+++ /dev/null
-/*
- Unix SMB/CIFS implementation.
- Samba database functions
- Copyright (C) Anton Blanchard 2001
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-#define STANDALONE 1
-
-#if HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#if STANDALONE
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <sys/stat.h>
-#include <time.h>
-#include <signal.h>
-#include "spinlock.h"
-
-#define DEBUG
-#else
-#include "includes.h"
-#endif
-
-#ifdef USE_SPINLOCKS
-
-/*
- * ARCH SPECIFIC
- */
-
-#if defined(SPARC_SPINLOCKS)
-
-static inline int __spin_trylock(spinlock_t *lock)
-{
- unsigned int result;
-
- asm volatile("ldstub [%1], %0"
- : "=r" (result)
- : "r" (lock)
- : "memory");
-
- return (result == 0) ? 0 : EBUSY;
-}
-
-static inline void __spin_unlock(spinlock_t *lock)
-{
- asm volatile("":::"memory");
- *lock = 0;
-}
-
-static inline void __spin_lock_init(spinlock_t *lock)
-{
- *lock = 0;
-}
-
-static inline int __spin_is_locked(spinlock_t *lock)
-{
- return (*lock != 0);
-}
-
-#elif defined(POWERPC_SPINLOCKS)
-
-static inline int __spin_trylock(spinlock_t *lock)
-{
- unsigned int result;
-
- __asm__ __volatile__(
-"1: lwarx %0,0,%1\n\
- cmpwi 0,%0,0\n\
- li %0,0\n\
- bne- 2f\n\
- li %0,1\n\
- stwcx. %0,0,%1\n\
- bne- 1b\n\
- isync\n\
-2:" : "=&r"(result)
- : "r"(lock)
- : "cr0", "memory");
-
- return (result == 1) ? 0 : EBUSY;
-}
-
-static inline void __spin_unlock(spinlock_t *lock)
-{
- asm volatile("eieio":::"memory");
- *lock = 0;
-}
-
-static inline void __spin_lock_init(spinlock_t *lock)
-{
- *lock = 0;
-}
-
-static inline int __spin_is_locked(spinlock_t *lock)
-{
- return (*lock != 0);
-}
-
-#elif defined(INTEL_SPINLOCKS)
-
-static inline int __spin_trylock(spinlock_t *lock)
-{
- int oldval;
-
- asm volatile("xchgl %0,%1"
- : "=r" (oldval), "=m" (*lock)
- : "0" (0)
- : "memory");
-
- return oldval > 0 ? 0 : EBUSY;
-}
-
-static inline void __spin_unlock(spinlock_t *lock)
-{
- asm volatile("":::"memory");
- *lock = 1;
-}
-
-static inline void __spin_lock_init(spinlock_t *lock)
-{
- *lock = 1;
-}
-
-static inline int __spin_is_locked(spinlock_t *lock)
-{
- return (*lock != 1);
-}
-
-#elif defined(MIPS_SPINLOCKS)
-
-static inline unsigned int load_linked(unsigned long addr)
-{
- unsigned int res;
-
- __asm__ __volatile__("ll\t%0,(%1)"
- : "=r" (res)
- : "r" (addr));
-
- return res;
-}
-
-static inline unsigned int store_conditional(unsigned long addr, unsigned int value)
-{
- unsigned int res;
-
- __asm__ __volatile__("sc\t%0,(%2)"
- : "=r" (res)
- : "0" (value), "r" (addr));
- return res;
-}
-
-static inline int __spin_trylock(spinlock_t *lock)
-{
- unsigned int mw;
-
- do {
- mw = load_linked(lock);
- if (mw)
- return EBUSY;
- } while (!store_conditional(lock, 1));
-
- asm volatile("":::"memory");
-
- return 0;
-}
-
-static inline void __spin_unlock(spinlock_t *lock)
-{
- asm volatile("":::"memory");
- *lock = 0;
-}
-
-static inline void __spin_lock_init(spinlock_t *lock)
-{
- *lock = 0;
-}
-
-static inline int __spin_is_locked(spinlock_t *lock)
-{
- return (*lock != 0);
-}
-
-#else
-#error Need to implement spinlock code in spinlock.c
-#endif
-
-/*
- * OS SPECIFIC
- */
-
-static void yield_cpu(void)
-{
- struct timespec tm;
-
-#ifdef USE_SCHED_YIELD
- sched_yield();
-#else
- /* Linux will busy loop for delays < 2ms on real time tasks */
- tm.tv_sec = 0;
- tm.tv_nsec = 2000000L + 1;
- nanosleep(&tm, NULL);
-#endif
-}
-
-static int this_is_smp(void)
-{
- return 0;
-}
-
-/*
- * GENERIC
- */
-
-static int smp_machine = 0;
-
-static inline void __spin_lock(spinlock_t *lock)
-{
- int ntries = 0;
-
- while(__spin_trylock(lock)) {
- while(__spin_is_locked(lock)) {
- if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
- continue;
- yield_cpu();
- }
- }
-}
-
-static void __read_lock(tdb_rwlock_t *rwlock)
-{
