Linux 2.6.39 compat, mutex owner

Prior to Linux 2.6.39 when CONFIG_DEBUG_MUTEXES was defined
the kernel stored a thread_info pointer as the mutex owner.
From this you could get the pointer of the current task_struct
to compare with get_current().

As of Linux 2.6.39 this behavior has changed and now the mutex
stores a pointer to the task_struct.  This commit detects the
type of pointer stored in the mutex and adjusts the mutex_owner()
and mutex_owned() functions to perform the correct comparision.
This commit is contained in:
Brian Behlendorf 2011-06-24 11:57:14 -07:00
parent 79593b0dec
commit 86fd39f354
4 changed files with 177 additions and 12 deletions

View File

@ -48,6 +48,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
SPL_AC_MONOTONIC_CLOCK
SPL_AC_INODE_I_MUTEX
SPL_AC_MUTEX_OWNER
SPL_AC_MUTEX_OWNER_TASK_STRUCT
SPL_AC_MUTEX_LOCK_NESTED
SPL_AC_3ARGS_ON_EACH_CPU
SPL_AC_KALLSYMS_LOOKUP_NAME
@ -1128,6 +1129,32 @@ AC_DEFUN([SPL_AC_MUTEX_OWNER], [
])
])
dnl #
dnl # 2.6.39 API change,
dnl # Owner type change. A Linux mutex prior to 2.6.39 would store
dnl # the owner as a thread_info pointer when CONFIG_DEBUG_MUTEXES
dnl # was defined. As of 2.6.39 this was changed to a task_struct
dnl # pointer which frankly makes a lot more sense.
dnl #
AC_DEFUN([SPL_AC_MUTEX_OWNER_TASK_STRUCT], [
AC_MSG_CHECKING([whether struct mutex owner is a task_struct])
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
SPL_LINUX_TRY_COMPILE([
#include <linux/mutex.h>
],[
struct mutex mtx __attribute__ ((unused));
mtx.owner = current;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_MUTEX_OWNER_TASK_STRUCT, 1,
[struct mutex owner is a task_struct])
],[
AC_MSG_RESULT(no)
])
EXTRA_KCFLAGS="$tmp_flags"
])
dnl #
dnl # 2.6.18 API change,
dnl # First introduced 'mutex_lock_nested()' in include/linux/mutex.h,

138
configure vendored
View File

@ -13687,6 +13687,75 @@ fi
{ $as_echo "$as_me:$LINENO: checking whether struct mutex owner is a task_struct" >&5
$as_echo_n "checking whether struct mutex owner is a task_struct... " >&6; }
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
cat confdefs.h - <<_ACEOF >conftest.c
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <linux/mutex.h>
int
main (void)
{
struct mutex mtx __attribute__ ((unused));
mtx.owner = current;
;
return 0;
}
_ACEOF
rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then
{ $as_echo "$as_me:$LINENO: result: yes" >&5
$as_echo "yes" >&6; }
cat >>confdefs.h <<\_ACEOF
#define HAVE_MUTEX_OWNER_TASK_STRUCT 1
_ACEOF
else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
{ $as_echo "$as_me:$LINENO: result: no" >&5
$as_echo "no" >&6; }
fi
rm -Rf build
EXTRA_KCFLAGS="$tmp_flags"
{ $as_echo "$as_me:$LINENO: checking whether mutex_lock_nested() is available" >&5
$as_echo_n "checking whether mutex_lock_nested() is available... " >&6; }
@ -17818,6 +17887,75 @@ fi
{ $as_echo "$as_me:$LINENO: checking whether struct mutex owner is a task_struct" >&5
$as_echo_n "checking whether struct mutex owner is a task_struct... " >&6; }
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
cat confdefs.h - <<_ACEOF >conftest.c
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <linux/mutex.h>
int
main (void)
{
struct mutex mtx __attribute__ ((unused));
mtx.owner = current;
;
return 0;
}
_ACEOF
rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then
{ $as_echo "$as_me:$LINENO: result: yes" >&5
$as_echo "yes" >&6; }
cat >>confdefs.h <<\_ACEOF
#define HAVE_MUTEX_OWNER_TASK_STRUCT 1
_ACEOF
else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
{ $as_echo "$as_me:$LINENO: result: no" >&5
$as_echo "no" >&6; }
fi
rm -Rf build
EXTRA_KCFLAGS="$tmp_flags"
{ $as_echo "$as_me:$LINENO: checking whether mutex_lock_nested() is available" >&5
$as_echo_n "checking whether mutex_lock_nested() is available... " >&6; }

View File

@ -48,21 +48,18 @@ typedef struct {
static inline kthread_t *
mutex_owner(kmutex_t *mp)
{
struct thread_info *owner;
#if defined(HAVE_MUTEX_OWNER_TASK_STRUCT)
return ACCESS_ONCE(mp->m.owner);
#else
struct thread_info *owner = ACCESS_ONCE(mp->m.owner);
if (owner)
return owner->task;
owner = ACCESS_ONCE(mp->m.owner);
if (owner)
return owner->task;
return NULL;
}
static inline int
mutex_owned(kmutex_t *mp)
{
return (ACCESS_ONCE(mp->m.owner) == current_thread_info());
return NULL;
#endif
}
#define mutex_owned(mp) (mutex_owner(mp) == current)
#define MUTEX_HELD(mp) mutex_owned(mp)
#define MUTEX_NOT_HELD(mp) (!MUTEX_HELD(mp))
#undef mutex_init

View File

@ -135,6 +135,9 @@
/* struct mutex has owner */
#undef HAVE_MUTEX_OWNER
/* struct mutex owner is a task_struct */
#undef HAVE_MUTEX_OWNER_TASK_STRUCT
/* next_online_pgdat() is available */
#undef HAVE_NEXT_ONLINE_PGDAT