On Fri, 2018-02-02 at 15:08 +0100, Roman Pen wrote:
> +static inline struct ibtrs_tag *
> +__ibtrs_get_tag(struct ibtrs_clt *clt, enum ibtrs_clt_con_type con_type)
> +{
> + size_t max_depth = clt->queue_depth;
> + struct ibtrs_tag *tag;
> + int cpu, bit;
> +
> + cpu = get_cpu();
> + do {
> + bit = find_first_zero_bit(clt->tags_map, max_depth);
> + if (unlikely(bit >= max_depth)) {
> + put_cpu();
> + return NULL;
> + }
> +
> + } while (unlikely(test_and_set_bit_lock(bit, clt->tags_map)));
> + put_cpu();
> +
> + tag = GET_TAG(clt, bit);
> + WARN_ON(tag->mem_id != bit);
> + tag->cpu_id = cpu;
> + tag->con_type = con_type;
> +
> + return tag;
> +}
> +
> +static inline void __ibtrs_put_tag(struct ibtrs_clt *clt,
> + struct ibtrs_tag *tag)
> +{
> + clear_bit_unlock(tag->mem_id, clt->tags_map);
> +}
> +
> +struct ibtrs_tag *ibtrs_clt_get_tag(struct ibtrs_clt *clt,
> + enum ibtrs_clt_con_type con_type,
> + int can_wait)
> +{
> + struct ibtrs_tag *tag;
> + DEFINE_WAIT(wait);
> +
> + tag = __ibtrs_get_tag(clt, con_type);
> + if (likely(tag) || !can_wait)
> + return tag;
> +
> + do {
> + prepare_to_wait(&clt->tags_wait, &wait, TASK_UNINTERRUPTIBLE);
> + tag = __ibtrs_get_tag(clt, con_type);
> + if (likely(tag))
> + break;
> +
> + io_schedule();
> + } while (1);
> +
> + finish_wait(&clt->tags_wait, &wait);
> +
> + return tag;
> +}
> +EXPORT_SYMBOL(ibtrs_clt_get_tag);
> +
> +void ibtrs_clt_put_tag(struct ibtrs_clt *clt, struct ibtrs_tag *tag)
> +{
> + if (WARN_ON(!test_bit(tag->mem_id, clt->tags_map)))
> + return;
> +
> + __ibtrs_put_tag(clt, tag);
> +
> + /*
> + * Putting a tag is a barrier, so we will observe
> + * new entry in the wait list, no worries.
> + */
> + if (waitqueue_active(&clt->tags_wait))
> + wake_up(&clt->tags_wait);
> +}
> +EXPORT_SYMBOL(ibtrs_clt_put_tag);
Do these functions have any advantage over the code in lib/sbitmap.c? If not,
please call the sbitmap functions instead of adding an additional tag allocator.
Thanks,
Bart.
