From: Francis Deslauriers <francis.deslauriers@efficios.com>
Date: Wed, 8 Mar 2017 04:37:30 +0000 (-0500)
Subject: Fix: kref changes for kernel 4.11
X-Git-Tag: v2.10.0-rc1~14
X-Git-Url: http://git.lttng.org/?p=lttng-modules.git;a=commitdiff_plain;h=77932315cd23b50c88462872a3b86ad5997e5b47

Fix: kref changes for kernel 4.11

The underlying type of `struct kref` changed in kernel 4.11 from an
atomic_t to a refcount_t. This change was introduced in kernel
commit:10383ae. This commit also added a builtin overflow checks to
`kref_get()` so we use it.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/wrapper/kref.h b/wrapper/kref.h
index f30a9aed..3f3be7a4 100644
--- a/wrapper/kref.h
+++ b/wrapper/kref.h
@@ -28,15 +28,24 @@
 
 #include <linux/kref.h>
 #include <linux/rculist.h>
+#include <linux/version.h>
 
 /*
  * lttng_kref_get: get reference count, checking for overflow.
  *
  * Return 1 if reference is taken, 0 otherwise (overflow).
  */
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))
+static inline int lttng_kref_get(struct kref *kref)
+{
+	kref_get(kref);
+	return 1;
+}
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
 static inline int lttng_kref_get(struct kref *kref)
 {
 	return atomic_add_unless(&kref->refcount, 1, INT_MAX);
 }
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
 
 #endif /* _LTTNG_WRAPPER_KREF_H */