Binary files rwsemref/ID and rwsem/ID differ diff -urN rwsemref/arch/alpha/config.in rwsem/arch/alpha/config.in --- rwsemref/arch/alpha/config.in Wed Apr 18 21:20:49 2001 +++ rwsem/arch/alpha/config.in Wed Apr 18 00:47:05 2001 @@ -5,6 +5,7 @@ define_bool CONFIG_ALPHA y define_bool CONFIG_UID16 n +define_bool CONFIG_GENERIC_RWSEM y mainmenu_name "Kernel configuration of Linux for Alpha machines" diff -urN rwsemref/arch/alpha/kernel/alpha_ksyms.c rwsem/arch/alpha/kernel/alpha_ksyms.c --- rwsemref/arch/alpha/kernel/alpha_ksyms.c Wed Apr 18 21:20:49 2001 +++ rwsem/arch/alpha/kernel/alpha_ksyms.c Wed Apr 18 00:47:05 2001 @@ -173,13 +173,6 @@ EXPORT_SYMBOL(down_interruptible); EXPORT_SYMBOL(down_trylock); EXPORT_SYMBOL(up); -EXPORT_SYMBOL(__down_read_failed); -EXPORT_SYMBOL(__down_write_failed); -EXPORT_SYMBOL(__rwsem_wake); -EXPORT_SYMBOL(down_read); -EXPORT_SYMBOL(down_write); -EXPORT_SYMBOL(up_read); -EXPORT_SYMBOL(up_write); /* * SMP-specific symbols. diff -urN rwsemref/arch/alpha/kernel/semaphore.c rwsem/arch/alpha/kernel/semaphore.c --- rwsemref/arch/alpha/kernel/semaphore.c Wed Apr 18 21:20:49 2001 +++ rwsem/arch/alpha/kernel/semaphore.c Wed Apr 18 00:47:05 2001 @@ -263,185 +263,3 @@ #endif __up(sem); } - - -/* - * RW Semaphores - */ - -void -__down_read_failed(struct rw_semaphore *sem, int count) -{ - DECLARE_WAITQUEUE(wait, current); - - retry_down: - if (count < 0) { - /* Waiting on multiple readers and/or writers. */ - - /* Undo the acquisition we started in down_read. */ - atomic_inc(&sem->count); - - current->state = TASK_UNINTERRUPTIBLE; - wmb(); - add_wait_queue(&sem->wait, &wait); - mb(); - while (atomic_read(&sem->count) < 0) { - schedule(); - set_task_state(current, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait, &wait); - current->state = TASK_RUNNING; - - mb(); - count = atomic_dec_return(&sem->count); - if (count <= 0) - goto retry_down; - } else { - /* Waiting on exactly one writer. */ - - current->state = TASK_UNINTERRUPTIBLE; - wmb(); - add_wait_queue(&sem->wait, &wait); - mb(); - - while (!test_and_clear_bit(0, &sem->granted)) { - schedule(); - set_task_state(current, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait, &wait); - current->state = TASK_RUNNING; - } -} - -void -__down_write_failed(struct rw_semaphore *sem, int count) -{ - DECLARE_WAITQUEUE(wait, current); - - retry_down: - if (count + RW_LOCK_BIAS < 0) { - /* Waiting on multiple readers and/or writers. */ - - /* Undo the acquisition we started in down_write. */ - atomic_add(RW_LOCK_BIAS, &sem->count); - - current->state = TASK_UNINTERRUPTIBLE; - wmb(); - add_wait_queue_exclusive(&sem->wait, &wait); - mb(); - - while (atomic_read(&sem->count) + RW_LOCK_BIAS < 0) { - schedule(); - set_task_state(current, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait, &wait); - current->state = TASK_RUNNING; - - count = atomic_sub_return(RW_LOCK_BIAS, &sem->count); - if (count != 0) - goto retry_down; - } else { - /* Waiting on exactly one writer. */ - - current->state = TASK_UNINTERRUPTIBLE; - wmb(); - add_wait_queue_exclusive(&sem->wait, &wait); - mb(); - - while (!test_and_clear_bit(1, &sem->granted)) { - schedule(); - set_task_state(current, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->write_bias_wait, &wait); - current->state = TASK_RUNNING; - - /* If the lock is currently unbiased, awaken the sleepers. - FIXME: This wakes up the readers early in a bit of a - stampede -> bad! */ - count = atomic_read(&sem->count); - if (__builtin_expect(count >= 0, 0)) - wake_up(&sem->wait); - } -} - -void -__rwsem_wake(struct rw_semaphore *sem, int readers) -{ - if (readers) { - if (test_and_set_bit(0, &sem->granted)) - BUG(); - wake_up(&sem->wait); - } else { - if (test_and_set_bit(1, &sem->granted)) - BUG(); - wake_up(&sem->write_bias_wait); - } -} - -void -down_read(struct rw_semaphore *sem) -{ -#if WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif - __down_read(sem); -#if WAITQUEUE_DEBUG - if (sem->granted & 2) - BUG(); - if (atomic_read(&sem->writers)) - BUG(); - atomic_inc(&sem->readers); -#endif -} - -void -down_write(struct rw_semaphore *sem) -{ -#if WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif - __down_write(sem); -#if WAITQUEUE_DEBUG - if (sem->granted & 3) - BUG(); - if (atomic_read(&sem->writers)) - BUG(); - if (atomic_read(&sem->readers)) - BUG(); - atomic_inc(&sem->writers); -#endif -} - -void -up_read(struct rw_semaphore *sem) -{ -#if WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); - if (sem->granted & 2) - BUG(); - if (atomic_read(&sem->writers)) - BUG(); - atomic_dec(&sem->readers); -#endif - __up_read(sem); -} - -void -up_write(struct rw_semaphore *sem) -{ -#if WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); - if (sem->granted & 3) - BUG(); - if (atomic_read(&sem->readers)) - BUG(); - if (atomic_read(&sem->writers) != 1) - BUG(); - atomic_dec(&sem->writers); -#endif - __up_write(sem); -} diff -urN rwsemref/arch/i386/config.in rwsem/arch/i386/config.in --- rwsemref/arch/i386/config.in Wed Apr 18 21:20:49 2001 +++ rwsem/arch/i386/config.in Wed Apr 18 00:47:05 2001 @@ -7,6 +7,7 @@ define_bool CONFIG_X86 y define_bool CONFIG_ISA y define_bool CONFIG_SBUS n +define_bool CONFIG_GENERIC_RWSEM y define_bool CONFIG_UID16 y diff -urN rwsemref/arch/i386/kernel/i386_ksyms.c rwsem/arch/i386/kernel/i386_ksyms.c --- rwsemref/arch/i386/kernel/i386_ksyms.c Wed Apr 18 21:20:49 2001 +++ rwsem/arch/i386/kernel/i386_ksyms.c Wed Apr 18 00:47:05 2001 @@ -80,9 +80,6 @@ EXPORT_SYMBOL_NOVERS(__down_failed_interruptible); EXPORT_SYMBOL_NOVERS(__down_failed_trylock); EXPORT_SYMBOL_NOVERS(__up_wakeup); -EXPORT_SYMBOL_NOVERS(__rwsem_down_write_failed); -EXPORT_SYMBOL_NOVERS(__rwsem_down_read_failed); -EXPORT_SYMBOL_NOVERS(__rwsem_wake); /* Networking helper routines. */ EXPORT_SYMBOL(csum_partial_copy_generic); /* Delay loops */ diff -urN rwsemref/arch/i386/lib/Makefile rwsem/arch/i386/lib/Makefile --- rwsemref/arch/i386/lib/Makefile Wed Apr 18 21:20:49 2001 +++ rwsem/arch/i386/lib/Makefile Wed Apr 18 00:47:05 2001 @@ -9,7 +9,7 @@ obj-y = checksum.o old-checksum.o delay.o \ usercopy.o getuser.o putuser.o \ - memcpy.o strstr.o rwsem.o + memcpy.o strstr.o obj-$(CONFIG_X86_USE_3DNOW) += mmx.o