| Message ID | 20230731084458.28096-1-ubizjak@gmail.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | locking/arch: Rewrite local_add_unless as static inline function | expand |
Le 31/07/2023 à 10:42, Uros Bizjak a écrit : > Rewrite local_add_unless as a static inline function with boolean > return value, similar to arch_atomic_add_unless arch fallbacks. > > The function is currently unused. Is it worth keeping the function if it is not used ? Christophe > > Cc: Will Deacon <will@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Boqun Feng <boqun.feng@gmail.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Richard Henderson <richard.henderson@linaro.org> > Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> > Cc: Matt Turner <mattst88@gmail.com> > Cc: Huacai Chen <chenhuacai@kernel.org> > Cc: WANG Xuerui <kernel@xen0n.name> > Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> > Cc: Jun Yi <yijun@loongson.cn> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Signed-off-by: Uros Bizjak <ubizjak@gmail.com> > --- > arch/alpha/include/asm/local.h | 33 +++++++++++++++--------------- > arch/loongarch/include/asm/local.h | 27 ++++++++++++++---------- > arch/mips/include/asm/local.h | 27 ++++++++++++++---------- > arch/powerpc/include/asm/local.h | 12 +++++------ > arch/x86/include/asm/local.h | 33 +++++++++++++++--------------- > 5 files changed, 70 insertions(+), 62 deletions(-) > > diff --git a/arch/alpha/include/asm/local.h b/arch/alpha/include/asm/local.h > index 0fcaad642cc3..88eb398947a5 100644 > --- a/arch/alpha/include/asm/local.h > +++ b/arch/alpha/include/asm/local.h > @@ -65,28 +65,27 @@ static __inline__ bool local_try_cmpxchg(local_t *l, long *old, long new) > #define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n))) > > /** > - * local_add_unless - add unless the number is a given value > + * local_add_unless - add unless the number is already a given value > * @l: pointer of type local_t > * @a: the amount to add to l... > * @u: ...unless l is equal to u. > * > - * Atomically adds @a to @l, so long as it was not @u. > - * Returns non-zero if @l was not @u, and zero otherwise. > + * Atomically adds @a to @l, if @v was not already @u. > + * Returns true if the addition was done. > */ > -#define local_add_unless(l, a, u) \ > -({ \ > - long c, old; \ > - c = local_read(l); \ > - for (;;) { \ > - if (unlikely(c == (u))) \ > - break; \ > - old = local_cmpxchg((l), c, c + (a)); \ > - if (likely(old == c)) \ > - break; \ > - c = old; \ > - } \ > - c != (u); \ > -}) > +static __inline__ bool > +local_add_unless(local_t *l, long a, long u) > +{ > + long c = local_read(l); > + > + do { > + if (unlikely(c == u)) > + return false; > + } while (!local_try_cmpxchg(l, &c, c + a)); > + > + return true; > +} > + > #define local_inc_not_zero(l) local_add_unless((l), 1, 0) > > #define local_add_negative(a, l) (local_add_return((a), (l)) < 0) > diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h > index 83e995b30e47..15bc3579f16c 100644 > --- a/arch/loongarch/include/asm/local.h > +++ b/arch/loongarch/include/asm/local.h > @@ -70,22 +70,27 @@ static inline bool local_try_cmpxchg(local_t *l, long *old, long new) > #define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (n))) > > /** > - * local_add_unless - add unless the number is a given value > + * local_add_unless - add unless the number is already a given value > * @l: pointer of type local_t > * @a: the amount to add to l... > * @u: ...unless l is equal to u. > * > - * Atomically adds @a to @l, so long as it was not @u. > - * Returns non-zero if @l was not @u, and zero otherwise. > + * Atomically adds @a to @l, if @v was not already @u. > + * Returns true if the addition was done. > */ > -#define local_add_unless(l, a, u) \ > -({ \ > - long c, old; \ > - c = local_read(l); \ > - while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \ > - c = old; \ > - c != (u); \ > -}) > +static inline bool > +local_add_unless(local_t *l, long a, long u) > +{ > + long c = local_read(l); > + > + do { > + if (unlikely(c == u)) > + return false; > + } while (!local_try_cmpxchg(l, &c, c + a)); > + > + return true; > +} > + > #define local_inc_not_zero(l) local_add_unless((l), 1, 0) > > #define local_dec_return(l) local_sub_return(1, (l)) > diff --git a/arch/mips/include/asm/local.h b/arch/mips/include/asm/local.h > index 5daf6fe8e3e9..90435158a083 100644 > --- a/arch/mips/include/asm/local.h > +++ b/arch/mips/include/asm/local.h > @@ -108,22 +108,27 @@ static __inline__ bool local_try_cmpxchg(local_t *l, long *old, long new) > #define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (n))) > > /** > - * local_add_unless - add unless the number is a given value > + * local_add_unless - add unless the number is already a given value > * @l: pointer of type local_t > * @a: the amount to add to l... > * @u: ...unless l is equal to u. > * > - * Atomically adds @a to @l, so long as it was not @u. > - * Returns non-zero if @l was not @u, and zero otherwise. > + * Atomically adds @a to @l, if @v was not already @u. > + * Returns true if the addition was done. > */ > -#define local_add_unless(l, a, u) \ > -({ \ > - long c, old; \ > - c = local_read(l); \ > - while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \ > - c = old; \ > - c != (u); \ > -}) > +static __inline__ bool > +local_add_unless(local_t *l, long a, long u) > +{ > + long c = local_read(l); > + > + do { > + if (unlikely(c == u)) > + return false; > + } while (!local_try_cmpxchg(l, &c, c + a)); > + > + return true; > +} > + > #define local_inc_not_zero(l) local_add_unless((l), 1, 0) > > #define local_dec_return(l) local_sub_return(1, (l)) > diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h > index 45492fb5bf22..ec6ced6d7ced 100644 > --- a/arch/powerpc/include/asm/local.h > +++ b/arch/powerpc/include/asm/local.h > @@ -115,23 +115,23 @@ static __inline__ long local_xchg(local_t *l, long n) > } > > /** > - * local_add_unless - add unless the number is a given value > + * local_add_unless - add unless the number is already a given value > * @l: pointer of type local_t > * @a: the amount to add to v... > * @u: ...unless v is equal to u. > * > - * Atomically adds @a to @l, so long as it was not @u. > - * Returns non-zero if @l was not @u, and zero otherwise. > + * Atomically adds @a to @l, if @v was not already @u. > + * Returns true if the addition was done. > */ > -static __inline__ int local_add_unless(local_t *l, long a, long u) > +static __inline__ bool local_add_unless(local_t *l, long a, long u) > { > unsigned long flags; > - int ret = 0; > + bool ret = false; > > powerpc_local_irq_pmu_save(flags); > if (l->v != u) { > l->v += a; > - ret = 1; > + ret = true; > } > powerpc_local_irq_pmu_restore(flags); > > diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h > index 56d4ef604b91..46ce92d4e556 100644 > --- a/arch/x86/include/asm/local.h > +++ b/arch/x86/include/asm/local.h > @@ -135,28 +135,27 @@ static inline bool local_try_cmpxchg(local_t *l, long *old, long new) > #define local_xchg(l, n) (xchg(&((l)->a.counter), (n))) > > /** > - * local_add_unless - add unless the number is a given value > + * local_add_unless - add unless the number is already a given value > * @l: pointer of type local_t > * @a: the amount to add to l... > * @u: ...unless l is equal to u. > * > - * Atomically adds @a to @l, so long as it was not @u. > - * Returns non-zero if @l was not @u, and zero otherwise. > + * Atomically adds @a to @l, if @v was not already @u. > + * Returns true if the addition was done. > */ > -#define local_add_unless(l, a, u) \ > -({ \ > - long c, old; \ > - c = local_read((l)); \ > - for (;;) { \ > - if (unlikely(c == (u))) \ > - break; \ > - old = local_cmpxchg((l), c, c + (a)); \ > - if (likely(old == c)) \ > - break; \ > - c = old; \ > - } \ > - c != (u); \ > -}) > +static __always_inline bool > +local_add_unless(local_t *l, long a, long u) > +{ > + long c = local_read(l); > + > + do { > + if (unlikely(c == u)) > + return false; > + } while (!local_try_cmpxchg(l, &c, c + a)); > + > + return true; > +} > + > #define local_inc_not_zero(l) local_add_unless((l), 1, 0) > > /* On x86_32, these are no better than the atomic variants.
