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Subject[PATCH 5/5] RISC-V: Move to queued RW locks
Date
From
From: Palmer Dabbelt <palmer@rivosinc.com>

With the move to fair spinlocks, we might as well move to fair rwlocks.

Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/Kbuild | 2 +
arch/riscv/include/asm/spinlock.h | 82 +------------------------
arch/riscv/include/asm/spinlock_types.h | 7 +--
4 files changed, 5 insertions(+), 87 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..feb7030cfb6d 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -38,6 +38,7 @@ config RISCV
select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
select ARCH_SUPPORTS_HUGETLBFS if MMU
select ARCH_USE_MEMTEST
+ select ARCH_USE_QUEUED_RWLOCKS
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 42b1961af1a6..e8714070cbb9 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -4,5 +4,7 @@ generic-y += flat.h
generic-y += kvm_para.h
generic-y += ticket-lock.h
generic-y += ticket-lock-types.h
+generic-y += qrwlock.h
+generic-y += qrwlock_types.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/riscv/include/asm/spinlock.h b/arch/riscv/include/asm/spinlock.h
index 38089cbdea92..97dfb150d18c 100644
--- a/arch/riscv/include/asm/spinlock.h
+++ b/arch/riscv/include/asm/spinlock.h
@@ -11,86 +11,6 @@
#include <asm/current.h>
#include <asm/fence.h>
#include <asm-generic/ticket-lock.h>
-
-static inline void arch_read_lock(arch_rwlock_t *lock)
-{
- int tmp;
-
- __asm__ __volatile__(
- "1: lr.w %1, %0\n"
- " bltz %1, 1b\n"
- " addi %1, %1, 1\n"
- " sc.w %1, %1, %0\n"
- " bnez %1, 1b\n"
- RISCV_ACQUIRE_BARRIER
- : "+A" (lock->lock), "=&r" (tmp)
- :: "memory");
-}
-
-static inline void arch_write_lock(arch_rwlock_t *lock)
-{
- int tmp;
-
- __asm__ __volatile__(
- "1: lr.w %1, %0\n"
- " bnez %1, 1b\n"
- " li %1, -1\n"
- " sc.w %1, %1, %0\n"
- " bnez %1, 1b\n"
- RISCV_ACQUIRE_BARRIER
- : "+A" (lock->lock), "=&r" (tmp)
- :: "memory");
-}
-
-static inline int arch_read_trylock(arch_rwlock_t *lock)
-{
- int busy;
-
- __asm__ __volatile__(
- "1: lr.w %1, %0\n"
- " bltz %1, 1f\n"
- " addi %1, %1, 1\n"
- " sc.w %1, %1, %0\n"
- " bnez %1, 1b\n"
- RISCV_ACQUIRE_BARRIER
- "1:\n"
- : "+A" (lock->lock), "=&r" (busy)
- :: "memory");
-
- return !busy;
-}
-
-static inline int arch_write_trylock(arch_rwlock_t *lock)
-{
- int busy;
-
- __asm__ __volatile__(
- "1: lr.w %1, %0\n"
- " bnez %1, 1f\n"
- " li %1, -1\n"
- " sc.w %1, %1, %0\n"
- " bnez %1, 1b\n"
- RISCV_ACQUIRE_BARRIER
- "1:\n"
- : "+A" (lock->lock), "=&r" (busy)
- :: "memory");
-
- return !busy;
-}
-
-static inline void arch_read_unlock(arch_rwlock_t *lock)
-{
- __asm__ __volatile__(
- RISCV_RELEASE_BARRIER
- " amoadd.w x0, %1, %0\n"
- : "+A" (lock->lock)
- : "r" (-1)
- : "memory");
-}
-
-static inline void arch_write_unlock(arch_rwlock_t *lock)
-{
- smp_store_release(&lock->lock, 0);
-}
+#include <asm/qrwlock.h>

#endif /* _ASM_RISCV_SPINLOCK_H */
diff --git a/arch/riscv/include/asm/spinlock_types.h b/arch/riscv/include/asm/spinlock_types.h
index 431ee08e26c4..3779f13706fa 100644
--- a/arch/riscv/include/asm/spinlock_types.h
+++ b/arch/riscv/include/asm/spinlock_types.h
@@ -11,11 +11,6 @@
#endif

#include <asm-generic/ticket-lock-types.h>
-
-typedef struct {
- volatile unsigned int lock;
-} arch_rwlock_t;
-
-#define __ARCH_RW_LOCK_UNLOCKED { 0 }
+#include <asm/qrwlock_types.h>

#endif /* _ASM_RISCV_SPINLOCK_TYPES_H */
--
2.34.1
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