On Sun, 2023-09-10 at 04:28 -0400, guoren@xxxxxxxxxx wrote:
> From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
>
> 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.
>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> ---
> 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));
> }
This one seems to be different in torvalds/master, but I suppose it's because of
the requirement patches I have not merged.
> @@ -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 */
FWIW, LGTM:
Reviewed-by: Leonardo Bras <leobras@xxxxxxxxxx>
Just a suggestion: In this patch I could see a lot of usage changes to
arch_spinlock_t, and only at the end I could see the actual change in the .h
file.
In cases like this, it looks nicer to see the .h file first.
I recently found out about this git diff.orderFile option, which helps to
achieve exactly this.
I use the following git.orderfile, adapted from qemu:
############################################################################
#
# order file for git, to produce patches which are easier to review
# by diffing the important stuff like interface changes first.
#
# one-off usage:
# git diff -O scripts/git.orderfile ...
#
# add to git config:
# git config diff.orderFile scripts/git.orderfile
#
MAINTAINERS
# Documentation
Documentation/*
*.rst
*.rst.inc
# build system
Kbuild
Makefile*
*.mak
# semantic patches
*.cocci
# headers
*.h
*.h.inc
# code
*.c
*.c.inc
