| #ifndef __ASM_SYNC_BITOPS_H__ | 
 | #define __ASM_SYNC_BITOPS_H__ | 
 |  | 
 | #include <asm/bitops.h> | 
 | #include <asm/cmpxchg.h> | 
 |  | 
 | /* sync_bitops functions are equivalent to the SMP implementation of the | 
 |  * original functions, independently from CONFIG_SMP being defined. | 
 |  * | 
 |  * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But | 
 |  * under Xen you might be communicating with a completely external entity | 
 |  * who might be on another CPU (e.g. two uniprocessor guests communicating | 
 |  * via event channels and grant tables). So we need a variant of the bit | 
 |  * ops which are SMP safe even on a UP kernel. | 
 |  */ | 
 |  | 
 | #define sync_set_bit(nr, p)            set_bit(nr, p) | 
 | #define sync_clear_bit(nr, p)          clear_bit(nr, p) | 
 | #define sync_change_bit(nr, p)         change_bit(nr, p) | 
 | #define sync_test_and_set_bit(nr, p)   test_and_set_bit(nr, p) | 
 | #define sync_test_and_clear_bit(nr, p) test_and_clear_bit(nr, p) | 
 | #define sync_test_and_change_bit(nr, p)        test_and_change_bit(nr, p) | 
 | #define sync_test_bit(nr, addr)                test_bit(nr, addr) | 
 | #define sync_cmpxchg                   cmpxchg | 
 |  | 
 | #endif |