obj-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o diff -urN rwsemref/arch/i386/lib/rwsem.S rwsem/arch/i386/lib/rwsem.S --- rwsemref/arch/i386/lib/rwsem.S Wed Apr 18 21:20:49 2001 +++ rwsem/arch/i386/lib/rwsem.S Thu Jan 1 01:00:00 1970 @@ -1,36 +0,0 @@ -/* rwsem.S: R/W semaphores, register saving wrapper function stubs - * - * Written by David Howells (dhowells@redhat.com). - * Derived from arch/i386/kernel/semaphore.c - */ - -.text -.align 4 -.globl __rwsem_down_read_failed -__rwsem_down_read_failed: - pushl %edx - pushl %ecx - call rwsem_down_read_failed - popl %ecx - popl %edx - ret - -.align 4 -.globl __rwsem_down_write_failed -__rwsem_down_write_failed: - pushl %edx - pushl %ecx - call rwsem_down_write_failed - popl %ecx - popl %edx - ret - -.align 4 -.globl __rwsem_wake -__rwsem_wake: - pushl %edx - pushl %ecx - call rwsem_wake - popl %ecx - popl %edx - ret diff -urN rwsemref/arch/ppc/config.in rwsem/arch/ppc/config.in --- rwsemref/arch/ppc/config.in Wed Apr 18 21:20:49 2001 +++ rwsem/arch/ppc/config.in Wed Apr 18 00:47:05 2001 @@ -3,6 +3,7 @@ # see Documentation/kbuild/config-language.txt. # define_bool CONFIG_UID16 n +define_bool CONFIG_GENERIC_RWSEM y mainmenu_name "Linux/PowerPC Kernel Configuration" diff -urN rwsemref/arch/ppc/kernel/ppc_ksyms.c rwsem/arch/ppc/kernel/ppc_ksyms.c --- rwsemref/arch/ppc/kernel/ppc_ksyms.c Wed Apr 18 21:20:49 2001 +++ rwsem/arch/ppc/kernel/ppc_ksyms.c Wed Apr 18 00:47:05 2001 @@ -332,8 +332,6 @@ EXPORT_SYMBOL(__down); EXPORT_SYMBOL(__down_interruptible); EXPORT_SYMBOL(__down_trylock); -EXPORT_SYMBOL(down_read_failed); -EXPORT_SYMBOL(down_write_failed); #if defined(CONFIG_KGDB) || defined(CONFIG_XMON) extern void (*debugger)(struct pt_regs *regs); diff -urN rwsemref/arch/ppc/kernel/semaphore.c rwsem/arch/ppc/kernel/semaphore.c --- rwsemref/arch/ppc/kernel/semaphore.c Wed Apr 18 21:20:49 2001 +++ rwsem/arch/ppc/kernel/semaphore.c Wed Apr 18 00:47:05 2001 @@ -137,44 +137,3 @@ { return waking_non_zero_trylock(sem); } - - -/* - * rw semaphores Ani Joshi - * based on alpha port by Andrea Arcangeli - */ - -void down_read_failed(struct rw_semaphore *sem) -{ - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - - add_wait_queue_exclusive(&sem->wait, &wait); - - do { - __set_task_state(tsk, TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&sem->lock); - schedule(); - spin_lock_irq(&sem->lock); - } while(sem->wr); - - remove_wait_queue(&sem->wait, &wait); -} - -void down_write_failed(struct rw_semaphore *sem) -{ - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - - add_wait_queue_exclusive(&sem->wait, &wait); - - do { - __set_task_state(tsk, TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&sem->lock); - schedule(); - spin_lock_irq(&sem->lock); - } while(sem->rd || sem->wr); - - remove_wait_queue(&sem->wait, &wait); -} - diff -urN rwsemref/include/asm-alpha/semaphore.h rwsem/include/asm-alpha/semaphore.h --- rwsemref/include/asm-alpha/semaphore.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/asm-alpha/semaphore.h Wed Apr 18 00:47:05 2001 @@ -13,6 +13,7 @@ #include #include /* __builtin_expect */ #include +#include #define DEBUG_SEMAPHORE 0 #define DEBUG_RW_SEMAPHORE 0 @@ -220,153 +221,6 @@ extern inline void up(struct semaphore *sem) { __up(sem); -} -#endif - -/* rw mutexes (should that be mutices? =) -- throw rw - * spinlocks and semaphores together, and this is what we - * end up with... - * - * The lock is initialized to BIAS. This way, a writer - * subtracts BIAS ands gets 0 for the case of an uncontended - * lock. Readers decrement by 1 and see a positive value - * when uncontended, negative if there are writers waiting - * (in which case it goes to sleep). - * - * The value 0x01000000 supports up to 128 processors and - * lots of processes. BIAS must be chosen such that subtracting - * BIAS once per CPU will result in the int remaining - * negative. - * In terms of fairness, this should result in the lock - * flopping back and forth between readers and writers - * under heavy use. - * - * -ben - * - * Once we start supporting machines with more than 128 CPUs, - * we should go for using a 64bit atomic type instead of 32bit - * as counter. We shall probably go for bias 0x80000000 then, - * so that single sethi can set it. - * - * -jj - */ - -#define RW_LOCK_BIAS 0x01000000 - -struct rw_semaphore { - atomic_t count; - /* bit 0 means read bias granted; - bit 1 means write bias granted. */ - unsigned granted; - wait_queue_head_t wait; - wait_queue_head_t write_bias_wait; -#if WAITQUEUE_DEBUG - long __magic; - atomic_t readers; - atomic_t writers; -#endif -}; - -#if WAITQUEUE_DEBUG -#define __RWSEM_DEBUG_INIT , ATOMIC_INIT(0), ATOMIC_INIT(0) -#else -#define __RWSEM_DEBUG_INIT /* */ -#endif - -#define __RWSEM_INITIALIZER(name,count) \ - { ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ - __WAIT_QUEUE_HEAD_INITIALIZER((name).write_bias_wait) \ - __SEM_DEBUG_INIT(name) __RWSEM_DEBUG_INIT } - -#define __DECLARE_RWSEM_GENERIC(name,count) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) - -#define DECLARE_RWSEM(name) \ - __DECLARE_RWSEM_GENERIC(name, RW_LOCK_BIAS) -#define DECLARE_RWSEM_READ_LOCKED(name) \ - __DECLARE_RWSEM_GENERIC(name, RW_LOCK_BIAS-1) -#define DECLARE_RWSEM_WRITE_LOCKED(name) \ - __DECLARE_RWSEM_GENERIC(name, 0) - -static inline void init_rwsem(struct rw_semaphore *sem) -{ - atomic_set (&sem->count, RW_LOCK_BIAS); - sem->granted = 0; - init_waitqueue_head(&sem->wait); - init_waitqueue_head(&sem->write_bias_wait); -#if WAITQUEUE_DEBUG - sem->__magic = (long)&sem->__magic; - atomic_set(&sem->readers, 0); - atomic_set(&sem->writers, 0); -#endif -} - -extern void down_read(struct rw_semaphore *); -extern void down_write(struct rw_semaphore *); -extern void up_read(struct rw_semaphore *); -extern void up_write(struct rw_semaphore *); -extern void __down_read_failed(struct rw_semaphore *, int); -extern void __down_write_failed(struct rw_semaphore *, int); -extern void __rwsem_wake(struct rw_semaphore *, int); - -static inline void __down_read(struct rw_semaphore *sem) -{ - long count = atomic_dec_return(&sem->count); - if (__builtin_expect(count < 0, 0)) - __down_read_failed(sem, count); -} - -static