C++ idr_get_new函数代码示例

static int add_client_resource(struct client *client,
			       struct client_resource *resource, gfp_t gfp_mask)
{
	unsigned long flags;
	int ret;

 retry:
	if (idr_pre_get(&client->resource_idr, gfp_mask) == 0)
		return -ENOMEM;

	spin_lock_irqsave(&client->lock, flags);
	if (client->in_shutdown)
		ret = -ECANCELED;
	else
		ret = idr_get_new(&client->resource_idr, resource,
				  &resource->handle);
	if (ret >= 0) {
		client_get(client);
		if (resource->release == release_iso_resource)
			schedule_iso_resource(container_of(resource,
						struct iso_resource, resource));
	}
	spin_unlock_irqrestore(&client->lock, flags);

	if (ret == -EAGAIN)
		goto retry;

	return ret < 0 ? ret : 0;
}

int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
{
	struct device *cd;
	int err = 0;

idr_try_again:
	if (!idr_pre_get(&dca_idr, GFP_KERNEL))
		return -ENOMEM;
	spin_lock(&dca_idr_lock);
	err = idr_get_new(&dca_idr, dca, &dca->id);
	spin_unlock(&dca_idr_lock);
	switch (err) {
	case 0:
		break;
	case -EAGAIN:
		goto idr_try_again;
	default:
		return err;
	}

	cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
	if (IS_ERR(cd)) {
		spin_lock(&dca_idr_lock);
		idr_remove(&dca_idr, dca->id);
		spin_unlock(&dca_idr_lock);
		return PTR_ERR(cd);
	}
	dca->cd = cd;
	return 0;
}

/**
 * hwmon_device_register - register w/ hwmon
 * @dev: the device to register
 *
 * hwmon_device_unregister() must be called when the device is no
 * longer needed.
 *
 * Returns the pointer to the new device.
 */
struct device *hwmon_device_register(struct device *dev)
{
	struct device *hwdev;
	int id, err;

again:
	if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
		return ERR_PTR(-ENOMEM);

	spin_lock(&idr_lock);
	err = idr_get_new(&hwmon_idr, NULL, &id);
	spin_unlock(&idr_lock);

	if (unlikely(err == -EAGAIN))
		goto again;
	else if (unlikely(err))
		return ERR_PTR(err);

	id = id & MAX_ID_MASK;
	hwdev = device_create(hwmon_class, dev, MKDEV(0, 0), NULL,
			      HWMON_ID_FORMAT, id);

	if (IS_ERR(hwdev)) {
		spin_lock(&idr_lock);
		idr_remove(&hwmon_idr, id);
		spin_unlock(&idr_lock);
	}

	return hwdev;
}

static int next_free_minor(struct mapped_device *md, int *minor)
{
	int r, m;

	r = idr_pre_get(&_minor_idr, GFP_KERNEL);
	if (!r)
		return -ENOMEM;

	spin_lock(&_minor_lock);

	r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
	if (r) {
		goto out;
	}

	if (m >= (1 << MINORBITS)) {
		idr_remove(&_minor_idr, m);
		r = -ENOSPC;
		goto out;
	}

	*minor = m;

out:
	spin_unlock(&_minor_lock);
	return r;
}

static int new_bat_id(void)
{
	int ret;

	while (1) {
		int id;

		ret = idr_pre_get(&bat_idr, GFP_KERNEL);
		if (ret == 0)
			return -ENOMEM;

		mutex_lock(&bat_idr_lock);
		ret = idr_get_new(&bat_idr, NULL, &id);
		mutex_unlock(&bat_idr_lock);

		if (ret == 0) {
			ret = id & MAX_ID_MASK;
			break;
		} else if (ret == -EAGAIN) {
			continue;
		} else {
			break;
		}
	}

	return ret;
}

static int next_free_minor(struct mapped_device *md, unsigned int *minor)
{
	int r;
	unsigned int m;

	down(&_minor_lock);

	r = idr_pre_get(&_minor_idr, GFP_KERNEL);
	if (!r) {
		r = -ENOMEM;
		goto out;
	}

	r = idr_get_new(&_minor_idr, md, &m);
	if (r) {
		goto out;
	}

	if (m >= (1 << MINORBITS)) {
		idr_remove(&_minor_idr, m);
		r = -ENOSPC;
		goto out;
	}

