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    Subject[PATCH 0001/001] xen: multi page ring support for block devices
    From: Santosh Jodh <santosh.jodh@citrix.com>

    Add support for multi page ring for block devices.
    The number of pages is configurable for blkback via module parameter.
    blkback reports max-ring-page-order to blkfront via xenstore.
    blkfront reports its supported ring-page-order to blkback via xenstore.
    blkfront reports multi page ring references via ring-refNN in xenstore.
    The change allows newer blkfront to work with older blkback and
    vice-versa.
    Based on original patch by Paul Durrant.

    Signed-off-by: Santosh Jodh <santosh.jodh@citrix.com>
    ---
    diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
    index 0088bf6..72f2e18 100644
    --- a/drivers/block/xen-blkback/blkback.c
    +++ b/drivers/block/xen-blkback/blkback.c
    @@ -60,6 +60,39 @@ static int xen_blkif_reqs = 64;
    module_param_named(reqs, xen_blkif_reqs, int, 0);
    MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate");

    +/* Order of maximum shared ring size advertised to the front end. */
    +int xen_blkif_max_ring_order = XENBUS_MAX_RING_ORDER;
    +
    +#define BLK_RING_SIZE(_order) __CONST_RING_SIZE(blkif, PAGE_SIZE << (_order))
    +
    +static int set_max_ring_order(const char *buf, struct kernel_param *kp)
    +{
    + int err;
    + unsigned long order;
    +
    + err = kstrtol(buf, 0, &order);
    + if (err ||
    + order < 0 ||
    + order > XENBUS_MAX_RING_ORDER)
    + return -EINVAL;
    +
    + if (xen_blkif_reqs < BLK_RING_SIZE(order))
    + printk(KERN_WARNING "WARNING: "
    + "I/O request space (%d reqs) < ring order %ld, "
    + "consider increasing %s.reqs to >= %ld.",
    + xen_blkif_reqs, order, KBUILD_MODNAME,
    + roundup_pow_of_two(BLK_RING_SIZE(order)));
    +
    + xen_blkif_max_ring_order = order;
    +
    + return 0;
    +}
    +
    +module_param_call(max_ring_order,
    + set_max_ring_order, param_get_int,
    + &xen_blkif_max_ring_order, 0644);
    +MODULE_PARM_DESC(max_ring_order, "log2 of maximum ring size, in pages.");
    +
    /* Run-time switchable: /sys/module/blkback/parameters/ */
    static unsigned int log_stats;
    module_param(log_stats, int, 0644);
    diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
    index d0ee7ed..5f33a1a 100644
    --- a/drivers/block/xen-blkback/common.h
    +++ b/drivers/block/xen-blkback/common.h
    @@ -126,6 +126,8 @@ struct blkif_x86_64_response {
    int16_t status; /* BLKIF_RSP_??? */
    };

    +extern int xen_blkif_max_ring_order;
    +
    DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
    struct blkif_common_response);
    DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
    diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
    index 24a2fb5..7a9d71d 100644
    --- a/drivers/block/xen-blkback/xenbus.c
    +++ b/drivers/block/xen-blkback/xenbus.c
    @@ -122,8 +122,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
    return blkif;
    }

    -static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
    - unsigned int evtchn)
    +static int xen_blkif_map(struct xen_blkif *blkif, int ring_ref[],
    + unsigned int ring_order, unsigned int evtchn)
    {
    int err;

    @@ -131,7 +131,8 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
    if (blkif->irq)
    return 0;

    - err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring);
    + err = xenbus_map_ring_valloc(blkif->be->dev, ring_ref, 1 << ring_order,
    + &blkif->blk_ring);
    if (err < 0)
    return err;

    @@ -140,21 +141,24 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
    {
    struct blkif_sring *sring;
    sring = (struct blkif_sring *)blkif->blk_ring;
    - BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
    + BACK_RING_INIT(&blkif->blk_rings.native, sring,
    + PAGE_SIZE << ring_order);
    break;
    }
    case BLKIF_PROTOCOL_X86_32:
    {
    struct blkif_x86_32_sring *sring_x86_32;
    sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring;
    - BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
    + BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32,
    + PAGE_SIZE << ring_order);
    break;
    }
    case BLKIF_PROTOCOL_X86_64:
    {
    struct blkif_x86_64_sring *sring_x86_64;
    sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring;
    - BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
    + BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64,
    + PAGE_SIZE << ring_order);
    break;
    }
    default:
    @@ -497,6 +501,11 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
    if (err)
    goto fail;