inline void __down_write(struct rw_semaphore *sem) -{ - long count = atomic_sub_return(RW_LOCK_BIAS, &sem->count); - if (__builtin_expect(count != 0, 0)) - __down_write_failed(sem, count); -} - -/* When a reader does a release, the only significant case is when there - was a writer waiting, and we've bumped the count to 0, then we must - wake the writer up. */ - -static inline void __up_read(struct rw_semaphore *sem) -{ - long count; - mb(); - count = atomic_inc_return(&sem->count); - if (__builtin_expect(count == 0, 0)) - __rwsem_wake(sem, 0); -} - -/* Releasing the writer is easy -- just release it and wake up - any sleepers. */ - -static inline void __up_write(struct rw_semaphore *sem) -{ - long count, wake; - mb(); - count = atomic_add_return(RW_LOCK_BIAS, &sem->count); - - /* Only do the wake if we were, but are no longer, negative. */ - wake = ((int)(count - RW_LOCK_BIAS) < 0) && count >= 0; - if (__builtin_expect(wake, 0)) - __rwsem_wake(sem, count); -} - -#if !WAITQUEUE_DEBUG && !DEBUG_RW_SEMAPHORE -extern inline void down_read(struct rw_semaphore *sem) -{ - __down_read(sem); -} -extern inline void down_write(struct rw_semaphore *sem) -{ - __down_write(sem); -} -extern inline void up_read(struct rw_semaphore *sem) -{ - __up_read(sem); -} -extern inline void up_write(struct rw_semaphore *sem) -{ - __up_write(sem); } #endif diff -urN rwsemref/include/asm-i386/rwsem-spin.h rwsem/include/asm-i386/rwsem-spin.h --- rwsemref/include/asm-i386/rwsem-spin.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/asm-i386/rwsem-spin.h Thu Jan 1 01:00:00 1970 @@ -1,324 +0,0 @@ -/* rwsem.h: R/W semaphores based on spinlocks - * - * Written by David Howells (dhowells@redhat.com). - * - * Derived from asm-i386/semaphore.h and asm-i386/spinlock.h - */ - -#ifndef _I386_RWSEM_SPIN_H -#define _I386_RWSEM_SPIN_H - -#include - -#ifndef _LINUX_RWSEM_H -#error please dont include asm/rwsem-spin.h directly, use linux/rwsem.h instead -#endif - -#include - -#ifdef __KERNEL__ - -#define CONFIG_USING_SPINLOCK_BASED_RWSEM 1 - -/* - * the semaphore definition - */ -struct rw_semaphore { - signed long count; -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - spinlock_t lock; -#define RWSEM_SPINLOCK_OFFSET_STR "4" /* byte offset of spinlock */ - wait_queue_head_t wait; -#define RWSEM_WAITING_FOR_READ WQ_FLAG_CONTEXT_0 /* bits to use in wait_queue_t.flags */ -#define RWSEM_WAITING_FOR_WRITE WQ_FLAG_CONTEXT_1 -#if RWSEM_DEBUG - int debug; -#endif -#if RWSEM_DEBUG_MAGIC - long __magic; - atomic_t readers; - atomic_t writers; -#endif -}; - -/* - * initialisation - */ -#if RWSEM_DEBUG -#define __RWSEM_DEBUG_INIT , 0 -#else -#define __RWSEM_DEBUG_INIT /* */ -#endif -#if RWSEM_DEBUG_MAGIC -#define __RWSEM_DEBUG_MINIT(name) , (int)&(name).__magic, ATOMIC_INIT(0), ATOMIC_INIT(0) -#else -#define __RWSEM_DEBUG_MINIT(name) /* */ -#endif - -#define __RWSEM_INITIALIZER(name,count) \ -{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \ - __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ - __RWSEM_DEBUG_INIT __RWSEM_DEBUG_MINIT(name) } - -#define __DECLARE_RWSEM_GENERIC(name,count) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) - -#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS) -#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1) -#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0) - -static inline void init_rwsem(struct rw_semaphore *sem) -{ - sem->count = RWSEM_UNLOCKED_VALUE; - spin_lock_init(&sem->lock); - init_waitqueue_head(&sem->wait); -#if RWSEM_DEBUG - sem->debug = 0; -#endif -#if RWSEM_DEBUG_MAGIC - sem->__magic = (long)&sem->__magic; - atomic_set(&sem->readers, 0); - atomic_set(&sem->writers, 0); -#endif -} - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - __asm__ __volatile__( - "# beginning down_read\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */ -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* release the spinlock */ -#endif - " js 4f\n\t" /* jump if we weren't granted the lock */ - "2:\n" - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - "4:\n\t" - " call __rwsem_down_read_failed\n\t" - " jmp 2b\n" - ".previous" - "# ending __down_read\n\t" - : "=m"(sem->count), "=m"(sem->lock) - : "a"(sem), "m"(sem->count), "m"(sem->lock) - : "memory"); -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - int tmp; - - tmp = RWSEM_ACTIVE_WRITE_BIAS; - __asm__ __volatile__( - "# beginning down_write\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " xchg %0,(%%eax)\n\t" /* retrieve the old value */ - " add %0,(%%eax)\n\t" /* add 0xffff0001, result in memory */ -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* release the spinlock */ -#endif - " testl %0,%0\n\t" /* was the count 0 before? */ - " jnz 4f\n\t" /* jump if we weren't granted the lock */ - "2:\n\t" - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - "4:\n\t" - " call __rwsem_down_write_failed\n\t" - " jmp 2b\n" - ".previous\n" - "# ending down_write" - : "+r"(tmp), "=m"(sem->count), "=m"(sem->lock) - : "a"(sem), "m"(sem->count), "m"(sem->lock) - : "memory"); -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - int tmp; - - tmp = -RWSEM_ACTIVE_READ_BIAS; - __asm__ __volatile__( - "# beginning __up_read\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " xchg %0,(%%eax)\n\t" /* retrieve the old value */ - " addl %0,(%%eax)\n\t" /* subtract 1, result in memory */ -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* release the spinlock */ -#endif - " js 4f\n\t" /* jump if the lock is being waited upon */ - "2:\n\t" - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - "4:\n\t" - " decl %0\n\t" /* xchg gave us the old count */ - " testl %4,%0\n\t" /* do nothing if still outstanding active readers */ - " jnz 2b\n\t" - " call __rwsem_wake\n\t" - " jmp 2b\n" - ".previous\n" - "# ending __up_read\n" - : "+r"(tmp), "=m"(sem->count), "=m"(sem->lock) - : "a"(sem), "i"(RWSEM_ACTIVE_MASK), "m"(sem->count), "m"(sem->lock) - : "memory"); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - __asm__ __volatile__( - "# beginning __up_write\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " addl %3,(%%eax)\n\t" /* adds 0x00010001 */ -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" /* release