From: Avi Kivity <avi@argo.co.il>
To: NeilBrown <neilb@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 000 of 35] Refactor block layer to improve support for stacked devices.
Date: Tue, 31 Jul 2007 18:28:52 +0300 [thread overview]
Message-ID: <46AF5534.3010902@argo.co.il> (raw)
In-Reply-To: <20070731112539.22428.patches@notabene>
NeilBrown wrote:
> To achieve this, the "for_each" macros are now somewhat more complex.
> For example, rq_for_each_segment is:
>
> #define bio_for_each_segment_offset(bv, bio, _i, offs, _size) \
> for (_i.i = 0, _i.offset = (bio)->bi_offset + offs, \
> _i.size = min_t(int, _size, (bio)->bi_size - offs); \
> _i.i < (bio)->bi_vcnt && _i.size > 0; \
> _i.i++) \
> if (bv = *bio_iovec_idx((bio), _i.i), \
> bv.bv_offset += _i.offset, \
> bv.bv_len <= _i.offset \
> ? (_i.offset -= bv.bv_len, 0) \
> : (bv.bv_len -= _i.offset, \
> _i.offset = 0, \
> bv.bv_len < _i.size \
> ? (_i.size -= bv.bv_len, 1) \
> : (bv.bv_len = _i.size, \
> _i.size = 0, \
> bv.bv_len > 0)))
>
> #define bio_for_each_segment(bv, bio, __i) \
> bio_for_each_segment_offset(bv, bio, __i, 0, (bio)->bi_size)
>
> It does some with some explanatory text in a comment, but it is still
> a bit daunting. Any suggestions on making this more approachable
> would be very welcome.
>
>
Well, I hesitate to state the obvious, but how about:
#define bio_for_each_segment_offset(bv, bio, _i, offs, _size) \
for (bio_iterator_init(&_i, ...); bio_iterator_cont(&_i, ...);
bio_iterator_advance(&_i, ...)) \
if (bio_iterator_want_segment(&_i, ...))
While this doesn't remove the complexity, at least it's readable.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2007-07-31 15:28 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-31 2:15 [PATCH 000 of 35] Refactor block layer to improve support for stacked devices NeilBrown
2007-07-31 2:15 ` [PATCH 001 of 35] Replace bio_data with blk_rq_data NeilBrown
2007-07-31 2:15 ` [PATCH 002 of 35] Replace bio_cur_sectors with blk_rq_cur_sectors NeilBrown
2007-07-31 2:16 ` [PATCH 003 of 35] Introduce rq_for_each_segment replacing rq_for_each_bio NeilBrown
2007-07-31 2:16 ` [PATCH 004 of 35] Merge blk_recount_segments into blk_recalc_rq_segments NeilBrown
2007-07-31 2:16 ` [PATCH 005 of 35] Stop updating bi_idx, bv_len, bv_offset when a request completes NeilBrown
2007-08-01 14:54 ` Tejun Heo
2007-07-31 2:16 ` [PATCH 006 of 35] Only call bi_end_io once for any bio NeilBrown
2007-07-31 2:16 ` [PATCH 007 of 35] Drop 'size' argument from bio_endio and bi_end_io NeilBrown
2007-08-01 15:17 ` Tejun Heo
2007-07-31 2:16 ` [PATCH 008 of 35] Introduce bi_iocnt to count requests sharing the one bio NeilBrown
2007-08-01 15:49 ` Tejun Heo
2007-07-31 2:16 ` [PATCH 009 of 35] Remove overloading of bi_hw_segments in raid5 NeilBrown
2007-07-31 2:16 ` [PATCH 010 of 35] New function blk_req_append_bio NeilBrown
2007-08-01 15:54 ` Christoph Hellwig
2007-07-31 2:16 ` [PATCH 011 of 35] Stop exporting blk_rq_bio_prep NeilBrown
2007-07-31 2:16 ` [PATCH 012 of 35] Share code between init_request_from_bio and blk_rq_bio_prep NeilBrown
2007-07-31 2:16 ` [PATCH 013 of 35] Don't update bi_hw_*_size if we aren't going to merge NeilBrown
2007-08-01 15:57 ` Tejun Heo
2007-08-02 3:37 ` Neil Brown
2007-07-31 2:17 ` [PATCH 014 of 35] Change blk_phys/hw_contig_segment to take requests, not bios NeilBrown
2007-07-31 2:17 ` [PATCH 015 of 35] Move hw_front_size and hw_back_size from bio to request NeilBrown
2007-07-31 2:17 ` [PATCH 016 of 35] Centralise setting for REQ_NOMERGE NeilBrown
2007-07-31 2:17 ` [PATCH 017 of 35] Fix various abuse of bio fields in umem.c NeilBrown
2007-07-31 2:17 ` [PATCH 018 of 35] Remove bi_idx NeilBrown
2007-07-31 2:17 ` [PATCH 019 of 35] Convert bio_for_each_segment to fill in a fresh bio_vec NeilBrown
2007-08-01 16:21 ` Tejun Heo
2007-07-31 2:17 ` [PATCH 020 of 35] Add bi_offset and allow a bio to reference only part of a bi_io_vec NeilBrown
2007-07-31 2:17 ` [PATCH 021 of 35] Teach umem.c about bi_offset and to limit to bi_size NeilBrown
2007-07-31 2:17 ` [PATCH 022 of 35] Teach dm-crypt to honour bi_offset and bi_size NeilBrown
2007-07-31 2:17 ` [PATCH 023 of 35] Teach pktcdvd.c " NeilBrown
2007-07-31 2:17 ` [PATCH 024 of 35] Allow request bio list not to end with NULL NeilBrown
2007-07-31 2:17 ` [PATCH 025 of 35] Treat rq->hard_nr_sectors as setting an overriding limit in the size of the request NeilBrown
2007-08-01 17:44 ` Tejun Heo
2007-08-02 3:31 ` Neil Brown
2007-08-02 5:03 ` Tejun Heo
2007-07-31 2:18 ` [PATCH 026 of 35] Split any large bios that arrive at __make_request NeilBrown
2007-08-01 17:56 ` Tejun Heo
2007-08-02 0:49 ` Neil Brown
2007-08-02 2:59 ` Tejun Heo
2007-08-02 3:16 ` Neil Brown
2007-07-31 2:18 ` [PATCH 028 of 35] Split arbitrarily large requests to md/raid0 and md/linear NeilBrown
2007-07-31 2:18 ` [PATCH 029 of 35] Teach md/raid10 to split arbitrarily large bios NeilBrown
2007-07-31 2:18 ` [PATCH 030 of 35] Teach raid5 to split incoming bios NeilBrown
2007-07-31 2:18 ` [PATCH 031 of 35] Use bio_multi_split to fully split bios for pktcdvd NeilBrown
2007-07-31 2:18 ` [PATCH 032 of 35] Remove blk_queue_merge_bvec and bio_split and related code NeilBrown
2007-07-31 2:18 ` [PATCH 033 of 35] Simplify stacking of IO restrictions NeilBrown
2007-07-31 2:18 ` [PATCH 034 of 35] Simplify bio_add_page and raid1/raid10 resync which use it NeilBrown
2007-07-31 2:18 ` [PATCH 035 of 35] Simplify bio splitting in dm NeilBrown
2007-07-31 15:28 ` Avi Kivity [this message]
2007-08-01 14:37 ` [PATCH 000 of 35] Refactor block layer to improve support for stacked devices Tejun Heo
2007-08-01 15:52 ` John Stoffel
2007-08-01 15:59 ` Tejun Heo
2007-08-02 3:43 ` Neil Brown
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