C++ disk_to_dev函数代码示例

int blk_register_queue(struct gendisk *disk)
{
	int ret;
	struct device *dev = disk_to_dev(disk);

	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return -ENXIO;

	ret = blk_trace_init_sysfs(dev);
	if (ret)
		return ret;

	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
	if (ret < 0)
		return ret;

	kobject_uevent(&q->kobj, KOBJ_ADD);

	if (!q->request_fn)
		return 0;

	ret = elv_register_queue(q);
	if (ret) {
		kobject_uevent(&q->kobj, KOBJ_REMOVE);
		kobject_del(&q->kobj);
		blk_trace_remove_sysfs(disk_to_dev(disk));
		return ret;
	}

	return 0;
}

/* always call with the tx_lock held */
static int nbd_send_req(struct nbd_device *nbd, struct request *req)
{
	int result, flags;
	struct nbd_request request;
	unsigned long size = blk_rq_bytes(req);
	u32 type;

	if (req->cmd_type == REQ_TYPE_DRV_PRIV)
		type = NBD_CMD_DISC;
	else if (req->cmd_flags & REQ_DISCARD)
		type = NBD_CMD_TRIM;
	else if (req->cmd_flags & REQ_FLUSH)
		type = NBD_CMD_FLUSH;
	else if (rq_data_dir(req) == WRITE)
		type = NBD_CMD_WRITE;
	else
		type = NBD_CMD_READ;

	memset(&request, 0, sizeof(request));
	request.magic = htonl(NBD_REQUEST_MAGIC);
	request.type = htonl(type);
	if (type != NBD_CMD_FLUSH && type != NBD_CMD_DISC) {
		request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
		request.len = htonl(size);
	}
	memcpy(request.handle, &req, sizeof(req));

	dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%[email protected]%llu,%uB)\n",
		req, nbdcmd_to_ascii(type),
		(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
	result = sock_xmit(nbd, 1, &request, sizeof(request),
			(type == NBD_CMD_WRITE) ? MSG_MORE : 0);
	if (result <= 0) {
		dev_err(disk_to_dev(nbd->disk),
			"Send control failed (result %d)\n", result);
		return -EIO;
	}

	if (type == NBD_CMD_WRITE) {
		struct req_iterator iter;
		struct bio_vec bvec;
		/*
		 * we are really probing at internals to determine
		 * whether to set MSG_MORE or not...
		 */
		rq_for_each_segment(bvec, req, iter) {
			flags = 0;
			if (!rq_iter_last(bvec, iter))
				flags = MSG_MORE;
			dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
				req, bvec.bv_len);
			result = sock_send_bvec(nbd, &bvec, flags);
			if (result <= 0) {
				dev_err(disk_to_dev(nbd->disk),
					"Send data failed (result %d)\n",
					result);
				return -EIO;
			}
		}
	}

/* always call with the tx_lock held */
static int nbd_send_req(struct nbd_device *nbd, struct request *req)
{
	int result, flags;
	struct nbd_request request;
	unsigned long size = blk_rq_bytes(req);

	request.magic = htonl(NBD_REQUEST_MAGIC);
	request.type = htonl(nbd_cmd(req));

	if (nbd_cmd(req) == NBD_CMD_FLUSH) {
		/* Other values are reserved for FLUSH requests.  */
		request.from = 0;
		request.len = 0;
	} else {
		request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
		request.len = htonl(size);
	}
	memcpy(request.handle, &req, sizeof(req));

	dprintk(DBG_TX, "%s: request %p: sending control (%[email protected]%llu,%uB)\n",
			nbd->disk->disk_name, req,
			nbdcmd_to_ascii(nbd_cmd(req)),
			(unsigned long long)blk_rq_pos(req) << 9,
			blk_rq_bytes(req));
	result = sock_xmit(nbd, 1, &request, sizeof(request),
			(nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
	if (result <= 0) {
		dev_err(disk_to_dev(nbd->disk),
			"Send control failed (result %d)\n", result);
		goto error_out;
	}

	if (nbd_cmd(req) == NBD_CMD_WRITE) {
		struct req_iterator iter;
		struct bio_vec *bvec;
		/*
		 * we are really probing at internals to determine
		 * whether to set MSG_MORE or not...
		 */
		rq_for_each_segment(bvec, req, iter) {
			flags = 0;
			if (!rq_iter_last(req, iter))
				flags = MSG_MORE;
			dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
					nbd->disk->disk_name, req, bvec->bv_len);
			result = sock_send_bvec(nbd, bvec, flags);
			if (result <= 0) {
				dev_err(disk_to_dev(nbd->disk),
					"Send data failed (result %d)\n",
					result);
				goto error_out;
			}
		}
	}

void blk_unregister_queue(struct gendisk *disk)
{
	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return;

	if (q->request_fn)
		elv_unregister_queue(q);

	kobject_uevent(&q->kobj, KOBJ_REMOVE);
	kobject_del(&q->kobj);
	blk_trace_remove_sysfs(disk_to_dev(disk));
	kobject_put(&disk_to_dev(disk)->kobj);
}

void register_disk(struct gendisk *disk)
{
	struct device *ddev = disk_to_dev(disk);
	struct block_device *bdev;
	struct disk_part_iter piter;
	struct hd_struct *part;
	int err;
#ifdef MY_ABC_HERE
	int error;
#endif

	ddev->parent = disk->driverfs_dev;

	dev_set_name(ddev, disk->disk_name);

