pktcdvd.c

Linux块设备驱动源码

	mempool_free(psd, psd_pool);
	pkt_bio_finished(pd);
	return 0;
}

static int pkt_make_request(request_queue_t *q, struct bio *bio)
{
	struct pktcdvd_device *pd;
	char b[BDEVNAME_SIZE];
	sector_t zone;
	struct packet_data *pkt;
	int was_empty, blocked_bio;
	struct pkt_rb_node *node;

	pd = q->queuedata;
	if (!pd) {
		printk("pktcdvd: %s incorrect request queue\n", bdevname(bio->bi_bdev, b));
		goto end_io;
	}

	/*
	 * Clone READ bios so we can have our own bi_end_io callback.
	 */
	if (bio_data_dir(bio) == READ) {
		struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);
		struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);

		psd->pd = pd;
		psd->bio = bio;
		cloned_bio->bi_bdev = pd->bdev;
		cloned_bio->bi_private = psd;
		cloned_bio->bi_end_io = pkt_end_io_read_cloned;
		pd->stats.secs_r += bio->bi_size >> 9;
		pkt_queue_bio(pd, cloned_bio);
		return 0;
	}

	if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
		printk("pktcdvd: WRITE for ro device %s (%llu)\n",
			pd->name, (unsigned long long)bio->bi_sector);
		goto end_io;
	}

	if (!bio->bi_size || (bio->bi_size % CD_FRAMESIZE)) {
		printk("pktcdvd: wrong bio size\n");
		goto end_io;
	}

	blk_queue_bounce(q, &bio);

	zone = ZONE(bio->bi_sector, pd);
	VPRINTK("pkt_make_request: start = %6llx stop = %6llx\n",
		(unsigned long long)bio->bi_sector,
		(unsigned long long)(bio->bi_sector + bio_sectors(bio)));

	/* Check if we have to split the bio */
	{
		struct bio_pair *bp;
		sector_t last_zone;
		int first_sectors;

		last_zone = ZONE(bio->bi_sector + bio_sectors(bio) - 1, pd);
		if (last_zone != zone) {
			BUG_ON(last_zone != zone + pd->settings.size);
			first_sectors = last_zone - bio->bi_sector;
			bp = bio_split(bio, bio_split_pool, first_sectors);
			BUG_ON(!bp);
			pkt_make_request(q, &bp->bio1);
			pkt_make_request(q, &bp->bio2);
			bio_pair_release(bp);
			return 0;
		}
	}

	/*
	 * If we find a matching packet in state WAITING or READ_WAIT, we can
	 * just append this bio to that packet.
	 */
	spin_lock(&pd->cdrw.active_list_lock);
	blocked_bio = 0;
	list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
		if (pkt->sector == zone) {
			spin_lock(&pkt->lock);
			if ((pkt->state == PACKET_WAITING_STATE) ||
			    (pkt->state == PACKET_READ_WAIT_STATE)) {
				pkt_add_list_last(bio, &pkt->orig_bios,
						  &pkt->orig_bios_tail);
				pkt->write_size += bio->bi_size / CD_FRAMESIZE;
				if ((pkt->write_size >= pkt->frames) &&
				    (pkt->state == PACKET_WAITING_STATE)) {
					atomic_inc(&pkt->run_sm);
					wake_up(&pd->wqueue);
				}
				spin_unlock(&pkt->lock);
				spin_unlock(&pd->cdrw.active_list_lock);
				return 0;
			} else {
				blocked_bio = 1;
			}
			spin_unlock(&pkt->lock);
		}
	}
	spin_unlock(&pd->cdrw.active_list_lock);

	/*
	 * No matching packet found. Store the bio in the work queue.
	 */
	node = mempool_alloc(pd->rb_pool, GFP_NOIO);
	node->bio = bio;
	spin_lock(&pd->lock);
	BUG_ON(pd->bio_queue_size < 0);
	was_empty = (pd->bio_queue_size == 0);
	pkt_rbtree_insert(pd, node);
	spin_unlock(&pd->lock);

	/*
	 * Wake up the worker thread.
	 */
	atomic_set(&pd->scan_queue, 1);
	if (was_empty) {
		/* This wake_up is required for correct operation */
		wake_up(&pd->wqueue);
	} else if (!list_empty(&pd->cdrw.pkt_free_list) && !blocked_bio) {
		/*
		 * This wake up is not required for correct operation,
		 * but improves performance in some cases.
		 */
		wake_up(&pd->wqueue);
	}
	return 0;
end_io:
	bio_io_error(bio, bio->bi_size);
	return 0;
}



static int pkt_merge_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *bvec)
{
	struct pktcdvd_device *pd = q->queuedata;
	sector_t zone = ZONE(bio->bi_sector, pd);
	int used = ((bio->bi_sector - zone) << 9) + bio->bi_size;
	int remaining = (pd->settings.size << 9) - used;
	int remaining2;

