From 726328d92a42b6d4b76078e2659f43067f82c4e8 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 26 May 2016 10:35:03 +0200 Subject: locking/spinlock, arch: Update and fix spin_unlock_wait() implementations This patch updates/fixes all spin_unlock_wait() implementations. The update is in semantics; where it previously was only a control dependency, we now upgrade to a full load-acquire to match the store-release from the spin_unlock() we waited on. This ensures that when spin_unlock_wait() returns, we're guaranteed to observe the full critical section we waited on. This fixes a number of spin_unlock_wait() users that (not unreasonably) rely on this. I also fixed a number of ticket lock versions to only wait on the current lock holder, instead of for a full unlock, as this is sufficient. Furthermore; again for ticket locks; I added an smp_rmb() in between the initial ticket load and the spin loop testing the current value because I could not convince myself the address dependency is sufficient, esp. if the loads are of different sizes. I'm more than happy to remove this smp_rmb() again if people are certain the address dependency does indeed work as expected. Note: PPC32 will be fixed independently Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: chris@zankel.net Cc: cmetcalf@mellanox.com Cc: davem@davemloft.net Cc: dhowells@redhat.com Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: linux@armlinux.org.uk Cc: mpe@ellerman.id.au Cc: ralf@linux-mips.org Cc: realmz6@gmail.com Cc: rkuo@codeaurora.org Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: vgupta@synopsys.com Cc: ysato@users.sourceforge.jp Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/hexagon/include/asm/spinlock.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/hexagon') diff --git a/arch/hexagon/include/asm/spinlock.h b/arch/hexagon/include/asm/spinlock.h index 12ca4ebc0338..a1c55788c5d6 100644 --- a/arch/hexagon/include/asm/spinlock.h +++ b/arch/hexagon/include/asm/spinlock.h @@ -23,6 +23,8 @@ #define _ASM_SPINLOCK_H #include +#include +#include /* * This file is pulled in for SMP builds. @@ -176,8 +178,12 @@ static inline unsigned int arch_spin_trylock(arch_spinlock_t *lock) * SMP spinlocks are intended to allow only a single CPU at the lock */ #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock) -#define arch_spin_unlock_wait(lock) \ - do {while (arch_spin_is_locked(lock)) cpu_relax(); } while (0) + +static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) +{ + smp_cond_load_acquire(&lock->lock, !VAL); +} + #define arch_spin_is_locked(x) ((x)->lock != 0) #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) -- cgit v1.2.3 From 4be7dd393515615430a4d07ca1ffceaf2a331620 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2016 01:16:07 +0200 Subject: locking/atomic, arch/hexagon: Implement atomic_fetch_{add,sub,and,or,xor}() Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Richard Kuo Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-hexagon@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/hexagon/include/asm/atomic.h | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) (limited to 'arch/hexagon') diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h index 55696c4100d4..07dbb3332b4a 100644 --- a/arch/hexagon/include/asm/atomic.h +++ b/arch/hexagon/include/asm/atomic.h @@ -110,7 +110,7 @@ static inline void atomic_##op(int i, atomic_t *v) \ ); \ } \ -#define ATOMIC_OP_RETURN(op) \ +#define ATOMIC_OP_RETURN(op) \ static inline int atomic_##op##_return(int i, atomic_t *v) \ { \ int output; \ @@ -127,16 +127,39 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return output; \ } -#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) +#define