	/* delay uevents, until we scanned partition table */
	dev_set_uevent_suppress(ddev, 1);

	if (device_add(ddev))
		return;
#ifdef MY_ABC_HERE
	if (ddev->parent) {
		char *class_name;
		class_name = make_class_name(ddev->class->name,
						&ddev->kobj);
		if (class_name) {
			error = sysfs_create_link(&ddev->parent->kobj,
						&ddev->kobj, class_name);
		}
		kfree(class_name);
	}

int blk_register_queue(struct gendisk *disk)
{
	int ret;

	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return -ENXIO;

	if (!q->request_fn)
		return 0;

	ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
			  "%s", "queue");
	if (ret < 0)
		return ret;

	kobject_uevent(&q->kobj, KOBJ_ADD);

	ret = elv_register_queue(q);
	if (ret) {
		kobject_uevent(&q->kobj, KOBJ_REMOVE);
		kobject_del(&q->kobj);
		return ret;
	}

	return 0;
}

int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
{
	struct request_queue *q;
	struct dm_target *immutable_tgt;
	int err;

	if (!dm_table_all_blk_mq_devices(t)) {
		DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
		return -EINVAL;
	}

	md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
	if (!md->tag_set)
		return -ENOMEM;

	md->tag_set->ops = &dm_mq_ops;
	md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
	md->tag_set->numa_node = md->numa_node_id;
	md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
	md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
	md->tag_set->driver_data = md;

	md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
	immutable_tgt = dm_table_get_immutable_target(t);
	if (immutable_tgt && immutable_tgt->per_io_data_size) {
		/* any target-specific per-io data is immediately after the tio */
		md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
		md->init_tio_pdu = true;
	}

	err = blk_mq_alloc_tag_set(md->tag_set);
	if (err)
		goto out_kfree_tag_set;

	q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
	if (IS_ERR(q)) {
		err = PTR_ERR(q);
		goto out_tag_set;
	}
	dm_init_md_queue(md);

	/* backfill 'mq' sysfs registration normally done in blk_register_queue */
	err = blk_mq_register_dev(disk_to_dev(md->disk), q);
	if (err)
		goto out_cleanup_queue;

	return 0;

out_cleanup_queue:
	blk_cleanup_queue(q);
out_tag_set:
	blk_mq_free_tag_set(md->tag_set);
out_kfree_tag_set:
	kfree(md->tag_set);

	return err;
}

/*
 *  Send or receive packet.
 */
static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
		int msg_flags)
{
	struct socket *sock = nbd->sock;
	int result;
	struct msghdr msg;
	struct kvec iov;
	sigset_t blocked, oldset;
	unsigned long pflags = current->flags;

	if (unlikely(!sock)) {
		dev_err(disk_to_dev(nbd->disk),
			"Attempted %s on closed socket in sock_xmit\n",
			(send ? "send" : "recv"));
		return -EINVAL;
	}

	/* Allow interception of SIGKILL only
	 * Don't allow other signals to interrupt the transmission */
	siginitsetinv(&blocked, sigmask(SIGKILL));
	sigprocmask(SIG_SETMASK, &blocked, &oldset);

	current->flags |= PF_MEMALLOC;
	do {
		sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
		iov.iov_base = buf;
		iov.iov_len = size;
		msg.msg_name = NULL;
		msg.msg_namelen = 0;
		msg.msg_control = NULL;
		msg.msg_controllen = 0;
		msg.msg_flags = msg_flags | MSG_NOSIGNAL;

		if (send)
			result = kernel_sendmsg(sock, &msg, &iov, 1, size);
		else
			result = kernel_recvmsg(sock, &msg, &iov, 1, size,
						msg.msg_flags);

		if (result <= 0) {
			if (result == 0)
				result = -EPIPE; /* short read */
			break;
		}
		size -= result;
		buf += result;
	} while (size > 0);

	sigprocmask(SIG_SETMASK, &oldset, NULL);
	tsk_restore_flags(current, pflags, PF_MEMALLOC);

	if (!send && nbd->xmit_timeout)
		mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);

	return result;
}

/*
 * Forcibly shutdown the socket causing all listeners to error
 */
static void sock_shutdown(struct nbd_device *nbd)
{
	if (!nbd->sock)
		return;

	dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
	kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
	nbd->sock = NULL;
	del_timer_sync(&nbd->timeout_timer);
}

int blk_register_queue(struct gendisk *disk)
{
	add_my_disk(disk);
	int ret;
	struct device *dev = disk_to_dev(disk);
	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return -ENXIO;

