rwsem_try_write

函数名称：This function must be called with the sem->wait_lock held to prevent* race conditions between checking the rwsem wait list and setting the* If wstate is WRITER_HANDOFF, it will make sure that either the handoff

函数原型：static inline bool rwsem_try_write_lock(struct rw_semaphore *sem, enum writer_wait_state wstate)

返回类型：bool

参数：

类型	参数	名称
struct rw_semaphore *	sem	>count accordingly.
enum writer_wait_state	wstate

568

lockdep_assert_held( & wait_lock)

570

count等于atomic_long_read( & count)

571

循环

572

has_handoff等于非非count按位与RWSEM_FLAG_HANDOFF的值

574

如果has_handoff且wstate恒等于 Writer is not first in wait list 则返回:false

577

new等于count

579

如果count按位与RWSEM_LOCK_MASK则

580

如果has_handoff或wstate不等于WRITER_HANDOFF则返回:false

583

new或等于RWSEM_FLAG_HANDOFF

584

否则

585

new或等于On 64-bit architectures, the bit definitions of the count are:* Bit 0 - writer locked bit* Bit 1 - waiters present bit* Bit 2 - lock handoff bit* Bits 3-7 - reserved* Bits 8-62 - 55-bit reader count* Bit 63 - read fail bit* On 32-bit architectures, the

586

new与等于RWSEM_FLAG_HANDOFF的反

588

如果链表只有一项则new与等于RWSEM_FLAG_WAITERS的反

591

当非atomic_long_try_cmpxchg_acquire( & count, & count, new)循环

597

如果new按位与RWSEM_FLAG_HANDOFF则返回:false

600

All writes to owner are protected by WRITE_ONCE() to make sure that* store tearing can't happen as optimistic spinners may read and use* the owner value concurrently without lock

601

返回:true

**调用者**
名称	描述
rwsem_down_write_slowpath	Wait until we successfully acquire the write lock

源代码转换工具开放的插件接口	X
支持：c/c++/esqlc/java Oracle/Informix/Mysql 插件可实现：逻辑报告代码生成和批量转换代码

函数逻辑报告