MDEV-26476: Implement futex for FreeBSD, DragonFly BSD

storage/innobase/include/rw_lock.h

 /*****************************************************************************
 
-Copyright (c) 2020, 2021, MariaDB Corporation.
+Copyright (c) 2020, 2022, MariaDB Corporation.
 
 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
@@ -20,9 +20,17 @@ this program; if not, write to the Free Software Foundation, Inc.,
 #include <atomic>
 #include "my_dbug.h"
 
-#if !(defined __linux__ || defined __OpenBSD__ || defined _WIN32)
-# define SUX_LOCK_GENERIC
-#elif 0 // defined SAFE_MUTEX
+#if defined __linux__
+/* futex(2): FUTEX_WAIT_PRIVATE, FUTEX_WAKE_PRIVATE */
+#elif defined __OpenBSD__ || defined __FreeBSD__ || defined __DragonFly__
+/* system calls similar to Linux futex(2) */
+#elif defined _WIN32
+/* SRWLOCK as well as WaitOnAddress(), WakeByAddressSingle() */
+#else
+# define SUX_LOCK_GENERIC /* fall back to generic synchronization primitives */
+#endif
+
+#if !defined SUX_LOCK_GENERIC && 0 /* defined SAFE_MUTEX */
 # define SUX_LOCK_GENERIC /* Use dummy implementation for debugging purposes */
 #endif
 

storage/innobase/sync/srw_lock.cc

 /*****************************************************************************
 
-Copyright (c) 2020, 2021, MariaDB Corporation.
+Copyright (c) 2020, 2022, MariaDB Corporation.
 
 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
@@ -339,6 +339,17 @@ void ssux_lock_impl<spinloop>::wake() { WakeByAddressSingle(&readers); }
 #   include <sys/futex.h>
 #   define SRW_FUTEX(a,op,n) \
     futex((volatile uint32_t*) a, FUTEX_ ## op, n, nullptr, nullptr)
+#  elif defined __FreeBSD__
+#   include <sys/types.h>
+#   include <sys/umtx.h>
+#   define FUTEX_WAKE UMTX_OP_WAKE_PRIVATE
+#   define FUTEX_WAIT UMTX_OP_WAIT_UINT_PRIVATE
+#   define SRW_FUTEX(a,op,n) _umtx_op(a, FUTEX_ ## op, n, nullptr, nullptr)
+#  elif defined __DragonFly__
+#   include <unistd.h>
+#   define FUTEX_WAKE(a,n) umtx_wakeup(a,n)
+#   define FUTEX_WAIT(a,n) umtx_sleep(a,n,0)
+#   define SRW_FUTEX(a,op,n) FUTEX_ ## op((volatile int*) a, int(n))
 #  else
 #   error "no futex support"
 #  endif