    + err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order",
    + "%u", xen_blkif_max_ring_order);
    + if (err)
    + goto fail;
    +
    err = xenbus_switch_state(dev, XenbusStateInitWait);
    if (err)
    goto fail;
    @@ -744,22 +753,80 @@ again:
    static int connect_ring(struct backend_info *be)
    {
    struct xenbus_device *dev = be->dev;
    - unsigned long ring_ref;
    + int ring_ref[XENBUS_MAX_RING_PAGES];
    + unsigned int ring_order;
    unsigned int evtchn;
    char protocol[64] = "";
    int err;

    DPRINTK("%s", dev->otherend);

    - err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
    - &ring_ref, "event-channel", "%u", &evtchn, NULL);
    - if (err) {
    - xenbus_dev_fatal(dev, err,
    - "reading %s/ring-ref and event-channel",
    + err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", "%u",
    + &evtchn);
    + if (err != 1) {
    + err = -EINVAL;
    +
    + xenbus_dev_fatal(dev, err, "reading %s/event-channel",
    dev->otherend);
    return err;
    }

    + printk(KERN_INFO "blkback: event-channel %u\n", evtchn);
    +
    + err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
    + &ring_order);
    + if (err != 1) {
    + DPRINTK("%s: using single page handshake", dev->otherend);
    +
    + ring_order = 0;
    +
    + err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref",
    + "%d", &ring_ref[0]);
    + if (err != 1) {
    + err = -EINVAL;
    +
    + xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
    + dev->otherend);
    + return err;
    + }
    +
    + printk(KERN_INFO "blkback: ring-ref %d\n", ring_ref[0]);
    + } else {
    + unsigned int i;
    +
    + if (ring_order > xen_blkif_max_ring_order) {
    + err = -EINVAL;
    +
    + xenbus_dev_fatal(dev, err,
    + "%s/ring-page-order too big",
    + dev->otherend);
    + return err;
    + }
    +
    + for (i = 0; i < (1u << ring_order); i++) {
    + char ring_ref_name[10];
    +
    + snprintf(ring_ref_name, sizeof(ring_ref_name),
    + "ring-ref%u", i);
    +
    + err = xenbus_scanf(XBT_NIL, dev->otherend,
    + ring_ref_name, "%d",
    + &ring_ref[i]);
    + if (err != 1) {
    + err = -EINVAL;
    +
    + xenbus_dev_fatal(dev, err,
    + "reading %s/%s",
    + dev->otherend,
    + ring_ref_name);
    + return err;
    + }
    +
    + printk(KERN_INFO "blkback: ring-ref%u %d\n", i,
    + ring_ref[i]);
    + }
    + }
    +
    be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
    err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
    "%63s", protocol, NULL);
    @@ -775,14 +842,11 @@ static int connect_ring(struct backend_info *be)
    xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
    return -1;
    }
    - pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n",
    - ring_ref, evtchn, be->blkif->blk_protocol, protocol);

    /* Map the shared frame, irq etc. */
    - err = xen_blkif_map(be->blkif, ring_ref, evtchn);
    + err = xen_blkif_map(be->blkif, ring_ref, ring_order, evtchn);
    if (err) {
    - xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u",
    - ring_ref, evtchn);
    + xenbus_dev_fatal(dev, err, "mapping ring-refs and evtchn");
    return err;
    }

    diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
    index 2f22874..485813a 100644
    --- a/drivers/block/xen-blkfront.c
    +++ b/drivers/block/xen-blkfront.c
    @@ -57,6 +57,10 @@

    #include <asm/xen/hypervisor.h>

    +static int xen_blkif_ring_order;
    +module_param_named(reqs, xen_blkif_ring_order, int, 0);
    +MODULE_PARM_DESC(reqs, "log2 of requested ring size, in pages.");
    +
    enum blkif_state {
    BLKIF_STATE_DISCONNECTED,
    BLKIF_STATE_CONNECTED,
    @@ -72,7 +76,8 @@ struct blk_shadow {
    static DEFINE_MUTEX(blkfront_mutex);
    static const struct block_device_operations xlvbd_block_fops;

    -#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
    +#define BLK_RING_SIZE(_order) __CONST_RING_SIZE(blkif, PAGE_SIZE << (_order))
    +#define BLK_MAX_RING_SIZE BLK_RING_SIZE(XENBUS_MAX_RING_ORDER)

    /*
    * We have one of these per vbd, whether ide, scsi or 'other'. They
    @@ -87,14 +92,15 @@ struct blkfront_info
    int vdevice;
    blkif_vdev_t handle;
    enum blkif_state connected;
    - int ring_ref;
    + int ring_ref[XENBUS_MAX_RING_PAGES];
    + int ring_order;
    struct blkif_front_ring ring;
    struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
    unsigned int evtchn, irq;
    struct request_queue *rq;
    struct work_struct work;
    struct gnttab_free_callback callback;
    - struct blk_shadow shadow[BLK_RING_SIZE];
    + struct blk_shadow shadow[BLK_MAX_RING_SIZE];
    unsigned long shadow_free;
    unsigned int feature_flush;
    unsigned int flush_op;
    @@ -111,9 +117,7 @@ static unsigned int nr_minors;
    static unsigned long *minors;
    static DEFINE_SPINLOCK(minor_lock);

