xen/9pfs: connect to the frontend
Write the limits of the backend to xenstore. Connect to the frontend. Upon connection, allocate the rings according to the protocol specification. Initialize a QEMUBH to schedule work upon receiving an event channel notification from the frontend. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> CC: anthony.perard@citrix.com CC: jgross@suse.com CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> CC: Greg Kurz <groug@kaod.org>
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			@ -17,8 +17,41 @@
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#include "qemu/config-file.h"
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#include "fsdev/qemu-fsdev.h"
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#define VERSIONS "1"
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#define MAX_RINGS 8
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#define MAX_RING_ORDER 8
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typedef struct Xen9pfsRing {
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    struct Xen9pfsDev *priv;
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    int ref;
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    xenevtchn_handle   *evtchndev;
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    int evtchn;
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    int local_port;
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    int ring_order;
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    struct xen_9pfs_data_intf *intf;
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    unsigned char *data;
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    struct xen_9pfs_data ring;
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    struct iovec *sg;
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    QEMUBH *bh;
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    /* local copies, so that we can read/write PDU data directly from
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     * the ring */
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    RING_IDX out_cons, out_size, in_cons;
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    bool inprogress;
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} Xen9pfsRing;
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typedef struct Xen9pfsDev {
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    struct XenDevice xendev;  /* must be first */
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    V9fsState state;
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    char *path;
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    char *security_model;
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    char *tag;
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    char *id;
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    int num_rings;
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    Xen9pfsRing *rings;
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} Xen9pfsDev;
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static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,
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			@ -67,22 +100,169 @@ static int xen_9pfs_init(struct XenDevice *xendev)
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    return 0;
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}
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static void xen_9pfs_bh(void *opaque)
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{
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}
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static void xen_9pfs_evtchn_event(void *opaque)
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{
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}
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static int xen_9pfs_free(struct XenDevice *xendev)
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{
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    return -1;
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    int i;
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    Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev);
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    g_free(xen_9pdev->id);
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    g_free(xen_9pdev->tag);
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    g_free(xen_9pdev->path);
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    g_free(xen_9pdev->security_model);
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    for (i = 0; i < xen_9pdev->num_rings; i++) {
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        if (xen_9pdev->rings[i].data != NULL) {
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            xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
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                    xen_9pdev->rings[i].data,
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                    (1 << xen_9pdev->rings[i].ring_order));
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        }
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        if (xen_9pdev->rings[i].intf != NULL) {
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            xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
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                    xen_9pdev->rings[i].intf,
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                    1);
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        }
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        if (xen_9pdev->rings[i].evtchndev > 0) {
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            qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
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                    NULL, NULL, NULL);
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            xenevtchn_unbind(xen_9pdev->rings[i].evtchndev,
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                             xen_9pdev->rings[i].local_port);
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        }
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        if (xen_9pdev->rings[i].bh != NULL) {
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            qemu_bh_delete(xen_9pdev->rings[i].bh);
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        }
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    }
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    g_free(xen_9pdev->rings);
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    return 0;
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}
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static int xen_9pfs_connect(struct XenDevice *xendev)
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{
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    int i;
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    Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev);
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    V9fsState *s = &xen_9pdev->state;
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    QemuOpts *fsdev;
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    if (xenstore_read_fe_int(&xen_9pdev->xendev, "num-rings",
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                             &xen_9pdev->num_rings) == -1 ||
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        xen_9pdev->num_rings > MAX_RINGS || xen_9pdev->num_rings < 1) {
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        return -1;
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    }
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    xen_9pdev->rings = g_malloc0(xen_9pdev->num_rings * sizeof(Xen9pfsRing));
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    for (i = 0; i < xen_9pdev->num_rings; i++) {
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        char *str;
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        int ring_order;
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        xen_9pdev->rings[i].priv = xen_9pdev;
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        xen_9pdev->rings[i].evtchn = -1;
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        xen_9pdev->rings[i].local_port = -1;
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        str = g_strdup_printf("ring-ref%u", i);
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        if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
