On Tue, 26 May 2015 16:42:35 -0700 Ming Lin <mlin@xxxxxxxxxx> wrote: > On Tue, May 26, 2015 at 4:03 PM, NeilBrown <neilb@xxxxxxx> wrote: > > On Tue, 26 May 2015 15:32:38 -0700 Ming Lin <mlin@xxxxxxxxxx> wrote: > > > >> On Tue, May 26, 2015 at 7:33 AM, Ming Lin <mlin@xxxxxxxxxx> wrote: > >> > On Mon, May 25, 2015 at 7:17 AM, Christoph Hellwig <hch@xxxxxx> wrote: > >> >> On Mon, May 25, 2015 at 05:54:14PM +1000, NeilBrown wrote: > >> >>> Did I write that? I guess I did :-( > >> >>> I meant *after*. Don't get rid of bio_fits_rdev until split_bio is in > >> >>> chunk_aligned_read(). > >> >> > >> >> I suspect the whole series could use some reordering. > >> > > >> > Nice reordering. > >> > I'll do this. > >> > >> Here is the reordering. > >> https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=block-generic-req > >> > >> I'll post it if you are OK. > >> > >> [PATCH 01/15] block: add blk_queue_split() > >> [PATCH 02/15] md: remove ->merge_bvec_fn > >> [PATCH 03/15] dm: remov merge functions > >> [PATCH 04/15] drbd: remove ->merge_bvec_fn > >> [PATCH 05/15] pktcdvd: remove ->merge_bvec_fn > >> [PATCH 06/15] rbd: remove ->merge_bvec_fn > >> [PATCH 07/15] bcache: remove driver private bio splitting code > >> [PATCH 08/15] btrfs: remove bio splitting and merge_bvec_fn() calls > >> [PATCH 09/15] block: call blk_queue_split() in make_request functions > >> [PATCH 10/15] block: kill ->merge_bvec_fn and simplify bio_add_page > >> [PATCH 11/15] block: remove split code in blkdev_issue_discard > >> [PATCH 12/15] md/raid5: get rid of bio_fits_rdev() > >> [PATCH 13/15] block: remove bio_get_nr_vecs() > >> [PATCH 14/15] fs: use helper bio_add_page() instead of open coding on > >> [PATCH 15/15] Documentation: update notes in biovecs about > > > > The changes to dm.c and dm.h should be in the "dm:" patch, not "md:". > > Will move it. > > > > > But I don't think the sequence is right. > > > > You cannot remove ->merge_bvec_fn for *any* stacked device until *all* devices > > make use of blk_queue_split() (or otherwise handle arbitrarily large bios). > > > > I think it would be easiest to: > > - add blk_queue_split() and call it from common code before ->make_request_fn > > is called. The ensure all devices can accept arbitrarily large bios. > > For "common code", do you mean "generic_make_request()" > > diff --git a/block/blk-core.c b/block/blk-core.c > index fbbb337..bb6455b 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1942,6 +1942,7 @@ void generic_make_request(struct bio *bio) > do { > struct request_queue *q = bdev_get_queue(bio->bi_bdev); > > + blk_queue_split(q, &bio, q->bio_split); > q->make_request_fn(q, bio); > > bio = bio_list_pop(current->bio_list); Yes, that is what I mean (assuming that is the only place that calls ->make_request_fn). Thanks, NeilBrown
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