    -#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
    - (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
    -#define GRANT_INVALID_REF 0
    +#define GRANT_INVALID_REF 0

    #define PARTS_PER_DISK 16
    #define PARTS_PER_EXT_DISK 256
    @@ -135,7 +139,7 @@ static DEFINE_SPINLOCK(minor_lock);
    static int get_id_from_freelist(struct blkfront_info *info)
    {
    unsigned long free = info->shadow_free;
    - BUG_ON(free >= BLK_RING_SIZE);
    + BUG_ON(free >= BLK_MAX_RING_SIZE);
    info->shadow_free = info->shadow[free].req.u.rw.id;
    info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
    return free;
    @@ -683,6 +687,8 @@ static void blkif_restart_queue(struct work_struct *work)

    static void blkif_free(struct blkfront_info *info, int suspend)
    {
    + int i;
    +
    /* Prevent new requests being issued until we fix things up. */
    spin_lock_irq(&blkif_io_lock);
    info->connected = suspend ?
    @@ -698,16 +704,19 @@ static void blkif_free(struct blkfront_info *info, int suspend)
    flush_work_sync(&info->work);

    /* Free resources associated with old device channel. */
    - if (info->ring_ref != GRANT_INVALID_REF) {
    - gnttab_end_foreign_access(info->ring_ref, 0,
    - (unsigned long)info->ring.sring);
    - info->ring_ref = GRANT_INVALID_REF;
    - info->ring.sring = NULL;
    + for (i = 0; i < (1 << info->ring_order); i++) {
    + if (info->ring_ref[i] != GRANT_INVALID_REF) {
    + gnttab_end_foreign_access(info->ring_ref[i], 0, 0);
    + info->ring_ref[i] = GRANT_INVALID_REF;
    + }
    }
    +
    + free_pages((unsigned long)info->ring.sring, info->ring_order);
    + info->ring.sring = NULL;
    +
    if (info->irq)
    unbind_from_irqhandler(info->irq, info);
    info->evtchn = info->irq = 0;
    -
    }

    static void blkif_completion(struct blk_shadow *s)
    @@ -828,25 +837,24 @@ static int setup_blkring(struct xenbus_device *dev,
    struct blkif_sring *sring;
    int err;

    - info->ring_ref = GRANT_INVALID_REF;
    -
    - sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
    + sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
    + info->ring_order);
    if (!sring) {
    xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
    return -ENOMEM;
    }
    SHARED_RING_INIT(sring);
    - FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
    + FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE << info->ring_order);

    sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);

    - err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
    + err = xenbus_grant_ring(dev, info->ring.sring, 1 << info->ring_order,
    + info->ring_ref);
    if (err < 0) {
    - free_page((unsigned long)sring);
    + free_pages((unsigned long)sring, info->ring_order);
    info->ring.sring = NULL;
    goto fail;
    }
    - info->ring_ref = err;

    err = xenbus_alloc_evtchn(dev, &info->evtchn);
    if (err)
    @@ -875,8 +883,27 @@ static int talk_to_blkback(struct xenbus_device *dev,
    {
    const char *message = NULL;
    struct xenbus_transaction xbt;
    + unsigned int ring_order;
    + int legacy_backend;
    + int i;
    int err;

    + for (i = 0; i < (1 << info->ring_order); i++)
    + info->ring_ref[i] = GRANT_INVALID_REF;
    +
    + err = xenbus_scanf(XBT_NIL, dev->otherend, "max-ring-page-order", "%u",
    + &ring_order);
    +
    + legacy_backend = !(err == 1);
    +
    + if (legacy_backend) {
    + info->ring_order = 0;
    + } else {
    + info->ring_order = (ring_order <= xen_blkif_ring_order) ?
    + ring_order :
    + xen_blkif_ring_order;
    + }
    +
    /* Create shared ring, alloc event channel. */
    err = setup_blkring(dev, info);
    if (err)
    @@ -889,12 +916,35 @@ again:
    goto destroy_blkring;
    }

