| Message ID | 20241119161157.1328171-2-hch@lst.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] block: don't bother checking the data direction for merges | expand |
On 19/11/2024 16:11, Christoph Hellwig wrote: > Because it already is encoded in the opcode. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > block/blk-merge.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index e0b28e9298c9..64860cbd5e27 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -864,9 +864,6 @@ static struct request *attempt_merge(struct request_queue *q, > if (req_op(req) != req_op(next)) > return NULL; > > - if (rq_data_dir(req) != rq_data_dir(next)) > - return NULL; > - > if (req->bio && next->bio) { > /* Don't merge requests with different write hints. */ > if (req->bio->bi_write_hint != next->bio->bi_write_hint) > @@ -986,10 +983,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) > if (req_op(rq) != bio_op(bio)) > return false; > > - /* different data direction or already started, don't merge */ I tried to check what is meant by "already started", but that comment pre-dates git. And even the code from then does not make it obvious, but I don't want to check further, so: Reviewed-by: John Garry <john.g.garry@oracle.com> > - if (bio_data_dir(bio) != rq_data_dir(rq)) > - return false; > - > /* don't merge across cgroup boundaries */ > if (!blk_cgroup_mergeable(rq, bio)) > return false;
On Tue, Nov 19, 2024 at 04:48:15PM +0000, John Garry wrote: > I tried to check what is meant by "already started", but that comment > pre-dates git. And even the code from then does not make it obvious, but I > don't want to check further, so: Back in the bad old days there was a separare prep_fn callback into the driver to prepare a request while it was still on the scheduler lists, and that then set a started flag. In other words the comment is long obsolete.
diff --git a/block/blk-merge.c b/block/blk-merge.c index e0b28e9298c9..64860cbd5e27 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -864,9 +864,6 @@ static struct request *attempt_merge(struct request_queue *q, if (req_op(req) != req_op(next)) return NULL; - if (rq_data_dir(req) != rq_data_dir(next)) - return NULL; - if (req->bio && next->bio) { /* Don't merge requests with different write hints. */ if (req->bio->bi_write_hint != next->bio->bi_write_hint) @@ -986,10 +983,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) if (req_op(rq) != bio_op(bio)) return false; - /* different data direction or already started, don't merge */ - if (bio_data_dir(bio) != rq_data_dir(rq)) - return false; - /* don't merge across cgroup boundaries */ if (!blk_cgroup_mergeable(rq, bio)) return false;
Because it already is encoded in the opcode. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/blk-merge.c | 7 ------- 1 file changed, 7 deletions(-)