From patchwork Fri Mar 22 14:30:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 10865909 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 22FCB6C2 for ; Fri, 22 Mar 2019 14:31:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F1B642A841 for ; Fri, 22 Mar 2019 14:31:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E488A2A83C; Fri, 22 Mar 2019 14:31:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9B9702A844 for ; Fri, 22 Mar 2019 14:31:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=qx69KahybPC/PWTkcgUlQkIBzFta/92TMSHAxTIpUvs=; b=YzcbfpahxGbeqXApeCP53BycFW 9DHfrKkDXM3XW1FKPsJJTP3JJL4vrogjd75RYBuAEtHnsu+F9YJLiMRzhNF/ftQd6dJQMrfjeazP3 W8RCTM9fRRy+MAot70bppfNd8mu3w0xKYFdG3fKVyf8gUhOKLqldxzjI9SB0+jsBsTbFN8FbKqPWa 0Y4bpylxNsTY6HvBrRgSxxnfJkL5vg7wY/NT/dTydFkK7FyqlcW/hwmTtViC0PYtgA1A1R0pYlzD/ fEYodvcHOUjeAs95iIcWFK8fuXWqTAijjrTPLxZxPrYctlU3gJ9IjqhEO5A2SXt67lX/FujtMYAQY U1LI9ukA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h7LCQ-0003aM-33; Fri, 22 Mar 2019 14:31:10 +0000 Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h7LBo-0002pR-Vb; Fri, 22 Mar 2019 14:30:39 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3A6295D671; Fri, 22 Mar 2019 14:30:32 +0000 (UTC) Received: from llong.com (dhcp-17-47.bos.redhat.com [10.18.17.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id F0C6960C05; Fri, 22 Mar 2019 14:30:24 +0000 (UTC) From: Waiman Long To: Peter Zijlstra , Ingo Molnar , Will Deacon , Thomas Gleixner Subject: [PATCH v5 2/3] locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archs Date: Fri, 22 Mar 2019 10:30:07 -0400 Message-Id: <20190322143008.21313-3-longman@redhat.com> In-Reply-To: <20190322143008.21313-1-longman@redhat.com> References: <20190322143008.21313-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 22 Mar 2019 14:30:32 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190322_073033_581009_F5DB2836 X-CRM114-Status: GOOD ( 18.56 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, linux-mips@vger.kernel.org, "H. Peter Anvin" , sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Davidlohr Bueso , linux-c6x-dev@linux-c6x.org, linux-hexagon@vger.kernel.org, x86@kernel.org, Waiman Long , uclinux-h8-devel@lists.sourceforge.jp, linux-xtensa@linux-xtensa.org, Arnd Bergmann , linux-um@lists.infradead.org, linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, Borislav Petkov , linux-arm-kernel@lists.infradead.org, Tim Chen , linux-parisc@vger.kernel.org, Linus Torvalds , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, nios2-dev@lists.rocketboards.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org MIME-Version: 1.0 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+patchwork-linux-riscv=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, we have two different implementation of rwsem: 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) As we are going to use a single generic implementation for rwsem-xadd.c and no architecture-specific code will be needed, there is no point in keeping two different implementations of rwsem. In most cases, the performance of rwsem-spinlock.c will be worse. It also doesn't get all the performance tuning and optimizations that had been implemented in rwsem-xadd.c over the years. For simplication, we are going to remove rwsem-spinlock.c and make all architectures use a single implementation of rwsem - rwsem-xadd.c. All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM in the code are removed. Suggested-by: Peter Zijlstra Signed-off-by: Waiman Long --- arch/alpha/Kconfig | 7 - arch/arc/Kconfig | 3 - arch/arm/Kconfig | 4 - arch/arm64/Kconfig | 3 - arch/c6x/Kconfig | 3 - arch/csky/Kconfig | 3 - arch/h8300/Kconfig | 3 - arch/hexagon/Kconfig | 6 - arch/ia64/Kconfig | 4 - arch/m68k/Kconfig | 7 - arch/microblaze/Kconfig | 6 - arch/mips/Kconfig | 7 - arch/nds32/Kconfig | 3 - arch/nios2/Kconfig | 3 - arch/openrisc/Kconfig | 6 - arch/parisc/Kconfig | 6 - arch/powerpc/Kconfig | 7 - arch/riscv/Kconfig | 3 - arch/s390/Kconfig | 6 - arch/sh/Kconfig | 6 - arch/sparc/Kconfig | 8 - arch/unicore32/Kconfig | 6 - arch/x86/Kconfig | 3 - arch/x86/um/Kconfig | 6 - arch/xtensa/Kconfig | 3 - include/linux/rwsem-spinlock.h | 47 ----- include/linux/rwsem.h | 5 - kernel/Kconfig.locks | 2 +- kernel/locking/Makefile | 4 +- kernel/locking/rwsem-spinlock.c | 339 -------------------------------- kernel/locking/rwsem.h | 3 - 31 files changed, 2 insertions(+), 520 deletions(-) delete mode 100644 include/linux/rwsem-spinlock.h delete mode 100644 kernel/locking/rwsem-spinlock.c diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 584a6e114853..27c871227eee 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -49,13 +49,6 @@ config MMU bool default y -config RWSEM_GENERIC_SPINLOCK - bool - -config RWSEM_XCHGADD_ALGORITHM - bool - default y - config ARCH_HAS_ILOG2_U32 bool default n diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index c781e45d1d99..23e063df5d2c 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -63,9 +63,6 @@ config SCHED_OMIT_FRAME_POINTER config GENERIC_CSUM def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - config ARCH_DISCONTIGMEM_ENABLE def_bool n diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 054ead960f98..c11c61093c6c 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -178,10 +178,6 @@ config TRACE_IRQFLAGS_SUPPORT bool default !CPU_V7M -config RWSEM_XCHGADD_ALGORITHM - bool - default y - config ARCH_HAS_ILOG2_U32 bool diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7e34b9eba5de..c62b9db2b5e8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -237,9 +237,6 @@ config LOCKDEP_SUPPORT config TRACE_IRQFLAGS_SUPPORT def_bool y -config RWSEM_XCHGADD_ALGORITHM - def_bool y - config GENERIC_BUG def_bool y depends on BUG diff --git a/arch/c6x/Kconfig b/arch/c6x/Kconfig index e5cd3c5f8399..ed92b5840c0a 100644 --- a/arch/c6x/Kconfig +++ b/arch/c6x/Kconfig @@ -27,9 +27,6 @@ config MMU config FPU def_bool n -config RWSEM_GENERIC_SPINLOCK - def_bool y - config GENERIC_CALIBRATE_DELAY def_bool y diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 725a115759c9..6555d1781132 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -92,9 +92,6 @@ config GENERIC_HWEIGHT config MMU def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - config STACKTRACE_SUPPORT def_bool y diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig index c071da34e081..61c01db6c292 100644 --- a/arch/h8300/Kconfig +++ b/arch/h8300/Kconfig @@ -27,9 +27,6 @@ config H8300 config CPU_BIG_ENDIAN def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - config GENERIC_HWEIGHT def_bool y diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig index ac441680dcc0..3e54a53208d5 100644 --- a/arch/hexagon/Kconfig +++ b/arch/hexagon/Kconfig @@ -65,12 +65,6 @@ config GENERIC_CSUM config GENERIC_IRQ_PROBE def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool n - -config RWSEM_XCHGADD_ALGORITHM - def_bool y - config GENERIC_HWEIGHT def_bool y diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 8d7396bd1790..73a26f04644e 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -83,10 +83,6 @@ config STACKTRACE_SUPPORT config GENERIC_LOCKBREAK def_bool n -config RWSEM_XCHGADD_ALGORITHM - bool - default y - config HUGETLB_PAGE_SIZE_VARIABLE bool depends on HUGETLB_PAGE diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index b54206408f91..f5661f48019c 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -32,13 +32,6 @@ config M68K config CPU_BIG_ENDIAN def_bool y -config RWSEM_GENERIC_SPINLOCK - bool - default y - -config RWSEM_XCHGADD_ALGORITHM - bool - config ARCH_HAS_ILOG2_U32 bool diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig index a51b965b3b82..a7a9a9d59f65 100644 --- a/arch/microblaze/Kconfig +++ b/arch/microblaze/Kconfig @@ -58,15 +58,9 @@ config CPU_LITTLE_ENDIAN endchoice -config RWSEM_GENERIC_SPINLOCK - def_bool y - config ZONE_DMA def_bool y -config RWSEM_XCHGADD_ALGORITHM - bool - config ARCH_HAS_ILOG2_U32 def_bool n diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 4a5f5b0ee9a9..b9c48b27162d 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1037,13 +1037,6 @@ source "arch/mips/paravirt/Kconfig" endmenu -config RWSEM_GENERIC_SPINLOCK - bool - default y - -config RWSEM_XCHGADD_ALGORITHM - bool - config GENERIC_HWEIGHT bool default y diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig index addb7f5f5264..55559ca0efe4 100644 --- a/arch/nds32/Kconfig +++ b/arch/nds32/Kconfig @@ -60,9 +60,6 @@ config GENERIC_LOCKBREAK def_bool y depends on PREEMPT -config RWSEM_GENERIC_SPINLOCK - def_bool y - config TRACE_IRQFLAGS_SUPPORT def_bool y diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig index 4ef15a61b7bc..56685fd45ed0 100644 --- a/arch/nios2/Kconfig +++ b/arch/nios2/Kconfig @@ -40,9 +40,6 @@ config NO_IOPORT_MAP config FPU def_bool n -config RWSEM_GENERIC_SPINLOCK - def_bool y - config TRACE_IRQFLAGS_SUPPORT def_bool n diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig index a5e361fbb75a..683511b8c9df 100644 --- a/arch/openrisc/Kconfig +++ b/arch/openrisc/Kconfig @@ -43,12 +43,6 @@ config CPU_BIG_ENDIAN config MMU def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - -config RWSEM_XCHGADD_ALGORITHM - def_bool n - config GENERIC_HWEIGHT def_bool y diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index c8e621296092..f1ed8ddfe486 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -75,12 +75,6 @@ config GENERIC_LOCKBREAK default y depends on SMP && PREEMPT -config RWSEM_GENERIC_SPINLOCK - def_bool y - -config RWSEM_XCHGADD_ALGORITHM - bool - config ARCH_HAS_ILOG2_U32 bool default n diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 2d0be82c3061..e5dd6aafaf68 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -103,13 +103,6 @@ config LOCKDEP_SUPPORT bool default y -config RWSEM_GENERIC_SPINLOCK - bool - -config RWSEM_XCHGADD_ALGORITHM - bool - default y - config GENERIC_LOCKBREAK bool default y diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index eb56c82d8aa1..0582260fb6c2 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -69,9 +69,6 @@ config STACKTRACE_SUPPORT config TRACE_IRQFLAGS_SUPPORT def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - config GENERIC_BUG def_bool y depends on BUG diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b6e3d0653002..c9300b437195 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -14,12 +14,6 @@ config LOCKDEP_SUPPORT config STACKTRACE_SUPPORT def_bool y -config RWSEM_GENERIC_SPINLOCK - bool - -config RWSEM_XCHGADD_ALGORITHM - def_bool y - config ARCH_HAS_ILOG2_U32 def_bool n diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index b1c91ea9a958..0be08d586d40 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -90,12 +90,6 @@ config ARCH_DEFCONFIG default "arch/sh/configs/shx3_defconfig" if SUPERH32 default "arch/sh/configs/cayman_defconfig" if SUPERH64 -config RWSEM_GENERIC_SPINLOCK - def_bool y - -config RWSEM_XCHGADD_ALGORITHM - bool - config GENERIC_BUG def_bool y depends on BUG && SUPERH32 diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 40f8f4f73fe8..16b620237816 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -191,14 +191,6 @@ config NR_CPUS source "kernel/Kconfig.hz" -config RWSEM_GENERIC_SPINLOCK - bool - default y if SPARC32 - -config RWSEM_XCHGADD_ALGORITHM - bool - default y if SPARC64 - config GENERIC_HWEIGHT bool default y diff --git a/arch/unicore32/Kconfig b/arch/unicore32/Kconfig index 817d82608712..0d5869c9bf03 100644 --- a/arch/unicore32/Kconfig +++ b/arch/unicore32/Kconfig @@ -38,12 +38,6 @@ config STACKTRACE_SUPPORT config LOCKDEP_SUPPORT def_bool y -config RWSEM_GENERIC_SPINLOCK - def_bool y - -config RWSEM_XCHGADD_ALGORITHM - bool - config ARCH_HAS_ILOG2_U32 bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c1f9b3cf437c..fec892bab654 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -268,9 +268,6 @@ config ARCH_MAY_HAVE_PC_FDC def_bool y depends on ISA_DMA_API -config RWSEM_XCHGADD_ALGORITHM - def_bool y - config GENERIC_CALIBRATE_DELAY def_bool y diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig index a9e80e44178c..a8985e1f7432 100644 --- a/arch/x86/um/Kconfig +++ b/arch/x86/um/Kconfig @@ -32,12 +32,6 @@ config ARCH_DEFCONFIG default "arch/um/configs/i386_defconfig" if X86_32 default "arch/um/configs/x86_64_defconfig" if X86_64 -config RWSEM_XCHGADD_ALGORITHM - def_bool 64BIT - -config RWSEM_GENERIC_SPINLOCK - def_bool !RWSEM_XCHGADD_ALGORITHM - config 3_LEVEL_PGTABLES bool "Three-level pagetables" if !64BIT default 64BIT diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 4b9aafe766c5..35c8d91e6106 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -46,9 +46,6 @@ config XTENSA with reasonable minimum requirements. The Xtensa Linux project has a home page at . -config RWSEM_XCHGADD_ALGORITHM - def_bool y - config GENERIC_HWEIGHT def_bool y diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h deleted file mode 100644 index e47568363e5e..000000000000 --- a/include/linux/rwsem-spinlock.h +++ /dev/null @@ -1,47 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* rwsem-spinlock.h: fallback C implementation - * - * Copyright (c) 2001 David Howells (dhowells@redhat.com). - * - Derived partially from ideas by Andrea Arcangeli - * - Derived also from comments by Linus - */ - -#ifndef _LINUX_RWSEM_SPINLOCK_H -#define _LINUX_RWSEM_SPINLOCK_H - -#ifndef _LINUX_RWSEM_H -#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead" -#endif - -#ifdef __KERNEL__ -/* - * the rw-semaphore definition - * - if count is 0 then there are no active readers or writers - * - if count is +ve then that is the number of active readers - * - if count is -1 then there is one active writer - * - if wait_list is not empty, then there are processes waiting for the semaphore - */ -struct rw_semaphore { - __s32 count; - raw_spinlock_t wait_lock; - struct list_head wait_list; -#ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map dep_map; -#endif -}; - -#define RWSEM_UNLOCKED_VALUE 0x00000000 - -extern void __down_read(struct rw_semaphore *sem); -extern int __must_check __down_read_killable(struct rw_semaphore *sem); -extern int __down_read_trylock(struct rw_semaphore *sem); -extern void __down_write(struct rw_semaphore *sem); -extern int __must_check __down_write_killable(struct rw_semaphore *sem); -extern int __down_write_trylock(struct rw_semaphore *sem); -extern void __up_read(struct rw_semaphore *sem); -extern void __up_write(struct rw_semaphore *sem); -extern void __downgrade_write(struct rw_semaphore *sem); -extern int rwsem_is_locked(struct rw_semaphore *sem); - -#endif /* __KERNEL__ */ -#endif /* _LINUX_RWSEM_SPINLOCK_H */ diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 6e56006b2cb6..0fc41062c649 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -22,10 +22,6 @@ struct rw_semaphore; -#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK -#include /* use a generic implementation */ -#define __RWSEM_INIT_COUNT(name) .count = RWSEM_UNLOCKED_VALUE -#else /* All arch specific implementations share the same struct */ struct rw_semaphore { atomic_long_t count; @@ -65,7 +61,6 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) #define RWSEM_UNLOCKED_VALUE 0L #define __RWSEM_INIT_COUNT(name) .count = ATOMIC_LONG_INIT(RWSEM_UNLOCKED_VALUE) -#endif /* Common initializer macros and functions */ diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index fbba478ae522..e335953fa704 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -229,7 +229,7 @@ config MUTEX_SPIN_ON_OWNER config RWSEM_SPIN_ON_OWNER def_bool y - depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW + depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW config LOCK_SPIN_ON_OWNER def_bool y diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index 392c7f23af76..1af83e9ce57d 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -3,7 +3,7 @@ # and is generally not a function of system call inputs. KCOV_INSTRUMENT := n -obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o +obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o rwsem-xadd.o ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE) @@ -25,8 +25,6 @@ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o -obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o -obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c deleted file mode 100644 index a7ffb2a96ede..000000000000 --- a/kernel/locking/rwsem-spinlock.c +++ /dev/null @@ -1,339 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* rwsem-spinlock.c: R/W semaphores: contention handling functions for - * generic spinlock implementation - * - * Copyright (c) 2001 David Howells (dhowells@redhat.com). - * - Derived partially from idea by Andrea Arcangeli - * - Derived also from comments by Linus - */ -#include -#include -#include -#include - -enum rwsem_waiter_type { - RWSEM_WAITING_FOR_WRITE, - RWSEM_WAITING_FOR_READ -}; - -struct rwsem_waiter { - struct list_head list; - struct task_struct *task; - enum rwsem_waiter_type type; -}; - -int rwsem_is_locked(struct rw_semaphore *sem) -{ - int ret = 1; - unsigned long flags; - - if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) { - ret = (sem->count != 0); - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - } - return ret; -} -EXPORT_SYMBOL(rwsem_is_locked); - -/* - * initialise the semaphore - */ -void __init_rwsem(struct rw_semaphore *sem, const char *name, - struct lock_class_key *key) -{ -#ifdef CONFIG_DEBUG_LOCK_ALLOC - /* - * Make sure we are not reinitializing a held semaphore: - */ - debug_check_no_locks_freed((void *)sem, sizeof(*sem)); - lockdep_init_map(&sem->dep_map, name, key, 0); -#endif - sem->count = 0; - raw_spin_lock_init(&sem->wait_lock); - INIT_LIST_HEAD(&sem->wait_list); -} -EXPORT_SYMBOL(__init_rwsem); - -/* - * handle the lock release when processes blocked on it that can now run - * - if we come here, then: - * - the 'active count' _reached_ zero - * - the 'waiting count' is non-zero - * - the spinlock must be held by the caller - * - woken process blocks are discarded from the list after having task zeroed - * - writers are only woken if wakewrite is non-zero - */ -static inline struct rw_semaphore * -__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite) -{ - struct rwsem_waiter *waiter; - struct task_struct *tsk; - int woken; - - waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); - - if (waiter->type == RWSEM_WAITING_FOR_WRITE) { - if (wakewrite) - /* Wake up a writer. Note that we do not grant it the - * lock - it will have to acquire it when it runs. */ - wake_up_process(waiter->task); - goto out; - } - - /* grant an infinite number of read locks to the front of the queue */ - woken = 0; - do { - struct list_head *next = waiter->list.next; - - list_del(&waiter->list); - tsk = waiter->task; - /* - * Make sure we do not wakeup the next reader before - * setting the nil condition to grant the next reader; - * otherwise we could miss the wakeup on the other - * side and end up sleeping again. See the pairing - * in rwsem_down_read_failed(). - */ - smp_mb(); - waiter->task = NULL; - wake_up_process(tsk); - put_task_struct(tsk); - woken++; - if (next == &sem->wait_list) - break; - waiter = list_entry(next, struct rwsem_waiter, list); - } while (waiter->type != RWSEM_WAITING_FOR_WRITE); - - sem->count += woken; - - out: - return sem; -} - -/* - * wake a single writer - */ -static inline struct rw_semaphore * -__rwsem_wake_one_writer(struct rw_semaphore *sem) -{ - struct rwsem_waiter *waiter; - - waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); - wake_up_process(waiter->task); - - return sem; -} - -/* - * get a read lock on the semaphore - */ -int __sched __down_read_common(struct rw_semaphore *sem, int state) -{ - struct rwsem_waiter waiter; - unsigned long flags; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - if (sem->count >= 0 && list_empty(&sem->wait_list)) { - /* granted */ - sem->count++; - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - goto out; - } - - /* set up my own style of waitqueue */ - waiter.task = current; - waiter.type = RWSEM_WAITING_FOR_READ; - get_task_struct(current); - - list_add_tail(&waiter.list, &sem->wait_list); - - /* wait to be given the lock */ - for (;;) { - if (!waiter.task) - break; - if (signal_pending_state(state, current)) - goto out_nolock; - set_current_state(state); - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - schedule(); - raw_spin_lock_irqsave(&sem->wait_lock, flags); - } - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - out: - return 0; - -out_nolock: - /* - * We didn't take the lock, so that there is a writer, which - * is owner or the first waiter of the