From 83e8fbd4e002627621fbdaaa23d3ae69d9a7da3e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 6 Jun 2023 22:04:01 +0800 Subject: [PATCH] locking/rwsem: Better collate rwsem_read_trylock() mainline inclusion from mainline-v5.11-rc1 commit 3379116a0ca965b00e6522c7ea3f16c9dbd8f9f9 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7A0N9 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3379116a0ca965b00e6522c7ea3f16c9dbd8f9f9 -------------------------------- All users of rwsem_read_trylock() do rwsem_set_reader_owned(sem) on success, move it into rwsem_read_trylock() proper. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20201207090243.GE3040@hirez.programming.kicks-ass.net Signed-off-by: Yang Yingliang (cherry picked from commit aa6c618f43c66c4aa102d29234b8d67e214334f8) --- kernel/locking/rwsem.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index cc5cc889b5b7..7bf45b0a1b1d 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -273,9 +273,16 @@ static inline void rwsem_set_nonspinnable(struct rw_semaphore *sem) static inline bool rwsem_read_trylock(struct rw_semaphore *sem) { long cnt = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count); + if (WARN_ON_ONCE(cnt < 0)) rwsem_set_nonspinnable(sem); - return !(cnt & RWSEM_READ_FAILED_MASK); + + if (!(cnt & RWSEM_READ_FAILED_MASK)) { + rwsem_set_reader_owned(sem); + return true; + } + + return false; } /* @@ -1340,8 +1347,6 @@ static inline void __down_read(struct rw_semaphore *sem) if (!rwsem_read_trylock(sem)) { rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE); DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); - } else { - rwsem_set_reader_owned(sem); } } @@ -1351,8 +1356,6 @@ static inline int __down_read_interruptible(struct rw_semaphore *sem) if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE))) return -EINTR; DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); - } else { - rwsem_set_reader_owned(sem); } return 0; } @@ -1363,8 +1366,6 @@ static inline int __down_read_killable(struct rw_semaphore *sem) if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_KILLABLE))) return -EINTR; DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); - } else { - rwsem_set_reader_owned(sem); } return 0; } -- GitLab