ATOMIC_FETCH_OP(op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + int output, val; \ + \ + __asm__ __volatile__ ( \ + "1: %0 = memw_locked(%2);\n" \ + " %1 = "#op "(%0,%3);\n" \ + " memw_locked(%2,P3)=%1;\n" \ + " if !P3 jump 1b;\n" \ + : "=&r" (output), "=&r" (val) \ + : "r" (&v->counter), "r" (i) \ + : "memory", "p3" \ + ); \ + return output; \ +} + +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op) ATOMIC_OPS(add) ATOMIC_OPS(sub) -ATOMIC_OP(and) -ATOMIC_OP(or) -ATOMIC_OP(xor) +#undef ATOMIC_OPS +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) + +#define atomic_fetch_or atomic_fetch_or + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) #undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP -- cgit v1.2.3 From b53d6bedbe781974097fd8c38263f6cc78ff9ea7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2016 00:58:25 +0200 Subject: locking/atomic: Remove linux/atomic.h:atomic_fetch_or() Since all architectures have this implemented now natively, remove this dead code. Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/alpha/include/asm/atomic.h | 2 -- arch/arc/include/asm/atomic.h | 2 -- arch/arm/include/asm/atomic.h | 2 -- arch/arm64/include/asm/atomic.h | 2 -- arch/avr32/include/asm/atomic.h | 2 -- arch/frv/include/asm/atomic.h | 2 -- arch/h8300/include/asm/atomic.h | 2 -- arch/hexagon/include/asm/atomic.h | 2 -- arch/m32r/include/asm/atomic.h | 2 -- arch/m68k/include/asm/atomic.h | 2 -- arch/metag/include/asm/atomic.h | 2 -- arch/mips/include/asm/atomic.h | 2 -- arch/mn10300/include/asm/atomic.h | 2 -- arch/parisc/include/asm/atomic.h | 2 -- arch/s390/include/asm/atomic.h | 2 -- arch/sh/include/asm/atomic.h | 2 -- arch/sparc/include/asm/atomic.h | 1 - arch/sparc/include/asm/atomic_32.h | 2 -- arch/tile/include/asm/atomic.h | 2 -- arch/x86/include/asm/atomic.h | 2 -- arch/xtensa/include/asm/atomic.h | 2 -- include/asm-generic/atomic.h | 2 -- include/linux/atomic.h | 21 --------------------- 23 files changed, 64 deletions(-) (limited to 'arch/hexagon') diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index 8243f17999e3..5377ca8bb503 100644 --- a/arch/alpha/include/asm/atomic.h +++ b/arch/alpha/include/asm/atomic.h @@ -153,8 +153,6 @@ ATOMIC_OPS(sub) #define atomic_andnot atomic_andnot #define atomic64_andnot atomic64_andnot -#define atomic_fetch_or atomic_fetch_or - #undef ATOMIC_OPS #define ATOMIC_OPS(op, asm) \ ATOMIC_OP(op, asm) \ diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index c066a21caaaf..bd9c51cb2bfd 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -189,8 +189,6 @@ ATOMIC_OPS(sub, -=, sub) #define atomic_andnot atomic_andnot -#define atomic_fetch_or atomic_fetch_or - #undef ATOMIC_OPS #define ATOMIC_OPS(op, c_op, asm_op) \ ATOMIC_OP(op, c_op, asm_op) \ diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index 0feb110ec542..66d0e215a773 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -201,8 +201,6 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \ return val; \ } -#define atomic_fetch_or atomic_fetch_or - static inline int atomic_cmpxchg(atomic_t *v, int old, int new) { int ret; diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h index 3128c3d7c1ff..c0235e0ff849 100644 --- a/arch/arm64/include/asm/atomic.h +++ b/arch/arm64/include/asm/atomic.h @@ -128,8 +128,6 @@ #define __atomic_add_unless(v, a, u) ___atomic_add_unless(v, a, u,) #define atomic_andnot atomic_andnot -#define atomic_fetch_or atomic_fetch_or - /* * 64-bit atomic operations. */ diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h index b8681fd495ef..3d5ce38a6f0b 100644 --- a/arch/avr32/include/asm/atomic.h +++ b/arch/avr32/include/asm/atomic.h @@ -66,8 +66,6 @@ ATOMIC_OP_RETURN(add, add, r) ATOMIC_FETCH_OP (sub, sub, rKs21) ATOMIC_FETCH_OP (add, add, r) -#define atomic_fetch_or atomic_fetch_or - #define ATOMIC_OPS(op, asm_op) \ ATOMIC_OP_RETURN(op, asm_op, r) \ static inline void atomic_##op(int i, atomic_t *v) \ diff --git a/arch/frv/include/asm/atomic.h b/arch/frv/include/asm/atomic.h index e3e06da0cd59..1c2a5e264fc7 100644 --- a/arch/frv/include/asm/atomic.h +++ b/arch/frv/include/asm/atomic.h @@ -74,8 +74,6 @@ static inline void atomic_dec(atomic_t *v) #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0) -#define atomic_fetch_or atomic_fetch_or - /* * 64-bit atomic ops */ diff --git a/arch/h8300/include/asm/atomic.h b/arch/h8300/include/asm/atomic.h index 0961b618bdde..349a47a918db 100644 --- a/arch/h8300/include/asm/atomic.h +++ b/arch/h8300/include/asm/atomic.h @@ -54,8 +54,6 @@ static inline void atomic_##op(int i, atomic_t *v) \ ATOMIC_OP_RETURN(add, +=) ATOMIC_OP_RETURN(sub, -=) -#define atomic_fetch_or atomic_fetch_or - #define ATOMIC_OPS(op, c_op) \ ATOMIC_OP(op, c_op) \ ATOMIC_FETCH_OP(op, c_op) diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h index 07dbb3332b4a..a62ba368b27d 100644 --- a/arch/hexagon/include/asm/atomic.h +++ b/arch/hexagon/include/asm/atomic.h @@ -152,8 +152,6 @@ ATOMIC_OPS(sub) #undef ATOMIC_OPS #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and) ATOMIC_OPS(or) ATOMIC_OPS(xor) diff --git a/arch/m32r/include/asm/atomic.h b/arch/m32r/include/asm/atomic.h index 8ba8a0ab5d5d..640cc1c7099f 100644 --- a/arch/m32r/include/asm/atomic.h +++ b/arch/m32r/include/asm/atomic.h @@ -121,8 +121,6 @@ ATOMIC_OPS(sub) #undef ATOMIC_OPS #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and) ATOMIC_OPS(or) ATOMIC_OPS(xor) diff --git a/arch/m68k/include/asm/atomic.h b/arch/m68k/include/asm/atomic.h index 5cf9b3b1b6ac..3e03de7ae33b 100644 --- a/arch/m68k/include/asm/atomic.h +++ b/arch/m68k/include/asm/atomic.h @@ -119,8 +119,6 @@ ATOMIC_OPS(sub, -=, sub) ATOMIC_OP(op, c_op, asm_op) \ ATOMIC_FETCH_OP(op, c_op, asm_op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and, &=, and) ATOMIC_OPS(or, |=, or) ATOMIC_OPS(xor, ^=, eor) diff --git a/arch/metag/include/asm/atomic.h b/arch/metag/include/asm/atomic.h index 6ca210de8a7d..470e365f04ea 100644 --- a/arch/metag/include/asm/atomic.h +++ b/arch/metag/include/asm/atomic.h @@ -17,8 +17,6 @@ #include #endif -#define atomic_fetch_or atomic_fetch_or - #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) #define atomic_dec_return(v) atomic_sub_return(1, (v)) diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h index 431079f8e483..387ce288334e 100644 --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -194,8 +194,6 @@ ATOMIC_OPS(sub, -=, subu) ATOMIC_OP(op, c_op, asm_op) \ ATOMIC_FETCH_OP(op, c_op, asm_op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and, &=, and) ATOMIC_OPS(or, |=, or) ATOMIC_OPS(xor, ^=, xor) diff --git a/arch/mn10300/include/asm/atomic.h b/arch/mn10300/include/asm/atomic.h index 3580f789f3a6..36389efd45e8 100644 --- a/arch/mn10300/include/asm/atomic.h +++ b/arch/mn10300/include/asm/atomic.h @@ -113,8 +113,6 @@ ATOMIC_OPS(sub) #undef ATOMIC_OPS #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and) ATOMIC_OPS(or) ATOMIC_OPS(xor) diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h index 29df1f871910..5394b9c5f914 100644 --- a/arch/parisc/include/asm/atomic.h +++ b/arch/parisc/include/asm/atomic.h @@ -148,8 +148,6 @@ ATOMIC_OPS(sub, -=) ATOMIC_OP(op, c_op) \ ATOMIC_FETCH_OP(op, c_op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and, &=) ATOMIC_OPS(or, |=) ATOMIC_OPS(xor, ^=) diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h index 2324e759b544..d28cc2f5b7b2 