On Mon, Aug 7, 2023 at 6:13 PM Christophe Leroy <christophe.leroy@csgroup.eu> wrote: > > > > Le 31/07/2023 à 10:42, Uros Bizjak a écrit : > > Rewrite local_add_unless as a static inline function with boolean > > return value, similar to arch_atomic_add_unless arch fallbacks. > > > > The function is currently unused. > > Is it worth keeping the function if it is not used ? We already have plenty of these kinds of unused locking functions in arch/*/include/asm/atomic.h, so I thought we could leave this one as well. Uros.
diff --git a/arch/alpha/include/asm/local.h b/arch/alpha/include/asm/local.h index 0fcaad642cc3..88eb398947a5 100644 --- a/arch/alpha/include/asm/local.h +++ b/arch/alpha/include/asm/local.h @@ -65,28 +65,27 @@ static __inline__ bool local_try_cmpxchg(local_t *l, long *old, long new) #define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n))) /** - * local_add_unless - add unless the number is a given value + * local_add_unless - add unless the number is already a given value * @l: pointer of type local_t * @a: the amount to add to l... * @u: ...unless l is equal to u. * - * Atomically adds @a to @l, so long as it was not @u. - * Returns non-zero if @l was not @u, and zero otherwise. + * Atomically adds @a to @l, if @v was not already @u. + * Returns true if the addition was done. */ -#define local_add_unless(l, a, u) \ -({ \ - long c, old; \ - c = local_read(l); \ - for (;;) { \ - if (unlikely(c == (u))) \ - break; \ - old = local_cmpxchg((l), c, c + (a)); \ - if (likely(old == c)) \ - break; \ - c = old; \ - } \ - c != (u); \ -}) +static __inline__ bool +local_add_unless(local_t *l, long a, long u) +{ + long c = local_read(l); + + do { + if (unlikely(c == u)) + return false; + } while (!local_try_cmpxchg(l, &c, c + a)); + + return true; +} + #define local_inc_not_zero(l) local_add_unless((l), 1, 0) #define local_add_negative(a, l) (local_add_return((a), (l)) < 0) diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h index 83e995b30e47..15bc3579f16c 100644 --- a/arch/loongarch/include/asm/local.h +++ b/arch/loongarch/include/asm/local.h @@ -70,22 +70,27 @@ static inline bool local_try_cmpxchg(local_t *l, long *old, long new) #define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (n))) /** - * local_add_unless - add unless the number is a given value + * local_add_unless - add unless the number is already a given value * @l: pointer of type local_t * @a: the amount to add to l... * @u: ...unless l is equal to u. * - * Atomically adds @a to @l, so long as it was not @u. - * Returns non-zero if @l was not @u, and zero otherwise. + * Atomically adds @a to @l, if @v was not already @u. + * Returns true if the addition was done. */ -#define local_add_unless(l, a, u) \ -({ \ - long c, old; \ - c = local_read(l); \ - while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \ - c = old; \ - c != (u); \ -}) +static inline bool +local_add_unless(local_t *l, long a, long u) +{ + long c = local_read(l); + + do { + if (unlikely(c == u)) + return false; + } while (!local_try_cmpxchg(l, &c, c + a)); + + return true; +} + #define local_inc_not_zero(l) local_add_unless((l), 1, 0) #define local_dec_return(l) local_sub_return(1, (l)) diff --git a/arch/mips/include/asm/local.h b/arch/mips/include/asm/local.h index 5daf6fe8e3e9..90435158a083 100644 --- a/arch/mips/include/asm/local.h +++ b/arch/mips/include/asm/local.h @@ -108,22 +108,27 @@ static __inline__ bool local_try_cmpxchg(local_t *l, long *old, long new) #define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (n))) /** - * local_add_unless - add unless the number is a given value + * local_add_unless - add unless the number is already a given value * @l: pointer of type local_t * @a: the amount to add to l... * @u: ...unless l is equal