the spinlock */ -#endif - " js 4f\n\t" /* jump if the lock is being waited upon */ - "2:\n\t" - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%%eax)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - "4:\n\t" - " call __rwsem_wake\n\t" - " jmp 2b\n" - ".previous\n" - "# ending __up_write\n" - : "=m"(sem->count), "=m"(sem->lock) - : "a"(sem), "i"(-RWSEM_ACTIVE_WRITE_BIAS), "m"(sem->count), "m"(sem->lock) - : "memory"); -} - -/* - * implement exchange and add functionality - */ -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) -{ - int tmp = delta; - - __asm__ __volatile__( - "# beginning rwsem_atomic_update\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%1)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " xchgl %0,(%1)\n\t" /* retrieve the old value */ - " addl %0,(%1)\n\t" /* add 0xffff0001, result in memory */ -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%1)\n\t" /* release the spinlock */ -#endif - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%1)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - ".previous\n" - "# ending rwsem_atomic_update\n\t" - : "+r"(tmp) - : "r"(sem) - : "memory"); - - return tmp+delta; -} - -/* - * implement compare and exchange functionality on the rw-semaphore count LSW - */ -static inline __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 old, __u16 new) -{ - __u16 prev; - - __asm__ __volatile__( - "# beginning rwsem_cmpxchgw\n\t" -#ifdef CONFIG_SMP -LOCK_PREFIX " decb "RWSEM_SPINLOCK_OFFSET_STR"(%3)\n\t" /* try to grab the spinlock */ - " js 3f\n" /* jump if failed */ - "1:\n\t" -#endif - " cmpw %w1,(%3)\n\t" - " jne 4f\n\t" /* jump if old doesn't match sem->count LSW */ - " movw %w2,(%3)\n\t" /* replace sem->count LSW with the new value */ - "2:\n\t" -#ifdef CONFIG_SMP - " movb $1,"RWSEM_SPINLOCK_OFFSET_STR"(%3)\n\t" /* release the spinlock */ -#endif - ".section .text.lock,\"ax\"\n" -#ifdef CONFIG_SMP - "3:\n\t" /* spin on the spinlock till we get it */ - " cmpb $0,"RWSEM_SPINLOCK_OFFSET_STR"(%3)\n\t" - " rep;nop \n\t" - " jle 3b\n\t" - " jmp 1b\n" -#endif - "4:\n\t" - " movw (%3),%w0\n" /* we'll want to return the current value */ - " jmp 2b\n" - ".previous\n" - "# ending rwsem_cmpxchgw\n\t" - : "=r"(prev) - : "r0"(old), "r"(new), "r"(sem) - : "memory"); - - return prev; -} - -#endif /* __KERNEL__ */ -#endif /* _I386_RWSEM_SPIN_H */ diff -urN rwsemref/include/asm-i386/rwsem-xadd.h rwsem/include/asm-i386/rwsem-xadd.h --- rwsemref/include/asm-i386/rwsem-xadd.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/asm-i386/rwsem-xadd.h Thu Jan 1 01:00:00 1970 @@ -1,198 +0,0 @@ -/* rwsem-xadd.h: R/W semaphores implemented using XADD/CMPXCHG - * - * Written by David Howells (dhowells@redhat.com), 2001. - * Derived from asm-i386/semaphore.h - */ - -#ifndef _I386_RWSEM_XADD_H -#define _I386_RWSEM_XADD_H - -#ifndef _LINUX_RWSEM_H -#error please dont include asm/rwsem-xadd.h directly, use linux/rwsem.h instead -#endif - -#ifdef __KERNEL__ - -/* - * the semaphore definition - */ -struct rw_semaphore { - signed long count; -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - wait_queue_head_t wait; -#define RWSEM_WAITING_FOR_READ WQ_FLAG_CONTEXT_0 /* bits to use in wait_queue_t.flags */ -#define RWSEM_WAITING_FOR_WRITE WQ_FLAG_CONTEXT_1 -#if RWSEM_DEBUG - int debug; -#endif -#if RWSEM_DEBUG_MAGIC - long __magic; - atomic_t readers; - atomic_t writers; -#endif -}; - -/* - * initialisation - */ -#if RWSEM_DEBUG -#define __RWSEM_DEBUG_INIT , 0 -#else -#define __RWSEM_DEBUG_INIT /* */ -#endif -#if RWSEM_DEBUG_MAGIC -#define __RWSEM_DEBUG_MINIT(name) , (int)&(name).__magic, ATOMIC_INIT(0), ATOMIC_INIT(0) -#else -#define __RWSEM_DEBUG_MINIT(name) /* */ -#endif - -#define __RWSEM_INITIALIZER(name,count) \ -{ RWSEM_UNLOCKED_VALUE, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ - __RWSEM_DEBUG_INIT __RWSEM_DEBUG_MINIT(name) } - -#define __DECLARE_RWSEM_GENERIC(name,count) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) - -#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS) -#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1) -#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0) - -static inline void init_rwsem(struct rw_semaphore *sem) -{ - sem->count = RWSEM_UNLOCKED_VALUE; - init_waitqueue_head(&sem->wait); -#if RWSEM_DEBUG - sem->debug = 0; -#endif -#if RWSEM_DEBUG_MAGIC - sem->__magic = (long)&sem->__magic; - atomic_set(&sem->readers, 0); - atomic_set(&sem->writers, 0); -#endif -} - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - __asm__ __volatile__( - "# beginning down_read\n\t" -LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */ - " js 2f\n\t" /* jump if we weren't granted the lock */ - "1:\n\t" - ".section .text.lock,\"ax\"\n" - "2:\n\t" - " call __rwsem_down_read_failed\n\t" - " jmp 1b\n" - ".previous" - "# ending down_read\n\t" - : "=m"(sem->count) - : "a"(sem), "m"(sem->count) - : "memory"); -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - int tmp; - - tmp = RWSEM_ACTIVE_WRITE_BIAS; - __asm__ __volatile__( - "# beginning down_write\n\t" -LOCK_PREFIX " xadd %0,(%%eax)\n\t" /* subtract 0x00010001, returns the old value */ - " testl %0,%0\n\t" /* was the count 0 before? */ - " jnz 2f\n\t" /* jump if we weren't granted the lock */ - "1:\n\t" - ".section .text.lock,\"ax\"\n" - "2:\n\t" - " call __rwsem_down_write_failed\n\t" - " jmp 1b\n" - ".previous\n" - "# ending down_write" - : "+r"(tmp), "=m"(sem->count) - : "a"(sem), "m"(sem->count) - : "memory"); -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - int tmp; - - tmp = -RWSEM_ACTIVE_READ_BIAS; - __asm__ __volatile__( - "# beginning __up_read\n\t" -LOCK_PREFIX " xadd %0,(%%eax)\n\t" /* subtracts 1, returns the old value */ - " js 2f\n\t" /* jump if the lock is being waited upon */ - "1:\n\t" - ".section .text.lock,\"ax\"\n" - "2:\n\t" - " decl %0\n\t" /* xadd gave us the old count */ - " testl %3,%0\n\t" /* do nothing if still outstanding active readers */ - " jnz 1b\n\t" - " call __rwsem_wake\n\t" - " jmp 1b\n" - ".previous\n" - "# ending __up_read\n" - : "+r"(tmp), "=m"(sem->count) - : "a"(sem), "i"(RWSEM_ACTIVE_MASK), "m"(sem->count) - : "memory"); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - __asm__ __volatile__( - "# beginning __up_write\n\t" -LOCK_PREFIX " addl %2,(%%eax)\n\t" /* adds 0x0000ffff */ - " js 2f\n\t" /* jump if the lock is being waited upon */ - "1:\n\t" - ".section .text.lock,\"ax\"\n" - "2:\n\t" - " call __rwsem_wake\n\t" - " jmp 1b\n" - ".previous\n" - "# ending __up_write\n" - : "=m"(sem->count) - : "a"(sem), "i"(-RWSEM_ACTIVE_WRITE_BIAS), "m"(sem->count) - : "memory"); -} - -/* - * implement exchange and add functionality - */ -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) -{ - int tmp = delta; - - __asm__ __volatile__( - LOCK_PREFIX "xadd %0,(%1)" - : "+r"(tmp) - : "r"(sem) - : "memory"); - - return tmp+delta; -} - -/* - * implement compare and exchange functionality on the rw-semaphore count LSW - */ -static inline __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 old, __u16 new) -{ - return cmpxchg((__u16*)&sem->count,0,RWSEM_ACTIVE_BIAS); -} - -#endif /* __KERNEL__ */ -#endif /* _I386_RWSEM_XADD_H */ diff -urN rwsemref/include/asm-i386/rwsem.h rwsem/include/asm-i386/rwsem.h --- rwsemref/include/asm-i386/rwsem.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/asm-i386/rwsem.h Thu Jan 1 01:00:00 1970 @@ -1,30 +0,0 @@ -/* rwsem.h: R/W semaphores based on spinlocks - * - * Written by David Howells (dhowells@redhat.com). - * - * Derived from asm-i386/semaphore.h - */ - -#ifndef _I386_RWSEM_H -#define _I386_RWSEM_H - -#ifndef _LINUX_RWSEM_H -#error please dont include asm/rwsem.h directly, use linux/rwsem.h instead -#endif - -#ifdef __KERNEL__ - -#define __HAVE_ARCH_SPECIFIC_RWSEM_IMPLEMENTATION 1 -#ifdef CONFIG_X86_XADD -#include /* use XADD based semaphores if possible */ -#else -#include /* use optimised spinlock based semaphores otherwise */ -#endif - -/* we use FASTCALL convention for the helpers */ -extern struct rw_semaphore *FASTCALL(__rwsem_down_read_failed(struct rw_semaphore *sem)); -extern struct rw_semaphore *FASTCALL(__rwsem_down_write_failed(struct rw_semaphore *sem)); -extern struct rw_semaphore *FASTCALL(__rwsem_wake(struct rw_semaphore *sem)); - -#endif /* __KERNEL__ */ -#endif /* _I386_RWSEM_H */ diff -urN rwsemref/include/asm-ppc/semaphore.h rwsem/include/asm-ppc/semaphore.h --- rwsemref/include/asm-ppc/semaphore.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/asm-ppc/semaphore.h Wed Apr 18 00:47:05 2001 @@ -106,100 +106,6 @@ __up(sem); } - -/* RW spinlock-based semaphores */ - -struct rw_semaphore -{ - spinlock_t lock; - int rd, wr; - wait_queue_head_t wait; -#if WAITQUEUE_DEBUG - long __magic; -#endif -}; - -#define RW_LOCK_BIAS 2 /* XXX bogus */ -#define __RWSEM_INITIALIZER(name, count) \ -{ \ - SPIN_LOCK_UNLOCKED, \ - (count) == 1, (count) == 0, \ - __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ - __SEM_DEBUG_INIT(name) \ -} - -#define __DECLARE_RWSEM_GENERIC(name, count) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name, count) - -#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name, RW_LOCK_BIAS) -#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name, RW_LOCK_BIAS-1) -#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name, 0) - -extern inline void init_rwsem(struct rw_semaphore *sem) -{ - spin_lock_init(&sem->lock); - sem->rd = sem->wr = 0; - init_waitqueue_head(&sem->wait); -#if WAITQUEUE_DEBUG - sem->__magic = (long)&sem->__magic; -#endif -} - -#ifndef CHECK_MAGIC -#define CHECK_MAGIC(x) -#endif - -extern void down_read_failed(struct rw_semaphore *); -extern void down_write_failed(struct rw_semaphore *); - -extern inline void down_read(struct rw_semaphore *sem) -{ - CHECK_MAGIC(sem->__magic); - - spin_lock_irq(&sem->lock); - if (sem->wr) - down_read_failed(sem); - sem->rd++; - spin_unlock_irq(&sem->lock); -} - -extern inline void down_write(struct rw_semaphore *sem) -{ - CHECK_MAGIC(sem->__magic); - - spin_lock(&sem->lock); - if(sem->rd || sem->wr) - down_write_failed(sem); - sem->wr = 1; - spin_unlock(&sem->lock); -} - -#define up_read(sem) \ - do { \ - unsigned long flags; \ - \ - CHECK_MAGIC((sem)->__magic); \ - \ - spin_lock_irqsave(&(sem)->lock, flags); \ - if (!--(sem)->rd && waitqueue_active(&(sem)->wait)) \ - wake_up(&(sem)->wait); \ - spin_unlock_irqrestore(&(sem)->lock, flags); \ - } while (0) - -#define up_write(sem) \ - do { \ - unsigned long flags; \ - \ - CHECK_MAGIC((sem)->__magic); \ - \ - spin_lock_irqsave(&(sem)->lock, flags); \ - (sem)->wr = 0; \ - if (waitqueue_active(&(sem)->wait)) \ - wake_up(&(sem)->wait); \ - spin_unlock_irqrestore(&(sem)->lock, flags); \ - } while (0) - - #endif /* __KERNEL__ */ #endif /* !(_PPC_SEMAPHORE_H) */ diff -urN rwsemref/include/linux/rwsem-spinlock.h rwsem/include/linux/rwsem-spinlock.h --- rwsemref/include/linux/rwsem-spinlock.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/linux/rwsem-spinlock.h Thu Jan 1 01:00:00 1970 @@ -1,174 +0,0 @@ -/* rwsem-spinlock.h: fallback C implementation - * - * Copyright (c) 2001 David Howells (dhowells@redhat.com). - */ - -#ifndef _LINUX_RWSEM_SPINLOCK_H -#define _LINUX_RWSEM_SPINLOCK_H - -#ifndef _LINUX_RWSEM_H -#error please dont include asm/rwsem-spinlock.h directly, use linux/rwsem.h instead -#endif - -#include - -#ifdef __KERNEL__ - -#define CONFIG_USING_SPINLOCK_BASED_RWSEM 1 - -/* - * the semaphore definition - */ -struct rw_semaphore { - signed long count; -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - spinlock_t lock; -#define RWSEM_SPINLOCK_OFFSET_STR "4" /* byte offset of spinlock */ - wait_queue_head_t wait; -#define RWSEM_WAITING_FOR_READ WQ_FLAG_CONTEXT_0 /* bits to use in wait_queue_t.flags */ -#define RWSEM_WAITING_FOR_WRITE WQ_FLAG_CONTEXT_1 -#if RWSEM_DEBUG - int debug; -#endif -#if RWSEM_DEBUG_MAGIC - long __magic; - atomic_t readers; - atomic_t writers; -#endif -}; - -/* - * initialisation - */ -#if RWSEM_DEBUG -#define __RWSEM_DEBUG_INIT , 0 -#else -#define __RWSEM_DEBUG_INIT /* */ -#endif -#if RWSEM_DEBUG_MAGIC -#define __RWSEM_DEBUG_MINIT(name) , (int)&(name).