void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, int64_t speed, BlockCompletionFunc *cb, void *opaque, Error **errp) { BlockJob *job; if (bs->job) { error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs)); return NULL; } bdrv_ref(bs); job = g_malloc0(driver->instance_size); error_setg(&job->blocker, "block device is in use by block job: %s", BlockJobType_lookup[driver->job_type]); bdrv_op_block_all(bs, job->blocker); bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker); job->driver = driver; job->bs = bs; job->cb = cb; job->opaque = opaque; job->busy = true; bs->job = job; /* Only set speed when necessary to avoid NotSupported error */ if (speed != 0) { Error *local_err = NULL; block_job_set_speed(job, speed, &local_err); if (local_err) { bs->job = NULL; bdrv_op_unblock_all(bs, job->blocker); error_free(job->blocker); g_free(job); error_propagate(errp, local_err); return NULL; } } return job; }
static void handle_notify(EventNotifier *e) { VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane, host_notifier); VirtIOBlock *vblk = VIRTIO_BLK(s->vdev); event_notifier_test_and_clear(&s->host_notifier); bdrv_io_plug(s->blk->conf.bs); for (;;) { MultiReqBuffer mrb = { .num_writes = 0, }; int ret; /* Disable guest->host notifies to avoid unnecessary vmexits */ vring_disable_notification(s->vdev, &s->vring); for (;;) { VirtIOBlockReq *req = virtio_blk_alloc_request(vblk); ret = vring_pop(s->vdev, &s->vring, &req->elem); if (ret < 0) { virtio_blk_free_request(req); break; /* no more requests */ } trace_virtio_blk_data_plane_process_request(s, req->elem.out_num, req->elem.in_num, req->elem.index); virtio_blk_handle_request(req, &mrb); } virtio_submit_multiwrite(s->blk->conf.bs, &mrb); if (likely(ret == -EAGAIN)) { /* vring emptied */ /* Re-enable guest->host notifies and stop processing the vring. * But if the guest has snuck in more descriptors, keep processing. */ if (vring_enable_notification(s->vdev, &s->vring)) { break; } } else { /* fatal error */ break; } } bdrv_io_unplug(s->blk->conf.bs); } /* Context: QEMU global mutex held */ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk, VirtIOBlockDataPlane **dataplane, Error **errp) { VirtIOBlockDataPlane *s; Error *local_err = NULL; BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); *dataplane = NULL; if (!blk->data_plane && !blk->iothread) { return; } /* Don't try if transport does not support notifiers. */ if (!k->set_guest_notifiers || !k->set_host_notifier) { error_setg(errp, "device is incompatible with x-data-plane " "(transport does not support notifiers)"); return; } /* If dataplane is (re-)enabled while the guest is running there could be * block jobs that can conflict. */ if (bdrv_op_is_blocked(blk->conf.bs, BLOCK_OP_TYPE_DATAPLANE, &local_err)) { error_setg(errp, "cannot start dataplane thread: %s", error_get_pretty(local_err)); error_free(local_err); return; } s = g_new0(VirtIOBlockDataPlane, 1); s->vdev = vdev; s->blk = blk; if (blk->iothread) { s->iothread = blk->iothread; object_ref(OBJECT(s->iothread)); } else { /* Create per-device IOThread if none specified. This is for * x-data-plane option compatibility. If x-data-plane is removed we * can drop this. */ object_initialize(&s->internal_iothread_obj, sizeof(s->internal_iothread_obj), TYPE_IOTHREAD); user_creatable_complete(OBJECT(&s->internal_iothread_obj), &error_abort); s->iothread = &s->internal_iothread_obj; } s->ctx = iothread_get_aio_context(s->iothread); s->bh = aio_bh_new(s->ctx, notify_guest_bh, s); error_setg(&s->blocker, "block device is in use by data plane"); bdrv_op_block_all(blk->conf.bs, s->blocker); bdrv_op_unblock(blk->conf.bs, BLOCK_OP_TYPE_RESIZE, s->blocker); bdrv_op_unblock(blk->conf.bs, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker); *dataplane = s; }