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                                 &xen_9pdev->rings[i].ref) == -1) {
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            goto out;
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        }
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        g_free(str);
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        str = g_strdup_printf("event-channel-%u", i);
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        if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
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                                 &xen_9pdev->rings[i].evtchn) == -1) {
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            goto out;
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        }
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        g_free(str);
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        xen_9pdev->rings[i].intf =  xengnttab_map_grant_ref(
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                xen_9pdev->xendev.gnttabdev,
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                xen_9pdev->xendev.dom,
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                xen_9pdev->rings[i].ref,
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                PROT_READ | PROT_WRITE);
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        if (!xen_9pdev->rings[i].intf) {
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            goto out;
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        }
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        ring_order = xen_9pdev->rings[i].intf->ring_order;
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        if (ring_order > MAX_RING_ORDER) {
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            goto out;
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        }
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        xen_9pdev->rings[i].ring_order = ring_order;
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        xen_9pdev->rings[i].data = xengnttab_map_domain_grant_refs(
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                xen_9pdev->xendev.gnttabdev,
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                (1 << ring_order),
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                xen_9pdev->xendev.dom,
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                xen_9pdev->rings[i].intf->ref,
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                PROT_READ | PROT_WRITE);
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        if (!xen_9pdev->rings[i].data) {
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            goto out;
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        }
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        xen_9pdev->rings[i].ring.in = xen_9pdev->rings[i].data;
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        xen_9pdev->rings[i].ring.out = xen_9pdev->rings[i].data +
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                                       XEN_FLEX_RING_SIZE(ring_order);
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        xen_9pdev->rings[i].bh = qemu_bh_new(xen_9pfs_bh, &xen_9pdev->rings[i]);
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        xen_9pdev->rings[i].out_cons = 0;
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        xen_9pdev->rings[i].out_size = 0;
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        xen_9pdev->rings[i].inprogress = false;
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        xen_9pdev->rings[i].evtchndev = xenevtchn_open(NULL, 0);
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        if (xen_9pdev->rings[i].evtchndev == NULL) {
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            goto out;
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        }
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        fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD, FD_CLOEXEC);
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        xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain
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                                            (xen_9pdev->rings[i].evtchndev,
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                                             xendev->dom,
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                                             xen_9pdev->rings[i].evtchn);
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        if (xen_9pdev->rings[i].local_port == -1) {
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            xen_pv_printf(xendev, 0,
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                          "xenevtchn_bind_interdomain failed port=%d\n",
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                          xen_9pdev->rings[i].evtchn);
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            goto out;
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        }
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        xen_pv_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
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        qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
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                xen_9pfs_evtchn_event, NULL, &xen_9pdev->rings[i]);
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    }
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    xen_9pdev->security_model = xenstore_read_be_str(xendev, "security_model");
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    xen_9pdev->path = xenstore_read_be_str(xendev, "path");
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    xen_9pdev->id = s->fsconf.fsdev_id =
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        g_strdup_printf("xen9p%d", xendev->dev);
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    xen_9pdev->tag = s->fsconf.tag = xenstore_read_fe_str(xendev, "tag");
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    v9fs_register_transport(s, &xen_9p_transport);
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    fsdev = qemu_opts_create(qemu_find_opts("fsdev"),
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            s->fsconf.tag,
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            1, NULL);
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    qemu_opt_set(fsdev, "fsdriver", "local", NULL);
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    qemu_opt_set(fsdev, "path", xen_9pdev->path, NULL);
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    qemu_opt_set(fsdev, "security_model", xen_9pdev->security_model, NULL);
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    qemu_opts_set_id(fsdev, s->fsconf.fsdev_id);
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    qemu_fsdev_add(fsdev);
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    v9fs_device_realize_common(s, NULL);
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    return 0;
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out:
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    xen_9pfs_free(xendev);
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    return -1;
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}
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static void xen_9pfs_alloc(struct XenDevice *xendev)
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{
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    xenstore_write_be_str(xendev, "versions", VERSIONS);
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    xenstore_write_be_int(xendev, "max-rings", MAX_RINGS);
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    xenstore_write_be_int(xendev, "max-ring-page-order", MAX_RING_ORDER);
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}
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static void xen_9pfs_disconnect(struct XenDevice *xendev)
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{
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    /* Dynamic hotplug of PV filesystems at runtime is not supported. */
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}
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struct XenDevOps xen_9pfs_ops = {
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