On 2020-05-04 19:09, Ming Lei wrote:
> @@ -310,19 +313,30 @@ static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
> /**
> * blk_mq_all_tag_busy_iter - iterate over all started requests in a tag map
> * @tags: Tag map to iterate over.
> - * @fn: Pointer to the function that will be called for each started
> - * request. @fn will be called as follows: @fn(rq, @priv,
> - * reserved) where rq is a pointer to a request. 'reserved'
> - * indicates whether or not @rq is a reserved request. Return
> - * true to continue iterating tags, false to stop.
> + * @fn: Pointer to the function that will be called for each request
> + * when .busy_rq_fn(rq) returns true. @fn will be called as
> + * follows: @fn(rq, @priv, reserved) where rq is a pointer to a
> + * request. 'reserved' indicates whether or not @rq is a reserved
> + * request. Return true to continue iterating tags, false to stop.
> + * @busy_rq_fn: Pointer to the function that will be called for each request,
> + * @busy_rq_fn's type is same with @fn. Only when @busy_rq_fn(rq,
> + * @priv, reserved) returns true, @fn will be called on this rq.
> * @priv: Will be passed as second argument to @fn.
> */
> -static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
> - busy_tag_iter_fn *fn, void *priv)
> +void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
> + busy_tag_iter_fn *fn, busy_rq_iter_fn *busy_rq_fn,
> + void *priv)
> {
The name 'busy_rq_fn' is not ideal because it is named after one
specific use case, namely checking whether or not a request is busy (has
already been started). How about using the name 'pred_fn' ('pred' from
predicate because it controls whether the other function is called)?
Since only the context that passes 'fn' can know what data structure
'priv' points to and since 'busy_rq_fn' is passed from another context,
can 'busy_rq_fn' even know what data 'priv' points at? Has it been
considered not to pass the 'priv' argument to 'busy_rq_fn'?
Thanks,
Bart.
