On Tue, 20 Sep 2022, Christoph Hellwig wrote:
> > @@ -289,6 +308,23 @@ static void brd_submit_bio(struct bio *b
> > struct bio_vec bvec;
> > struct bvec_iter iter;
> >
> > + if (bio_op(bio) == REQ_OP_DISCARD) {
> > + sector_t len = bio_sectors(bio);
> > + sector_t front_pad = -sector & (PAGE_SECTORS - 1);
> > + sector += front_pad;
> > + if (unlikely(len <= front_pad))
> > + goto endio;
> > + len -= front_pad;
> > + len = round_down(len, PAGE_SECTORS);
> > + while (len) {
> > + brd_free_page(brd, sector);
> > + sector += PAGE_SECTORS;
> > + len -= PAGE_SECTORS;
> > + cond_resched();
> > + }
> > + goto endio;
> > + }
> > +
> > bio_for_each_segment(bvec, bio, iter) {
>
> Please add separate helpers to each type of IO and just make the
> main submit_bio method a dispatch on the types instead of this
> spaghetti code.
>
> > + disk->queue->limits.discard_granularity = PAGE_SIZE;
> > + blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
>
> We'll probably want an opt in for this new feature.
OK. I addressed these concerns and I'll send a second version of the patch
set.
Mikulas
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