2 Unix SMB/CIFS implementation.
3 Samba database functions
4 Copyright (C) Anton Blanchard 2001
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31 #define _KLIBC_HAS_ARCH_SIG_ATOMIC_T
54 #if defined(SPARC_SPINLOCKS)
56 static inline int __spin_trylock(spinlock_t *lock)
60 asm volatile("ldstub [%1], %0"
65 return (result == 0) ? 0 : EBUSY;
68 static inline void __spin_unlock(spinlock_t *lock)
70 asm volatile("":::"memory");
74 static inline void __spin_lock_init(spinlock_t *lock)
79 static inline int __spin_is_locked(spinlock_t *lock)
84 #elif defined(POWERPC_SPINLOCKS)
86 static inline int __spin_trylock(spinlock_t *lock)
103 return (result == 1) ? 0 : EBUSY;
106 static inline void __spin_unlock(spinlock_t *lock)
108 asm volatile("eieio":::"memory");
112 static inline void __spin_lock_init(spinlock_t *lock)
117 static inline int __spin_is_locked(spinlock_t *lock)
122 #elif defined(INTEL_SPINLOCKS)
124 static inline int __spin_trylock(spinlock_t *lock)
128 asm volatile("xchgl %0,%1"
129 : "=r" (oldval), "=m" (*lock)
133 return oldval > 0 ? 0 : EBUSY;
136 static inline void __spin_unlock(spinlock_t *lock)
138 asm volatile("":::"memory");
142 static inline void __spin_lock_init(spinlock_t *lock)
147 static inline int __spin_is_locked(spinlock_t *lock)
152 #elif defined(MIPS_SPINLOCKS)
154 static inline unsigned int load_linked(unsigned long addr)
158 __asm__ __volatile__("ll\t%0,(%1)"
165 static inline unsigned int store_conditional(unsigned long addr, unsigned int value)
169 __asm__ __volatile__("sc\t%0,(%2)"
171 : "0" (value), "r" (addr));
175 static inline int __spin_trylock(spinlock_t *lock)
180 mw = load_linked(lock);
183 } while (!store_conditional(lock, 1));
185 asm volatile("":::"memory");
190 static inline void __spin_unlock(spinlock_t *lock)
192 asm volatile("":::"memory");
196 static inline void __spin_lock_init(spinlock_t *lock)
201 static inline int __spin_is_locked(spinlock_t *lock)
207 #error Need to implement spinlock code in spinlock.c
214 static void yield_cpu(void)
218 #ifdef USE_SCHED_YIELD
221 /* Linux will busy loop for delays < 2ms on real time tasks */
223 tm.tv_nsec = 2000000L + 1;
224 nanosleep(&tm, NULL);
228 static int this_is_smp(void)
237 static int smp_machine = 0;
239 static inline void __spin_lock(spinlock_t *lock)
243 while(__spin_trylock(lock)) {
244 while(__spin_is_locked(lock)) {
245 if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
252 static void __read_lock(tdb_rwlock_t *rwlock)
257 __spin_lock(&rwlock->lock);
259 if (!(rwlock->count & RWLOCK_BIAS)) {
261 __spin_unlock(&rwlock->lock);
265 __spin_unlock(&rwlock->lock);
267 while(rwlock->count & RWLOCK_BIAS) {
268 if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
275 static void __write_lock(tdb_rwlock_t *rwlock)
280 __spin_lock(&rwlock->lock);
282 if (rwlock->count == 0) {
283 rwlock->count |= RWLOCK_BIAS;
284 __spin_unlock(&rwlock->lock);
288 __spin_unlock(&rwlock->lock);
290 while(rwlock->count != 0) {
291 if (smp_machine && ntries++ < MAX_BUSY_LOOPS)
298 static void __write_unlock(tdb_rwlock_t *rwlock)
300 __spin_lock(&rwlock->lock);
302 if (!(rwlock->count & RWLOCK_BIAS))
303 dbg("bug: write_unlock");
305 rwlock->count &= ~RWLOCK_BIAS;
306 __spin_unlock(&rwlock->lock);
309 static void __read_unlock(tdb_rwlock_t *rwlock)
311 __spin_lock(&rwlock->lock);
314 dbg("bug: read_unlock");
316 if (rwlock->count & RWLOCK_BIAS)
317 dbg("bug: read_unlock");
320 __spin_unlock(&rwlock->lock);
325 /* lock a list in the database. list -1 is the alloc list */
326 int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type)
328 tdb_rwlock_t *rwlocks;
330 if (!tdb->map_ptr) return -1;
331 rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
335 __read_lock(&rwlocks[list+1]);
339 __write_lock(&rwlocks[list+1]);
343 return TDB_ERRCODE(TDB_ERR_LOCK, -1);
348 /* unlock the database. */
349 int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type)
351 tdb_rwlock_t *rwlocks;
353 if (!tdb->map_ptr) return -1;
354 rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
358 __read_unlock(&rwlocks[list+1]);
362 __write_unlock(&rwlocks[list+1]);
366 return TDB_ERRCODE(TDB_ERR_LOCK, -1);
372 int tdb_create_rwlocks(int fd, unsigned int hash_size)
375 tdb_rwlock_t *rwlocks;
377 size = (hash_size + 1) * sizeof(tdb_rwlock_t);
378 rwlocks = malloc(size);
382 for(i = 0; i < hash_size+1; i++) {
383 __spin_lock_init(&rwlocks[i].lock);
384 rwlocks[i].count = 0;
387 /* Write it out (appending to end) */
388 if (write(fd, rwlocks, size) != size) {
392 smp_machine = this_is_smp();
397 int tdb_clear_spinlocks(TDB_CONTEXT *tdb)
399 tdb_rwlock_t *rwlocks;
402 if (tdb->header.rwlocks == 0) return 0;
403 if (!tdb->map_ptr) return -1;
405 /* We're mmapped here */
406 rwlocks = (tdb_rwlock_t *)((char *)tdb->map_ptr + tdb->header.rwlocks);
407 for(i = 0; i < tdb->header.hash_size+1; i++) {
408 __spin_lock_init(&rwlocks[i].lock);
409 rwlocks[i].count = 0;
414 int tdb_create_rwlocks(int fd, unsigned int hash_size) { return 0; }
415 int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type) { return -1; }
416 int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type) { return -1; }
418 /* Non-spinlock version: remove spinlock pointer */
419 int tdb_clear_spinlocks(TDB_CONTEXT *tdb)
421 tdb_off off = (tdb_off)((char *)&tdb->header.rwlocks
422 - (char *)&tdb->header);
424 tdb->header.rwlocks = 0;
425 if (lseek(tdb->fd, off, SEEK_SET) != off
426 || write(tdb->fd, (void *)&tdb->header.rwlocks,
427 sizeof(tdb->header.rwlocks))
428 != sizeof(tdb->header.rwlocks))