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Diffstat (limited to 'source/tdb/spinlock.c')
-rw-r--r-- | source/tdb/spinlock.c | 472 |
1 files changed, 0 insertions, 472 deletions
diff --git a/source/tdb/spinlock.c b/source/tdb/spinlock.c deleted file mode 100644 index e42a6901c71..00000000000 --- a/source/tdb/spinlock.c +++ /dev/null @@ -1,472 +0,0 @@ -/* - Unix SMB/CIFS implementation. - - trivial database library - - Copyright (C) Anton Blanchard 2001 - - ** NOTE! The following LGPL license applies to the tdb - ** library. This does NOT imply that all of Samba is released - ** under the LGPL - - This library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2 of the License, or (at your option) any later version. - - This library 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with this library; if not, write to the Free Software - Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA -*/ -#if HAVE_CONFIG_H -#include <config.h> -#endif - -#ifdef 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 "tdb.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) && defined(sgi) && (_COMPILER_VERSION >= 730) - -/* Implement spinlocks on IRIX using the MIPSPro atomic fetch operations. See - * sync(3) for the details of the intrinsic operations. - * - * "sgi" and "_COMPILER_VERSION" are always defined by MIPSPro. - */ - -#ifdef STANDALONE - -/* MIPSPro 7.3 has "__inline" as an extension, but not "inline. */ -#define inline __inline - -#endif /* STANDALONE */ - -/* Returns 0 if the lock is acquired, EBUSY otherwise. */ -static inline int __spin_trylock(spinlock_t *lock) -{ - unsigned int val; - val = __lock_test_and_set(lock, 1); - return val == 0 ? 0 : EBUSY; -} - -static inline void __spin_unlock(spinlock_t *lock) -{ - __lock_release(lock); -} - -static inline void __spin_lock_init(spinlock_t *lock) -{ - __lock_release(lock); -} - -/* Returns 1 if the lock is held, 0 otherwise. */ -static inline int __spin_is_locked(spinlock_t *lock) -{ - unsigned int val; - val = __add_and_fetch(lock, 0); - return val; -} - -#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 -} - -/* - * 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 = TDB_SPINLOCK_SIZE(hash_size); - 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 |