5 * 'Big Reader' read-write spinlocks. See linux/brlock.h for details.
7 * Copyright 2000, Ingo Molnar <mingo@redhat.com>
8 * Copyright 2000, David S. Miller <davem@redhat.com>
11 #include <linux/config.h>
15 #include <linux/sched.h>
16 #include <linux/brlock.h>
18 #ifdef __BRLOCK_USE_ATOMICS
20 brlock_read_lock_t __brlock_array
[NR_CPUS
][__BR_IDX_MAX
] =
21 { [0 ... NR_CPUS
-1] = { [0 ... __BR_IDX_MAX
-1] = RW_LOCK_UNLOCKED
} };
23 void __br_write_lock (enum brlock_indices idx
)
27 for (i
= 0; i
< smp_num_cpus
; i
++)
28 write_lock(__brlock_array
[idx
] + cpu_logical_map(i
));
31 void __br_write_unlock (enum brlock_indices idx
)
35 for (i
= 0; i
< smp_num_cpus
; i
++)
36 write_unlock(__brlock_array
[idx
] + cpu_logical_map(i
));
39 #else /* ! __BRLOCK_USE_ATOMICS */
41 brlock_read_lock_t __brlock_array
[NR_CPUS
][__BR_IDX_MAX
] =
42 { [0 ... NR_CPUS
-1] = { [0 ... __BR_IDX_MAX
-1] = 0 } };
44 struct br_wrlock __br_write_locks
[__BR_IDX_MAX
] =
45 { [0 ... __BR_IDX_MAX
-1] = { SPIN_LOCK_UNLOCKED
} };
47 void __br_write_lock (enum brlock_indices idx
)
51 spin_lock(&__br_write_locks
[idx
].lock
);
53 for (i
= 0; i
< smp_num_cpus
; i
++)
54 if (__brlock_array
[cpu_logical_map(i
)][idx
] != 0)
58 void __br_write_unlock (enum brlock_indices idx
)
60 spin_unlock(&__br_write_locks
[idx
].lock
);
63 #endif /* __BRLOCK_USE_ATOMICS */
65 #endif /* CONFIG_SMP */