* [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 [-- Attachment #1: Type: text/plain, Size: 2192 bytes --] 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 > [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 488 bytes --] ^ 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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