchg(&rc->callback, 1, 0))
+		rc->cb(rc->priv);
+}
+
+bool env_refcnt_inc(struct env_refcnt  *rc)
+{
+	int val;
+
+	if (!env_atomic_read(&rc->freeze)) {
+		val = env_atomic_inc_return(&rc->counter);
+		if (!env_atomic_read(&rc->freeze))
+			return !!val;
+		else
+			env_refcnt_dec(rc);
+	}
+
+	return 0;
+}
+
+
+void env_refcnt_freeze(struct env_refcnt *rc)
+{
+	env_atomic_inc(&rc->freeze);
+}
+
+void env_refcnt_register_zero_cb(struct env_refcnt *rc, env_refcnt_cb_t cb,
+		void *priv)
+{
+	ENV_BUG_ON(!env_atomic_read(&rc->freeze));
+	ENV_BUG_ON(env_atomic_read(&rc->callback));
+
+	env_atomic_inc(&rc->counter);
+	rc->cb = cb;
+	rc->priv = priv;
+	env_atomic_set(&rc->callback, 1);
+	env_refcnt_dec(rc);
+}
+
+void env_refcnt_unfreeze(struct env_refcnt *rc)
+{
+	int val = env_atomic_dec_return(&rc->freeze);
+	ENV_BUG_ON(val < 0);
+}
+
+bool env_refcnt_frozen(struct env_refcnt *rc)
+{
+	return !!env_atomic_read(&rc->freeze);
+}
+
+bool env_refcnt_zeroed(struct env_refcnt *rc)
+{
+	return (env_atomic_read(&rc->counter) == 0);
+}

env/posix/ocf_env_refcnt.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright(c) 2019-2021 Intel Corporation
+ * Copyright(c) 2024-2025 Huawei Technologies
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __OCF_ENV_REFCNT_H__
+#define __OCF_ENV_REFCNT_H__
+
+#include "ocf_env.h"
+
+typedef void (*env_refcnt_cb_t)(void *priv);
+
+struct env_refcnt
+{
+	env_atomic counter __attribute__((aligned(64)));
+	env_atomic freeze;
+	env_atomic callback;
+	env_refcnt_cb_t cb;
+	void *priv;
+};
+
+/* Initialize reference counter */
+int env_refcnt_init(struct env_refcnt *rc, const char *name, size_t name_len);
+
+void env_refcnt_deinit(struct env_refcnt *rc);
+
+/* Try to increment counter. Returns true if successfull, false
+ * if counter is frozen */
+bool env_refcnt_inc(struct env_refcnt  *rc);
+
+/* Decrement reference counter */
+void env_refcnt_dec(struct env_refcnt *rc);
+
+/* Disallow incrementing of underlying counter - attempts to increment counter
+ * will be failing until env_refcnt_unfreeze is calleed.
+ * It's ok to call freeze multiple times, in which case counter is frozen
+ * until all freeze calls are offset by a corresponding unfreeze.*/
+void env_refcnt_freeze(struct env_refcnt *rc);
+
+/* Cancel the effect of single env_refcnt_freeze call */
+void env_refcnt_unfreeze(struct env_refcnt *rc);
+
+bool env_refcnt_frozen(struct env_refcnt *rc);
+
+bool env_refcnt_zeroed(struct env_refcnt *rc);
+
+/* Register callback to be called when reference counter drops to 0.
+ * Must be called after counter is frozen.
+ * Cannot be called until previously regsitered callback had fired. */
+void env_refcnt_register_zero_cb(struct env_refcnt *rc, env_refcnt_cb_t cb,
+		void *priv);
+
+#endif // __OCF_ENV_REFCNT_H__