    - err = xenbus_printf(xbt, dev->nodename,
    - "ring-ref", "%u", info->ring_ref);
    - if (err) {
    - message = "writing ring-ref";
    - goto abort_transaction;
    + if (legacy_backend) {
    + err = xenbus_printf(xbt, dev->nodename,
    + "ring-ref", "%d", info->ring_ref[0]);
    + if (err) {
    + message = "writing ring-ref";
    + goto abort_transaction;
    + }
    + } else {
    + for (i = 0; i < (1 << info->ring_order); i++) {
    + char key[sizeof("ring-ref") + 2];
    +
    + sprintf(key, "ring-ref%d", i);
    +
    + err = xenbus_printf(xbt, dev->nodename,
    + key, "%d", info->ring_ref[i]);
    + if (err) {
    + message = "writing ring-ref";
    + goto abort_transaction;
    + }
    + }
    +
    + err = xenbus_printf(xbt, dev->nodename,
    + "ring-page-order", "%u", info->ring_order);
    + if (err) {
    + message = "writing ring-order";
    + goto abort_transaction;
    + }
    }
    +
    err = xenbus_printf(xbt, dev->nodename,
    "event-channel", "%u", info->evtchn);
    if (err) {
    @@ -996,21 +1046,14 @@ static int blkfront_probe(struct xenbus_device *dev,
    info->connected = BLKIF_STATE_DISCONNECTED;
    INIT_WORK(&info->work, blkif_restart_queue);

    - for (i = 0; i < BLK_RING_SIZE; i++)
    + for (i = 0; i < BLK_MAX_RING_SIZE; i++)
    info->shadow[i].req.u.rw.id = i+1;
    - info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
    + info->shadow[BLK_MAX_RING_SIZE-1].req.u.rw.id = 0x0fffffff;

    /* Front end dir is a number, which is used as the id. */
    info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
    dev_set_drvdata(&dev->dev, info);

    - err = talk_to_blkback(dev, info);
    - if (err) {
    - kfree(info);
    - dev_set_drvdata(&dev->dev, NULL);
    - return err;
    - }
    -
    return 0;
    }

    @@ -1031,13 +1074,13 @@ static int blkif_recover(struct blkfront_info *info)

    /* Stage 2: Set up free list. */
    memset(&info->shadow, 0, sizeof(info->shadow));
    - for (i = 0; i < BLK_RING_SIZE; i++)
    + for (i = 0; i < BLK_MAX_RING_SIZE; i++)
    info->shadow[i].req.u.rw.id = i+1;
    info->shadow_free = info->ring.req_prod_pvt;
    - info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
    + info->shadow[BLK_MAX_RING_SIZE-1].req.u.rw.id = 0x0fffffff;

    /* Stage 3: Find pending requests and requeue them. */
    - for (i = 0; i < BLK_RING_SIZE; i++) {
    + for (i = 0; i < BLK_RING_SIZE(info->ring_order); i++) {
    /* Not in use? */
    if (!copy[i].request)
    continue;
    @@ -1299,7 +1342,6 @@ static void blkback_changed(struct xenbus_device *dev,

    switch (backend_state) {
    case XenbusStateInitialising:
    - case XenbusStateInitWait:
    case XenbusStateInitialised:
    case XenbusStateReconfiguring:
    case XenbusStateReconfigured:
    @@ -1307,6 +1349,10 @@ static void blkback_changed(struct xenbus_device *dev,
    case XenbusStateClosed:
    break;

    + case XenbusStateInitWait:
    + talk_to_blkback(dev, info);
    + break;
    +
    case XenbusStateConnected:
    blkfront_connect(info);
    break;
    diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
    index 94b79c3..f93b59a 100644
    --- a/drivers/net/xen-netback/common.h
    +++ b/drivers/net/xen-netback/common.h
    @@ -130,8 +130,8 @@ int xen_netbk_must_stop_queue(struct xenvif *vif);
    /* (Un)Map communication rings. */
    void xen_netbk_unmap_frontend_rings(struct xenvif *vif);
    int xen_netbk_map_frontend_rings(struct xenvif *vif,
    - grant_ref_t tx_ring_ref,
    - grant_ref_t rx_ring_ref);
    + int tx_ring_ref,
    + int rx_ring_ref);

    /* (De)Register a xenvif with the netback backend. */
    void xen_netbk_add_xenvif(struct xenvif *vif);
    diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
    index 59effac..0b014cf 100644
    --- a/drivers/net/xen-netback/netback.c
    +++ b/drivers/net/xen-netback/netback.c
    @@ -1594,8 +1594,8 @@ void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
    }

    int xen_netbk_map_frontend_rings(struct xenvif *vif,
    - grant_ref_t tx_ring_ref,
    - grant_ref_t rx_ring_ref)
    + int tx_ring_ref,
    + int rx_ring_ref)
    {
    void *addr;
    struct xen_netif_tx_sring *txs;
    @@ -1604,7 +1604,7 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
    int err = -ENOMEM;

    err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
    - tx_ring_ref, &addr);
    + &tx_ring_ref, 1, &addr);
    if (err)
    goto err;

    @@ -1612,7 +1612,7 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
    BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);

    err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
    - rx_ring_ref, &addr);
    + &rx_ring_ref, 1, &addr);
    if (err)
    goto err;

    diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
    index 698b905..521a595 100644
    --- a/drivers/net/xen-netfront.c
    +++ b/drivers/net/xen-netfront.c
    @@ -1496,13 +1496,12 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
    SHARED_RING_INIT(txs);
    FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);

