From patchwork Fri Oct 22 11:59:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12577583 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1639BC433F5 for ; Fri, 22 Oct 2021 12:01:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECBBA610D2 for ; Fri, 22 Oct 2021 12:01:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230230AbhJVMD3 (ORCPT ); Fri, 22 Oct 2021 08:03:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:57228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbhJVMD2 (ORCPT ); Fri, 22 Oct 2021 08:03:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BEB6660C4C; Fri, 22 Oct 2021 12:01:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634904070; bh=qtLhW6yJc0m7cAPxwCcpju0k0Trvuqus6DX8RjrMrwQ=; h=From:To:Cc:Subject:Date:From; b=SAu9tSKCbqiJGF0fecRlvTkO/vclPKkUQHrLN615nSNbXoZjf33R7XvYXI5QsEkG+ c2EPr9rRutH1pzDZpBdjqtFclTmCJY2KuDd9ND8HboYNcNPjWcQ1Xoxw1E0ccYFfpa Y+lpOpH2rdPgBzWPapFLNfYOReMJTfoQlRAJotreNpssaXo83NTLDnXaWHRHrK7UaS OjqCeDgCfW/uJHO9Q3z46GJbdNJcU0Ig2mNldTDelBss2UrmemrQdjUJ5oEri8e3fV pXex+MOYJcIpeh9QjfL9ehSGPNv+sT2If1HZwy4L6gFxVglwCpW7yBWAdP0UulQXQw hrZ3PBI60yxzg== From: Arnd Bergmann To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: Arnd Bergmann , Waiman Long , Boqun Feng , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Alexander Gordeev , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org Subject: [PATCH] locking: remove spin_lock_flags() etc Date: Fri, 22 Oct 2021 13:59:38 +0200 Message-Id: <20211022120058.1031690-1-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org From: Arnd Bergmann parisc, ia64 and powerpc32 are the only remaining architectures that provide custom arch_{spin,read,write}_lock_flags() functions, which are meant to re-enable interrupts while waiting for a spinlock. However, none of these can actually run into this codepath, because it is only called on architectures without CONFIG_GENERIC_LOCKBREAK, or when CONFIG_DEBUG_LOCK_ALLOC is set without CONFIG_LOCKDEP, and none of those combinations are possible on the three architectures. Going back in the git history, it appears that arch/mn10300 may have been able to run into this code path, but there is a good chance that it never worked. On the architectures that still exist, it was already impossible to hit back in 2008 after the introduction of CONFIG_GENERIC_LOCKBREAK, and possibly earlier. As this is all dead code, just remove it and the helper functions built around it. For arch/ia64, the inline asm could be cleaned up, but it seems safer to leave it untouched. Signed-off-by: Arnd Bergmann Acked-by: Helge Deller # parisc --- arch/ia64/include/asm/spinlock.h | 23 ++++++---------------- arch/openrisc/include/asm/spinlock.h | 3 --- arch/parisc/include/asm/spinlock.h | 15 -------------- arch/powerpc/include/asm/simple_spinlock.h | 21 -------------------- arch/s390/include/asm/spinlock.h | 8 -------- include/linux/lockdep.h | 17 ---------------- include/linux/rwlock.h | 15 -------------- include/linux/rwlock_api_smp.h | 6 ++---- include/linux/spinlock.h | 13 ------------ include/linux/spinlock_api_smp.h | 9 --------- include/linux/spinlock_up.h | 1 - kernel/locking/spinlock.c | 3 +-- 12 files changed, 9 insertions(+), 125 deletions(-) diff --git a/arch/ia64/include/asm/spinlock.h b/arch/ia64/include/asm/spinlock.h index 864775970c50..0e5c1ad3239c 100644 --- a/arch/ia64/include/asm/spinlock.h +++ b/arch/ia64/include/asm/spinlock.h @@ -124,18 +124,13 @@ static __always_inline void arch_spin_unlock(arch_spinlock_t *lock) __ticket_spin_unlock(lock); } -static __always_inline void arch_spin_lock_flags(arch_spinlock_t *lock, - unsigned long flags) -{ - arch_spin_lock(lock); -} -#define arch_spin_lock_flags arch_spin_lock_flags - #ifdef ASM_SUPPORTED static __always_inline void -arch_read_lock_flags(arch_rwlock_t *lock, unsigned long flags) +arch_read_lock(arch_rwlock_t *lock) { + unsigned long flags = 0; + __asm__ __volatile__ ( "tbit.nz p6, p0 = %1,%2\n" "br.few 3f\n" @@ -157,13 +152,8 @@ arch_read_lock_flags(arch_rwlock_t *lock, unsigned long flags) : "p6", "p7", "r2", "memory"); } -#define arch_read_lock_flags arch_read_lock_flags -#define arch_read_lock(lock) arch_read_lock_flags(lock, 0) - #else /* !ASM_SUPPORTED */ -#define arch_read_lock_flags(rw, flags) arch_read_lock(rw) - #define arch_read_lock(rw) \ do { \ arch_rwlock_t *__read_lock_ptr = (rw); \ @@ -186,8 +176,10 @@ do { \ #ifdef ASM_SUPPORTED static __always_inline void -arch_write_lock_flags(arch_rwlock_t *lock, unsigned long flags) +arch_write_lock(arch_rwlock_t *lock) { + unsigned long flags = 0; + __asm__ __volatile__ ( "tbit.nz p6, p0 = %1, %2\n" "mov ar.ccv = r0\n" @@ -210,9 +202,6 @@ arch_write_lock_flags(arch_rwlock_t *lock, unsigned long flags) : "ar.ccv", "p6", "p7", "r2", "r29", "memory"); } -#define arch_write_lock_flags arch_write_lock_flags -#define arch_write_lock(rw) arch_write_lock_flags(rw, 0) - #define arch_write_trylock(rw) \ ({ \ register long result; \ diff --git a/arch/openrisc/include/asm/spinlock.h b/arch/openrisc/include/asm/spinlock.h index a8940bdfcb7e..264944a71535 100644 --- a/arch/openrisc/include/asm/spinlock.h +++ b/arch/openrisc/include/asm/spinlock.h @@ -19,9 +19,6 @@ #include -#define arch_read_lock_flags(lock, flags) arch_read_lock(lock) -#define arch_write_lock_flags(lock, flags) arch_write_lock(lock) - #define arch_spin_relax(lock) cpu_relax() #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h index fa5ee8a45dbd..a6e5d66a7656 100644 --- a/arch/parisc/include/asm/spinlock.h +++ b/arch/parisc/include/asm/spinlock.h @@ -23,21 +23,6 @@ static inline void arch_spin_lock(arch_spinlock_t *x) continue; } -static inline void arch_spin_lock_flags(arch_spinlock_t *x, - unsigned long flags) -{ - volatile unsigned int *a; - - a = __ldcw_align(x); - while (__ldcw(a) == 0) - while (*a == 0) - if (flags & PSW_SM_I) { - local_irq_enable(); - local_irq_disable(); - } -} -#define arch_spin_lock_flags arch_spin_lock_flags - static inline void arch_spin_unlock(arch_spinlock_t *x) { volatile unsigned int *a; diff --git a/arch/powerpc/include/asm/simple_spinlock.h b/arch/powerpc/include/asm/simple_spinlock.h index 8985791a2ba5..7ae6aeef8464 100644 --- a/arch/powerpc/include/asm/simple_spinlock.h +++ b/arch/powerpc/include/asm/simple_spinlock.h @@ -123,27 +123,6 @@ static inline void arch_spin_lock(arch_spinlock_t *lock) } } -static inline -void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) -{ - unsigned long flags_dis; - - while (1) { - if (likely(__arch_spin_trylock(lock) == 0)) - break; - local_save_flags(flags_dis); - local_irq_restore(flags); - do { - HMT_low(); - if (is_shared_processor()) - splpar_spin_yield(lock); - } while (unlikely(lock->slock != 0)); - HMT_medium(); - local_irq_restore(flags_dis); - } -} -#define arch_spin_lock_flags arch_spin_lock_flags - static inline void arch_spin_unlock(arch_spinlock_t *lock) { __asm__ __volatile__("# arch_spin_unlock\n\t" diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h index ef59588a3042..888a2f1c9ee3 100644 --- a/arch/s390/include/asm/spinlock.h +++ b/arch/s390/include/asm/spinlock.h @@ -67,14 +67,6 @@ static inline void arch_spin_lock(arch_spinlock_t *lp) arch_spin_lock_wait(lp); } -static inline void arch_spin_lock_flags(arch_spinlock_t *lp, - unsigned long flags) -{ - if (!arch_spin_trylock_once(lp)) - arch_spin_lock_wait(lp); -} -#define arch_spin_lock_flags arch_spin_lock_flags - static inline int arch_spin_trylock(arch_spinlock_t *lp) { if (!arch_spin_trylock_once(lp)) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 9fe165beb0f9..467b94257105 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -481,23 +481,6 @@ do { \ #endif /* CONFIG_LOCK_STAT */ -#ifdef CONFIG_LOCKDEP - -/* - * On lockdep we dont want the hand-coded irq-enable of - * _raw_*_lock_flags() code, because lockdep assumes - * that interrupts are not re-enabled during lock-acquire: - */ -#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ - LOCK_CONTENDED((_lock), (try), (lock)) - -#else /* CONFIG_LOCKDEP */ - -#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ - lockfl((_lock), (flags)) - -#endif /* CONFIG_LOCKDEP */ - #ifdef CONFIG_PROVE_LOCKING extern void print_irqtrace_events(struct task_struct *curr); #else diff --git a/include/linux/rwlock.h b/include/linux/rwlock.h index 7ce9a51ae5c0..2c0ad417ce3c 100644 --- a/include/linux/rwlock.h +++ b/include/linux/rwlock.h @@ -30,31 +30,16 @@ do { \ #ifdef CONFIG_DEBUG_SPINLOCK extern void do_raw_read_lock(rwlock_t *lock) __acquires(lock); -#define do_raw_read_lock_flags(lock, flags) do_raw_read_lock(lock) extern int do_raw_read_trylock(rwlock_t *lock); extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock); extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock); -#define do_raw_write_lock_flags(lock, flags) do_raw_write_lock(lock) extern int do_raw_write_trylock(rwlock_t *lock); extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock); #else - -#ifndef arch_read_lock_flags -# define arch_read_lock_flags(lock, flags) arch_read_lock(lock) -#endif - -#ifndef arch_write_lock_flags -# define arch_write_lock_flags(lock, flags) arch_write_lock(lock) -#endif - # define