git: 840680e601f1 - main - Wrap mutex(9), rwlock(9) and sx(9) macros into __extension__ ({}) instead of do {} while (0).
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Date: Thu, 28 Oct 2021 02:00:28 UTC
The branch main has been updated by glebius:
URL: https://cgit.FreeBSD.org/src/commit/?id=840680e601f15b25abed3fad31399a9ce838f13a
commit 840680e601f15b25abed3fad31399a9ce838f13a
Author: Gleb Smirnoff <glebius@FreeBSD.org>
AuthorDate: 2021-10-27 17:33:01 +0000
Commit: Gleb Smirnoff <glebius@FreeBSD.org>
CommitDate: 2021-10-28 01:58:36 +0000
Wrap mutex(9), rwlock(9) and sx(9) macros into __extension__ ({})
instead of do {} while (0).
This makes them real void expressions, and they can be used anywhere
where a void function call can be used, for example in a conditional
operator.
Reviewed by: kib, mjg
Differential revision: https://reviews.freebsd.org/D32696
---
sys/sys/mutex.h | 28 ++++++++++++++++------------
sys/sys/rwlock.h | 15 +++++++++------
sys/sys/sx.h | 5 +++--
3 files changed, 28 insertions(+), 20 deletions(-)
diff --git a/sys/sys/mutex.h b/sys/sys/mutex.h
index f35cdd7413a6..04e2c823541a 100644
--- a/sys/sys/mutex.h
+++ b/sys/sys/mutex.h
@@ -236,14 +236,15 @@ void _thread_lock(struct thread *);
*/
/* Lock a normal mutex. */
-#define __mtx_lock(mp, tid, opts, file, line) do { \
+#define __mtx_lock(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
uintptr_t _v = MTX_UNOWNED; \
\
if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__acquire) ||\
!_mtx_obtain_lock_fetch((mp), &_v, _tid))) \
_mtx_lock_sleep((mp), _v, (opts), (file), (line)); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
/*
* Lock a spin mutex. For spinlocks, we handle recursion inline (it
@@ -252,7 +253,7 @@ void _thread_lock(struct thread *);
* inlining this code is not too big a deal.
*/
#ifdef SMP
-#define __mtx_lock_spin(mp, tid, opts, file, line) do { \
+#define __mtx_lock_spin(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
uintptr_t _v = MTX_UNOWNED; \
\
@@ -260,7 +261,8 @@ void _thread_lock(struct thread *);
if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire) || \
!_mtx_obtain_lock_fetch((mp), &_v, _tid))) \
_mtx_lock_spin((mp), _v, (opts), (file), (line)); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
#define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
int _ret; \
@@ -277,7 +279,7 @@ void _thread_lock(struct thread *);
_ret; \
})
#else /* SMP */
-#define __mtx_lock_spin(mp, tid, opts, file, line) do { \
+#define __mtx_lock_spin(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
\
spinlock_enter(); \
@@ -287,7 +289,8 @@ void _thread_lock(struct thread *);
KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
(mp)->mtx_lock = _tid; \
} \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
#define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
int _ret; \
@@ -305,13 +308,14 @@ void _thread_lock(struct thread *);
#endif /* SMP */
/* Unlock a normal mutex. */
-#define __mtx_unlock(mp, tid, opts, file, line) do { \
+#define __mtx_unlock(mp, tid, opts, file, line) __extension__ ({ \
uintptr_t _v = (uintptr_t)(tid); \
\
if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__release) ||\
!_mtx_release_lock_fetch((mp), &_v))) \
_mtx_unlock_sleep((mp), _v, (opts), (file), (line)); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
/*
* Unlock a spin mutex. For spinlocks, we can handle everything
@@ -324,7 +328,7 @@ void _thread_lock(struct thread *);
* releasing a spin lock. This includes the recursion cases.
*/
#ifdef SMP
-#define __mtx_unlock_spin(mp) do { \
+#define __mtx_unlock_spin(mp) __extension__ ({ \
if (mtx_recursed((mp))) \
(mp)->mtx_recurse--; \
else { \
@@ -332,9 +336,9 @@ void _thread_lock(struct thread *);
_mtx_release_lock_quick((mp)); \
} \
spinlock_exit(); \
-} while (0)
+})
#else /* SMP */
-#define __mtx_unlock_spin(mp) do { \
+#define __mtx_unlock_spin(mp) __extension__ ({ \
if (mtx_recursed((mp))) \
(mp)->mtx_recurse--; \
else { \
@@ -342,7 +346,7 @@ void _thread_lock(struct thread *);
(mp)->mtx_lock = MTX_UNOWNED; \
} \
spinlock_exit(); \
-} while (0)
+})
#endif /* SMP */
/*
diff --git a/sys/sys/rwlock.h b/sys/sys/rwlock.h
index 4e7768595737..99e885e07aaf 100644
--- a/sys/sys/rwlock.h
+++ b/sys/sys/rwlock.h
@@ -103,23 +103,25 @@
*/
/* Acquire a write lock. */
-#define __rw_wlock(rw, tid, file, line) do { \
+#define __rw_wlock(rw, tid, file, line) __extension__ ({ \
uintptr_t _tid = (uintptr_t)(tid); \
uintptr_t _v = RW_UNLOCKED; \
\
if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__acquire) || \
!_rw_write_lock_fetch((rw), &_v, _tid))) \
_rw_wlock_hard((rw), _v, (file), (line)); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
/* Release a write lock. */
-#define __rw_wunlock(rw, tid, file, line) do { \
+#define __rw_wunlock(rw, tid, file, line) __extension__ ({ \
uintptr_t _v = (uintptr_t)(tid); \
\
if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__release) || \
!_rw_write_unlock_fetch((rw), &_v))) \
_rw_wunlock_hard((rw), _v, (file), (line)); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
/*
* Function prototypes. Routines that start with _ are not part of the
@@ -231,12 +233,13 @@ void __rw_assert(const volatile uintptr_t *c, int what, const char *file,
#define rw_try_upgrade(rw) _rw_try_upgrade((rw), LOCK_FILE, LOCK_LINE)
#define rw_try_wlock(rw) _rw_try_wlock((rw), LOCK_FILE, LOCK_LINE)
#define rw_downgrade(rw) _rw_downgrade((rw), LOCK_FILE, LOCK_LINE)
-#define rw_unlock(rw) do { \
+#define rw_unlock(rw) __extension__ ({ \
if (rw_wowned(rw)) \
rw_wunlock(rw); \
else \
rw_runlock(rw); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
#define rw_sleep(chan, rw, pri, wmesg, timo) \
_sleep((chan), &(rw)->lock_object, (pri), (wmesg), \
tick_sbt * (timo), 0, C_HARDCLOCK)
diff --git a/sys/sys/sx.h b/sys/sys/sx.h
index 1e6b9f3f8a46..bd164a96558b 100644
--- a/sys/sys/sx.h
+++ b/sys/sys/sx.h
@@ -253,12 +253,13 @@ __sx_xunlock(struct sx *sx, struct thread *td, const char *file, int line)
(((sx)->sx_lock & ~(SX_LOCK_FLAGMASK & ~SX_LOCK_SHARED)) == \
(uintptr_t)curthread)
-#define sx_unlock_(sx, file, line) do { \
+#define sx_unlock_(sx, file, line) __extension__ ({ \
if (sx_xlocked(sx)) \
sx_xunlock_(sx, file, line); \
else \
sx_sunlock_(sx, file, line); \
-} while (0)
+ (void)0; /* ensure void type for expression */ \
+})
#define sx_unlock(sx) sx_unlock_((sx), LOCK_FILE, LOCK_LINE)