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: Stefano Stabellini <stef...@aporeto.com>
CC: anthony.per...@citrix.com
CC: jgr...@suse.com
CC: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
CC: Greg Kurz <gr...@kaod.org>
---
hw/9pfs/xen-9p-backend.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 97 insertions(+), 2 deletions(-)
diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
index 8820e8f..9068703 100644
--- a/hw/9pfs/xen-9p-backend.c
+++ b/hw/9pfs/xen-9p-backend.c
@@ -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)
--
1.9.1
