From patchwork Sat Mar 22 01:26:11 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 14026132 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E549322092 for ; Sat, 22 Mar 2025 01:26:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742606809; cv=none; b=bdDTCHUmMY4rm0fzIisjz/Fp2bAiIFftUW143/FGWuhZxyDWR/1qspbfW0IpsOTs7zpJrtE0cpH5BWOYqZ/xiQl1WfNTDXBdCnyyuO/e9gnGenPHseJ+EOJ40QjNERl5qz219ODCwhnVDaTTxEpTg5HynFGKMY5BlWWNCh+0Gow= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742606809; c=relaxed/simple; bh=ji1sRegqjSVwQiJ2xNw4Njz1M4wboAw3I0wGi/TwJNc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=axcWNNPQ+DQkOoVTO+Gq2nEuIHG/zbLXzduDtFqXaCxpECWNaOycvzJzRrzXwZD9soThl11XsMDril0uuLZc5/YHfNj1IlfvEkTB5icW1Wy1DcUX8BRMA4vehD0mmN796oaLrJwdR5YbB9XcqUEGXR6zspqkbUpXNEa+oyKZi2Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=f2Z3gbzV; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="f2Z3gbzV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742606806; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fvGGio2j5n49ikbHTGHuqn4ZMHcD0HlG1CIFleYx4FY=; b=f2Z3gbzVWFivnD2c6mqLLx6GQZZ67XnaPtXnLBF7oTlehuocByBGAJW37nKr6ei/v9lDTE dmjWAv3hRmkQVG9ncvfPpe++A1Uot3aJwb4E9ZVJUkZKJsL6c0MKkDxBErQhzJj0ig8+bA QEB2P5EUspy0946do+D/rOxr+H6h2ys= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-680-jwQZ7UqxNbeUXiFw2CIxEQ-1; Fri, 21 Mar 2025 21:26:43 -0400 X-MC-Unique: jwQZ7UqxNbeUXiFw2CIxEQ-1 X-Mimecast-MFC-AGG-ID: jwQZ7UqxNbeUXiFw2CIxEQ_1742606802 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9E2611956067; Sat, 22 Mar 2025 01:26:41 +0000 (UTC) Received: from localhost (unknown [10.72.120.2]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0B9271955BFE; Sat, 22 Mar 2025 01:26:39 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Christoph Hellwig , Jooyung Han , Mike Snitzer , zkabelac@redhat.com, dm-devel@lists.linux.dev, Alasdair Kergon , Mikulas Patocka , Ming Lei Subject: [PATCH V3 2/5] loop: cleanup lo_rw_aio() Date: Sat, 22 Mar 2025 09:26:11 +0800 Message-ID: <20250322012617.354222-3-ming.lei@redhat.com> In-Reply-To: <20250322012617.354222-1-ming.lei@redhat.com> References: <20250322012617.354222-1-ming.lei@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Cleanup lo_rw_aio() a bit by refactoring it into three parts: - lo_cmd_nr_bvec(), for calculating how many bvecs in this request - lo_rw_aio_prep(), for preparing loop command, which need to be called once - lo_submit_rw_aio(), for submitting this lo command, which can be called multiple times Prepare for trying to handle loop command by NOWAIT read/write IO first. Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei --- drivers/block/loop.c | 81 ++++++++++++++++++++++++++++++-------------- 1 file changed, 56 insertions(+), 25 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 339b19671450..419ca675342a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -386,7 +386,6 @@ static void lo_rw_aio_do_completion(struct loop_cmd *cmd) if (!atomic_dec_and_test(&cmd->ref)) return; kfree(cmd->bvec); - cmd->bvec = NULL; if (likely(!blk_should_fake_timeout(rq->q))) blk_mq_complete_request(rq); } @@ -399,24 +398,29 @@ static void lo_rw_aio_complete(struct kiocb *iocb, long