* [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions
[not found] <20170629235918.GA6445@linux.vnet.ibm.com>
@ 2017-06-30 0:01 ` Paul E. McKenney
2017-07-02 3:58 ` Boqun Feng
0 siblings, 1 reply; 3+ messages in thread
From: Paul E. McKenney @ 2017-06-30 0:01 UTC (permalink / raw)
To: linux-kernel
Cc: netfilter-devel, netdev, oleg, akpm, mingo, dave, manfred, tj,
arnd, linux-arch, will.deacon, peterz, stern, parri.andrea,
torvalds, Paul E. McKenney, Benjamin Herrenschmidt,
Paul Mackerras, Michael Ellerman, linuxppc-dev
There is no agreed-upon definition of spin_unlock_wait()'s semantics,
and it appears that all callers could do just as well with a lock/unlock
pair. This commit therefore removes the underlying arch-specific
arch_spin_unlock_wait().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: <linuxppc-dev@lists.ozlabs.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/powerpc/include/asm/spinlock.h | 33 ---------------------------------
1 file changed, 33 deletions(-)
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 8c1b913de6d7..d256e448ea49 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -170,39 +170,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
lock->slock = 0;
}
-static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
-{
- arch_spinlock_t lock_val;
-
- smp_mb();
-
- /*
- * Atomically load and store back the lock value (unchanged). This
- * ensures that our observation of the lock value is ordered with
- * respect to other lock operations.
- */
- __asm__ __volatile__(
-"1: " PPC_LWARX(%0, 0, %2, 0) "\n"
-" stwcx. %0, 0, %2\n"
-" bne- 1b\n"
- : "=&r" (lock_val), "+m" (*lock)
- : "r" (lock)
- : "cr0", "xer");
-
- if (arch_spin_value_unlocked(lock_val))
- goto out;
-
- while (lock->slock) {
- HMT_low();
- if (SHARED_PROCESSOR)
- __spin_yield(lock);
- }
- HMT_medium();
-
-out:
- smp_mb();
-}
-
/*
* Read-write spinlocks, allowing multiple readers
* but only one writer.
--
2.5.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions
2017-06-30 0:01 ` [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions Paul E. McKenney
@ 2017-07-02 3:58 ` Boqun Feng
2017-07-05 23:57 ` Paul E. McKenney
0 siblings, 1 reply; 3+ messages in thread
From: Boqun Feng @ 2017-07-02 3:58 UTC (permalink / raw)
To: Paul E. McKenney
Cc: linux-kernel, linux-arch, parri.andrea, dave, manfred, arnd,
peterz, netdev, linuxppc-dev, will.deacon, oleg, mingo,
netfilter-devel, tj, stern, akpm, torvalds, Paul Mackerras
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On Thu, Jun 29, 2017 at 05:01:29PM -0700, Paul E. McKenney wrote:
> There is no agreed-upon definition of spin_unlock_wait()'s semantics,
> and it appears that all callers could do just as well with a lock/unlock
> pair. This commit therefore removes the underlying arch-specific
> arch_spin_unlock_wait().
>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: <linuxppc-dev@lists.ozlabs.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Andrea Parri <parri.andrea@gmail.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Regards,
Boqun
> ---
> arch/powerpc/include/asm/spinlock.h | 33 ---------------------------------
> 1 file changed, 33 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
> index 8c1b913de6d7..d256e448ea49 100644
> --- a/arch/powerpc/include/asm/spinlock.h
> +++ b/arch/powerpc/include/asm/spinlock.h
> @@ -170,39 +170,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
> lock->slock = 0;
> }
>
> -static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
> -{
> - arch_spinlock_t lock_val;
> -
> - smp_mb();
> -
> - /*
> - * Atomically load and store back the lock value (unchanged). This
> - * ensures that our observation of the lock value is ordered with
> - * respect to other lock operations.