	/*
	 * A bio <= PAGE_SIZE must be allowed. If it crosses a packet
	 * boundary, pkt_make_request() will split the bio.
	 */
	remaining2 = PAGE_SIZE - bio->bi_size;
	remaining = max(remaining, remaining2);

	BUG_ON(remaining < 0);
	return remaining;
}

static void pkt_init_queue(struct pktcdvd_device *pd)
{
	request_queue_t *q = pd->disk->queue;

	blk_queue_make_request(q, pkt_make_request);
	blk_queue_hardsect_size(q, CD_FRAMESIZE);
	blk_queue_max_sectors(q, PACKET_MAX_SECTORS);
	blk_queue_merge_bvec(q, pkt_merge_bvec);
	q->queuedata = pd;
}

static int pkt_seq_show(struct seq_file *m, void *p)
{
	struct pktcdvd_device *pd = m->private;
	char *msg;
	char bdev_buf[BDEVNAME_SIZE];
	int states[PACKET_NUM_STATES];

	seq_printf(m, "Writer %s mapped to %s:\n", pd->name,
		   bdevname(pd->bdev, bdev_buf));

	seq_printf(m, "\nSettings:\n");
	seq_printf(m, "\tpacket size:\t\t%dkB\n", pd->settings.size / 2);

	if (pd->settings.write_type == 0)
		msg = "Packet";
	else
		msg = "Unknown";
	seq_printf(m, "\twrite type:\t\t%s\n", msg);

	seq_printf(m, "\tpacket type:\t\t%s\n", pd->settings.fp ? "Fixed" : "Variable");
	seq_printf(m, "\tlink loss:\t\t%d\n", pd->settings.link_loss);

	seq_printf(m, "\ttrack mode:\t\t%d\n", pd->settings.track_mode);

	if (pd->settings.block_mode == PACKET_BLOCK_MODE1)
		msg = "Mode 1";
	else if (pd->settings.block_mode == PACKET_BLOCK_MODE2)
		msg = "Mode 2";
	else
		msg = "Unknown";
	seq_printf(m, "\tblock mode:\t\t%s\n", msg);

	seq_printf(m, "\nStatistics:\n");
	seq_printf(m, "\tpackets started:\t%lu\n", pd->stats.pkt_started);
	seq_printf(m, "\tpackets ended:\t\t%lu\n", pd->stats.pkt_ended);
	seq_printf(m, "\twritten:\t\t%lukB\n", pd->stats.secs_w >> 1);
	seq_printf(m, "\tread gather:\t\t%lukB\n", pd->stats.secs_rg >> 1);
	seq_printf(m, "\tread:\t\t\t%lukB\n", pd->stats.secs_r >> 1);

	seq_printf(m, "\nMisc:\n");
	seq_printf(m, "\treference count:\t%d\n", pd->refcnt);
	seq_printf(m, "\tflags:\t\t\t0x%lx\n", pd->flags);
	seq_printf(m, "\tread speed:\t\t%ukB/s\n", pd->read_speed);
	seq_printf(m, "\twrite speed:\t\t%ukB/s\n", pd->write_speed);
	seq_printf(m, "\tstart offset:\t\t%lu\n", pd->offset);
	seq_printf(m, "\tmode page offset:\t%u\n", pd->mode_offset);

	seq_printf(m, "\nQueue state:\n");
	seq_printf(m, "\tbios queued:\t\t%d\n", pd->bio_queue_size);
	seq_printf(m, "\tbios pending:\t\t%d\n", atomic_read(&pd->cdrw.pending_bios));
	seq_printf(m, "\tcurrent sector:\t\t0x%llx\n", (unsigned long long)pd->current_sector);

	pkt_count_states(pd, states);
	seq_printf(m, "\tstate:\t\t\ti:%d ow:%d rw:%d ww:%d rec:%d fin:%d\n",
		   states[0], states[1], states[2], states[3], states[4], states[5]);

	return 0;
}

static int pkt_seq_open(struct inode *inode, struct file *file)
{
	return single_open(file, pkt_seq_show, PDE(inode)->data);
}

static struct file_operations pkt_proc_fops = {
	.open	= pkt_seq_open,
	.read	= seq_read,
	.llseek	= seq_lseek,
	.release = single_release
};

static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
{
	int i;
	int ret = 0;
	char b[BDEVNAME_SIZE];
	struct proc_dir_entry *proc;
	struct block_device *bdev;

	if (pd->pkt_dev == dev) {
		printk("pktcdvd: Recursive setup not allowed\n");
		return -EBUSY;
	}
	for (i = 0; i < MAX_WRITERS; i++) {
		struct pktcdvd_device *pd2 = pkt_devs[i];
		if (!pd2)
			continue;
		if (pd2->bdev->bd_dev == dev) {
			printk("pktcdvd: %s already setup\n", bdevname(pd2->bdev, b));
			return -EBUSY;
		}
		if (pd2->pkt_dev == dev) {
			printk("pktcdvd: Can't chain pktcdvd devices\n");
			return -EBUSY;
		}
	}

	bdev = bdget(dev);
	if (!bdev)
		return -ENOMEM;
	ret = blkdev_get(bdev, FMODE_READ, O_RDONLY | O_NONBLOCK);
	if (ret)
		return ret;

	/* This is safe, since we have a reference from open(). */
	__module_get(THIS_MODULE);

	if (!pkt_grow_pktlist(pd, CONFIG_CDROM_PKTCDVD_BUFFERS)) {
		printk("pktcdvd: not enough memory for buffers\n");
		ret = -ENOMEM;
		goto out_mem;
	}

	pd->bdev = bdev;
	set_blocksize(bdev, CD_FRAMESIZE);

	pkt_init_queue(pd);

	atomic_set(&pd->cdrw.pending_bios, 0);
	pd->cdrw.thread = kthread_run(kcdrwd, pd, "%s", pd->name);
	if (IS_ERR(pd->cdrw.thread)) {
		printk("pktcdvd: can't start kernel thread\n");
		ret = -ENOMEM;
		goto out_thread;
	}

	proc = create_proc_entry(pd->name, 0, pkt_proc);
	if (proc) {
		proc->data = pd;
		proc->proc_fops = &pkt_proc_fops;
	}
	DPRINTK("pktcdvd: writer %s mapped to %s\n", pd->name, bdevname(bdev, b));
	return 0;

out_thread:
	pkt_shrink_pktlist(pd);
out_mem:
	blkdev_put(bdev);
	/* This is safe: open() is still holding a reference. */
	module_put(THIS_MODULE);
	return ret;
}

static int pkt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	struct pktcdvd_device *pd = inode->i_bdev->bd_disk->private_data;

	VPRINTK("pkt_ioctl: cmd %x, dev %d:%d\n", cmd, imajor(inode), iminor(inode));

	switch (cmd) {
	/*
	 * forward selected CDROM ioctls to CD-ROM, for UDF
	 */
	case CDROMMULTISESSION:
	case CDROMREADTOCENTRY:
	case CDROM_LAST_WRITTEN:
	case CDROM_SEND_PACKET:
	case SCSI_IOCTL_SEND_COMMAND:
		return blkdev_ioctl(pd->bdev->bd_inode, file, cmd, arg);

	case CDROMEJECT:
		/*
		 * The door gets locked when the device is opened, so we
		 * have to unlock it or else the eject command fails.
		 */
		pkt_lock_door(pd, 0);
		return blkdev_ioctl(pd->bdev->bd_inode, file, cmd, arg);

	default:
		printk("pktcdvd: Unknown ioctl for %s (%x)\n", pd->name, cmd);
		return -ENOTTY;
	}

	return 0;
}

static int pkt_media_changed(struct gendisk *disk)
{
	struct pktcdvd_device *pd = disk->private_data;
	struct gendisk *attached_disk;

	if (!pd)
		return 0;
	if (!pd->bdev)
		return 0;
	attached_disk = pd->bdev->bd_disk;
	if (!attached_disk)
		return 0;
	return attached_disk->fops->media_changed(attached_disk);
}

static struct block_device_operations pktcdvd_ops = {
	.owner =		THIS_MODULE,
	.open =			pkt_open,
	.release =		pkt_close,
	.ioctl =		pkt_ioctl,
	.media_changed =	pkt_media_changed,
};