    - err = xenbus_grant_ring(dev, virt_to_mfn(txs));
    + err = xenbus_grant_ring(dev, txs, 1, &info->tx_ring_ref);
    if (err < 0) {
    free_page((unsigned long)txs);
    goto fail;
    }

    - info->tx_ring_ref = err;
    rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
    if (!rxs) {
    err = -ENOMEM;
    @@ -1512,12 +1511,11 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
    SHARED_RING_INIT(rxs);
    FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);

    - err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
    + err = xenbus_grant_ring(dev, rxs, 1, &info->rx_ring_ref);
    if (err < 0) {
    free_page((unsigned long)rxs);
    goto fail;
    }
    - info->rx_ring_ref = err;

    err = xenbus_alloc_evtchn(dev, &info->evtchn);
    if (err)
    diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
    index 1620088..95109d8 100644
    --- a/drivers/pci/xen-pcifront.c
    +++ b/drivers/pci/xen-pcifront.c
    @@ -768,12 +768,10 @@ static int pcifront_publish_info(struct pcifront_device *pdev)
    int err = 0;
    struct xenbus_transaction trans;

    - err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
    + err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &pdev->gnt_ref);
    if (err < 0)
    goto out;

    - pdev->gnt_ref = err;
    -
    err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
    if (err)
    goto out;
    diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
    index 64b11f9..e0834cd 100644
    --- a/drivers/xen/xen-pciback/xenbus.c
    +++ b/drivers/xen/xen-pciback/xenbus.c
    @@ -108,7 +108,7 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
    "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
    gnt_ref, remote_evtchn);

    - err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
    + err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
    if (err < 0) {
    xenbus_dev_fatal(pdev->xdev, err,
    "Error mapping other domain page in ours.");
    diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
    index 566d2ad..3a14524 100644
    --- a/drivers/xen/xenbus/xenbus_client.c
    +++ b/drivers/xen/xenbus/xenbus_client.c
    @@ -53,14 +53,16 @@ struct xenbus_map_node {
    struct vm_struct *area; /* PV */
    struct page *page; /* HVM */
    };
    - grant_handle_t handle;
    + grant_handle_t handle[XENBUS_MAX_RING_PAGES];
    + unsigned int nr_handles;
    };

    static DEFINE_SPINLOCK(xenbus_valloc_lock);
    static LIST_HEAD(xenbus_valloc_pages);

    struct xenbus_ring_ops {
    - int (*map)(struct xenbus_device *dev, int gnt, void **vaddr);
    + int (*map)(struct xenbus_device *dev, int gnt[], int nr_gnts,
    + void **vaddr);
    int (*unmap)(struct xenbus_device *dev, void *vaddr);
    };

    @@ -356,17 +358,38 @@ static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
    /**
    * xenbus_grant_ring
    * @dev: xenbus device
    - * @ring_mfn: mfn of ring to grant
    -
    - * Grant access to the given @ring_mfn to the peer of the given device. Return
    - * 0 on success, or -errno on error. On error, the device will switch to
    - * XenbusStateClosing, and the error will be saved in the store.
    + * @vaddr: starting virtual address of the ring
    + * @nr_pages: number of page to be granted
    + * @grefs: grant reference array to be filled in
    + * Grant access to the given @vaddr to the peer of the given device.
    + * Then fill in @grefs with grant references. Return 0 on success, or
    + * -errno on error. On error, the device will switch to
    + * XenbusStateClosing, and the first error will be saved in the store.
    */
    -int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
    +int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
    + int nr_pages, int grefs[])
    {
    - int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
    - if (err < 0)
    - xenbus_dev_fatal(dev, err, "granting access to ring page");
    + int i;
    + int err;
    +
    + for (i = 0; i < nr_pages; i++) {
    + unsigned long addr = (unsigned long)vaddr +
    + (PAGE_SIZE * i);
    + err = gnttab_grant_foreign_access(dev->otherend_id,
    + virt_to_mfn(addr), 0);
    + if (err < 0) {
    + xenbus_dev_fatal(dev, err,
    + "granting access to ring page");
    + goto fail;
    + }
    + grefs[i] = err;
    + }
    +
    + return 0;
    +
    +fail:
    + for ( ; i >= 0; i--)
    + gnttab_end_foreign_access_ref(grefs[i], 0);
    return err;
    }
    EXPORT_SYMBOL_GPL(xenbus_grant_ring);
    @@ -447,7 +470,8 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
    /**
    * xenbus_map_ring_valloc
    * @dev: xenbus device
    - * @gnt_ref: grant reference
    + * @gnt_ref: grant reference array
    + * @nr_grefs: number of grant reference
    * @vaddr: pointer to address to be filled out by mapping
    *
    * Based on Rusty Russell's skeleton driver's map_page.
    @@ -458,23 +482,28 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
    * or -ENOMEM on error. If an error is returned, device will switch to
    * XenbusStateClosing and the error message will be saved in XenStore.
    */
    -int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
    +int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref[],
    + int nr_grefs, void **vaddr)
    {
    - return ring_ops->map(dev, gnt_ref, vaddr);
    + return ring_ops->map(dev, gnt_ref, nr_grefs, vaddr);
    }
    EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);