sem. If it's a waiter, - * it will be woken by current owner. Not need to wake anybody. - */ - list_del(&waiter.list); - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - return -EINTR; -} - -void __sched __down_read(struct rw_semaphore *sem) -{ - __down_read_common(sem, TASK_UNINTERRUPTIBLE); -} - -int __sched __down_read_killable(struct rw_semaphore *sem) -{ - return __down_read_common(sem, TASK_KILLABLE); -} - -/* - * trylock for reading -- returns 1 if successful, 0 if contention - */ -int __down_read_trylock(struct rw_semaphore *sem) -{ - unsigned long flags; - int ret = 0; - - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - if (sem->count >= 0 && list_empty(&sem->wait_list)) { - /* granted */ - sem->count++; - ret = 1; - } - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - - return ret; -} - -/* - * get a write lock on the semaphore - */ -int __sched __down_write_common(struct rw_semaphore *sem, int state) -{ - struct rwsem_waiter waiter; - unsigned long flags; - int ret = 0; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - /* set up my own style of waitqueue */ - waiter.task = current; - waiter.type = RWSEM_WAITING_FOR_WRITE; - list_add_tail(&waiter.list, &sem->wait_list); - - /* wait for someone to release the lock */ - for (;;) { - /* - * That is the key to support write lock stealing: allows the - * task already on CPU to get the lock soon rather than put - * itself into sleep and waiting for system woke it or someone - * else in the head of the wait list up. - */ - if (sem->count == 0) - break; - if (signal_pending_state(state, current)) - goto out_nolock; - - set_current_state(state); - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - schedule(); - raw_spin_lock_irqsave(&sem->wait_lock, flags); - } - /* got the lock */ - sem->count = -1; - list_del(&waiter.list); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - - return ret; - -out_nolock: - list_del(&waiter.list); - if (!list_empty(&sem->wait_list) && sem->count >= 0) - __rwsem_do_wake(sem, 0); - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - - return -EINTR; -} - -void __sched __down_write(struct rw_semaphore *sem) -{ - __down_write_common(sem, TASK_UNINTERRUPTIBLE); -} - -int __sched __down_write_killable(struct rw_semaphore *sem) -{ - return __down_write_common(sem, TASK_KILLABLE); -} - -/* - * trylock for writing -- returns 1 if successful, 0 if contention - */ -int __down_write_trylock(struct rw_semaphore *sem) -{ - unsigned long flags; - int ret = 0; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - if (sem->count == 0) { - /* got the lock */ - sem->count = -1; - ret = 1; - } - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - - return ret; -} - -/* - * release a read lock on the semaphore - */ -void __up_read(struct rw_semaphore *sem) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - if (--sem->count == 0 && !list_empty(&sem->wait_list)) - sem = __rwsem_wake_one_writer(sem); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); -} - -/* - * release a write lock on the semaphore - */ -void __up_write(struct rw_semaphore *sem) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - sem->count = 0; - if (!list_empty(&sem->wait_list)) - sem = __rwsem_do_wake(sem, 1); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); -} - -/* - * downgrade a write lock into a read lock - * - just wake up any readers at the front of the queue - */ -void __downgrade_write(struct rw_semaphore *sem) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - sem->count = 1; - if (!list_empty(&sem->wait_list)) - sem = __rwsem_do_wake(sem, 0); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); -} - diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 067e265fa5c1..45ee00236e03 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -153,7 +153,6 @@ static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) } #endif -#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM /* * lock for reading */ @@ -260,5 +259,3 @@ static inline void __downgrade_write(struct rw_semaphore *sem) if (tmp < 0) rwsem_downgrade_wake(sem); } - -#endif /* CONFIG_RWSEM_XCHGADD_ALGORITHM */