	*minor = m;

out:
	up(&_minor_lock);
	return r;
}

static int uio_get_minor(struct uio_device *idev)
{
	int retval = -ENOMEM;
	int id;

	mutex_lock(&minor_lock);
	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
		goto exit;

	retval = idr_get_new(&uio_idr, idev, &id);
	if (retval < 0) {
		if (retval == -EAGAIN)
			retval = -ENOMEM;
		goto exit;
	}
	if (id < UIO_MAX_DEVICES) {
		idev->minor = id;
	} else {
		dev_err(idev->dev, "too many uio devices\n");
		retval = -EINVAL;
		idr_remove(&uio_idr, id);
	}
exit:
	mutex_unlock(&minor_lock);
	return retval;
}

int v9fs_get_idpool(struct v9fs_idpool *p)
{
	int i = 0;
	int error;

retry:
	if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
		return 0;

	if (down_interruptible(&p->lock) == -EINTR) {
		eprintk(KERN_WARNING, "Interrupted while locking\n");
		return -1;
	}

	/* no need to store exactly p, we just need something non-null */
	error = idr_get_new(&p->pool, p, &i);
	up(&p->lock);

	if (error == -EAGAIN)
		goto retry;
	else if (error)
		return -1;

	return i;
}

/**
 * blk_alloc_devt - allocate a dev_t for a partition
 * @part: partition to allocate dev_t for
 * @devt: out parameter for resulting dev_t
 *
 * Allocate a dev_t for block device.
 *
 * RETURNS:
 * 0 on success, allocated dev_t is returned in *@devt.  -errno on
 * failure.
 *
 * CONTEXT:
 * Might sleep.
 */
int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
{
	struct gendisk *disk = part_to_disk(part);
	int idx, rc;

	/* in consecutive minor range? */
	if (part->partno < disk->minors) {
		*devt = MKDEV(disk->major, disk->first_minor + part->partno);
		return 0;
	}

	/* allocate ext devt */
	do {
		if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
			return -ENOMEM;
		rc = idr_get_new(&ext_devt_idr, part, &idx);
	} while (rc == -EAGAIN);

	if (rc)
		return rc;

	if (idx > MAX_EXT_DEVT) {
		idr_remove(&ext_devt_idr, idx);
		return -EBUSY;
	}

	*devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
	return 0;
}

int pps_register_cdev(struct pps_device *pps)
{
	int err;
	dev_t devt;

	mutex_lock(&pps_idr_lock);
	
	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
		mutex_unlock(&pps_idr_lock);
		return -ENOMEM;
	}

	err = idr_get_new(&pps_idr, pps, &pps->id);
	mutex_unlock(&pps_idr_lock);

	if (err < 0)
		return err;

	pps->id &= MAX_ID_MASK;
	if (pps->id >= PPS_MAX_SOURCES) {
		pr_err("%s: too many PPS sources in the system\n",
					pps->info.name);
		err = -EBUSY;
		goto free_idr;
	}

	devt = MKDEV(MAJOR(pps_devt), pps->id);

	cdev_init(&pps->cdev, &pps_cdev_fops);
	pps->cdev.owner = pps->info.owner;

	err = cdev_add(&pps->cdev, devt, 1);
	if (err) {
		pr_err("%s: failed to add char device %d:%d\n",
				pps->info.name, MAJOR(pps_devt), pps->id);
		goto free_idr;
	}
	pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
							"pps%d", pps->id);
	if (IS_ERR(pps->dev))
		goto del_cdev;

	pps->dev->release = pps_device_destruct;

	pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
			MAJOR(pps_devt), pps->id);

	return 0;

del_cdev:
	cdev_del(&pps->cdev);

free_idr:
	mutex_lock(&pps_idr_lock);
	idr_remove(&pps_idr, pps->id);
	mutex_unlock(&pps_idr_lock);

	return err;
}

static int bq27x00_battery_probe(struct i2c_client *client,
				 const struct i2c_device_id *id)
{
	char *name;
	struct bq27x00_device_info *di;
	int num;
	int retval = 0;

	/* Get new ID for the new battery device */
	retval = idr_pre_get(&battery_id, GFP_KERNEL);
	if (retval == 0)
		return -ENOMEM;
	mutex_lock(&battery_mutex);
	retval = idr_get_new(&battery_id, client, &num);
	mutex_unlock(&battery_mutex);
	if (retval < 0)
		return retval;

	name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
	if (!name) {
		dev_err(&client->dev, "failed to allocate device name\n");
		retval = -ENOMEM;
		goto batt_failed_1;
	}

	di = kzalloc(sizeof(*di), GFP_KERNEL);
	if (!di) {
		dev_err(&client->dev, "failed to allocate device info data\n");
		retval = -ENOMEM;
		goto batt_failed_2;
	}

