Stage compat_log2.h.

Signed-off-by: Marcelo Vanzin <mvanzin@vmware.com>

diff --git a/open-vm-tools/modules/linux/shared/compat_log2.h b/open-vm-tools/modules/linux/shared/compat_log2.h
new file mode 100644 (file)
index 0000000..3183049
--- /dev/null
+++ b/open-vm-tools/modules/linux/shared/compat_log2.h
@@ -0,0 +1,60 @@
+/*********************************************************
+ * Copyright (C) 2011 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ *********************************************************/
+
+#ifndef __COMPAT_LOG2_H__
+#   define __COMPAT_LOG2_H__
+
+#ifndef LINUX_VERSION_CODE
+#   error "Include compat_version.h before compat_log2.h"
+#endif
+
+/* linux/log2.h was introduced in 2.6.20. */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 19)
+#   include <linux/log2.h>
+#endif
+
+/*
+ * is_power_of_2 was introduced in 2.6.21. This implementation is almost
+ * identical to the one found there.
+ */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 20)
+#define compat_is_power_of_2(n) is_power_of_2(n)
+#else
+static inline __attribute__((const))
+int compat_is_power_of_2(unsigned long n)
+{
+       return (n != 0 && ((n && (n - 1)) == 0));
+}
+#endif
+
+/*
+ * rounddown_power_of_two was introduced in 2.6.24. This implementation is
+ * similar to the one in log2.h but with input of int instead of long to
+ * avoid more version related checks for fls_long().
+ */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
+#define compat_rounddown_pow_of_two(n) rounddown_pow_of_two(n)
+#else
+static inline __attribute__((const))
+unsigned int compat_rounddown_pow_of_two(unsigned int n)
+{
+       return 1U << (fls(n) -1);
+}
+#endif
+
+#endif /* __COMPAT_LOG2_H__ */