diff --git a/config/spl-build.m4 b/config/spl-build.m4 index b9c04a95e01d..55453c822e7d 100644 --- a/config/spl-build.m4 +++ b/config/spl-build.m4 @@ -44,6 +44,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [ SPL_AC_USLEEP_RANGE SPL_AC_KMEM_CACHE_ALLOCFLAGS SPL_AC_WAIT_ON_BIT + SPL_AC_MUTEX_OWNER ]) AC_DEFUN([SPL_AC_MODULE_SYMVERS], [ @@ -1447,3 +1448,31 @@ AC_DEFUN([SPL_AC_WAIT_ON_BIT], [ AC_MSG_RESULT(no) ]) ]) + +dnl # +dnl # Check whether mutex has owner with task_struct type. +dnl # +dnl # Note that before Linux 3.0, mutex owner is of type thread_info. +dnl # +dnl # Note that in Linux 3.18, the condition for owner is changed from +dnl # defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) to +dnl # defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER) +dnl # +AC_DEFUN([SPL_AC_MUTEX_OWNER], [ + AC_MSG_CHECKING([whether mutex has owner]) + tmp_flags="$EXTRA_KCFLAGS" + EXTRA_KCFLAGS="-Werror" + SPL_LINUX_TRY_COMPILE([ + #include + ],[ + DEFINE_MUTEX(m); + struct task_struct *t __attribute__ ((unused)); + t = m.owner; + ],[ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_MUTEX_OWNER, 1, [yes]) + ],[ + AC_MSG_RESULT(no) + ]) + EXTRA_KCFLAGS="$tmp_flags" +]) diff --git a/include/sys/mutex.h b/include/sys/mutex.h index fba35f3f9813..31923522308e 100644 --- a/include/sys/mutex.h +++ b/include/sys/mutex.h @@ -40,7 +40,10 @@ typedef enum { typedef struct { struct mutex m_mutex; spinlock_t m_lock; /* used for serializing mutex_exit */ +#ifndef HAVE_MUTEX_OWNER + /* only when kernel doesn't have owner */ kthread_t *m_owner; +#endif #ifdef CONFIG_LOCKDEP kmutex_type_t m_type; #endif /* CONFIG_LOCKDEP */ @@ -51,16 +54,28 @@ typedef struct { static inline void spl_mutex_set_owner(kmutex_t *mp) { + /* + * kernel will handle its owner, so we don't need to do anything if it + * is defined. + */ +#ifndef HAVE_MUTEX_OWNER mp->m_owner = current; +#endif } static inline void spl_mutex_clear_owner(kmutex_t *mp) { +#ifndef HAVE_MUTEX_OWNER mp->m_owner = NULL; +#endif } +#ifdef HAVE_MUTEX_OWNER +#define mutex_owner(mp) (ACCESS_ONCE(MUTEX(mp)->owner)) +#else #define mutex_owner(mp) (ACCESS_ONCE((mp)->m_owner)) +#endif #define mutex_owned(mp) (mutex_owner(mp) == current) #define MUTEX_HELD(mp) mutex_owned(mp) #define MUTEX_NOT_HELD(mp) (!MUTEX_HELD(mp))