	di->id = num;
	di->dev = &client->dev;
	di->chip = id->driver_data;
	di->bat.name = name;
	di->bus.read = &bq27x00_read_i2c;

	if (bq27x00_powersupply_init(di))
		goto batt_failed_3;

	i2c_set_clientdata(client, di);

	return 0;

batt_failed_3:
	kfree(di);
batt_failed_2:
	kfree(name);
batt_failed_1:
	mutex_lock(&battery_mutex);
	idr_remove(&battery_id, num);
	mutex_unlock(&battery_mutex);

	return retval;
}

uint32_t ctdb_reqid_new(struct ctdb_context *ctdb, void *state)
{
	int id = idr_get_new_above(ctdb->idr, state, ctdb->lastid+1, INT_MAX);
	if (id < 0) {
		DEBUG(DEBUG_DEBUG, ("Reqid wrap!\n"));
		id = idr_get_new(ctdb->idr, state, INT_MAX);
	}
	ctdb->lastid = id;
	return id;
}

static int ocrdma_get_instance(void)
{
	int instance = 0;

	/* Assign an unused number */
	if (!idr_pre_get(&ocrdma_dev_id, GFP_KERNEL))
		return -1;
	if (idr_get_new(&ocrdma_dev_id, NULL, &instance))
		return -1;
	return instance;
}

/*
  make a remote ctdb call - async send. Called in daemon context.

  This constructs a ctdb_call request and queues it for processing. 
  This call never blocks.
*/
struct ctdb_call_state *ctdb_daemon_call_send_remote(struct ctdb_db_context *ctdb_db, 
						     struct ctdb_call *call, 
						     struct ctdb_ltdb_header *header)
{
	uint32_t len;
	struct ctdb_call_state *state;
	struct ctdb_context *ctdb = ctdb_db->ctdb;

	state = talloc_zero(ctdb_db, struct ctdb_call_state);
	CTDB_NO_MEMORY_NULL(ctdb, state);

	len = offsetof(struct ctdb_req_call, data) + call->key.dsize + call->call_data.dsize;
	state->c = ctdb->methods->allocate_pkt(state, len);
	CTDB_NO_MEMORY_NULL(ctdb, state->c);
	talloc_set_name_const(state->c, "req_call packet");

	state->c->hdr.length    = len;
	state->c->hdr.ctdb_magic = CTDB_MAGIC;
	state->c->hdr.ctdb_version = CTDB_VERSION;
	state->c->hdr.operation = CTDB_REQ_CALL;
	state->c->hdr.destnode  = header->dmaster;
	state->c->hdr.srcnode   = ctdb->vnn;
	/* this limits us to 16k outstanding messages - not unreasonable */
	state->c->hdr.reqid     = idr_get_new(ctdb->idr, state, 0xFFFF);
	state->c->flags         = call->flags;
	state->c->db_id         = ctdb_db->db_id;
	state->c->callid        = call->call_id;
	state->c->keylen        = call->key.dsize;
	state->c->calldatalen   = call->call_data.dsize;
	memcpy(&state->c->data[0], call->key.dptr, call->key.dsize);
	memcpy(&state->c->data[call->key.dsize], 
	       call->call_data.dptr, call->call_data.dsize);
	state->call                = *call;
	state->call.call_data.dptr = &state->c->data[call->key.dsize];
	state->call.key.dptr       = &state->c->data[0];

	state->node   = ctdb->nodes[header->dmaster];
	state->state  = CTDB_CALL_WAIT;
	state->header = *header;
	state->ctdb_db = ctdb_db;

	talloc_set_destructor(state, ctdb_call_destructor);

	ctdb_queue_packet(ctdb, &state->c->hdr);

	event_add_timed(ctdb->ev, state, timeval_current_ofs(CTDB_REQ_TIMEOUT, 0), 
			ctdb_call_timeout, state);
	return state;
}

/*
 * Get a unique NFSv4.0 callback identifier which will be used
 * by the V4.0 callback service to lookup the nfs_client struct
 */
static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
{
	int ret = 0;
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->rpc_ops->version != 4 || minorversion != 0)
		return ret;
retry:
	if (!idr_pre_get(&nn->cb_ident_idr, GFP_KERNEL))
		return -ENOMEM;
	spin_lock(&nn->nfs_client_lock);
	ret = idr_get_new(&nn->cb_ident_idr, clp, &clp->cl_cb_ident);
	spin_unlock(&nn->nfs_client_lock);
	if (ret == -EAGAIN)
		goto retry;
	return ret;
}