__magic, ATOMIC_INIT(0), ATOMIC_INIT(0) -#else -#define __RWSEM_DEBUG_MINIT(name) /* */ -#endif - -#define __RWSEM_INITIALIZER(name,count) \ -{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \ - __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ - __RWSEM_DEBUG_INIT __RWSEM_DEBUG_MINIT(name) } - -#define __DECLARE_RWSEM_GENERIC(name,count) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) - -#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS) -#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1) -#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0) - -static inline void init_rwsem(struct rw_semaphore *sem) -{ - sem->count = RWSEM_UNLOCKED_VALUE; - spin_lock_init(&sem->lock); - init_waitqueue_head(&sem->wait); -#if RWSEM_DEBUG - sem->debug = 0; -#endif -#if RWSEM_DEBUG_MAGIC - sem->__magic = (long)&sem->__magic; - atomic_set(&sem->readers, 0); - atomic_set(&sem->writers, 0); -#endif -} - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - int count; - spin_lock(&sem->lock); - sem->count += RWSEM_ACTIVE_READ_BIAS; - count = sem->count; - spin_unlock(&sem->lock); - if (count<0) - rwsem_down_read_failed(sem); -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - int count; - spin_lock(&sem->lock); - count = sem->count; - sem->count += RWSEM_ACTIVE_WRITE_BIAS; - spin_unlock(&sem->lock); - if (count) - rwsem_down_write_failed(sem); -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - int count; - spin_lock(&sem->lock); - count = sem->count; - sem->count -= RWSEM_ACTIVE_READ_BIAS; - spin_unlock(&sem->lock); - if (count<0 && !((count-RWSEM_ACTIVE_READ_BIAS)&RWSEM_ACTIVE_MASK)) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - int count; - spin_lock(&sem->lock); - sem->count -= RWSEM_ACTIVE_WRITE_BIAS; - count = sem->count; - spin_unlock(&sem->lock); - if (count<0) - rwsem_wake(sem); -} - -/* - * implement exchange and add functionality - */ -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) -{ - int count; - - spin_lock(&sem->lock); - sem->count += delta; - count = sem->count; - spin_unlock(&sem->lock); - - return count; -} - -/* - * implement compare and exchange functionality on the rw-semaphore count LSW - */ -static inline __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 old, __u16 new) -{ - __u16 prev; - - spin_lock(&sem->lock); - prev = sem->count & RWSEM_ACTIVE_MASK; - if (prev==old) - sem->count = (sem->count & ~RWSEM_ACTIVE_MASK) | new; - spin_unlock(&sem->lock); - - return prev; -} - -#endif /* __KERNEL__ */ -#endif /* _LINUX_RWSEM_SPINLOCK_H */ diff -urN rwsemref/include/linux/rwsem.h rwsem/include/linux/rwsem.h --- rwsemref/include/linux/rwsem.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/linux/rwsem.h Wed Apr 18 20:47:30 2001 @@ -1,148 +1,132 @@ -/* rwsem.h: R/W semaphores, public interface - * - * Written by David Howells (dhowells@redhat.com). - * Derived from asm-i386/semaphore.h - * - * - * The MSW of the count is the negated number of active writers and waiting - * lockers, and the LSW is the total number of active locks - * - * The lock count is initialized to 0 (no active and no waiting lockers). - * - * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an - * uncontended lock. This can be determined because XADD returns the old value. - * Readers increment by 1 and see a positive value when uncontended, negative - * if there are writers (and maybe) readers waiting (in which case it goes to - * sleep). - * - * The value of WAITING_BIAS supports up to 32766 waiting processes. This can - * be extended to 65534 by manually checking the whole MSW rather than relying - * on the S flag. - * - * The value of ACTIVE_BIAS supports up to 65535 active processes. - * - * This should be totally fair - if anything is waiting, a process that wants a - * lock will go to the back of the queue. When the currently active lock is - * released, if there's a writer at the front of the queue, then that and only - * that will be woken up; if there's a bunch of consequtive readers at the - * front, then they'll all be woken up, but no other readers will be. - */ - #ifndef _LINUX_RWSEM_H #define _LINUX_RWSEM_H -#include +#ifdef __KERNEL__ -#define RWSEM_DEBUG 0 -#define RWSEM_DEBUG_MAGIC 0 +#include -#ifdef __KERNEL__ +#ifndef CONFIG_GENERIC_RWSEM +#include +#else /* CONFIG_GENERIC_RWSEM */ -#include -#include #include +struct rw_semaphore +{ + spinlock_t lock; + int count; + struct list_head wait; +#if RWSEM_DEBUG + long __magic; +#endif +}; + #if RWSEM_DEBUG -#define rwsemdebug(FMT, ARGS...) do { if (sem->debug) printk(FMT,##ARGS); } while(0) +#define __SEM_DEBUG_INIT(name) \ + , (int)&(name).__magic +#define RWSEM_MAGIC(x) \ + do { \ + if ((x) != (long)&(x)) { \ + printk("rwsem bad magic %lx (should be %lx), ", \ + (long)x, (long)&(x)); \ + BUG(); \ + } \ + } while (0) #else -#define rwsemdebug(FMT, ARGS...) +#define __SEM_DEBUG_INIT(name) +#define CHECK_MAGIC(x) #endif -/* we use FASTCALL convention for the helpers */ -extern struct rw_semaphore *FASTCALL(rwsem_down_read_failed(struct rw_semaphore *sem)); -extern struct rw_semaphore *FASTCALL(rwsem_down_write_failed(struct rw_semaphore *sem)); -extern struct rw_semaphore *FASTCALL(rwsem_wake(struct rw_semaphore *sem)); +#define __RWSEM_INITIALIZER(name, count) \ +{ \ + SPIN_LOCK_UNLOCKED, \ + (count), \ + LIST_HEAD_INIT((name).wait) \ + __SEM_DEBUG_INIT(name) \ +} +#define RWSEM_INITIALIZER(name) __RWSEM_INITIALIZER(name, 0) -#include /* find the arch specific bits */ +#define __DECLARE_RWSEM(name, count) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name, count) +#define DECLARE_RWSEM(name) __DECLARE_RWSEM(name, 0) +#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM(name, 1) +#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM(name, -1) -#ifndef __HAVE_ARCH_SPECIFIC_RWSEM_IMPLEMENTATION -#include -#endif +#define RWSEM_WAITQUEUE_READ 0 +#define RWSEM_WAITQUEUE_WRITE 1 -/* - * lock for reading - */ -static inline void down_read(struct rw_semaphore *sem) -{ - rwsemdebug("Entering down_read(count=%08lx)\n",sem->count); +extern void down_failed(struct rw_semaphore *, int); +extern void rwsem_wake(struct rw_semaphore *); -#if RWSEM_DEBUG_MAGIC - if (sem->__magic != (long)&sem->__magic) - BUG(); +static inline void init_rwsem(struct rw_semaphore *sem) +{ + spin_lock_init(&sem->lock); + sem->count = 0; + INIT_LIST_HEAD(&sem->wait); +#if RWSEM_DEBUG + sem->__magic = (long)&sem->__magic; #endif +} - __down_read(sem); - -#if RWSEM_DEBUG_MAGIC - if (atomic_read(&sem->writers)) - BUG(); - atomic_inc(&sem->readers); -#endif +static inline void down_read(struct rw_semaphore *sem) +{ + CHECK_MAGIC(sem->__magic); - rwsemdebug("Leaving down_read(count=%08lx)\n",sem->count); + spin_lock_irq(&sem->lock); + if (sem->count < 0 || !list_empty(&sem->wait)) + goto slow_path; + sem->count++; + out: + spin_unlock_irq(&sem->lock); + return; + + slow_path: + down_failed(sem, RWSEM_WAITQUEUE_READ); + goto out; } -/* - * lock for writing - */ static inline void down_write(struct rw_semaphore *sem) { - rwsemdebug("Entering down_write(count=%08lx)\n",sem->count); - -#if RWSEM_DEBUG_MAGIC - if (sem->__magic != (long)&sem->__magic) - BUG(); -#endif + CHECK_MAGIC(sem->__magic); - __down_write(sem); - -#if RWSEM_DEBUG_MAGIC - if (atomic_read(&sem->writers)) - BUG(); - if (atomic_read(&sem->readers)) - BUG(); - atomic_inc(&sem->writers); -#endif - - rwsemdebug("Leaving down_write(count=%08lx)\n",sem->count); + spin_lock_irq(&sem->lock); + if (sem->count || !list_empty(&sem->wait)) + goto slow_path; + sem->count = -1; + out: + spin_unlock_irq(&sem->lock); + return; + + slow_path: + down_failed(sem, RWSEM_WAITQUEUE_WRITE); + goto out; } -/* - * release a read lock - */ static inline void up_read(struct rw_semaphore *sem) { - rwsemdebug("Entering up_read(count=%08lx)\n",sem->count); + unsigned long flags; -#if RWSEM_DEBUG_MAGIC - if (atomic_read(&sem->writers)) - BUG(); - atomic_dec(&sem->readers); -#endif - __up_read(sem); + CHECK_MAGIC(sem->__magic); - rwsemdebug("Leaving up_read(count=%08lx)\n",sem->count); + spin_lock_irqsave(&sem->lock, flags); + if (!--sem->count && !list_empty(&sem->wait)) + rwsem_wake(sem); + spin_unlock_irqrestore(&sem->lock, flags); } -/* - * release a write lock - */ static inline void up_write(struct rw_semaphore *sem) { - rwsemdebug("Entering up_write(count=%08lx)\n",sem->count); + unsigned long flags; -#if RWSEM_DEBUG_MAGIC - if (atomic_read(&sem->readers)) - BUG(); - if (atomic_read(&sem->writers) != 1) - BUG(); - atomic_dec(&sem->writers); -#endif - __up_write(sem); + CHECK_MAGIC(sem->__magic); - rwsemdebug("Leaving up_write(count=%08lx)\n",sem->count); + spin_lock_irqsave(&sem->lock, flags); + sem->count = 0; + if (!list_empty(&sem->wait)) + rwsem_wake(sem); + spin_unlock_irqrestore(&sem->lock, flags); } - +#endif /* CONFIG_GENERIC_RWSEM */ #endif /* __KERNEL__ */ #endif /* _LINUX_RWSEM_H */ diff -urN rwsemref/include/linux/sched.h rwsem/include/linux/sched.h --- rwsemref/include/linux/sched.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/linux/sched.h Wed Apr 18 20:47:30 2001 @@ -240,7 +240,7 @@ mm_users: ATOMIC_INIT(2), \ mm_count: ATOMIC_INIT(1), \ map_count: 1, \ - mmap_sem: __RWSEM_INITIALIZER(name.mmap_sem, RW_LOCK_BIAS), \ + mmap_sem: RWSEM_INITIALIZER(name.mmap_sem), \ page_table_lock: SPIN_LOCK_UNLOCKED, \ mmlist: LIST_HEAD_INIT(name.mmlist), \ } @@ -552,8 +552,6 @@ extern void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr)); extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr)); -extern int FASTCALL(__wake_up_ctx(wait_queue_head_t *q, unsigned int mode, int count, int bit)); -extern int FASTCALL(__wake_up_sync_ctx(wait_queue_head_t *q, unsigned int mode, int count, int bit)); extern void FASTCALL(sleep_on(wait_queue_head_t *q)); extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q, signed long timeout)); diff -urN rwsemref/include/linux/wait.h rwsem/include/linux/wait.h --- rwsemref/include/linux/wait.h Wed Apr 18 21:20:49 2001 +++ rwsem/include/linux/wait.h Wed Apr 18 20:47:30 2001 @@ -26,14 +26,6 @@ struct __wait_queue { unsigned int flags; #define WQ_FLAG_EXCLUSIVE 0x01 -#define WQ_FLAG_CONTEXT_0 8 /* context specific flag bit numbers */ -#define WQ_FLAG_CONTEXT_1 9 -#define WQ_FLAG_CONTEXT_2 10 -#define WQ_FLAG_CONTEXT_3 11 -#define WQ_FLAG_CONTEXT_4 12 -#define WQ_FLAG_CONTEXT_5 13 -#define WQ_FLAG_CONTEXT_6 14 -#define WQ_FLAG_CONTEXT_7 15 struct task_struct * task; struct list_head task_list; #if WAITQUEUE_DEBUG diff -urN rwsemref/kernel/sched.c rwsem/kernel/sched.c --- rwsemref/kernel/sched.c Wed Apr 18 21:20:49 2001 +++ rwsem/kernel/sched.c Wed Apr 18 01:26:42 2001 @@ -836,75 +836,6 @@ } } -/* - * wake up processes in the wait queue depending on the state of a context bit in the flags - * - wakes up a process if the specified bit is set in the flags member - * - the context bit is cleared if the process is woken up - * - if the bit number is negative, then the loop stops at the first unset context bit encountered - * - returns the number of processes woken - */ -static inline int __wake_up_ctx_common (wait_queue_head_t *q, - int count, int bit, const int sync) -{ - struct list_head *tmp, *head; - struct task_struct *p; - int stop, woken; - - woken = 0; - stop = bit<0; - if (bit<0) bit = -bit; - - CHECK_MAGIC_WQHEAD(q); - head = &q->task_list; - WQ_CHECK_LIST_HEAD(head); - tmp = head->next; - while (tmp != head) { - wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); - - tmp = tmp->next; - CHECK_MAGIC(curr->__magic); - p = curr->task; - if (!test_and_clear_bit(bit,&curr->flags)) { - if (stop) - break; - continue; - } - - WQ_NOTE_WAKER(curr); - try_to_wake_up(p,sync); - - woken++; - if (woken>=count) - break; - } - - return woken; -} - -int __wake_up_ctx(wait_queue_head_t *q, unsigned int mode, int count, int bit) -{ - int woken = 0; - if (q && count) { - unsigned long flags; - wq_read_lock_irqsave(&q->lock, flags); - woken = __wake_up_ctx_common(q, count, bit, 0); - wq_read_unlock_irqrestore(&q->lock, flags); - } - return woken; -} - -int __wake_up_ctx_sync(wait_queue_head_t *q, unsigned int mode, int count, int bit) -{ - int woken = 0; - if (q && count) { - unsigned long flags; - wq_read_lock_irqsave(&q->lock, flags); - woken = __wake_up_ctx_common(q, count, bit, 1); - wq_read_unlock_irqrestore(&q->lock, flags); - } - return woken; -} - #define SLEEP_ON_VAR \ unsigned long flags; \ wait_queue_t wait; \ diff -urN rwsemref/lib/Makefile rwsem/lib/Makefile --- rwsemref/lib/Makefile Wed Apr 18 21:20:49 2001 +++ rwsem/lib/Makefile Wed Apr 18 00:47:05 2001 @@ -10,10 +10,12 @@ export-objs := cmdline.o rwsem.o -obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o rwsem.o +obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o