block: improve the gap check in __bio_add_pc_page

If we can add more data into an existing segment we do not create a gap
per definition, so move the check for a gap after the attempt to merge
into the segment.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2019-08-12 17:39:56 +02:00 committed by Jens Axboe
parent e9e006f5fc
commit 320ea869a1

View File

@ -710,18 +710,18 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
goto done;
}
/*
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
if (bvec_gap_to_prev(q, bvec, offset))
return 0;
if (page_is_mergeable(bvec, page, len, offset, &same_page) &&
can_add_page_to_seg(q, bvec, page, len, offset)) {
bvec->bv_len += len;
goto done;
}
/*
* If the queue doesn't support SG gaps and adding this segment
* would create a gap, disallow it.
*/
if (bvec_gap_to_prev(q, bvec, offset))
return 0;
}
if (bio_full(bio, len))