    +static int __xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev,
    + struct xenbus_map_node *node);
    +
    static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
    - int gnt_ref, void **vaddr)
    + int gnt_ref[], int nr_grefs, void **vaddr)
    {
    - struct gnttab_map_grant_ref op = {
    - .flags = GNTMAP_host_map | GNTMAP_contains_pte,
    - .ref = gnt_ref,
    - .dom = dev->otherend_id,
    - };
    + struct gnttab_map_grant_ref op[XENBUS_MAX_RING_PAGES];
    struct xenbus_map_node *node;
    struct vm_struct *area;
    - pte_t *pte;
    + pte_t *pte[XENBUS_MAX_RING_PAGES];
    + int i;
    + int err = 0;
    +
    + if (nr_grefs > XENBUS_MAX_RING_PAGES)
    + return -EINVAL;

    *vaddr = NULL;

    @@ -482,28 +511,44 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
    if (!node)
    return -ENOMEM;

    - area = alloc_vm_area(PAGE_SIZE, &pte);
    + area = alloc_vm_area(PAGE_SIZE * nr_grefs, pte);
    if (!area) {
    kfree(node);
    return -ENOMEM;
    }

    - op.host_addr = arbitrary_virt_to_machine(pte).maddr;
    + for (i = 0; i < nr_grefs; i++) {
    + op[i].flags = GNTMAP_host_map | GNTMAP_contains_pte,
    + op[i].ref = gnt_ref[i],
    + op[i].dom = dev->otherend_id,
    + op[i].host_addr = arbitrary_virt_to_machine(pte[i]).maddr;
    + };

    if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
    BUG();

    - if (op.status != GNTST_okay) {
    - free_vm_area(area);
    - kfree(node);
    - xenbus_dev_fatal(dev, op.status,
    - "mapping in shared page %d from domain %d",
    - gnt_ref, dev->otherend_id);
    - return op.status;
    + node->nr_handles = nr_grefs;
    + node->area = area;
    +
    + for (i = 0; i < nr_grefs; i++) {
    + if (op[i].status != GNTST_okay) {
    + err = op[i].status;
    + node->handle[i] = INVALID_GRANT_HANDLE;
    + continue;
    + }
    + node->handle[i] = op[i].handle;
    }

    - node->handle = op.handle;
    - node->area = area;
    + if (err != 0) {
    + for (i = 0; i < nr_grefs; i++)
    + xenbus_dev_fatal(dev, op[i].status,
    + "mapping in shared page %d from domain %d",
    + gnt_ref[i], dev->otherend_id);
    +
    + __xenbus_unmap_ring_vfree_pv(dev, node);
    +
    + return err;
    + }

    spin_lock(&xenbus_valloc_lock);
    list_add(&node->next, &xenbus_valloc_pages);
    @@ -514,25 +559,29 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
    }

    static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
    - int gnt_ref, void **vaddr)
    + int gnt_ref[], int nr_grefs, void **vaddr)
    {
    struct xenbus_map_node *node;
    int err;
    void *addr;

    + if (nr_grefs > XENBUS_MAX_RING_PAGES)
    + return -EINVAL;
    +
    *vaddr = NULL;

    node = kzalloc(sizeof(*node), GFP_KERNEL);
    if (!node)
    return -ENOMEM;

    - err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
    + err = alloc_xenballooned_pages(nr_grefs, &node->page,
    + false /* lowmem */);
    if (err)
    goto out_err;

    addr = pfn_to_kaddr(page_to_pfn(node->page));

    - err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
    + err = xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handle, addr);
    if (err)
    goto out_err;

    @@ -544,7 +593,7 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
    return 0;

