From fa1f51162338b3e2f520d4bfedc42b3b2e00da6d Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 19 Mar 2024 19:20:50 +0100 Subject: [PATCH] locking: Make rwsem_assert_held_write_nolockdep() build with PREEMPT_RT=y The commit cited below broke the build for PREEMPT_RT because rwsem_assert_held_write_nolockdep() passes a struct rw_semaphore but rw_base_assert_held_write() expects struct rwbase_rt. Fixing the type alone leads to the problem that WARN_ON() is not found because bug.h is missing. In order to resolve this: - Keep the assert (WARN_ON()) in rwsem.h (not rwbase_rt.h) - Make rwsem_assert_held_write_nolockdep() do the implementation specific (rw_base) writer check. - Replace the "inline" with __always_inline which was used before. Fixes: f70405afc99b1 ("locking: Add rwsem_assert_held() and rwsem_assert_held_write()") Reported-by: Clark Williams Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Reviewed-by: Waiman Long Link: https://lore.kernel.org/r/20240319182050.U4AzUF3I@linutronix.de --- include/linux/rwbase_rt.h | 4 ++-- include/linux/rwsem.h | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/rwbase_rt.h b/include/linux/rwbase_rt.h index 29c4e4f243e4..f2394a409c9d 100644 --- a/include/linux/rwbase_rt.h +++ b/include/linux/rwbase_rt.h @@ -31,9 +31,9 @@ static __always_inline bool rw_base_is_locked(const struct rwbase_rt *rwb) return atomic_read(&rwb->readers) != READER_BIAS; } -static inline void rw_base_assert_held_write(const struct rwbase_rt *rwb) +static __always_inline bool rw_base_is_write_locked(const struct rwbase_rt *rwb) { - WARN_ON(atomic_read(&rwb->readers) != WRITER_BIAS); + return atomic_read(&rwb->readers) == WRITER_BIAS; } static __always_inline bool rw_base_is_contended(const struct rwbase_rt *rwb) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 4f1c18992f76..c8b543d428b0 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -167,14 +167,14 @@ static __always_inline int rwsem_is_locked(const struct rw_semaphore *sem) return rw_base_is_locked(&sem->rwbase); } -static inline void rwsem_assert_held_nolockdep(const struct rw_semaphore *sem) +static __always_inline void rwsem_assert_held_nolockdep(const struct rw_semaphore *sem) { WARN_ON(!rwsem_is_locked(sem)); } -static inline void rwsem_assert_held_write_nolockdep(const struct rw_semaphore *sem) +static __always_inline void rwsem_assert_held_write_nolockdep(const struct rw_semaphore *sem) { - rw_base_assert_held_write(sem); + WARN_ON(!rw_base_is_write_locked(&sem->rwbase)); } static __always_inline int rwsem_is_contended(struct rw_semaphore *sem)