Date: Tue, 5 Mar 2013 07:00:06 +0000 (UTC) From: Bryan Venteicher <bryanv@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r247829 - head/sys/dev/virtio/block Message-ID: <201303050700.r257066g068978@svn.freebsd.org>
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Author: bryanv Date: Tue Mar 5 07:00:05 2013 New Revision: 247829 URL: http://svnweb.freebsd.org/changeset/base/247829 Log: Only set the barrier flag if the feature was negotiated When the VirtIO barrier feature is not negotiated, the driver must enforce the proper ordering for BIO_ORDERED BIOs. All the in-flight BIOs must complete before starting the BIO, and the ordered BIO must complete before subsequent BIOs can start. Also fix a few whitespace nits. Reported by: neel Approved by: grehan (mentor) MFC after: 3 days Modified: head/sys/dev/virtio/block/virtio_blk.c Modified: head/sys/dev/virtio/block/virtio_blk.c ============================================================================== --- head/sys/dev/virtio/block/virtio_blk.c Tue Mar 5 06:43:54 2013 (r247828) +++ head/sys/dev/virtio/block/virtio_blk.c Tue Mar 5 07:00:05 2013 (r247829) @@ -72,6 +72,7 @@ struct vtblk_softc { #define VTBLK_FLAG_DETACH 0x0004 #define VTBLK_FLAG_SUSPEND 0x0008 #define VTBLK_FLAG_DUMPING 0x0010 +#define VTBLK_FLAG_BARRIER 0x0020 struct virtqueue *vtblk_vq; struct sglist *vtblk_sglist; @@ -81,7 +82,8 @@ struct vtblk_softc { TAILQ_HEAD(, vtblk_request) vtblk_req_free; TAILQ_HEAD(, vtblk_request) - vtblk_req_ready; + vtblk_req_ready; + struct vtblk_request *vtblk_req_ordered; struct taskqueue *vtblk_tq; struct task vtblk_intr_task; @@ -278,9 +280,10 @@ vtblk_attach(device_t dev) if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC)) sc->vtblk_flags |= VTBLK_FLAG_INDIRECT; - if (virtio_with_feature(dev, VIRTIO_BLK_F_RO)) sc->vtblk_flags |= VTBLK_FLAG_READONLY; + if (virtio_with_feature(dev, VIRTIO_BLK_F_BARRIER)) + sc->vtblk_flags |= VTBLK_FLAG_BARRIER; /* Get local copy of config. */ virtio_read_device_config(dev, 0, &blkcfg, @@ -766,25 +769,45 @@ vtblk_bio_request(struct vtblk_softc *sc bp->bio_cmd); } - if (bp->bio_flags & BIO_ORDERED) - req->vbr_hdr.type |= VIRTIO_BLK_T_BARRIER; - return (req); } static int vtblk_execute_request(struct vtblk_softc *sc, struct vtblk_request *req) { + struct virtqueue *vq; struct sglist *sg; struct bio *bp; - int readable, writable, error; + int ordered, readable, writable, error; + vq = sc->vtblk_vq; sg = sc->vtblk_sglist; bp = req->vbr_bp; + ordered = 0; writable = 0; VTBLK_LOCK_ASSERT(sc); + /* + * Wait until the ordered request completes before + * executing subsequent requests. + */ + if (sc->vtblk_req_ordered != NULL) + return (EBUSY); + + if (bp->bio_flags & BIO_ORDERED) { + if ((sc->vtblk_flags & VTBLK_FLAG_BARRIER) == 0) { + /* + * This request will be executed once all + * the in-flight requests are completed. + */ + if (!virtqueue_empty(vq)) + return (EBUSY); + ordered = 1; + } else + req->vbr_hdr.type |= VIRTIO_BLK_T_BARRIER; + } + sglist_reset(sg); sglist_append(sg, &req->vbr_hdr, sizeof(struct virtio_blk_outhdr)); @@ -802,10 +825,13 @@ vtblk_execute_request(struct vtblk_softc writable++; sglist_append(sg, &req->vbr_ack, sizeof(uint8_t)); - readable = sg->sg_nseg - writable; - return (virtqueue_enqueue(sc->vtblk_vq, req, sg, readable, writable)); + error = virtqueue_enqueue(vq, req, sg, readable, writable); + if (error == 0 && ordered) + sc->vtblk_req_ordered = req; + + return (error); } static int @@ -1013,6 +1039,12 @@ vtblk_finish_completed(struct vtblk_soft while ((req = virtqueue_dequeue(sc->vtblk_vq, NULL)) != NULL) { bp = req->vbr_bp; + if (sc->vtblk_req_ordered != NULL) { + /* This should be the only outstanding request. */ + MPASS(sc->vtblk_req_ordered == req); + sc->vtblk_req_ordered = NULL; + } + error = vtblk_request_error(req); if (error) disk_err(bp, "hard error", -1, 1); @@ -1039,6 +1071,7 @@ vtblk_drain_vq(struct vtblk_softc *sc, i vtblk_enqueue_request(sc, req); } + sc->vtblk_req_ordered = NULL; KASSERT(virtqueue_empty(vq), ("virtqueue not empty")); }
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