From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031638AbXEHTql (ORCPT ); Tue, 8 May 2007 15:46:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031626AbXEHTq3 (ORCPT ); Tue, 8 May 2007 15:46:29 -0400 Received: from mx1.redhat.com ([66.187.233.31]:48999 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031621AbXEHTqZ (ORCPT ); Tue, 8 May 2007 15:46:25 -0400 Date: Tue, 8 May 2007 20:45:17 +0100 From: Alasdair G Kergon To: Andrew Morton Cc: dm-devel@redhat.com, linux-kernel@vger.kernel.org, olaf.kirch@oracle.com Subject: [2.6.22 PATCH 07/26] dm crypt: use smaller bvecs in clones Message-ID: <20070508194517.GN24114@agk.fab.redhat.com> Mail-Followup-To: Andrew Morton , dm-devel@redhat.com, linux-kernel@vger.kernel.org, olaf.kirch@oracle.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Organization: Red Hat UK Ltd. Registered in England and Wales, number 04098903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: olaf.kirch@oracle.com Allocate smaller clones With the previous dm-crypt fixes, there is no need for the clone bios to have the same bvec size as the original - we just need to make them big enough for the remaining number of pages. The only requirement is that we clear the "out" index in convert_context, so that crypt_convert starts storing data at the right position within the clone bio. Signed-off-by: olaf.kirch@oracle.com Signed-off-by: Alasdair G Kergon --- drivers/md/dm-crypt.c | 29 ++++++++--------------------- 1 files changed, 8 insertions(+), 21 deletions(-) Index: linux-2.6.21/drivers/md/dm-crypt.c =================================================================== --- linux-2.6.21.orig/drivers/md/dm-crypt.c 2007-05-01 17:40:48.000000000 +0100 +++ linux-2.6.21/drivers/md/dm-crypt.c 2007-05-01 17:40:49.000000000 +0100 @@ -379,8 +379,7 @@ static int crypt_convert(struct crypt_co * This should never violate the device limitations * May return a smaller bio when running out of pages */ -static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size, - unsigned int *bio_vec_idx) +static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size) { struct crypt_config *cc = io->target->private; struct bio *clone; @@ -394,16 +393,7 @@ static struct bio *crypt_alloc_buffer(st clone_init(io, clone); - /* if the last bio was not complete, continue where that one ended */ - clone->bi_idx = *bio_vec_idx; - clone->bi_vcnt = *bio_vec_idx; - clone->bi_size = 0; - clone->bi_flags &= ~(1 << BIO_SEG_VALID); - - /* clone->bi_idx pages have already been allocated */ - size -= clone->bi_idx * PAGE_SIZE; - - for (i = clone->bi_idx; i < nr_iovecs; i++) { + for (i = 0; i < nr_iovecs; i++) { struct bio_vec *bv = bio_iovec_idx(clone, i); bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask); @@ -415,7 +405,7 @@ static struct bio *crypt_alloc_buffer(st * return a partially allocated bio, the caller will then try * to allocate additional bios while submitting this partial bio */ - if ((i - clone->bi_idx) == (MIN_BIO_PAGES - 1)) + if (i == (MIN_BIO_PAGES - 1)) gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; bv->bv_offset = 0; @@ -434,12 +424,6 @@ static struct bio *crypt_alloc_buffer(st return NULL; } - /* - * Remember the last bio_vec allocated to be able - * to correctly continue after the splitting. - */ - *bio_vec_idx = clone->bi_vcnt; - return clone; } @@ -597,7 +581,6 @@ static void process_write(struct crypt_i struct convert_context ctx; unsigned remaining = base_bio->bi_size; sector_t sector = base_bio->bi_sector - io->target->begin; - unsigned bvec_idx = 0; atomic_inc(&io->pending); @@ -608,13 +591,14 @@ static void process_write(struct crypt_i * so repeat the whole process until all the data can be handled. */ while (remaining) { - clone = crypt_alloc_buffer(io, base_bio->bi_size, &bvec_idx); + clone = crypt_alloc_buffer(io, remaining); if (unlikely(!clone)) { dec_pending(io, -ENOMEM); return; } ctx.bio_out = clone; + ctx.idx_out = 0; if (unlikely(crypt_convert(cc, &ctx) < 0)) { crypt_free_buffer_pages(cc, clone, clone->bi_size); @@ -623,6 +607,9 @@ static void process_write(struct crypt_i return; } + /* crypt_convert should have filled the clone bio */ + BUG_ON(ctx.idx_out < clone->bi_vcnt); + clone->bi_sector = cc->start + sector; remaining -= clone->bi_size; sector += bio_sectors(clone);