100644 --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -135,8 +135,6 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \ return __ATOMIC_LOOP(v, i, __ATOMIC_##OP, __ATOMIC_BARRIER); \ } -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and, AND) ATOMIC_OPS(or, OR) ATOMIC_OPS(xor, XOR) diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h index d93ed7ce1b2f..c399e1c55685 100644 --- a/arch/sh/include/asm/atomic.h +++ b/arch/sh/include/asm/atomic.h @@ -25,8 +25,6 @@ #include #endif -#define atomic_fetch_or atomic_fetch_or - #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) #define atomic_dec_return(v) atomic_sub_return(1, (v)) #define atomic_inc_return(v) atomic_add_return(1, (v)) diff --git a/arch/sparc/include/asm/atomic.h b/arch/sparc/include/asm/atomic.h index 1f741bcc73b7..8ff83d8cc33f 100644 --- a/arch/sparc/include/asm/atomic.h +++ b/arch/sparc/include/asm/atomic.h @@ -5,5 +5,4 @@ #else #include #endif -#define atomic_fetch_or atomic_fetch_or #endif diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h index 5cfb20a599d9..ee3f11c43cda 100644 --- a/arch/sparc/include/asm/atomic_32.h +++ b/arch/sparc/include/asm/atomic_32.h @@ -36,8 +36,6 @@ void atomic_set(atomic_t *, int); #define atomic_inc(v) ((void)atomic_add_return( 1, (v))) #define atomic_dec(v) ((void)atomic_add_return( -1, (v))) -#define atomic_fetch_or atomic_fetch_or - #define atomic_and(i, v) ((void)atomic_fetch_and((i), (v))) #define atomic_or(i, v) ((void)atomic_fetch_or((i), (v))) #define atomic_xor(i, v) ((void)atomic_fetch_xor((i), (v))) diff --git a/arch/tile/include/asm/atomic.h b/arch/tile/include/asm/atomic.h index 9807030557c4..8dda3c8ff5ab 100644 --- a/arch/tile/include/asm/atomic.h +++ b/arch/tile/include/asm/atomic.h @@ -48,8 +48,6 @@ static inline int atomic_read(const atomic_t *v) #define atomic_fetch_sub(i, v) atomic_fetch_add(-(int)(i), (v)) -#define atomic_fetch_or atomic_fetch_or - /** * atomic_sub - subtract integer from atomic variable * @i: integer value to subtract diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index 73b8463b89e9..a58b99811105 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -217,8 +217,6 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \ ATOMIC_OP(op) \ ATOMIC_FETCH_OP(op, c_op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and, &) ATOMIC_OPS(or , |) ATOMIC_OPS(xor, ^) diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h index d95a8aa1a6d3..e7a23f2a519a 100644 --- a/arch/xtensa/include/asm/atomic.h +++ b/arch/xtensa/include/asm/atomic.h @@ -188,8 +188,6 @@ ATOMIC_OPS(sub) #undef ATOMIC_OPS #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) -#define atomic_fetch_or atomic_fetch_or - ATOMIC_OPS(and) ATOMIC_OPS(or) ATOMIC_OPS(xor) diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index a2304ccf4ed0..9ed8b987185b 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -137,8 +137,6 @@ ATOMIC_FETCH_OP(and, &) #endif #ifndef atomic_fetch_or -#define atomic_fetch_or atomic_fetch_or - ATOMIC_FETCH_OP(or, |) #endif diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 2e6c013ac5a4..0b3802d33125 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -573,27 +573,6 @@ static inline int atomic_dec_if_positive(atomic_t *v) } #endif -/** - * atomic_fetch_or - perform *p |= mask and return old value of *p - * @mask: mask to OR on the atomic_t - * @p: pointer to atomic_t - */ -#ifndef atomic_fetch_or -static inline int atomic_fetch_or(int mask, atomic_t *p) -{ - int old, val = atomic_read(p); - - for (;;) { - old = atomic_cmpxchg(p, val, val | mask); - if (old == val) - break; - val = old; - } - - return old; -} -#endif - #ifdef CONFIG_GENERIC_ATOMIC64 #include #endif -- cgit v1.2.3