fix: double defined LTTNG_KERNEL_VERSION

[lttng-modules.git] / include / lttng / kernel-version.h

diff --git a/include/lttng/kernel-version.h b/include/lttng/kernel-version.h
index 773de29515c78aa12872c8911993b5bc0461d3c3..a41829f0a6160ee33be6f8ea9da258910148c752 100644 (file)
--- a/include/lttng/kernel-version.h
+++ b/include/lttng/kernel-version.h
@@ -2,7 +2,7 @@
  *
  * lttng/kernel-version.h
  *
- * Contains helpers to check more complex kernel version conditions.
+ * Contains helpers to check kernel version conditions.
  *
  * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
@@ -13,9 +13,49 @@
 #include <linux/version.h>
 #include <generated/utsrelease.h>
 
+/*
+ * The following defines are extracted from the toplevel Linux Makefile and
+ * passed on the command line -with '-D'.
+ */
+
+#ifndef LTTNG_LINUX_MAJOR
+#define LTTNG_LINUX_MAJOR 0
+#endif
+
+#ifndef LTTNG_LINUX_MINOR
+#define LTTNG_LINUX_MINOR 0
+#endif
+
+#ifndef LTTNG_LINUX_PATCH
+#define LTTNG_LINUX_PATCH 0
+#endif
+
+/*
+ * Some stable releases have overflowed the 8bits allocated to the sublevel in
+ * the version code. To determine if the current kernel is affected, use the
+ * sublevel version from the Makefile. This is currently true for the 4.4.256
+ * and 4.9.256 stable releases.
+ *
+ * When the sublevel has overflowed, use the values from the Makefile instead
+ * of LINUX_VERSION_CODE from the kernel headers and allocate 16bits.
+ * Otherwise, keep using the version code from the headers to minimise the
+ * behavior change and avoid regressions.
+ */
+#if (LTTNG_LINUX_PATCH >= 256)
+
+#define LTTNG_KERNEL_VERSION(a, b, c) \
+       (((a) << 24) + ((b) << 16) + (c))
+
+#define LTTNG_LINUX_VERSION_CODE \
+       LTTNG_KERNEL_VERSION(LTTNG_LINUX_MAJOR, LTTNG_LINUX_MINOR, LTTNG_LINUX_PATCH)
+
+#else
+
 #define LTTNG_KERNEL_VERSION(a, b, c) KERNEL_VERSION(a, b, c)
 #define LTTNG_LINUX_VERSION_CODE LINUX_VERSION_CODE
 
+#endif
+
 /*
  * This macro checks if the kernel version is between the two specified
  * versions (lower limit inclusive, upper limit exclusive).
@@ -27,11 +67,11 @@
 /* Ubuntu */
 
 #define LTTNG_UBUNTU_KERNEL_VERSION(a, b, c, d) \
-       (((LTTNG_KERNEL_VERSION(a, b, c)) << 8) + (d))
+       (((LTTNG_KERNEL_VERSION(a, b, c)) << 16) + (d))
 
 #ifdef UTS_UBUNTU_RELEASE_ABI
 #define LTTNG_UBUNTU_VERSION_CODE \
-       ((LTTNG_LINUX_VERSION_CODE << 8) + UTS_UBUNTU_RELEASE_ABI)
+       ((LTTNG_LINUX_VERSION_CODE << 16) + UTS_UBUNTU_RELEASE_ABI)
 #else
 #define LTTNG_UBUNTU_VERSION_CODE      0
 #endif