> - */
> - __asm__ __volatile__(
> -"1: " PPC_LWARX(%0, 0, %2, 0) "\n"
> -" stwcx. %0, 0, %2\n"
> -" bne- 1b\n"
> - : "=&r" (lock_val), "+m" (*lock)
> - : "r" (lock)
> - : "cr0", "xer");
> -
> - if (arch_spin_value_unlocked(lock_val))
> - goto out;
> -
> - while (lock->slock) {
> - HMT_low();
> - if (SHARED_PROCESSOR)
> - __spin_yield(lock);
> - }
> - HMT_medium();
> -
> -out:
> - smp_mb();
> -}
> -
> /*
> * Read-write spinlocks, allowing multiple readers
> * but only one writer.
> --
> 2.5.2
>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions
2017-07-02 3:58 ` Boqun Feng
@ 2017-07-05 23:57 ` Paul E. McKenney
0 siblings, 0 replies; 3+ messages in thread
From: Paul E. McKenney @ 2017-07-05 23:57 UTC (permalink / raw)
To: Boqun Feng
Cc: linux-kernel, linux-arch, parri.andrea, dave, manfred, arnd,
peterz, netdev, linuxppc-dev, will.deacon, oleg, mingo,
netfilter-devel, tj, stern, akpm, torvalds, Paul Mackerras
On Sun, Jul 02, 2017 at 11:58:07AM +0800, Boqun Feng wrote:
> On Thu, Jun 29, 2017 at 05:01:29PM -0700, Paul E. McKenney wrote:
> > There is no agreed-upon definition of spin_unlock_wait()'s semantics,
> > and it appears that all callers could do just as well with a lock/unlock
> > pair. This commit therefore removes the underlying arch-specific
> > arch_spin_unlock_wait().
> >
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Cc: Paul Mackerras <paulus@samba.org>
> > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > Cc: <linuxppc-dev@lists.ozlabs.org>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Alan Stern <stern@rowland.harvard.edu>
> > Cc: Andrea Parri <parri.andrea@gmail.com>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
>
> Acked-by: Boqun Feng <boqun.feng@gmail.com>
And finally applied in preparation for v2 of the patch series.
Thank you!!!
Thanx, Paul
> Regards,
> Boqun
>
> > ---
> > arch/powerpc/include/asm/spinlock.h | 33 ---------------------------------
> > 1 file changed, 33 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
> > index 8c1b913de6d7..d256e448ea49 100644
> > --- a/arch/powerpc/include/asm/spinlock.h
> > +++ b/arch/powerpc/include/asm/spinlock.h
> > @@ -170,39 +170,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
> > lock->slock = 0;
> > }
> >
> > -static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
> > -{
> > - arch_spinlock_t lock_val;
> > -
> > - smp_mb();
> > -
> > - /*
> > - * Atomically load and store back the lock value (unchanged). This
> > - * ensures that our observation of the lock value is ordered with
> > - * respect to other lock operations.
> > - */
> > - __asm__ __volatile__(
> > -"1: " PPC_LWARX(%0, 0, %2, 0) "\n"
> > -" stwcx. %0, 0, %2\n"
> > -" bne- 1b\n"
> > - : "=&r" (lock_val), "+m" (*lock)
> > - : "r" (lock)
> > - : "cr0", "xer");
> > -
> > - if (arch_spin_value_unlocked(lock_val))
> > - goto out;
> > -
> > - while (lock->slock) {
> > - HMT_low();
> > - if (SHARED_PROCESSOR)
> > - __spin_yield(lock);
> > - }
> > - HMT_medium();
> > -
> > -out:
> > - smp_mb();
> > -}
> > -
> > /*
> > * Read-write spinlocks, allowing multiple readers
> > * but only one writer.
> > --
> > 2.5.2
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-06-30 0:01 ` [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions Paul E. McKenney
2017-07-02 3:58 ` Boqun Feng
2017-07-05 23:57 ` Paul E. McKenney
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