From: Dongsu Park <dongsu.park@profitbricks.com>
To: linux-kernel@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>, Kent Overstreet <kmo@daterainc.com>,
Ming Lin <mlin@minggr.net>,
Dongsu Park <dongsu.park@profitbricks.com>
Subject: [RFC PATCH 11/17] block: allow __blk_queue_bounce() to handle bios larger than BIO_MAX_PAGES
Date: Mon, 22 Dec 2014 12:48:38 +0100 [thread overview]
Message-ID: <abe647cf7cf272220227fad4dac9c43641192f01.1419241597.git.dongsu.park@profitbricks.com> (raw)
In-Reply-To: <4334b90a56b96ad7a11e4ba7eb97c2cf4405950d.1419241597.git.dongsu.park@profitbricks.com>
In-Reply-To: <cover.1419241597.git.dongsu.park@profitbricks.com>
From: Kent Overstreet <kmo@daterainc.com>
Allow __blk_queue_bounce() to handle bios with more than BIO_MAX_PAGES
segments. Doing that, it becomes possible to simplify the block layer
in the kernel.
The issue is that any code that clones the bio and must clone the biovec
(i.e. it can't use bio_clone_fast()) won't be able to allocate a bio with
more than BIO_MAX_PAGES - bio_alloc_bioset() always fails in that case.
Fortunately, it's easy to make __blk_queue_bounce() just process part of
the bio if necessary, using bi_remaining to count the splits and punting
the rest back to generic_make_request().
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com>
Cc: Jens Axboe <axboe@kernel.dk>
---
block/bounce.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 52 insertions(+), 8 deletions(-)
diff --git a/block/bounce.c b/block/bounce.c
index ab21ba2..689ea89 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -196,6 +196,43 @@ static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
}
#endif /* CONFIG_NEED_BOUNCE_POOL */
+static struct bio *bio_clone_segments(struct bio *bio_src, gfp_t gfp_mask,
+ struct bio_set *bs, unsigned nsegs)
+{
+ struct bvec_iter iter;
+ struct bio_vec bv;
+ struct bio *bio;
+
+ bio = bio_alloc_bioset(gfp_mask, nsegs, bs);
+ if (!bio)
+ return NULL;
+
+ bio->bi_bdev = bio_src->bi_bdev;
+ bio->bi_rw = bio_src->bi_rw;
+ bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
+
+ bio_for_each_segment(bv, bio_src, iter) {
+ bio->bi_io_vec[bio->bi_vcnt++] = bv;
+ bio->bi_iter.bi_size += bv.bv_len;
+ if (!--nsegs)
+ break;
+ }
+
+ if (bio_integrity(bio_src)) {
+ int ret;
+
+ ret = bio_integrity_clone(bio, bio_src, gfp_mask);
+ if (ret < 0) {
+ bio_put(bio);
+ return NULL;
+ }
+ }
+
+ bio_src->bi_iter = iter;
+
+ return bio;
+}
+
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
mempool_t *pool, int force)
{
@@ -203,17 +240,24 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
int rw = bio_data_dir(*bio_orig);
struct bio_vec *to, from;
struct bvec_iter iter;
- unsigned i;
+ int i, nsegs = 0, bounce = force;
- if (force)
- goto bounce;
- bio_for_each_segment(from, *bio_orig, iter)
+ bio_for_each_segment(from, *bio_orig, iter) {
+ nsegs++;
if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
- goto bounce;
+ bounce = 1;
+ }
+
+ if (!bounce)
+ return;
- return;
-bounce:
- bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
+ bio = bio_clone_segments(*bio_orig, GFP_NOIO, fs_bio_set,
+ min(nsegs, BIO_MAX_PAGES));
+
+ if ((*bio_orig)->bi_iter.bi_size) {
+ atomic_inc(&(*bio_orig)->bi_remaining);
+ generic_make_request(*bio_orig);
+ }
bio_for_each_segment_all(to, bio, i) {
struct page *page = to->bv_page;
--
2.1.0
