From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754317Ab0FZT5V (ORCPT ); Sat, 26 Jun 2010 15:57:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58423 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753986Ab0FZT5S (ORCPT ); Sat, 26 Jun 2010 15:57:18 -0400 From: Mike Snitzer To: Christoph Hellwig Cc: axboe@kernel.dk, dm-devel@redhat.com, James.Bottomley@suse.de, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, akpm@linux-foundation.org Subject: [PATCH 2/2] block: defer the use of inline biovecs for discard requests Date: Sat, 26 Jun 2010 15:56:51 -0400 Message-Id: <1277582211-10725-2-git-send-email-snitzer@redhat.com> In-Reply-To: <20100622180029.GA15950@redhat.com> References: <20100622180029.GA15950@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't alloc discard bio with a biovec in blkdev_issue_discard. Doing so means bio_has_data() will not be true until the SCSI layer adds the payload to the discard request via blk_add_request_payload. bio_{enable,disable}_inline_vecs are not expected to be widely used so they were exported using EXPORT_SYMBOL_GPL. This patch avoids the need for the following VM accounting fix for discards: http://lkml.org/lkml/2010/6/23/361 NOTE: Jens, you said you applied Tao Ma's fix but I cannot see it in your linux-2.6-block's for-next or for-2.6.36... as such I didn't revert it in this patch. Signed-off-by: Mike Snitzer --- block/blk-core.c | 2 ++ block/blk-lib.c | 2 +- fs/bio.c | 19 +++++++++++++++++-- include/linux/bio.h | 3 +++ 4 files changed, 23 insertions(+), 3 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 07925aa..457fc29 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1153,6 +1153,7 @@ void blk_add_request_payload(struct request *rq, struct page *page, { struct bio *bio = rq->bio; + bio_enable_inline_vecs(bio); bio->bi_io_vec->bv_page = page; bio->bi_io_vec->bv_offset = 0; bio->bi_io_vec->bv_len = len; @@ -1187,6 +1188,7 @@ void blk_clear_request_payload(struct request *rq) bio->bi_io_vec->bv_page = NULL; bio->bi_io_vec->bv_len = 0; + bio_disable_inline_vecs(bio); } EXPORT_SYMBOL_GPL(blk_clear_request_payload); diff --git a/block/blk-lib.c b/block/blk-lib.c index e16185b..345a4b6 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -54,7 +54,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, unsigned int max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); - bio = bio_alloc(gfp_mask, 1); + bio = bio_alloc(gfp_mask, 0); if (!bio) { ret = -ENOMEM; break; diff --git a/fs/bio.c b/fs/bio.c index 8abb2df..e47d0a6 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -260,6 +260,21 @@ void bio_init(struct bio *bio) } EXPORT_SYMBOL(bio_init); +void bio_enable_inline_vecs(struct bio *bio) +{ + bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; + bio->bi_max_vecs = BIO_INLINE_VECS; + bio->bi_io_vec = bio->bi_inline_vecs;; +} +EXPORT_SYMBOL_GPL(bio_enable_inline_vecs); + +void bio_disable_inline_vecs(struct bio *bio) +{ + bio->bi_max_vecs = 0; + bio->bi_io_vec = NULL; +} +EXPORT_SYMBOL_GPL(bio_disable_inline_vecs); + /** * bio_alloc_bioset - allocate a bio for I/O * @gfp_mask: the GFP_ mask given to the slab allocator @@ -293,8 +308,8 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) goto out_set; if (nr_iovecs <= BIO_INLINE_VECS) { - bvl = bio->bi_inline_vecs; - nr_iovecs = BIO_INLINE_VECS; + bio_enable_inline_vecs(bio); + return bio; } else { bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); if (unlikely(!bvl)) diff --git a/include/linux/bio.h b/include/linux/bio.h index 4d379c8..3135631 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -403,6 +403,9 @@ extern struct bio *bio_clone(struct bio *, gfp_t); extern void bio_init(struct bio *); +extern void bio_enable_inline_vecs(struct bio *); +extern void bio_disable_inline_vecs(struct bio *); + extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, unsigned int, unsigned int); -- 1.6.5.rc2