    out_err:
    - free_xenballooned_pages(1, &node->page);
    + free_xenballooned_pages(nr_grefs, &node->page);
    kfree(node);
    return err;
    }
    @@ -553,36 +602,51 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
    /**
    * xenbus_map_ring
    * @dev: xenbus device
    - * @gnt_ref: grant reference
    - * @handle: pointer to grant handle to be filled
    + * @gnt_ref: grant reference array
    + * @nr_grefs: number of grant references
    + * @handle: pointer to grant handle array to be filled, mind the size
    * @vaddr: address to be mapped to
    *
    - * Map a page of memory into this domain from another domain's grant table.
    + * Map pages of memory into this domain from another domain's grant table.
    * xenbus_map_ring does not allocate the virtual address space (you must do
    - * this yourself!). It only maps in the page to the specified address.
    + * this yourself!). It only maps in the pages to the specified address.
    * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
    * or -ENOMEM on error. If an error is returned, device will switch to
    - * XenbusStateClosing and the error message will be saved in XenStore.
    + * XenbusStateClosing and the last error message will be saved in XenStore.
    */
    -int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
    - grant_handle_t *handle, void *vaddr)
    +int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref[], int nr_grefs,
    + grant_handle_t handle[], void *vaddr)
    {
    - struct gnttab_map_grant_ref op;
    -
    - gnttab_set_map_op(&op, (phys_addr_t)vaddr, GNTMAP_host_map, gnt_ref,
    - dev->otherend_id);
    + struct gnttab_map_grant_ref op[XENBUS_MAX_RING_PAGES];
    + int i;
    + int err = GNTST_okay; /* 0 */
    +
    + for (i = 0; i < nr_grefs; i++) {
    + unsigned long addr = (unsigned long)vaddr +
    + (PAGE_SIZE * i);
    + gnttab_set_map_op(&op[i], (phys_addr_t)addr,
    + GNTMAP_host_map, gnt_ref[i],
    + dev->otherend_id);
    + }

    - if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
    + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, op, nr_grefs))
    BUG();

    - if (op.status != GNTST_okay) {
    - xenbus_dev_fatal(dev, op.status,
    - "mapping in shared page %d from domain %d",
    - gnt_ref, dev->otherend_id);
    - } else
    - *handle = op.handle;
    + for (i = 0; i < nr_grefs; i++) {
    + if (op[i].status != GNTST_okay) {
    + err = op[i].status;
    + xenbus_dev_fatal(dev, err,
    + "mapping in shared page %d from domain %d",
    + gnt_ref[i], dev->otherend_id);
    + handle[i] = INVALID_GRANT_HANDLE;
    + } else
    + handle[i] = op[i].handle;
    + }

    - return op.status;
    + if (err != GNTST_okay)
    + xenbus_unmap_ring(dev, handle, nr_grefs, vaddr);
    +
    + return err;
    }
    EXPORT_SYMBOL_GPL(xenbus_map_ring);

    @@ -605,13 +669,53 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
    }
    EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);

    +static int __xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev,
    + struct xenbus_map_node *node)
    +{
    + struct gnttab_unmap_grant_ref op[XENBUS_MAX_RING_PAGES];
    + unsigned int level;
    + int i, j;
    + int err = GNTST_okay;
    +
    + j = 0;
    + for (i = 0; i < node->nr_handles; i++) {
    + unsigned long vaddr = (unsigned long)node->area->addr +
    + (PAGE_SIZE * i);
    + if (node->handle[i] != INVALID_GRANT_HANDLE) {
    + memset(&op[j], 0, sizeof(op[0]));
    + op[j].host_addr = arbitrary_virt_to_machine(
    + lookup_address(vaddr, &level)).maddr;
    + op[j].handle = node->handle[i];
    + j++;
    + node->handle[i] = INVALID_GRANT_HANDLE;
    + }
    + }
    +
    + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, op, j))
    + BUG();
    +
    + node->nr_handles = 0;
    +
    + for (i = 0; i < j; i++) {
    + if (op[i].status != GNTST_okay) {
    + err = op[i].status;
    + xenbus_dev_error(dev, err,
    + "unmapping page %d at handle %d error %d",
    + i, op[i].handle, err);
    + }
    + }
    +
    + if (err == GNTST_okay)
    + free_vm_area(node->area);
    +
    + kfree(node);
    +
    + return err;
    +}
    +
    static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
    {
    struct xenbus_map_node *node;
    - struct gnttab_unmap_grant_ref op = {
    - .host_addr = (unsigned long)vaddr,
    - };
    - unsigned int level;

    spin_lock(&xenbus_valloc_lock);
    list_for_each_entry(node, &xenbus_valloc_pages, next) {
    @@ -626,33 +730,18 @@ static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)

    if (!node) {
    xenbus_dev_error(dev, -ENOENT,
    - "can't find mapped virtual address %p", vaddr);
    + "can't find mapped virtual address %p", vaddr);
    return GNTST_bad_virt_addr;
    }

