/* * NOTE: * We assume (dlen + skip) == sizeof(channel packet). */ int vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip) { uint32_t rindex, br_dsize = rbr->rxbr_dsize; KASSERT(dlen + skip > 0, ("invalid dlen %d, offset %u", dlen, skip)); mtx_lock_spin(&rbr->rxbr_lock); if (vmbus_rxbr_avail(rbr) < dlen + skip + sizeof(uint64_t)) { mtx_unlock_spin(&rbr->rxbr_lock); return (EAGAIN); } /* * Copy channel packet from RX bufring. */ rindex = VMBUS_BR_IDXINC(rbr->rxbr_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. */ __compiler_membar(); rbr->rxbr_rindex = rindex; mtx_unlock_spin(&rbr->rxbr_lock); return (0); }
/* * 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; }
int vmbus_rxbr_peek(struct vmbus_rxbr *rbr, void *data, int dlen) { mtx_lock_spin(&rbr->rxbr_lock); /* * The requested data and the 64bits channel packet * offset should be there at least. */ if (vmbus_rxbr_avail(rbr) < dlen + sizeof(uint64_t)) { mtx_unlock_spin(&rbr->rxbr_lock); return (EAGAIN); } vmbus_rxbr_copyfrom(rbr, rbr->rxbr_rindex, data, dlen); mtx_unlock_spin(&rbr->rxbr_lock); return (0); }