Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754440Ab2FRKVS (ORCPT ); Mon, 18 Jun 2012 06:21:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63921 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751125Ab2FRKVR (ORCPT ); Mon, 18 Jun 2012 06:21:17 -0400 Date: Mon, 18 Jun 2012 13:21:08 +0300 From: "Michael S. Tsirkin" To: Asias He Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , Christoph Hellwig , Minchan Kim Subject: Re: [PATCH 3/3] virtio-blk: Add bio-based IO path for virtio-blk Message-ID: <20120618102108.GD23134@redhat.com> References: <1340002390-3950-1-git-send-email-asias@redhat.com> <1340002390-3950-4-git-send-email-asias@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1340002390-3950-4-git-send-email-asias@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1841 Lines: 63 On Mon, Jun 18, 2012 at 02:53:10PM +0800, Asias He wrote: > +static void virtblk_make_request(struct request_queue *q, struct bio *bio) > +{ > + struct virtio_blk *vblk = q->queuedata; > + unsigned int num, out = 0, in = 0; > + struct virtblk_req *vbr; > + > + BUG_ON(bio->bi_phys_segments + 2 > vblk->sg_elems); > + BUG_ON(bio->bi_rw & (REQ_FLUSH | REQ_FUA)); > + > + vbr = virtblk_alloc_req(vblk, GFP_NOIO); > + if (!vbr) { > + bio_endio(bio, -ENOMEM); > + return; > + } > + > + vbr->bio = bio; > + vbr->req = NULL; > + vbr->out_hdr.type = 0; > + vbr->out_hdr.sector = bio->bi_sector; > + vbr->out_hdr.ioprio = bio_prio(bio); > + > + sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); > + > + num = blk_bio_map_sg(q, bio, vbr->sg + out); > + > + sg_set_buf(&vbr->sg[num + out + in++], &vbr->status, > + sizeof(vbr->status)); > + > + if (num) { > + if (bio->bi_rw & REQ_WRITE) { > + vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; > + out += num; > + } else { > + vbr->out_hdr.type |= VIRTIO_BLK_T_IN; > + in += num; > + } > + } > + > + spin_lock_irq(vblk->disk->queue->queue_lock); > + if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr, > + GFP_ATOMIC) < 0) { > + spin_unlock_irq(vblk->disk->queue->queue_lock); Any implications of dropping lock like that? E.g. for suspend. like we are still discussing with unlocked kick? > + virtblk_add_buf_wait(vblk, vbr, out, in); > + } else { > + virtqueue_kick(vblk->vq); Why special case the first call? task state manipulation so expensive? > + spin_unlock_irq(vblk->disk->queue->queue_lock); > + } > +} > + -- 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/