[src/trunk]: src/sys/external/bsd/drm2/include/linux Linux refcount API

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/245d3c2a7bfa
branches:  trunk
changeset: 1028362:245d3c2a7bfa
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 10:48:37 2021 +0000

description:
Linux refcount API

diffstat:

 sys/external/bsd/drm2/include/linux/kref.h     |    3 +-
 sys/external/bsd/drm2/include/linux/refcount.h |  130 +++++++++++++++++++++++++
 2 files changed, 132 insertions(+), 1 deletions(-)

diffs (151 lines):

diff -r e9d639c0c544 -r 245d3c2a7bfa sys/external/bsd/drm2/include/linux/kref.h
--- a/sys/external/bsd/drm2/include/linux/kref.h        Sun Dec 19 10:48:29 2021 +0000
+++ b/sys/external/bsd/drm2/include/linux/kref.h        Sun Dec 19 10:48:37 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kref.h,v 1.9 2021/12/19 01:46:01 riastradh Exp $       */
+/*     $NetBSD: kref.h,v 1.10 2021/12/19 10:48:37 riastradh Exp $      */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -37,6 +37,7 @@
 #include <sys/systm.h>
 
 #include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/mutex.h>
 
 struct kref {
diff -r e9d639c0c544 -r 245d3c2a7bfa sys/external/bsd/drm2/include/linux/refcount.h
--- a/sys/external/bsd/drm2/include/linux/refcount.h    Sun Dec 19 10:48:29 2021 +0000
+++ b/sys/external/bsd/drm2/include/linux/refcount.h    Sun Dec 19 10:48:37 2021 +0000
@@ -0,0 +1,130 @@
+/*     $NetBSD: refcount.h,v 1.2 2021/12/19 10:48:37 riastradh Exp $   */
+
+/*-
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_REFCOUNT_H_
+#define _LINUX_REFCOUNT_H_
+
+#include <linux/atomic.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+
+typedef struct refcount refcount_t;
+
+struct refcount {
+       atomic_t        rc_count;
+};
+
+static inline void
+refcount_set(struct refcount *rc, int n)
+{
+       atomic_set(&rc->rc_count, n);
+}
+
+static inline void
+refcount_inc(struct refcount *rc)
+{
+       atomic_inc(&rc->rc_count);
+}
+
+static inline int __must_check
+refcount_inc_not_zero(struct refcount *rc)
+{
+       unsigned old, new;
+
+       do {
+               old = atomic_read(&rc->rc_count);
+               if (old == 0)
+                       break;
+               new = old + 1;
+       } while (atomic_cmpxchg(&rc->rc_count, old, new) != old);
+
+       return old;
+}
+
+static inline bool __must_check
+refcount_dec_and_test(struct refcount *rc)
+{
+       unsigned old, new;
+
+       do {
+               old = atomic_read(&rc->rc_count);
+               KASSERT(old);
+               new = old - 1;
+       } while (atomic_cmpxchg(&rc->rc_count, old, new) != old);
+
+       return old == 1;
+}
+
+static inline bool __must_check
+refcount_dec_and_lock_irqsave(struct refcount *rc, struct spinlock *lock,
+    unsigned long *flagsp)
+{
+       unsigned old, new;
+
+       do {
+               old = atomic_read(&rc->rc_count);
+               KASSERT(old);
+               if (old == 1) {
+                       spin_lock_irqsave(lock, *flagsp);
+                       if (atomic_dec_return(&rc->rc_count) == 0)
+                               return true;
+                       spin_unlock_irqrestore(lock, *flagsp);
+                       return false;
+               }
+               new = old - 1;
+       } while (atomic_cmpxchg(&rc->rc_count, old, new) != old);
+
+       KASSERT(old != 1);
+       KASSERT(new != 0);
+       return false;
+}
+
+static inline bool __must_check
+refcount_dec_and_mutex_lock(struct refcount *rc, struct mutex *lock)
+{
+       unsigned old, new;
+
+       do {
+               old = atomic_read(&rc->rc_count);
+               KASSERT(old);
+               if (old == 1) {
+                       mutex_lock(lock);
+                       if (atomic_dec_return(&rc->rc_count) == 0)
+                               return true;
+                       mutex_unlock(lock);
+                       return false;
+               }
+               new = old - 1;
+       } while (atomic_cmpxchg(&rc->rc_count, old, new) != old);
+
+       KASSERT(old != 1);
+       KASSERT(new != 0);
+       return false;
+}
+
+#endif  /* _LINUX_REFCOUNT_H_ */