Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753498AbbD1Gte (ORCPT ); Tue, 28 Apr 2015 02:49:34 -0400 Received: from mail.kernel.org ([198.145.29.136]:39389 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753443AbbD1Gt0 (ORCPT ); Tue, 28 Apr 2015 02:49:26 -0400 From: Ming Lin To: linux-kernel@vger.kernel.org Cc: Christoph Hellwig , Jens Axboe , Kent Overstreet , Dongsu Park , Ming Lin , Christoph Hellwig Subject: [PATCH 03/10] block: allow __blk_queue_bounce() to handle bios larger than BIO_MAX_PAGES Date: Mon, 27 Apr 2015 23:48:30 -0700 Message-Id: <1430203717-13307-4-git-send-email-mlin@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1430203717-13307-1-git-send-email-mlin@kernel.org> References: <1430203717-13307-1-git-send-email-mlin@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3309 Lines: 113 From: Kent Overstreet 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(). Cc: Christoph Hellwig Cc: Jens Axboe Signed-off-by: Kent Overstreet [dpark: add more description in commit message] Signed-off-by: Dongsu Park Signed-off-by: Ming Lin --- 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; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/