ifneq ($(CONFIG_HAVE_DEC_LOCK),y) obj-y += dec_and_lock.o endif + +obj-$(CONFIG_GENERIC_RWSEM) += rwsem.o include $(TOPDIR)/Rules.make diff -urN rwsemref/lib/rwsem.c rwsem/lib/rwsem.c --- rwsemref/lib/rwsem.c Wed Apr 18 21:20:49 2001 +++ rwsem/lib/rwsem.c Wed Apr 18 20:45:05 2001 @@ -1,156 +1,52 @@ -/* rwsem.c: R/W semaphores: contention handling functions - * - * Written by David Howells (dhowells@redhat.com). - * Derived from arch/i386/kernel/semaphore.c +/* + * generic rw_semaphores + * Copyright (C) 2001 Andrea Arcangeli SuSE */ -#include + #include #include +#include -/* - * wait for the read lock to be granted - * - need to repeal the increment made inline by the caller - * - need to throw a write-lock style spanner into the works (sub 0x00010000 from count) - */ -struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem) +void down_failed(struct rw_semaphore *sem, int flags) { struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait,tsk); - signed long count; + DECLARE_WAITQUEUE(wait, tsk); - rwsemdebug("[%d] Entering rwsem_down_read_failed(%08lx)\n",current->pid,sem->count); + wait.flags = flags; + list_add(&wait.task_list, &sem->wait); - /* this waitqueue context flag will be cleared when we are granted the lock */ - __set_bit(RWSEM_WAITING_FOR_READ,&wait.flags); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - - add_wait_queue_exclusive(&sem->wait, &wait); /* FIFO */ - - /* note that we're now waiting on the lock, but no longer actively read-locking */ - count = rwsem_atomic_update(RWSEM_WAITING_BIAS-RWSEM_ACTIVE_BIAS,sem); - rwsemdebug("X(%08lx)\n",count); - - /* if there are no longer active locks, wake the front queued process(es) up - * - it might even be this process, since the waker takes a more active part - */ - if (!(count & RWSEM_ACTIVE_MASK)) - rwsem_wake(sem); - - /* wait to be given the lock */ - for (;;) { - if (!test_bit(RWSEM_WAITING_FOR_READ,&wait.flags)) - break; + do { + __set_task_state(tsk, TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&sem->lock); schedule(); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait,&wait); - tsk->state = TASK_RUNNING; - - rwsemdebug("[%d] Leaving rwsem_down_read_failed(%08lx)\n",current->pid,sem->count); - - return sem; + spin_lock_irq(&sem->lock); + } while(wait.task_list.next); } -/* - * wait for the write lock to be granted - */ -struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem) +void rwsem_wake(struct rw_semaphore *sem) { - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait,tsk); - signed long count; - - rwsemdebug("[%d] Entering rwsem_down_write_failed(%08lx)\n",current->pid,sem->count); + struct list_head * entry, * head = &sem->wait; - /* this waitqueue context flag will be cleared when we are granted the lock */ - __set_bit(RWSEM_WAITING_FOR_WRITE,&wait.flags); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - - add_wait_queue_exclusive(&sem->wait, &wait); /* FIFO */ - - /* note that we're waiting on the lock, but no longer actively locking */ - count = rwsem_atomic_update(-RWSEM_ACTIVE_BIAS,sem); - rwsemdebug("[%d] updated(%08lx)\n",current->pid,count); - - /* if there are no longer active locks, wake the front queued process(es) up - * - it might even be this process, since the waker takes a more active part - */ - if (!(count & RWSEM_ACTIVE_MASK)) - rwsem_wake(sem); - - /* wait to be given the lock */ - for (;;) { - if (!test_bit(RWSEM_WAITING_FOR_WRITE,&wait.flags)) - break; - schedule(); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait,&wait); - tsk->state = TASK_RUNNING; + while ((entry = head->prev) != head) { + wait_queue_t * wait; - rwsemdebug("[%d] Leaving rwsem_down_write_failed(%08lx)\n",current->pid,sem->count); + wait = list_entry(entry, wait_queue_t, task_list); - return sem; -} - -/* - * handle the lock being released whilst there are processes blocked on it that can now run - * - if we come here, then: - * - the 'active part' of the count (&0x0000ffff) reached zero (but may no longer be zero) - * - the 'waiting part' of the count (&0xffff0000) is negative (and will still be so) - */ -struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) -{ - signed long count; - int woken; - - rwsemdebug("[%d] Entering rwsem_wake(%08lx)\n",current->pid,sem->count); - - try_again: - /* try to grab an 'activity' marker - * - need to make sure two copies of rwsem_wake() don't do this for two separate processes - * simultaneously - * - be horribly naughty, and only deal with the LSW of the atomic counter - */ - if (rwsem_cmpxchgw(sem,0,RWSEM_ACTIVE_BIAS)!=0) { - rwsemdebug("[%d] rwsem_wake: abort wakeup due to renewed activity\n",current->pid); - goto out; + if (wait->flags == RWSEM_WAITQUEUE_WRITE) { + if (!sem->count) { + sem->count = -1; + list_del(entry); + entry->next = NULL; + wake_up_process(wait->task); + } + break; + } + sem->count++; + list_del(entry); + entry->next = NULL; + wake_up_process(wait->task); } - - /* try to grant a single write lock if there's a writer at the front of the queue - * - note we leave the 'active part' of the count incremented by 1 and the waiting part - * incremented by 0x00010000 - */ - if (wake_up_ctx(&sem->wait,1,-RWSEM_WAITING_FOR_WRITE)==1) - goto out; - - /* grant an infinite number of read locks to the readers at the front of the queue - * - note we increment the 'active part' of the count by the number of readers just woken, - * less one for the activity decrement we've already done - */ - woken = wake_up_ctx(&sem->wait,65535,-RWSEM_WAITING_FOR_READ); - if (woken<=0) - goto counter_correction; - - woken *= RWSEM_ACTIVE_BIAS-RWSEM_WAITING_BIAS; - woken -= RWSEM_ACTIVE_BIAS; - rwsem_atomic_update(woken,sem); - - out: - rwsemdebug("[%d] Leaving rwsem_wake(%08lx)\n",current->pid,sem->count); - return sem; - - /* come here if we need to correct the counter for odd SMP-isms */ - counter_correction: - count = rwsem_atomic_update(-RWSEM_ACTIVE_BIAS,sem); - rwsemdebug("[%d] corrected(%08lx)\n",current->pid,count); - if (!(count & RWSEM_ACTIVE_MASK)) - goto try_again; - goto out; } -EXPORT_SYMBOL(rwsem_down_read_failed); -EXPORT_SYMBOL(rwsem_down_write_failed); +EXPORT_SYMBOL(down_failed); EXPORT_SYMBOL(rwsem_wake);