| Date | Fri, 16 Nov 2018 14:53:08 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH V10 14/19] block: enable multipage bvecs |
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> - > - if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) { > - bv->bv_len += len; > - bio->bi_iter.bi_size += len; > - return true; > - } > + struct request_queue *q = NULL; > + > + if (page == bv->bv_page && off == (bv->bv_offset + bv->bv_len) > + && (off + len) <= PAGE_SIZE)
How could the page struct be the same, but the range beyond PAGE_SIZE (at least with the existing callers)?
Also no need for the inner btraces, and the && always goes on the first line.
> + if (bio->bi_disk) > + q = bio->bi_disk->queue; > + > + /* disable multi-page bvec too if cluster isn't enabled */ > + if (!q || !blk_queue_cluster(q) || > + ((page_to_phys(bv->bv_page) + bv->bv_offset + bv->bv_len) != > + (page_to_phys(page) + off))) > + return false; > + merge: > + bv->bv_len += len; > + bio->bi_iter.bi_size += len; > + return true;
Ok, this is scary, as it will give differen results depending on when bi_disk is assigned. But then again we shouldn't really do the cluster check here, but rather when splitting the bio for the actual low-level driver.
(and eventually we should kill this clustering setting off in favor of our normal segment limits).
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