Linux 4.8 compat: rw_semaphore atomic_long_t count

For non-rwsem-spinlocks the "count" member was changed from a
"long" to "atomic_long_t" type.  A configure check has been
added to detect this change along with new versions of the
_rwsem_tryupgrade() function and RWSEM_COUNT() macro.  See
https://github.com/torvalds/linux/commit/8ee62b18 for complete
details.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #563
This commit is contained in:
Brian Behlendorf
2016-07-26 23:37:46 +00:00
parent d2f97b2a26
commit b7c7008ba2
3 changed files with 41 additions and 3 deletions
+26
View File
@@ -40,6 +40,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
SPL_AC_SHRINK_CONTROL_STRUCT
SPL_AC_RWSEM_SPINLOCK_IS_RAW
SPL_AC_RWSEM_ACTIVITY
SPL_AC_RWSEM_ATOMIC_LONG_COUNT
SPL_AC_SCHED_RT_HEADER
SPL_AC_2ARGS_VFS_GETATTR
SPL_AC_USLEEP_RANGE
@@ -1341,6 +1342,31 @@ AC_DEFUN([SPL_AC_RWSEM_ACTIVITY], [
EXTRA_KCFLAGS="$tmp_flags"
])
dnl #
dnl # 4.8 API Change
dnl #
dnl # rwsem "->count" changed to atomic_long_t type
dnl #
AC_DEFUN([SPL_AC_RWSEM_ATOMIC_LONG_COUNT], [
AC_MSG_CHECKING(
[whether struct rw_semaphore has atomic_long_t member count])
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
SPL_LINUX_TRY_COMPILE([
#include <linux/rwsem.h>
],[
DECLARE_RWSEM(dummy_semaphore);
(void) atomic_long_read(&dummy_semaphore.count);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RWSEM_ATOMIC_LONG_COUNT, 1,
[struct rw_semaphore has atomic_long_t member count])
],[
AC_MSG_RESULT(no)
])
EXTRA_KCFLAGS="$tmp_flags"
])
dnl #
dnl # 3.9 API change,
dnl # Moved things from linux/sched.h to linux/sched/rt.h