    - op.handle = node->handle;
    - op.host_addr = arbitrary_virt_to_machine(
    - lookup_address((unsigned long)vaddr, &level)).maddr;
    -
    - if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
    - BUG();
    -
    - if (op.status == GNTST_okay)
    - free_vm_area(node->area);
    - else
    - xenbus_dev_error(dev, op.status,
    - "unmapping page at handle %d error %d",
    - node->handle, op.status);
    -
    - kfree(node);
    - return op.status;
    + return __xenbus_unmap_ring_vfree_pv(dev, node);
    }

    static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
    {
    int rv;
    struct xenbus_map_node *node;
    - void *addr;
    + void *addr = NULL;

    spin_lock(&xenbus_valloc_lock);
    list_for_each_entry(node, &xenbus_valloc_pages, next) {
    @@ -668,14 +757,14 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)

    if (!node) {
    xenbus_dev_error(dev, -ENOENT,
    - "can't find mapped virtual address %p", vaddr);
    + "can't find mapped virtual address %p", vaddr);
    return GNTST_bad_virt_addr;
    }

    - rv = xenbus_unmap_ring(dev, node->handle, addr);
    + rv = xenbus_unmap_ring(dev, node->handle, node->nr_handles, addr);

    if (!rv)
    - free_xenballooned_pages(1, &node->page);
    + free_xenballooned_pages(node->nr_handles, &node->page);
    else
    WARN(1, "Leaking %p\n", vaddr);

    @@ -687,6 +776,7 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
    * xenbus_unmap_ring
    * @dev: xenbus device
    * @handle: grant handle
    + * @nr_handles: number of grant handle
    * @vaddr: addr to unmap
    *
    * Unmap a page of memory in this domain that was imported from another domain.
    @@ -694,21 +784,37 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
    * (see xen/include/interface/grant_table.h).
    */
    int xenbus_unmap_ring(struct xenbus_device *dev,
    - grant_handle_t handle, void *vaddr)
    + grant_handle_t handle[], int nr_handles,
    + void *vaddr)
    {
    - struct gnttab_unmap_grant_ref op;
    -
    - gnttab_set_unmap_op(&op, (phys_addr_t)vaddr, GNTMAP_host_map, handle);
    + struct gnttab_unmap_grant_ref op[XENBUS_MAX_RING_PAGES];
    + int i, j;
    + int err = GNTST_okay;
    +
    + j = 0;
    + for (i = 0; i < nr_handles; i++) {
    + unsigned long addr = (unsigned long)vaddr +
    + (PAGE_SIZE * i);
    + if (handle[i] != INVALID_GRANT_HANDLE) {
    + gnttab_set_unmap_op(&op[j++], (phys_addr_t)addr,
    + GNTMAP_host_map, handle[i]);
    + handle[i] = INVALID_GRANT_HANDLE;
    + }
    + }

    - if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
    + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, op, j))
    BUG();

    - if (op.status != GNTST_okay)
    - xenbus_dev_error(dev, op.status,
    - "unmapping page at handle %d error %d",
    - handle, op.status);
    + for (i = 0; i < j; i++) {
    + if (op[i].status != GNTST_okay) {
    + err = op[i].status;
    + xenbus_dev_error(dev, err,
    + "unmapping page at handle %d error %d",
    + handle[i], err);
    + }
    + }

    - return op.status;
    + return err;
    }
    EXPORT_SYMBOL_GPL(xenbus_unmap_ring);

    diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
    index 3864967..62b92d2 100644
    --- a/drivers/xen/xenbus/xenbus_probe.c
    +++ b/drivers/xen/xenbus/xenbus_probe.c
    @@ -718,6 +718,7 @@ static int __init xenstored_local_init(void)
    return err;
    }

    +extern void xenbus_ring_ops_init(void);
    static int __init xenbus_init(void)
    {
    int err = 0;
    @@ -767,6 +768,8 @@ static int __init xenbus_init(void)
    proc_mkdir("xen", NULL);
    #endif

    + xenbus_ring_ops_init();
    +
    out_error:
    return err;
    }
    diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
    index e8c599b..cdbd948 100644
    --- a/include/xen/xenbus.h
    +++ b/include/xen/xenbus.h
    @@ -195,15 +195,23 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
    const char *pathfmt, ...);

    int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
    -int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
    -int xenbus_map_ring_valloc(struct xenbus_device *dev,
    - int gnt_ref, void **vaddr);
    -int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
    - grant_handle_t *handle, void *vaddr);
    +
    +#define XENBUS_MAX_RING_ORDER 2
    +#define XENBUS_MAX_RING_PAGES (1 << XENBUS_MAX_RING_ORDER)
    +
    +#define INVALID_GRANT_HANDLE (~0U)
    +
    +int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
    + int nr_pages, int grefs[]);
    +int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref[],
    + int nr_grefs, void **vaddr);
    +int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref[], int nr_grefs,
    + grant_handle_t handle[], void *vaddr);

    int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
    int xenbus_unmap_ring(struct xenbus_device *dev,
    - grant_handle_t handle, void *vaddr);
    + grant_handle_t handle[], int nr_handles,
    + void *vaddr);

    int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
    int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);

    \
     
     \ /
      Last update: 2012-03-05 22:51    [W:0.092 / U:156.908 seconds]
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