github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

locking/rwsem: Add context analysis

Browse Source 
Add compiler context analysis annotations.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260306101417.GT1282955@noisy.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra 2026-03-06 10:43:56 +01:00
parent 90bb681dcd
commit 739690915c
4 changed files with 28 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/rwsem.h
View File

@ -57,7 +57,7 @@ context_lock_struct(rw_semaphore) {
struct optimistic_spin_queue osq; /* spinner MCS lock */
#endif
raw_spinlock_t wait_lock;
struct rwsem_waiter *first_waiter;
struct rwsem_waiter *first_waiter __guarded_by(&wait_lock);
#ifdef CONFIG_DEBUG_RWSEMS
void *magic;
#endif
@ -131,7 +131,7 @@ do { \
*/
static inline bool rwsem_is_contended(struct rw_semaphore *sem)
{
return sem->first_waiter != NULL;
return data_race(sem->first_waiter != NULL);
}
#if defined(CONFIG_DEBUG_RWSEMS) || defined(CONFIG_DETECT_HUNG_TASK_BLOCKER)

1
kernel/locking/Makefile
View File

@ -6,6 +6,7 @@ KCOV_INSTRUMENT := n
CONTEXT_ANALYSIS_mutex.o := y
CONTEXT_ANALYSIS_rtmutex_api.o := y
CONTEXT_ANALYSIS_ww_rt_mutex.o := y
CONTEXT_ANALYSIS_rwsem.o := y
obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o

1
kernel/locking/rwbase_rt.c
View File

@ -186,6 +186,7 @@ static __always_inline void rwbase_read_unlock(struct rwbase_rt *rwb,
static inline void __rwbase_write_unlock(struct rwbase_rt *rwb, int bias,
unsigned long flags)
__releases(&rwb->rtmutex.wait_lock)
{
struct rt_mutex_base *rtm = &rwb->rtmutex;

27
kernel/locking/rwsem.c
View File

@ -72,7 +72,7 @@
#c, atomic_long_read(&(sem)->count), \
(unsigned long) sem->magic, \
atomic_long_read(&(sem)->owner), (long)current, \
(sem)->first_waiter ? "" : "not ")) \
rwsem_is_contended(sem) ? "" : "not ")) \
debug_locks_off(); \
} while (0)
#else
@ -320,9 +320,10 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name,
sem->magic = sem;
#endif
atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE);
raw_spin_lock_init(&sem->wait_lock);
sem->first_waiter = NULL;
atomic_long_set(&sem->owner, 0L);
scoped_guard (raw_spinlock_init, &sem->wait_lock) {
sem->first_waiter = NULL;
}
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
osq_lock_init(&sem->osq);
#endif
@ -365,6 +366,7 @@ enum rwsem_wake_type {
static inline
bool __rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter)
__must_hold(&sem->wait_lock)
{
if (list_empty(&waiter->list)) {
sem->first_waiter = NULL;
@ -401,6 +403,7 @@ rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter)
static inline
struct rwsem_waiter *next_waiter(const struct rw_semaphore *sem,
const struct rwsem_waiter *waiter)
__must_hold(&sem->wait_lock)
{
struct rwsem_waiter *next = list_first_entry(&waiter->list,
struct rwsem_waiter, list);
@ -621,6 +624,7 @@ rwsem_del_wake_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter,
*/
static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
struct rwsem_waiter *waiter)
__must_hold(&sem->wait_lock)
{
struct rwsem_waiter *first = sem->first_waiter;
long count, new;
@ -1558,6 +1562,7 @@ static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
* lock for reading
*/
void __sched down_read(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
@ -1567,6 +1572,7 @@ void __sched down_read(struct rw_semaphore *sem)
EXPORT_SYMBOL(down_read);
int __sched down_read_interruptible(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
@ -1581,6 +1587,7 @@ int __sched down_read_interruptible(struct rw_semaphore *sem)
EXPORT_SYMBOL(down_read_interruptible);
int __sched down_read_killable(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
@ -1598,6 +1605,7 @@ EXPORT_SYMBOL(down_read_killable);
* trylock for reading -- returns 1 if successful, 0 if contention
*/
int down_read_trylock(struct rw_semaphore *sem)
__no_context_analysis
{
int ret = __down_read_trylock(sem);
@ -1611,6 +1619,7 @@ EXPORT_SYMBOL(down_read_trylock);
* lock for writing
*/
void __sched down_write(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
@ -1622,6 +1631,7 @@ EXPORT_SYMBOL(down_write);
* lock for writing
*/
int __sched down_write_killable(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
@ -1640,6 +1650,7 @@ EXPORT_SYMBOL(down_write_killable);
* trylock for writing -- returns 1 if successful, 0 if contention
*/
int down_write_trylock(struct rw_semaphore *sem)
__no_context_analysis
{
int ret = __down_write_trylock(sem);
@ -1654,6 +1665,7 @@ EXPORT_SYMBOL(down_write_trylock);
* release a read lock
*/
void up_read(struct rw_semaphore *sem)
__no_context_analysis
{
rwsem_release(&sem->dep_map, _RET_IP_);
__up_read(sem);
@ -1664,6 +1676,7 @@ EXPORT_SYMBOL(up_read);
* release a write lock
*/
void up_write(struct rw_semaphore *sem)
__no_context_analysis
{
rwsem_release(&sem->dep_map, _RET_IP_);
__up_write(sem);
@ -1674,6 +1687,7 @@ EXPORT_SYMBOL(up_write);
* downgrade write lock to read lock
*/
void downgrade_write(struct rw_semaphore *sem)
__no_context_analysis
{
lock_downgrade(&sem->dep_map, _RET_IP_);
__downgrade_write(sem);
@ -1683,6 +1697,7 @@ EXPORT_SYMBOL(downgrade_write);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void down_read_nested(struct rw_semaphore *sem, int subclass)
__no_context_analysis
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
@ -1691,6 +1706,7 @@ void down_read_nested(struct rw_semaphore *sem, int subclass)
EXPORT_SYMBOL(down_read_nested);
int down_read_killable_nested(struct rw_semaphore *sem, int subclass)
__no_context_analysis
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
@ -1705,6 +1721,7 @@ int down_read_killable_nested(struct rw_semaphore *sem, int subclass)
EXPORT_SYMBOL(down_read_killable_nested);
void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
__no_context_analysis
{
might_sleep();
rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);
@ -1713,6 +1730,7 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
EXPORT_SYMBOL(_down_write_nest_lock);
void down_read_non_owner(struct rw_semaphore *sem)
__no_context_analysis
{
might_sleep();
__down_read(sem);
@ -1727,6 +1745,7 @@ void down_read_non_owner(struct rw_semaphore *sem)
EXPORT_SYMBOL(down_read_non_owner);
void down_write_nested(struct rw_semaphore *sem, int subclass)
__no_context_analysis
{
might_sleep();
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
@ -1735,6 +1754,7 @@ void down_write_nested(struct rw_semaphore *sem, int subclass)
EXPORT_SYMBOL(down_write_nested);
int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
__no_context_analysis
{
might_sleep();
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
@ -1750,6 +1770,7 @@ int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
EXPORT_SYMBOL(down_write_killable_nested);
void up_read_non_owner(struct rw_semaphore *sem)
__no_context_analysis
{
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
__up_read(sem);