Commit 40a23892 authored by Stefano Stabellini's avatar Stefano Stabellini
Browse files

xen/9pfs: implement in/out_iov_from_pdu and vmarshal/vunmarshal 



Implement xen_9pfs_init_in/out_iov_from_pdu and
xen_9pfs_pdu_vmarshal/vunmarshall by creating new sg pointing to the
data on the ring.

This is safe as we only handle one request per ring at any given time.

Signed-off-by: default avatarStefano 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>
parent 47b70fb1

hw/9pfs/xen-9p-backend.c

+97 −2
Original line number Diff line number Diff line
@@ -54,12 +54,81 @@ typedef struct Xen9pfsDev { 
    Xen9pfsRing *rings;

} Xen9pfsDev;



static void xen_9pfs_in_sg(Xen9pfsRing *ring,

                           struct iovec *in_sg,

                           int *num,

                           uint32_t idx,

                           uint32_t size)

{

    RING_IDX cons, prod, masked_prod, masked_cons;



    cons = ring->intf->in_cons;

    prod = ring->intf->in_prod;

    xen_rmb();

    masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order));

    masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order));



    if (masked_prod < masked_cons) {

        in_sg[0].iov_base = ring->ring.in + masked_prod;

        in_sg[0].iov_len = masked_cons - masked_prod;

        *num = 1;

    } else {

        in_sg[0].iov_base = ring->ring.in + masked_prod;

        in_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) - masked_prod;

        in_sg[1].iov_base = ring->ring.in;

        in_sg[1].iov_len = masked_cons;

        *num = 2;

    }

}



static void xen_9pfs_out_sg(Xen9pfsRing *ring,

                            struct iovec *out_sg,

                            int *num,

                            uint32_t idx)

{

    RING_IDX cons, prod, masked_prod, masked_cons;



    cons = ring->intf->out_cons;

    prod = ring->intf->out_prod;

    xen_rmb();

    masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order));

    masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order));



    if (masked_cons < masked_prod) {

        out_sg[0].iov_base = ring->ring.out + masked_cons;

        out_sg[0].iov_len = ring->out_size;

        *num = 1;

    } else {

        if (ring->out_size >

            (XEN_FLEX_RING_SIZE(ring->ring_order) - masked_cons)) {

            out_sg[0].iov_base = ring->ring.out + masked_cons;

            out_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) -

                                masked_cons;

            out_sg[1].iov_base = ring->ring.out;

            out_sg[1].iov_len = ring->out_size -

                                (XEN_FLEX_RING_SIZE(ring->ring_order) -

                                 masked_cons);

            *num = 2;

        } else {

            out_sg[0].iov_base = ring->ring.out + masked_cons;

            out_sg[0].iov_len = ring->out_size;

            *num = 1;

        }

    }

}



static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,

                                     size_t offset,

                                     const char *fmt,

                                     va_list ap)

{

    return 0;

    Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);

    struct iovec in_sg[2];

    int num;



    xen_9pfs_in_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],

                   in_sg, &num, pdu->idx, ROUND_UP(offset + 128, 512));

    return v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap);

}



static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
@@ -67,13 +136,29 @@ static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu, 
                                       const char *fmt,

                                       va_list ap)

{

    return 0;

    Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);

    struct iovec out_sg[2];

    int num;



    xen_9pfs_out_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],

                    out_sg, &num, pdu->idx);

    return v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap);

}



static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,

                                           struct iovec **piov,

                                           unsigned int *pniov)

{

    Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);

    Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings];

    int num;



    g_free(ring->sg);



    ring->sg = g_malloc0(sizeof(*ring->sg) * 2);

    xen_9pfs_out_sg(ring, ring->sg, &num, pdu->idx);

    *piov = ring->sg;

    *pniov = num;

}



static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu,
@@ -81,6 +166,16 @@ static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu, 
                                          unsigned int *pniov,

                                          size_t size)

{

    Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);

    Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings];

    int num;



    g_free(ring->sg);



    ring->sg = g_malloc0(sizeof(*ring->sg) * 2);

    xen_9pfs_in_sg(ring, ring->sg, &num, pdu->idx, size);

    *piov = ring->sg;

    *pniov = num;

}



static void xen_9pfs_push_and_notify(V9fsPDU *pdu)