ret) lo_rw_aio_do_completion(cmd); } -static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos) +static inline unsigned lo_cmd_nr_bvec(struct loop_cmd *cmd) { - struct iov_iter iter; struct req_iterator rq_iter; - struct bio_vec *bvec; struct request *rq = blk_mq_rq_from_pdu(cmd); - int dir = (req_op(rq) == REQ_OP_READ) ? ITER_DEST : ITER_SOURCE; - struct bio *bio = rq->bio; - struct file *file = lo->lo_backing_file; struct bio_vec tmp; - unsigned int offset; int nr_bvec = 0; - int ret; rq_for_each_bvec(tmp, rq, rq_iter) nr_bvec++; + return nr_bvec; +} + +static int lo_rw_aio_prep(struct loop_device *lo, struct loop_cmd *cmd, + unsigned nr_bvec) +{ + struct request *rq = blk_mq_rq_from_pdu(cmd); + loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; + if (rq->bio != rq->biotail) { + struct req_iterator rq_iter; + struct bio_vec *bvec; + struct bio_vec tmp; bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), GFP_NOIO); @@ -434,35 +438,62 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos) *bvec = tmp; bvec++; } - bvec = cmd->bvec; - offset = 0; } else { + cmd->bvec = NULL; + } + cmd->iocb.ki_pos = pos; + cmd->iocb.ki_filp = lo->lo_backing_file; + cmd->iocb.ki_complete = lo_rw_aio_complete; + cmd->iocb.ki_flags = IOCB_DIRECT; + cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); + + return 0; +} + +static int lo_submit_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, + int nr_bvec) +{ + struct request *rq = blk_mq_rq_from_pdu(cmd); + int dir = (req_op(rq) == REQ_OP_READ) ? ITER_DEST : ITER_SOURCE; + struct file *file = lo->lo_backing_file; + struct iov_iter iter; + int ret; + + if (cmd->bvec) { + iov_iter_bvec(&iter, dir, cmd->bvec, nr_bvec, blk_rq_bytes(rq)); + iter.iov_offset = 0; + } else { + struct bio *bio = rq->bio; + struct bio_vec *bvec = __bvec_iter_bvec(bio->bi_io_vec, + bio->bi_iter); + /* * Same here, this bio may be started from the middle of the * 'bvec' because of bio splitting, so offset from the bvec * must be passed to iov iterator */ - offset = bio->bi_iter.bi_bvec_done; - bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); + iov_iter_bvec(&iter, dir, bvec, nr_bvec, blk_rq_bytes(rq)); + iter.iov_offset = bio->bi_iter.bi_bvec_done; } - atomic_set(&cmd->ref, 2); - - iov_iter_bvec(&iter, dir, bvec, nr_bvec, blk_rq_bytes(rq)); - iter.iov_offset = offset; - - cmd->iocb.ki_pos = pos; - cmd->iocb.ki_filp = file; - cmd->iocb.ki_complete = lo_rw_aio_complete; - cmd->iocb.ki_flags = IOCB_DIRECT; - cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); + atomic_set(&cmd->ref, 2); if (dir == ITER_SOURCE) ret = file->f_op->write_iter(&cmd->iocb, &iter); else ret = file->f_op->read_iter(&cmd->iocb, &iter); - lo_rw_aio_do_completion(cmd); + return ret; +} + + +static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd) +{ + unsigned int nr_bvec = lo_cmd_nr_bvec(cmd); + int ret = lo_rw_aio_prep(lo, cmd, nr_bvec); + + if (ret >= 0) + ret = lo_submit_rw_aio(lo, cmd, nr_bvec); if (ret != -EIOCBQUEUED) lo_rw_aio_complete(&cmd->iocb, ret); return 0; @@ -499,7 +530,7 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq) case REQ_OP_WRITE: case REQ_OP_READ: if (cmd->use_aio) - return lo_rw_aio(lo, cmd, pos); + return lo_rw_aio(lo, cmd); else return lo_rw_simple(lo, rq, pos); default: