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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: 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>
This commit is contained in:
Stefano Stabellini 2017-03-22 10:16:06 -07:00
parent 47b70fb1e4
commit 40a2389207
1 changed files with 97 additions and 2 deletions
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99
hw/9pfs/xen-9p-backend.c
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@ -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)