do_raw_read_lock(rwlock) do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0) -# define do_raw_read_lock_flags(lock, flags) \ - do {__acquire(lock); arch_read_lock_flags(&(lock)->raw_lock, *(flags)); } while (0) # define do_raw_read_trylock(rwlock) arch_read_trylock(&(rwlock)->raw_lock) # define do_raw_read_unlock(rwlock) do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0) # define do_raw_write_lock(rwlock) do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0) -# define do_raw_write_lock_flags(lock, flags) \ - do {__acquire(lock); arch_write_lock_flags(&(lock)->raw_lock, *(flags)); } while (0) # define do_raw_write_trylock(rwlock) arch_write_trylock(&(rwlock)->raw_lock) # define do_raw_write_unlock(rwlock) do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0) #endif diff --git a/include/linux/rwlock_api_smp.h b/include/linux/rwlock_api_smp.h index abfb53ab11be..f1db6f17c4fb 100644 --- a/include/linux/rwlock_api_smp.h +++ b/include/linux/rwlock_api_smp.h @@ -157,8 +157,7 @@ static inline unsigned long __raw_read_lock_irqsave(rwlock_t *lock) local_irq_save(flags); preempt_disable(); rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_); - LOCK_CONTENDED_FLAGS(lock, do_raw_read_trylock, do_raw_read_lock, - do_raw_read_lock_flags, &flags); + LOCK_CONTENDED(lock, do_raw_read_trylock, do_raw_read_lock); return flags; } @@ -184,8 +183,7 @@ static inline unsigned long __raw_write_lock_irqsave(rwlock_t *lock) local_irq_save(flags); preempt_disable(); rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); - LOCK_CONTENDED_FLAGS(lock, do_raw_write_trylock, do_raw_write_lock, - do_raw_write_lock_flags, &flags); + LOCK_CONTENDED(lock, do_raw_write_trylock, do_raw_write_lock); return flags; } diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index c04e99edfe92..40e467cdee2d 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -176,7 +176,6 @@ do { \ #ifdef CONFIG_DEBUG_SPINLOCK extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); -#define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) extern int do_raw_spin_trylock(raw_spinlock_t *lock); extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); #else @@ -187,18 +186,6 @@ static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) mmiowb_spin_lock(); } -#ifndef arch_spin_lock_flags -#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock) -#endif - -static inline void -do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) -{ - __acquire(lock); - arch_spin_lock_flags(&lock->raw_lock, *flags); - mmiowb_spin_lock(); -} - static inline int do_raw_spin_trylock(raw_spinlock_t *lock) { int ret = arch_spin_trylock(&(lock)->raw_lock); diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h index 6b8e1a0b137b..51fa0dab68c4 100644 --- a/include/linux/spinlock_api_smp.h +++ b/include/linux/spinlock_api_smp.h @@ -108,16 +108,7 @@ static inline unsigned long __raw_spin_lock_irqsave(raw_spinlock_t *lock) local_irq_save(flags); preempt_disable(); spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); - /* - * On lockdep we dont want the hand-coded irq-enable of - * do_raw_spin_lock_flags() code, because lockdep assumes - * that interrupts are not re-enabled during lock-acquire: - */ -#ifdef CONFIG_LOCKDEP LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); -#else - do_raw_spin_lock_flags(lock, &flags); -#endif return flags; } diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h index 0ac9112c1bbe..16521074b6f7 100644 --- a/include/linux/spinlock_up.h +++ b/include/linux/spinlock_up.h @@ -62,7 +62,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock) #define arch_spin_is_locked(lock) ((void)(lock), 0) /* for sched/core.c and kernel_lock.c: */ # define arch_spin_lock(lock) do { barrier(); (void)(lock); } while (0) -# define arch_spin_lock_flags(lock, flags) do { barrier(); (void)(lock); } while (0) # define arch_spin_unlock(lock) do { barrier(); (void)(lock); } while (0) # define arch_spin_trylock(lock) ({ barrier(); (void)(lock); 1; }) #endif /* DEBUG_SPINLOCK */ diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c index c5830cfa379a..b562f9289372 100644 --- a/kernel/locking/spinlock.c +++ b/kernel/locking/spinlock.c @@ -378,8 +378,7 @@ unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock, local_irq_save(flags); preempt_disable(); spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); - LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock, - do_raw_spin_lock_flags, &flags); + LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); return flags; } EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);