refcount: Split out refcount_types.h

More trimming of sched.h dependencies.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/refcount_types.h b/include/linux/refcount_types.h
new file mode 100644
index 000000000000..162004f06edf
--- /dev/null
+++ b/include/linux/refcount_types.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_REFCOUNT_TYPES_H
+#define _LINUX_REFCOUNT_TYPES_H
+
+#include <linux/types.h>
+
+/**
+ * typedef refcount_t - variant of atomic_t specialized for reference counts
+ * @refs: atomic_t counter field
+ *
+ * The counter saturates at REFCOUNT_SATURATED and will not move once
+ * there. This avoids wrapping the counter and causing 'spurious'
+ * use-after-free bugs.
+ */
+typedef struct refcount_struct {
+	atomic_t refs;
+} refcount_t;
+
+#endif /* _LINUX_REFCOUNT_TYPES_H */