/*
 * Set up mapping from pktcdvd device to CD-ROM device.
 */
static int pkt_setup_dev(struct pkt_ctrl_command *ctrl_cmd)
{
	int idx;
	int ret = -ENOMEM;
	struct pktcdvd_device *pd;
	struct gendisk *disk;
	dev_t dev = new_decode_dev(ctrl_cmd->dev);

	for (idx = 0; idx < MAX_WRITERS; idx++)
		if (!pkt_devs[idx])
			break;
	if (idx == MAX_WRITERS) {
		printk("pktcdvd: max %d writers supported\n", MAX_WRITERS);
		return -EBUSY;
	}

	pd = kzalloc(sizeof(struct pktcdvd_device), GFP_KERNEL);
	if (!pd)
		return ret;

	pd->rb_pool = mempool_create(PKT_RB_POOL_SIZE, pkt_rb_alloc, pkt_rb_free, NULL);
	if (!pd->rb_pool)
		goto out_mem;

	disk = alloc_disk(1);
	if (!disk)
		goto out_mem;
	pd->disk = disk;

	spin_lock_init(&pd->lock);
	spin_lock_init(&pd->iosched.lock);
	sprintf(pd->name, "pktcdvd%d", idx);
	init_waitqueue_head(&pd->wqueue);
	pd->bio_queue = RB_ROOT;

	disk->major = pkt_major;
	disk->first_minor = idx;
	disk->fops = &pktcdvd_ops;
	disk->flags = GENHD_FL_REMOVABLE;
	sprintf(disk->disk_name, "pktcdvd%d", idx);
	disk->private_data = pd;
	disk->queue = blk_alloc_queue(GFP_KERNEL);
	if (!disk->queue)
		goto out_mem2;

	pd->pkt_dev = MKDEV(disk->major, disk->first_minor);
	ret = pkt_new_dev(pd, dev);
	if (ret)
		goto out_new_dev;

	add_disk(disk);
	pkt_devs[idx] = pd;
	ctrl_cmd->pkt_dev = new_encode_dev(pd->pkt_dev);
	return 0;

out_new_dev:
	blk_put_queue(disk->queue);
out_mem2:
	put_disk(disk);
out_mem:
	if (pd->rb_pool)
		mempool_destroy(pd->rb_pool);
	kfree(pd);
	return ret;
}

/*
 * Tear down mapping from pktcdvd device to CD-ROM device.
 */
static int pkt_remove_dev(struct pkt_ctrl_command *ctrl_cmd)
{
	struct pktcdvd_device *pd;
	int idx;
	dev_t pkt_dev = new_decode_dev(ctrl_cmd->pkt_dev);

	for (idx = 0; idx < MAX_WRITERS; idx++) {
		pd = pkt_devs[idx];
		if (pd && (pd->pkt_dev == pkt_dev))
			break;
	}
	if (idx == MAX_WRITERS) {
		DPRINTK("pktcdvd: dev not setup\n");
		return -ENXIO;
	}

	if (pd->refcnt > 0)
		return -EBUSY;

	if (!IS_ERR(pd->cdrw.thread))
		kthread_stop(pd->cdrw.thread);

	blkdev_put(pd->bdev);

	pkt_shrink_pktlist(pd);

	remove_proc_entry(pd->name, pkt_proc);
	DPRINTK("pktcdvd: writer %s unmapped\n", pd->name);

	del_gendisk(pd->disk);
	blk_put_queue(pd->disk->queue);
	put_disk(pd->disk);

	pkt_devs[idx] = NULL;
	mempool_destroy(pd->rb_pool);
	kfree(pd);

	/* This is safe: open() is still holding a reference. */
	module_put(THIS_MODULE);
	return 0;
}

static void pkt_get_status(struct pkt_ctrl_command *ctrl_cmd)
{
	struct pktcdvd_device *pd = pkt_find_dev_from_minor(ctrl_cmd->dev_index);
	if (pd) {
		ctrl_cmd->dev = new_encode_dev(pd->bdev->bd_dev);
		ctrl_cmd->pkt_dev = new_encode_dev(pd->pkt_dev);
	} else {
		ctrl_cmd->dev = 0;
		ctrl_cmd->pkt_dev = 0;
	}
	ctrl_cmd->num_devices = MAX_WRITERS;
}

static int pkt_ctl_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	struct pkt_ctrl_command ctrl_cmd;
	int ret = 0;

	if (cmd != PACKET_CTRL_CMD)
		return -ENOTTY;

	if (copy_from_user(&ctrl_cmd, argp, sizeof(struct pkt_ctrl_command)))
		return -EFAULT;

	switch (ctrl_cmd.command) {
	case PKT_CTRL_CMD_SETUP:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
		down(&ctl_mutex);
		ret = pkt_setup_dev(&ctrl_cmd);
		up(&ctl_mutex);
		break;
	case PKT_CTRL_CMD_TEARDOWN:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
		down(&ctl_mutex);
		ret = pkt_remove_dev(&ctrl_cmd);
		up(&ctl_mutex);
		break;
	case PKT_CTRL_CMD_STATUS: