| 1 | /* SPDX-License-Identifier: GPL-2.0 |
| 2 | * |
| 3 | * wrapper/kref.h |
| 4 | * |
| 5 | * wrapper around linux/kref.h. |
| 6 | * |
| 7 | * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 8 | * |
| 9 | * This wrapper code is derived from Linux 3.19.2 include/linux/list.h |
| 10 | * and include/linux/rculist.h, hence the GPLv2 license applied to this |
| 11 | * file. |
| 12 | */ |
| 13 | |
| 14 | #ifndef _LTTNG_WRAPPER_KREF_H |
| 15 | #define _LTTNG_WRAPPER_KREF_H |
| 16 | |
| 17 | #include <linux/kref.h> |
| 18 | #include <linux/rculist.h> |
| 19 | #include <linux/version.h> |
| 20 | |
| 21 | /* |
| 22 | * lttng_kref_get: get reference count, checking for overflow. |
| 23 | * |
| 24 | * Return 1 if reference is taken, 0 otherwise (overflow). |
| 25 | */ |
| 26 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) |
| 27 | static inline int lttng_kref_get(struct kref *kref) |
| 28 | { |
| 29 | kref_get(kref); |
| 30 | return 1; |
| 31 | } |
| 32 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */ |
| 33 | static inline int lttng_kref_get(struct kref *kref) |
| 34 | { |
| 35 | return atomic_add_unless(&kref->refcount, 1, INT_MAX); |
| 36 | } |
| 37 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */ |
| 38 | |
| 39 | #endif /* _LTTNG_WRAPPER_KREF_H */ |