to u. * - * Atomically adds @a to @l, so long as it was not @u. - * Returns non-zero if @l was not @u, and zero otherwise. + * Atomically adds @a to @l, if @v was not already @u. + * Returns true if the addition was done. */ -#define local_add_unless(l, a, u) \ -({ \ - long c, old; \ - c = local_read(l); \ - while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \ - c = old; \ - c != (u); \ -}) +static __inline__ bool +local_add_unless(local_t *l, long a, long u) +{ + long c = local_read(l); + + do { + if (unlikely(c == u)) + return false; + } while (!local_try_cmpxchg(l, &c, c + a)); + + return true; +} + #define local_inc_not_zero(l) local_add_unless((l), 1, 0) #define local_dec_return(l) local_sub_return(1, (l)) diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h index 45492fb5bf22..ec6ced6d7ced 100644 --- a/arch/powerpc/include/asm/local.h +++ b/arch/powerpc/include/asm/local.h @@ -115,23 +115,23 @@ static __inline__ long local_xchg(local_t *l, long n) } /** - * local_add_unless - add unless the number is a given value + * local_add_unless - add unless the number is already a given value * @l: pointer of type local_t * @a: the amount to add to v... * @u: ...unless v is equal to u. * - * Atomically adds @a to @l, so long as it was not @u. - * Returns non-zero if @l was not @u, and zero otherwise. + * Atomically adds @a to @l, if @v was not already @u. + * Returns true if the addition was done. */ -static __inline__ int local_add_unless(local_t *l, long a, long u) +static __inline__ bool local_add_unless(local_t *l, long a, long u) { unsigned long flags; - int ret = 0; + bool ret = false; powerpc_local_irq_pmu_save(flags); if (l->v != u) { l->v += a; - ret = 1; + ret = true; } powerpc_local_irq_pmu_restore(flags); diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h index 56d4ef604b91..46ce92d4e556 100644 --- a/arch/x86/include/asm/local.h +++ b/arch/x86/include/asm/local.h @@ -135,28 +135,27 @@ static inline bool local_try_cmpxchg(local_t *l, long *old, long new) #define local_xchg(l, n) (xchg(&((l)->a.counter), (n))) /** - * local_add_unless - add unless the number is a given value + * local_add_unless - add unless the number is already a given value * @l: pointer of type local_t * @a: the amount to add to l... * @u: ...unless l is equal to u. * - * Atomically adds @a to @l, so long as it was not @u. - * Returns non-zero if @l was not @u, and zero otherwise. + * Atomically adds @a to @l, if @v was not already @u. + * Returns true if the addition was done. */ -#define local_add_unless(l, a, u) \ -({ \ - long c, old; \ - c = local_read((l)); \ - for (;;) { \ - if (unlikely(c == (u))) \ - break; \ - old = local_cmpxchg((l), c, c + (a)); \ - if (likely(old == c)) \ - break; \ - c = old; \ - } \ - c != (u); \ -}) +static __always_inline bool +local_add_unless(local_t *l, long a, long u) +{ + long c = local_read(l); + + do { + if (unlikely(c == u)) + return false; + } while (!local_try_cmpxchg(l, &c, c + a)); + + return true; +} + #define local_inc_not_zero(l) local_add_unless((l), 1, 0) /* On x86_32, these are no better than the atomic variants.
Rewrite local_add_unless as a static inline function with boolean return value, similar to arch_atomic_add_unless arch fallbacks. The function is currently unused. Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Jun Yi <yijun@loongson.cn> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> --- arch/alpha/include/asm/local.h | 33 +++++++++++++++--------------- arch/loongarch/include/asm/local.h | 27 ++++++++++++++---------- arch/mips/include/asm/local.h | 27 ++++++++++++++---------- arch/powerpc/include/asm/local.h | 12 +++++------ arch/x86/include/asm/local.h | 33 +++++++++++++++--------------- 5 files changed, 70 insertions(+), 62 deletions(-)