Re: [PATCH 3/4] brd: enable discard
From: Christoph Hellwig <hch@infradead.org>
Date: 2022-09-20 07:40:10
Also in:
dm-devel
quoted hunk ↗ jump to hunk
@@ -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.