On Fri, May 08, 2020 at 08:08:23PM -0700, Bart Van Assche wrote:
> On 2020-05-08 19:05, Ming Lei wrote:
> > Fine, then we can save one callback, how about the following way?
> >
> > diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
> > index 586c9d6e904a..5e9c743d887b 100644
> > --- a/block/blk-mq-tag.c
> > +++ b/block/blk-mq-tag.c
> > @@ -257,6 +257,7 @@ struct bt_tags_iter_data {
> > busy_tag_iter_fn *fn;
> > void *data;
> > bool reserved;
> > + bool iterate_all;
> > };
> >
> > static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
> > @@ -274,8 +275,10 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
> > * test and set the bit before assining ->rqs[].
> > */
> > rq = tags->rqs[bitnr];
> > - if (rq && blk_mq_request_started(rq))
> > - return iter_data->fn(rq, iter_data->data, reserved);
> > + if (rq) {
> > + if (iter_data->iterate_all || blk_mq_request_started(rq))
> > + return iter_data->fn(rq, iter_data->data, reserved);
> > + }
>
> How about combining the two if-statements above in the following single
> if-statement:
>
> if (rq && (iter_data->iterate_all || blk_mq_request_started(rq)))
> ...
OK.
>
> > @@ -321,8 +326,30 @@ static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
> > busy_tag_iter_fn *fn, void *priv)
> > {
> > if (tags->nr_reserved_tags)
> > - bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
> > - bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
> > + bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true,
> > + false);
> > + bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false, false);
> > +}
>
> How about inserting comments like /*reserved=*/ and /*iterate_all=*/ in
> the bt_tags_for_each() call in front of "false" to make these calls
> easier to read?
I think it isn't necessary, given both two are self-documented from
the name of bt_tags_for_each's parameters.
>
> > +/**
> > + * blk_mq_all_tag_iter - iterate over all requests in a tag map
> > + * @tags: Tag map to iterate over.
> > + * @fn: Pointer to the function that will be called for each
> > + * 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.
> > + * @priv: Will be passed as second argument to @fn.
> > + *
> > + * It is the caller's responsility to check rq's state in @fn.
> ^^^^^^^^^^^^
> responsibility?
OK.
Thanks,
Ming