- int ntries = 0;
-
- while(1) {
- __spin_lock(&rwlock->lock);
-
- if (!(rwlock->count & RWLOCK_BIAS)) {
- rwlock->count++;
- __spin_unlock(&rwlock->lock);
- return;
- }
-
- __spin_unlock(&rwlock->lock);
-
- while(rwlock->count & RWLOCK_BIAS) {
- if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
- continue;
- yield_cpu();
- }
- }
-}
-
-static void __write_lock(tdb_rwlock_t *rwlock)
-{
- int ntries = 0;
-
- while(1) {
- __spin_lock(&rwlock->lock);
-
- if (rwlock->count == 0) {
- rwlock->count |= RWLOCK_BIAS;
- __spin_unlock(&rwlock->lock);
- return;
- }
-
- __spin_unlock(&rwlock->lock);
-
- while(rwlock->count != 0) {
- if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
- continue;
- yield_cpu();
- }
- }
-}
-
-static void __write_unlock(tdb_rwlock_t *rwlock)
-{
- __spin_lock(&rwlock->lock);
-
-#ifdef DEBUG
- if (!(rwlock->count & RWLOCK_BIAS))
- fprintf(stderr, "bug: write_unlock\n");
-#endif
-
- rwlock->count &= ~RWLOCK_BIAS;
- __spin_unlock(&rwlock->lock);
-}
-
-static void __read_unlock(tdb_rwlock_t *rwlock)
-{
- __spin_lock(&rwlock->lock);
-
-#ifdef DEBUG
- if (!rwlock->count)
- fprintf(stderr, "bug: read_unlock\n");
-
- if (rwlock->count & RWLOCK_BIAS)
- fprintf(stderr, "bug: read_unlock\n");
-#endif
-
- rwlock->count--;
- __spin_unlock(&rwlock->lock);
-}
-
-/* TDB SPECIFIC */
-
-/* lock a list in the database. list -1 is the alloc list */
-int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type)
-{
- tdb_rwlock_t *rwlocks;
-
- if (!tdb->map_ptr) return -1;
- rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
-
- switch(rw_type) {
- case F_RDLCK:
- __read_lock(&rwlocks[list+1]);
- break;
-
- case F_WRLCK:
- __write_lock(&rwlocks[list+1]);
- break;
-
- default:
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
- }
- return 0;
-}
-
-/* unlock the database. */
-int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type)
-{
- tdb_rwlock_t *rwlocks;
-
- if (!tdb->map_ptr) return -1;
- rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
-
- switch(rw_type) {
- case F_RDLCK:
- __read_unlock(&rwlocks[list+1]);
- break;
-
- case F_WRLCK:
- __write_unlock(&rwlocks[list+1]);
- break;
-
- default:
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
- }
-
- return 0;
-}
-
-int tdb_create_rwlocks(int fd, unsigned int hash_size)
-{
- unsigned size, i;
- tdb_rwlock_t *rwlocks;
-
- size = (hash_size + 1) * sizeof(tdb_rwlock_t);
- rwlocks = malloc(size);
- if (!rwlocks)
- return -1;
-
- for(i = 0; i < hash_size+1; i++) {
- __spin_lock_init(&rwlocks[i].lock);
- rwlocks[i].count = 0;
- }
-
- /* Write it out (appending to end) */
- if (write(fd, rwlocks, size) != size) {
- free(rwlocks);
- return -1;
- }
- smp_machine = this_is_smp();
- free(rwlocks);
- return 0;
-}
-
-int tdb_clear_spinlocks(TDB_CONTEXT *tdb)
-{
- tdb_rwlock_t *rwlocks;
- unsigned i;
-
- if (tdb->header.rwlocks == 0) return 0;
- if (!tdb->map_ptr) return -1;
-
- /* We're mmapped here */
- rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
- for(i = 0; i < tdb->header.hash_size+1; i++) {
- __spin_lock_init(&rwlocks[i].lock);
- rwlocks[i].count = 0;
- }
- return 0;
-}
-#else
-int tdb_create_rwlocks(int fd, unsigned int hash_size) { return 0; }
-int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type) { return -1; }
-int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type) { return -1; }
-
-/* Non-spinlock version: remove spinlock pointer */
-int tdb_clear_spinlocks(TDB_CONTEXT *tdb)
-{
- tdb_off off = (tdb_off)((char *)&tdb->header.rwlocks
- - (char *)&tdb->header);
-
- tdb->header.rwlocks = 0;
- if (lseek(tdb->fd, off, SEEK_SET) != off
- || write(tdb->fd, (void *)&tdb->header.rwlocks,
- sizeof(tdb->header.rwlocks))
- != sizeof(tdb->header.rwlocks))
- return -1;
- return 0;
-}
-#endif
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