	/*
	 * SCSI probing may synchronously create and destroy a lot of
	 * request_queues for non-existent devices.  Shutting down a fully
	 * functional queue takes measureable wallclock time as RCU grace
	 * periods are involved.  To avoid excessive latency in these
	 * cases, a request_queue starts out in a degraded mode which is
	 * faster to shut down and is made fully functional here as
	 * request_queues for non-existent devices never get registered.
	 */
	if (!blk_queue_init_done(q)) {
		queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
		blk_queue_bypass_end(q);
		if (q->mq_ops)
			blk_mq_finish_init(q);
	}

	ret = blk_trace_init_sysfs(dev);
	if (ret)
		return ret;

	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
	if (ret < 0) {
		blk_trace_remove_sysfs(dev);
		return ret;
	}

	kobject_uevent(&q->kobj, KOBJ_ADD);

	if (q->mq_ops)
		blk_mq_register_disk(disk);

	if (!q->request_fn)
		return 0;

	ret = elv_register_queue(q);
	if (ret) {
		kobject_uevent(&q->kobj, KOBJ_REMOVE);
		kobject_del(&q->kobj);
		blk_trace_remove_sysfs(dev);
		kobject_put(&dev->kobj);
		return ret;
	}

	return 0;
}

/*
 * Forcibly shutdown the socket causing all listeners to error
 */
static void sock_shutdown(struct nbd_device *nbd, int lock)
{
	if (lock)
		mutex_lock(&nbd->tx_lock);
	if (nbd->sock) {
		dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
		kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
		nbd->sock = NULL;
	}
	if (lock)
		mutex_unlock(&nbd->tx_lock);
}

static struct zram *dev_to_zram(struct device *dev)
{
	int i;
	struct zram *zram = NULL;

	for (i = 0; i < zram_get_num_devices(); i++) {
		zram = &zram_devices[i];
		if (disk_to_dev(zram->disk) == dev)
			break;
	}

	return zram;
}

static struct xzram *dev_to_xzram(struct device *dev)
{
    int i;
    struct xzram *xzram = NULL;

    for (i = 0; i < xzram_num_devices; i++) {
        xzram = &xzram_devices[i];
        if (disk_to_dev(xzram->disk) == dev)
            break;
    }

    return xzram;
}

struct hd_struct *add_partition(struct gendisk *disk, int partno,
				sector_t start, sector_t len, int flags,
				struct partition_meta_info *info)
{
	struct hd_struct *p;
	dev_t devt = MKDEV(0, 0);
	struct device *ddev = disk_to_dev(disk);
	struct device *pdev;
	struct disk_part_tbl *ptbl;
	const char *dname;
	int err;

	err = disk_expand_part_tbl(disk, partno);
	if (err)
		return ERR_PTR(err);
	ptbl = disk->part_tbl;

	if (ptbl->part[partno])
		return ERR_PTR(-EBUSY);

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (!p)
		return ERR_PTR(-EBUSY);

	if (!init_part_stats(p)) {
		err = -ENOMEM;
		goto out_free;
	}

	seqcount_init(&p->nr_sects_seq);
	pdev = part_to_dev(p);

	p->start_sect = start;
	p->alignment_offset =
		queue_limit_alignment_offset(&disk->queue->limits, start);
	p->discard_alignment =
		queue_limit_discard_alignment(&disk->queue->limits, start);
	p->nr_sects = len;
	p->partno = partno;
	p->policy = get_disk_ro(disk);

	if (info) {
		struct partition_meta_info *pinfo = alloc_part_info(disk);
		if (!pinfo)
			goto out_free_stats;
		memcpy(pinfo, info, sizeof(*info));
		p->info = pinfo;
	}

	dname = dev_name(ddev);
	if (isdigit(dname[strlen(dname) - 1]

/*
 *  Send or receive packet.
 */
static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
		int msg_flags)
{
	struct socket *sock = nbd->sock;
	int result;
	struct msghdr msg;
	struct kvec iov;
	unsigned long pflags = current->flags;

	if (unlikely(!sock)) {
		dev_err(disk_to_dev(nbd->disk),
			"Attempted %s on closed socket in sock_xmit\n",
			(send ? "send" : "recv"));
		return -EINVAL;
	}

	current->flags |= PF_MEMALLOC;
	do {
		sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
		iov.iov_base = buf;
		iov.iov_len = size;
		msg.msg_name = NULL;
		msg.msg_namelen = 0;
		msg.msg_control = NULL;
		msg.msg_controllen = 0;
		msg.msg_flags = msg_flags | MSG_NOSIGNAL;

		if (send)
			result = kernel_sendmsg(sock, &msg, &iov, 1, size);
		else
			result = kernel_recvmsg(sock, &msg, &iov, 1, size,
						msg.msg_flags);

		if (result <= 0) {
			if (result == 0)
				result = -EPIPE; /* short read */
			break;
		}
		size -= result;
		buf += result;
	} while (size > 0);

	tsk_restore_flags(current, pflags, PF_MEMALLOC);

	if (!send && nbd->xmit_timeout)
		mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);

	return result;
}