Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 3998cdf..5fda40f 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -3,41 +3,52 @@
#define _LINUX_PERCPU_RWSEM_H
#include <linux/atomic.h>
-#include <linux/rwsem.h>
#include <linux/percpu.h>
#include <linux/rcuwait.h>
+#include <linux/wait.h>
#include <linux/rcu_sync.h>
#include <linux/lockdep.h>
struct percpu_rw_semaphore {
struct rcu_sync rss;
unsigned int __percpu *read_count;
- struct rw_semaphore rw_sem; /* slowpath */
- struct rcuwait writer; /* blocked writer */
- int readers_block;
+ struct rcuwait writer;
+ wait_queue_head_t waiters;
+ atomic_t block;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname },
+#else
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)
+#endif
+
#define __DEFINE_PERCPU_RWSEM(name, is_static) \
static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \
is_static struct percpu_rw_semaphore name = { \
.rss = __RCU_SYNC_INITIALIZER(name.rss), \
.read_count = &__percpu_rwsem_rc_##name, \
- .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \
.writer = __RCUWAIT_INITIALIZER(name.writer), \
+ .waiters = __WAIT_QUEUE_HEAD_INITIALIZER(name.waiters), \
+ .block = ATOMIC_INIT(0), \
+ __PERCPU_RWSEM_DEP_MAP_INIT(name) \
}
+
#define DEFINE_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, /* not static */)
#define DEFINE_STATIC_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, static)
-extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
-extern void __percpu_up_read(struct percpu_rw_semaphore *);
+extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool);
static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
{
might_sleep();
- rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 0, _RET_IP_);
+ rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
preempt_disable();
/*
@@ -48,8 +59,9 @@
* and that once the synchronize_rcu() is done, the writer will see
* anything we did within this RCU-sched read-size critical section.
*/
- __this_cpu_inc(*sem->read_count);
- if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+ if (likely(rcu_sync_is_idle(&sem->rss)))
+ this_cpu_inc(*sem->read_count);
+ else
__percpu_down_read(sem, false); /* Unconditional memory barrier */
/*
* The preempt_enable() prevents the compiler from
@@ -58,16 +70,17 @@
preempt_enable();
}
-static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
+static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
{
- int ret = 1;
+ bool ret = true;
preempt_disable();
/*
* Same as in percpu_down_read().
*/
- __this_cpu_inc(*sem->read_count);
- if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+ if (likely(rcu_sync_is_idle(&sem->rss)))
+ this_cpu_inc(*sem->read_count);
+ else
ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */
preempt_enable();
/*
@@ -76,24 +89,36 @@
*/
if (ret)
- rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 1, _RET_IP_);
+ rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
{
+ rwsem_release(&sem->dep_map, _RET_IP_);
+
preempt_disable();
/*
* Same as in percpu_down_read().
*/
- if (likely(rcu_sync_is_idle(&sem->rss)))
- __this_cpu_dec(*sem->read_count);
- else
- __percpu_up_read(sem); /* Unconditional memory barrier */
+ if (likely(rcu_sync_is_idle(&sem->rss))) {
+ this_cpu_dec(*sem->read_count);
+ } else {
+ /*
+ * slowpath; reader will only ever wake a single blocked
+ * writer.
+ */
+ smp_mb(); /* B matches C */
+ /*
+ * In other words, if they see our decrement (presumably to
+ * aggregate zero, as that is the only time it matters) they
+ * will also see our critical section.
+ */
+ this_cpu_dec(*sem->read_count);
+ rcuwait_wake_up(&sem->writer);
+ }
preempt_enable();
-
- rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
}
extern void percpu_down_write(struct percpu_rw_semaphore *);
@@ -110,29 +135,19 @@
__percpu_init_rwsem(sem, #sem, &rwsem_key); \
})
-#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
-
-#define percpu_rwsem_assert_held(sem) \
- lockdep_assert_held(&(sem)->rw_sem)
+#define percpu_rwsem_is_held(sem) lockdep_is_held(sem)
+#define percpu_rwsem_assert_held(sem) lockdep_assert_held(sem)
static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
- lock_release(&sem->rw_sem.dep_map, 1, ip);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
- if (!read)
- atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN);
-#endif
+ lock_release(&sem->dep_map, ip);
}
static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
- lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
- if (!read)
- atomic_long_set(&sem->rw_sem.owner, (long)current);
-#endif
+ lock_acquire(&sem->dep_map, 0, 1, read, 1, NULL, ip);
}
#endif