[PATCH v2 08/10] asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock

Alexandre Ghiti
2024-06-26T13:12:02Z

From: Guo Ren <guoren@linux.alibaba.com>

The arch_spinlock_t of qspinlock has contained the atomic_t val, which
satisfies the ticket-lock requirement. Thus, unify the arch_spinlock_t
into qspinlock_types.h. This is the preparation for the next combo
spinlock.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/linux-riscv/CAK8P3a2rnz9mQqhN6-e0CGUUv9rntRELFdxt_weiD7FxH7fkfQ@mail.gmail.com/
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
---
include/asm-generic/spinlock.h | 14 +++++++-------
include/asm-generic/spinlock_types.h | 12 ++----------
2 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/include/asm-generic/spinlock.h b/include/asm-generic/spinlock.h
index 90803a826ba0..4773334ee638 100644
--- a/include/asm-generic/spinlock.h
+++ b/include/asm-generic/spinlock.h
@@ -32,7 +32,7 @@

static __always_inline void arch_spin_lock(arch_spinlock_t *lock)
{
- u32 val = atomic_fetch_add(1<<16, lock);
+ u32 val = atomic_fetch_add(1<<16, &lock->val);
u16 ticket = val >> 16;

if (ticket == (u16)val)
@@ -46,31 +46,31 @@ static __always_inline void arch_spin_lock(arch_spinlock_t *lock)
* have no outstanding writes due to the atomic_fetch_add() the extra
* orderings are free.
*/
- atomic_cond_read_acquire(lock, ticket == (u16)VAL);
+ atomic_cond_read_acquire(&lock->val, ticket == (u16)VAL);
smp_mb();
}

static __always_inline bool arch_spin_trylock(arch_spinlock_t *lock)
{
- u32 old = atomic_read(lock);
+ u32 old = atomic_read(&lock->val);

if ((old >> 16) != (old & 0xffff))
return false;

- return atomic_try_cmpxchg(lock, &old, old + (1<<16)); /* SC, for RCsc */
+ return atomic_try_cmpxchg(&lock->val, &old, old + (1<<16)); /* SC, for RCsc */
}

static __always_inline void arch_spin_unlock(arch_spinlock_t *lock)
{
u16 *ptr = (u16 *)lock + IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
- u32 val = atomic_read(lock);
+ u32 val = atomic_read(&lock->val);

smp_store_release(ptr, (u16)val + 1);
}

static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
{
- u32 val = lock.counter;
+ u32 val = lock.val.counter;

return ((val >> 16) == (val & 0xffff));
}
@@ -84,7 +84,7 @@ static __always_inline int arch_spin_is_locked(arch_spinlock_t *lock)

static __always_inline int arch_spin_is_contended(arch_spinlock_t *lock)
{
- u32 val = atomic_read(lock);
+ u32 val = atomic_read(&lock->val);

return (s16)((val >> 16) - (val & 0xffff)) > 1;
}
diff --git a/include/asm-generic/spinlock_types.h b/include/asm-generic/spinlock_types.h
index 8962bb730945..f534aa5de394 100644
--- a/include/asm-generic/spinlock_types.h
+++ b/include/asm-generic/spinlock_types.h
@@ -3,15 +3,7 @@
#ifndef __ASM_GENERIC_SPINLOCK_TYPES_H
#define __ASM_GENERIC_SPINLOCK_TYPES_H

-#include <linux/types.h>
-typedef atomic_t arch_spinlock_t;
-
-/*
- * qrwlock_types depends on arch_spinlock_t, so we must typedef that before the
- * include.
- */
-#include <asm/qrwlock_types.h>
-
-#define __ARCH_SPIN_LOCK_UNLOCKED ATOMIC_INIT(0)
+#include <asm-generic/qspinlock_types.h>
+#include <asm-generic/qrwlock_types.h>

#endif /* __ASM_GENERIC_SPINLOCK_TYPES_H */
--
2.39.2