/*
* Copy data from receive ring and change index
* NOTE:
* We assume (dlen + skip) == sizeof(channel packet).
*/
int
vmbus_rxbr_read(struct vmbus_br *rbr, void *data, size_t dlen, size_t skip)
{
struct vmbus_bufring *vbr = rbr->vbr;
uint32_t br_dsize = rbr->dsize;
uint32_t rindex;
if (vmbus_br_availread(rbr) < dlen + skip + sizeof(uint64_t))
return -EAGAIN;
/* Record where host was when we started read (for debug) */
rbr->windex = rbr->vbr->windex;
/*
* Copy channel packet from RX bufring.
*/
rindex = vmbus_br_idxinc(rbr->vbr->rindex, skip, br_dsize);
rindex = vmbus_rxbr_copyfrom(rbr, rindex, data, dlen);
/*
* Discard this channel packet's 64bits offset, which is useless to us.
*/
rindex = vmbus_br_idxinc(rindex, sizeof(uint64_t), br_dsize);
/* Update the read index _after_ the channel packet is fetched. */
rte_compiler_barrier();
vbr->rindex = rindex;
return 0;
}
/* Copy data from receive ring but don't change index */
int
vmbus_rxbr_peek(const struct vmbus_br *rbr, void *data, size_t dlen)
{
uint32_t avail;
/*
* The requested data and the 64bits channel packet
* offset should be there at least.
*/
avail = vmbus_br_availread(rbr);
if (avail < dlen + sizeof(uint64_t))
return -EAGAIN;
vmbus_rxbr_copyfrom(rbr, rbr->vbr->rindex, data, dlen);
return 0;
}
static void vmbus_dump_ring(FILE *f, const char *id, const struct vmbus_br *br)
{
const struct vmbus_bufring *vbr = br->vbr;
struct vmbus_chanpkt_hdr pkt;
fprintf(f, "%s windex=%u rindex=%u mask=%u pending=%u feature=%#x\n",
id, vbr->windex, vbr->rindex, vbr->imask,
vbr->pending_send, vbr->feature_bits.value);
fprintf(f, " size=%u avail write=%u read=%u\n",
br->dsize, vmbus_br_availwrite(br, vbr->windex),
vmbus_br_availread(br));
if (vmbus_rxbr_peek(br, &pkt, sizeof(pkt)) == 0)
fprintf(f, " pkt type %#x len %u flags %#x xactid %#"PRIx64"\n",
pkt.type,
pkt.tlen << VMBUS_CHANPKT_SIZE_SHIFT,
pkt.flags, pkt.xactid);
}