next prev parent reply other threads:[~2014-12-22 11:53 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-22 11:48 [RFC PATCH 00/17] simplify block layer based on immutable biovecs Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 01/17] block: make generic_make_request handle arbitrarily sized bios Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 02/17] block: simplify bio_add_page() Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 03/17] block: simplify issueing discard, write_same, zeroout Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 04/17] bcache: clean up hacks around bio_split_pool Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 05/17] btrfs: remove bio splitting and merge_bvec_fn() calls Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 06/17] btrfs: make use of immutable biovecs Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 07/17] block: replace sg_iovec with iov_iter Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 08/17] block: refactor __bio_copy_iov() Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 09/17] block: refactor iov_count_pages() from bio_{copy,map}_user_iov() Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 10/17] block: refactor bio_get_user_pages() from __bio_map_user_iov() Dongsu Park
2014-12-22 11:48 ` Dongsu Park [this message]
2014-12-22 11:48 ` [RFC PATCH 12/17] md/raid10: make sync_request_write() call bio_copy_data() Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 13/17] md/raid5: get rid of bio_fits_rdev() Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 14/17] block: kill merge_bvec_fn() completely Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 15/17] fs: use helper bio_add_page() instead of open coding on bi_io_vec Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 16/17] fs: convert buffer head etc. to use immutable biovecs API Dongsu Park
2014-12-22 11:48 ` [RFC PATCH 17/17] Documentation: update notes in biovecs about arbitrarily sized bios Dongsu Park
2014-12-23 10:52 ` Christoph Hellwig
2014-12-23 12:34 ` Dongsu Park
2014-12-23 10:51 ` [RFC PATCH 16/17] fs: convert buffer head etc. to use immutable biovecs API Christoph Hellwig
2014-12-23 12:33 ` Dongsu Park
2014-12-22 15:22 ` [RFC PATCH 15/17] fs: use helper bio_add_page() instead of open coding on bi_io_vec Dave Kleikamp
2014-12-22 15:22 ` Dave Kleikamp
2014-12-23 10:48 ` [RFC PATCH 12/17] md/raid10: make sync_request_write() call bio_copy_data() Christoph Hellwig
2014-12-23 12:31 ` Dongsu Park
2014-12-23 10:45 ` [RFC PATCH 08/17] block: refactor __bio_copy_iov() Christoph Hellwig
2014-12-23 12:24 ` Dongsu Park
2014-12-23 10:44 ` [RFC PATCH 07/17] block: replace sg_iovec with iov_iter Christoph Hellwig
2014-12-23 12:18 ` Dongsu Park
2014-12-27 15:03 ` Christoph Hellwig
2014-12-23 10:35 ` [RFC PATCH 06/17] btrfs: make use of immutable biovecs Christoph Hellwig
2014-12-23 12:09 ` Dongsu Park
[not found] ` <e4b7b017eaa81784889ebb2a4e6a7d4366adf13a.1419241597.git.dongsu.park@profit bricks.com>
2014-12-23 14:44 ` [RFC PATCH 05/17] btrfs: remove bio splitting and merge_bvec_fn() calls Chris Mason
2014-12-23 10:23 ` [RFC PATCH 03/17] block: simplify issueing discard, write_same, zeroout Christoph Hellwig
2014-12-23 10:22 ` [RFC PATCH 02/17] block: simplify bio_add_page() Christoph Hellwig
2014-12-23 11:46 ` Dongsu Park
2014-12-23 10:16 ` [RFC PATCH 01/17] block: make generic_make_request handle arbitrarily sized bios Christoph Hellwig
2014-12-23 11:41 ` Dongsu Park
2014-12-27 15:02 ` Christoph Hellwig
2014-12-23 19:14 ` Geoff Levand
2014-12-24 10:37 ` Dongsu Park
2014-12-25 6:09 ` Ming Lei
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