From patchwork Thu Nov 19 16:49:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 11918343 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40DFCC56201 for ; Thu, 19 Nov 2020 16:50:12 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 457F922227 for ; Thu, 19 Nov 2020 16:50:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 457F922227 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-539-9_NovrWQP_O0be8i8MzQZA-1; Thu, 19 Nov 2020 11:50:06 -0500 X-MC-Unique: 9_NovrWQP_O0be8i8MzQZA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8249AA0CA0; Thu, 19 Nov 2020 16:50:01 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5EC7F5C1D1; Thu, 19 Nov 2020 16:50:01 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 287C54EBC6; Thu, 19 Nov 2020 16:50:01 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0AJGngkN004039 for ; Thu, 19 Nov 2020 11:49:42 -0500 Received: by smtp.corp.redhat.com (Postfix) id E3CA52166B2D; Thu, 19 Nov 2020 16:49:41 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast03.extmail.prod.ext.rdu2.redhat.com [10.11.55.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DA25F2166B29 for ; Thu, 19 Nov 2020 16:49:39 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 72A03811E76 for ; Thu, 19 Nov 2020 16:49:39 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-39-sDxyZOmNNgm-LXi0mfZaYQ-1; Thu, 19 Nov 2020 11:49:33 -0500 X-MC-Unique: sDxyZOmNNgm-LXi0mfZaYQ-1 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 44A50AC65; Thu, 19 Nov 2020 16:49:31 +0000 (UTC) From: Hannes Reinecke To: Mike Snitzer Date: Thu, 19 Nov 2020 17:49:23 +0100 Message-Id: <20201119164924.74401-2-hare@suse.de> In-Reply-To: <20201119164924.74401-1-hare@suse.de> References: <20201119164924.74401-1-hare@suse.de> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: dm-devel@redhat.com Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, Christoph Hellwig , Sergei Shtepa Subject: [dm-devel] [PATCH 1/2] blk_interposer - Block Layer Interposer X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com From: Sergei Shtepa The block layer interposer allows to intercept bio requests. This allows you to connect device mapper and other kernel modules to the block device stack on the fly. Signed-off-by: Sergei Shtepa Signed-off-by: Hannes Reinecke --- block/blk-core.c | 34 +++++++++++++++++++++++++++++ block/genhd.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/blk_types.h | 6 ++++-- include/linux/genhd.h | 19 ++++++++++++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 2db8bda43b6e..130f0124d939 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1030,6 +1030,37 @@ static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) return ret; } +static blk_qc_t __submit_bio_interposed(struct bio *bio) +{ + struct bio_list bio_list[2] = { }; + blk_qc_t ret = BLK_QC_T_NONE; + + current->bio_list = bio_list; + if (likely(bio_queue_enter(bio) == 0)) { + struct gendisk *disk = bio->bi_disk; + + bio_set_flag(bio, BIO_INTERPOSED); + if (likely(blk_has_interposer(disk))) { + struct blk_interposer *ip = disk->interposer; + ret = ip->ip_submit_bio(ip, bio); + + if (ret == BLK_QC_T_NONE) + blk_queue_exit(disk->queue); + } else { + /* interposer was removed */ + bio_list_add(¤t->bio_list[0], bio); + blk_queue_exit(bio->bi_disk->queue); + } + } + current->bio_list = NULL; + + /* Resubmit remaining bios */ + while ((bio = bio_list_pop(&bio_list[0]))) + ret = submit_bio_noacct(bio); + + return ret; +} + /** * submit_bio_noacct - re-submit a bio to the block device layer for I/O * @bio: The bio describing the location in memory and on the device. @@ -1055,6 +1086,9 @@ blk_qc_t submit_bio_noacct(struct bio *bio) return BLK_QC_T_NONE; } + if (blk_has_interposer(bio->bi_disk) && + !bio_flagged(bio, BIO_INTERPOSED)) + return __submit_bio_interposed(bio); if (!bio->bi_disk->fops->submit_bio) return __submit_bio_noacct_mq(bio); return __submit_bio_noacct(bio); diff --git a/block/genhd.c b/block/genhd.c index 9387f050c248..17b43e2ed06a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -2364,3 +2364,58 @@ static void disk_release_events(struct gendisk *disk) WARN_ON_ONCE(disk->ev && disk->ev->block != 1); kfree(disk->ev); } + +/** + * blk_interposer_attach - Attach interposer to disk + * @disk: target disk + * @interposer: block device interposer + * + * Returns: + * -EINVAL if @interposer is NULL. + * -ENODEV if interposer is not initialized, + * -EBUSY if the block device already has interposer. + */ +int blk_interposer_attach(struct gendisk *disk, + struct blk_interposer *interposer) +{ + int ret = 0; + + if (!interposer) + return -EINVAL; + + blk_mq_freeze_queue(disk->queue); + blk_mq_quiesce_queue(disk->queue); + if (blk_has_interposer(disk)) + ret = -EBUSY; + else + disk->interposer = interposer; + blk_mq_unquiesce_queue(disk->queue); + blk_mq_unfreeze_queue(disk->queue); + + return ret; +} +EXPORT_SYMBOL_GPL(blk_interposer_attach); + +/** + * blk_interposer_detach - Detach interposer from disk + * @disk: target disk + * + * Returns the attached interposer or NULL if none was attached. + */ +struct blk_interposer *blk_interposer_detach(struct gendisk *disk) +{ + struct blk_interposer *interposer; + + if (WARN_ON(!disk)) + return NULL; + + blk_mq_freeze_queue(disk->queue); + blk_mq_quiesce_queue(disk->queue); + interposer = disk->interposer; + disk->interposer = NULL; + blk_mq_unquiesce_queue(disk->queue); + blk_mq_unfreeze_queue(disk->queue); + + return interposer; +} +EXPORT_SYMBOL_GPL(blk_interposer_detach); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d9b69bbde5cc..996b803e5aa1 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -207,7 +207,7 @@ struct bio { * top bits REQ_OP. Use * accessors. */ - unsigned short bi_flags; /* status, etc and bvec pool number */ + unsigned int bi_flags; /* status, etc and bvec pool number */ unsigned short bi_ioprio; unsigned short bi_write_hint; blk_status_t bi_status; @@ -284,6 +284,8 @@ enum { * of this bio. */ BIO_CGROUP_ACCT, /* has been accounted to a cgroup */ BIO_TRACKED, /* set if bio goes through the rq_qos path */ + BIO_INTERPOSED, /* bio has been interposed and can be moved to + * a different disk */ BIO_FLAG_LAST }; @@ -302,7 +304,7 @@ enum { * freed. */ #define BVEC_POOL_BITS (3) -#define BVEC_POOL_OFFSET (16 - BVEC_POOL_BITS) +#define BVEC_POOL_OFFSET (32 - BVEC_POOL_BITS) #define BVEC_POOL_IDX(bio) ((bio)->bi_flags >> BVEC_POOL_OFFSET) #if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1) # error "BVEC_POOL_BITS is too small" diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 03da3f603d30..f58ab391deda 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -164,6 +164,15 @@ struct blk_integrity { unsigned char tag_size; }; +struct blk_interposer; +typedef blk_qc_t (*ip_submit_bio_t) (struct blk_interposer *ip, struct bio *bio); + +struct blk_interposer { + struct gendisk *ip_disk; + ip_submit_bio_t ip_submit_bio; + void *ip_private; +}; + struct gendisk { /* major, first_minor and minors are input parameters only, * don't use directly. Use disk_devt() and disk_max_parts(). @@ -188,6 +197,7 @@ struct gendisk { const struct block_device_operations *fops; struct request_queue *queue; + struct blk_interposer *interposer; void *private_data; int flags; @@ -409,4 +419,13 @@ static inline dev_t blk_lookup_devt(const char *name, int partno) } #endif /* CONFIG_BLOCK */ +/* + * Block device interposing + */ +#define blk_has_interposer(d) ((d)->interposer != NULL) +#define blk_interposer_active(ip) ((ip)->ip_disk != NULL) + +int blk_interposer_attach(struct gendisk *, struct blk_interposer *); +struct blk_interposer * blk_interposer_detach(struct gendisk *); + #endif /* _LINUX_GENHD_H */