Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933043AbWLSWNq (ORCPT ); Tue, 19 Dec 2006 17:13:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933046AbWLSWNq (ORCPT ); Tue, 19 Dec 2006 17:13:46 -0500 Received: from mx1.redhat.com ([66.187.233.31]:44796 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933043AbWLSWNo (ORCPT ); Tue, 19 Dec 2006 17:13:44 -0500 Date: Tue, 19 Dec 2006 17:13:18 -0500 (EST) Message-Id: <20061219.171318.31636037.k-ueda@ct.jp.nec.com> To: jens.axboe@oracle.com, agk@redhat.com, mchristi@redhat.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com Cc: j-nomura@ce.jp.nec.com, k-ueda@ct.jp.nec.com Subject: [RFC PATCH 5/8] rqbased-dm: add device initialization code From: Kiyoshi Ueda X-Mailer: Mew version 2.3 on Emacs 20.7 / Mule 4.1 =?iso-2022-jp?B?KBskQjAqGyhCKQ==?= Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6060 Lines: 201 This patch adds device initialization code for request-based dm. By checking md->features, the mapped device can be distinguished whether it is request-based or not (bio-based). The pointer to __make_request() is saved in md->saved_make_request_fn to use in dm_make_request() which is set as md->queue->make_request_fn. By doing that, __make_request() can be called without definition change though it is static function in block/ll_rw_blk.c Because this patch set doesn't split request, only one clone is created per original request and counting of number of clones isn't needed. So struct dm_io and struct target_io in bio-based dm are merged into struct rq_target_io, and it is attached to each clone. As a result, md->io_pool isn't used in request-based dm. Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura diff -rupN 4-add-ioctl/drivers/md/dm.c 5-core-init/drivers/md/dm.c --- 4-add-ioctl/drivers/md/dm.c 2006-12-15 10:24:52.000000000 -0500 +++ 5-core-init/drivers/md/dm.c 2006-12-19 15:40:39.000000000 -0500 @@ -51,6 +51,24 @@ struct target_io { union map_info info; }; +/* + * For request based dm. + * One of these is allocated per target (cloned request). + * + * Since request based dm doesn't split request, we can assume + * "original request : cloned request" is 1:1. + * So a counter of number of clones like struct dm_io.io_count isn't needed, + * and the roles of struct dm_io and struct target_io in bio-based dm + * are merged into struct rq_target_io. + */ +struct rq_target_io { + struct mapped_device *md; + int error; + struct request *rq; + struct dm_target *ti; + union map_info info; +}; + union map_info *dm_get_mapinfo(struct bio *bio) { if (bio && bio->bi_private) @@ -69,6 +87,13 @@ union map_info *dm_get_mapinfo(struct bi #define DMF_FREEING 3 #define DMF_DELETING 4 +/* + * Bits for the md->features field. + */ +#define DM_FEAT_REQUEST_BASE (1 << 0) + +#define dm_feat_rq_base(md) ((md)->features & DM_FEAT_REQUEST_BASE) + struct mapped_device { struct rw_semaphore io_lock; struct semaphore suspend_lock; @@ -77,6 +102,7 @@ struct mapped_device { atomic_t open_count; unsigned long flags; + unsigned long features; request_queue_t *queue; struct gendisk *disk; @@ -118,11 +144,15 @@ struct mapped_device { /* forced geometry settings */ struct hd_geometry geometry; + + /* For saving the address of __make_request for request based dm */ + make_request_fn *saved_make_request_fn; }; #define MIN_IOS 256 static kmem_cache_t *_io_cache; static kmem_cache_t *_tio_cache; +static kmem_cache_t *_rq_tio_cache; /* For request based dm */ static int __init local_init(void) { @@ -142,9 +172,19 @@ static int __init local_init(void) return -ENOMEM; } + _rq_tio_cache = kmem_cache_create("dm_rq_tio", + sizeof(struct rq_target_io), + 0, 0, NULL, NULL); + if (!_rq_tio_cache) { + kmem_cache_destroy(_tio_cache); + kmem_cache_destroy(_io_cache); + return -ENOMEM; + } + _major = major; r = register_blkdev(_major, _name); if (r < 0) { + kmem_cache_destroy(_rq_tio_cache); kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); return r; @@ -158,6 +198,7 @@ static int __init local_init(void) static void local_exit(void) { + kmem_cache_destroy(_rq_tio_cache); kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); @@ -342,6 +383,17 @@ static inline void free_tio(struct mappe mempool_free(tio, md->tio_pool); } +static inline struct rq_target_io *alloc_rq_tio(struct mapped_device *md) +{ + return mempool_alloc(md->tio_pool, GFP_ATOMIC); +} + +static inline void free_rq_tio(struct mapped_device *md, + struct rq_target_io *tio) +{ + mempool_free(tio, md->tio_pool); +} + static void start_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; @@ -953,23 +1005,37 @@ static struct mapped_device *alloc_dev(i atomic_set(&md->open_count, 0); atomic_set(&md->event_nr, 0); - md->queue = blk_alloc_queue(GFP_KERNEL); + if (request_base) { + md->features |= DM_FEAT_REQUEST_BASE; + md->queue = blk_init_queue(dm_request_fn, NULL); + } else { + md->queue = blk_alloc_queue(GFP_KERNEL); + } if (!md->queue) goto bad1_free_minor; md->queue->queuedata = md; md->queue->backing_dev_info.congested_fn = dm_any_congested; md->queue->backing_dev_info.congested_data = md; - blk_queue_make_request(md->queue, dm_request); + if (request_base) { + md->saved_make_request_fn = md->queue->make_request_fn; + blk_queue_make_request(md->queue, dm_make_request); + blk_queue_prep_rq(md->queue, dm_prep_fn); + } else { + blk_queue_make_request(md->queue, dm_request); + } blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); md->queue->unplug_fn = dm_unplug_all; md->queue->issue_flush_fn = dm_flush_all; - md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); - if (!md->io_pool) - goto bad2; + if (!request_base) { + md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); + if (!md->io_pool) + goto bad2; + } - md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); + md->tio_pool = mempool_create_slab_pool(MIN_IOS, + request_base ? _rq_tio_cache : _tio_cache); if (!md->tio_pool) goto bad3; @@ -1008,7 +1074,8 @@ static struct mapped_device *alloc_dev(i bad_no_bioset: mempool_destroy(md->tio_pool); bad3: - mempool_destroy(md->io_pool); + if (md->io_pool) + mempool_destroy(md->io_pool); bad2: blk_cleanup_queue(md->queue); bad1_free_minor: @@ -1029,7 +1096,8 @@ static void free_dev(struct mapped_devic bdput(md->suspended_bdev); } mempool_destroy(md->tio_pool); - mempool_destroy(md->io_pool); + if (md->io_pool) + mempool_destroy(md->io_pool); bioset_free(md->bs); del_gendisk(md->disk); free_minor(minor); - 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/