On Mon, Sep 09, 2013 at 09:42:46PM -0700, John Stultz wrote:
> @@ -38,10 +39,58 @@
> */
> typedef struct seqcount {
> unsigned sequence;
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> + struct lockdep_map dep_map;
> +#endif
> } seqcount_t;
>
> -#define SEQCNT_ZERO { 0 }
> -#define seqcount_init(x) do { *(x) = (seqcount_t) SEQCNT_ZERO; } while
> (0)
> +
> +
> +
> +static inline void __seqcount_init(seqcount_t *s, const char *name,
> + struct lock_class_key *key)
> +{
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> + /*
> + * Make sure we are not reinitializing a held lock:
> + */
> + lockdep_init_map(&s->dep_map, name, key, 0);
> +#endif
> + s->sequence = 0;
> +}
> +
> +
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +# define SEQCOUNT_DEP_MAP_INIT(lockname) \
> + .dep_map = { .name = #lockname } \
> +
> +# define seqcount_init(s) \
> + do { \
> + static struct lock_class_key __key; \
> + __seqcount_init((s), #s, &__key); \
> + } while (0)
> +
> +static inline void seqcount_reader_access(const seqcount_t *s)
> +{
> + seqcount_t *l = (seqcount_t *)s;
> + unsigned long flags;
> +
> + preempt_disable();
> + local_irq_save(flags);
> + seqcount_acquire_read(&l->dep_map, 0, 0, _RET_IP_);
> + seqcount_release(&l->dep_map, 1, _RET_IP_);
> + local_irq_restore(flags);
> + preempt_enable();
> +}
Why the preempt and local_irq thing? Also preempt_disable is quite
superfluous if you do local_irq_disable().
> +
> +#else
> +# define SEQCOUNT_DEP_MAP_INIT(lockname)
> +# define seqcount_init(s) __seqcount_init(s, NULL, NULL)
> +# define seqcount_reader_access(x)
> +#endif
> +
> +#define SEQCNT_ZERO(lockname) { .sequence = 0,
> SEQCOUNT_DEP_MAP_INIT(lockname)}
> +
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
