1 files changed, 576 insertions, 0 deletions
diff --git a/block/bsg.c b/block/bsg.c
new file mode 100644
index 000000000..9a442c23a
--- /dev/null
+++ b/block/bsg.c
@@ -0,0 +1,576 @@
+/*
+ * bsg.c - block layer implementation of the sg v4 interface
+ *
+ * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
+ * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License version 2.  See the file "COPYING" in the main directory of this
+ *  archive for more details.
+ *
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/blkdev.h>
+#include <linux/cdev.h>
+#include <linux/jiffies.h>
+#include <linux/percpu.h>
+#include <linux/idr.h>
+#include <linux/bsg.h>
+#include <linux/slab.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/sg.h>
+
+#define BSG_DESCRIPTION	"Block layer SCSI generic (bsg) driver"
+#define BSG_VERSION	"0.4"
+
+#define bsg_dbg(bd, fmt, ...) \
+	pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
+
+struct bsg_device {
+	struct request_queue *queue;
+	spinlock_t lock;
+	struct hlist_node dev_list;
+	refcount_t ref_count;
+	char name[20];
+	int max_queue;
+};
+
+#define BSG_DEFAULT_CMDS	64
+#define BSG_MAX_DEVS		32768
+
+static DEFINE_MUTEX(bsg_mutex);
+static DEFINE_IDR(bsg_minor_idr);
+
+#define BSG_LIST_ARRAY_SIZE	8
+static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
+
+static struct class *bsg_class;
+static int bsg_major;
+
+static inline struct hlist_head *bsg_dev_idx_hash(int index)
+{
+	return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
+}
+
+#define uptr64(val) ((void __user *)(uintptr_t)(val))
+
+static int bsg_scsi_check_proto(struct sg_io_v4 *hdr)
+{
+	if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
+	    hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
+		return -EINVAL;
+	return 0;
+}
+
+static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
+		fmode_t mode)
+{
+	struct scsi_request *sreq = scsi_req(rq);
+
+	sreq->cmd_len = hdr->request_len;
+	if (sreq->cmd_len > BLK_MAX_CDB) {
+		sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
+		if (!sreq->cmd)
+			return -ENOMEM;
+	}
+
+	if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
+		return -EFAULT;
+	if (blk_verify_command(sreq->cmd, mode))
+		return -EPERM;
+	return 0;
+}
+
+static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
+{
+	struct scsi_request *sreq = scsi_req(rq);
+	int ret = 0;
+
+	/*
+	 * fill in all the output members
+	 */
+	hdr->device_status = sreq->result & 0xff;
+	hdr->transport_status = host_byte(sreq->result);
+	hdr->driver_status = driver_byte(sreq->result);
+	hdr->info = 0;
+	if (hdr->device_status || hdr->transport_status || hdr->driver_status)
+		hdr->info |= SG_INFO_CHECK;
+	hdr->response_len = 0;
+
+	if (sreq->sense_len && hdr->response) {
+		int len = min_t(unsigned int, hdr->max_response_len,
+					sreq->sense_len);
+
+		if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
+			ret = -EFAULT;
+		else
+			hdr->response_len = len;
+	}
+
+	if (rq->next_rq) {
+		hdr->dout_resid = sreq->resid_len;
+		hdr->din_resid = scsi_req(rq->next_rq)->resid_len;
+	} else if (rq_data_dir(rq) == READ) {
+		hdr->din_resid = sreq->resid_len;
+	} else {
+		hdr->dout_resid = sreq->resid_len;
+	}
+
+	return ret;
+}
+
+static void bsg_scsi_free_rq(struct request *rq)
+{
+	scsi_req_free_cmd(scsi_req(rq));
+}
+
+static const struct bsg_ops bsg_scsi_ops = {
+	.check_proto		= bsg_scsi_check_proto,
+	.fill_hdr		= bsg_scsi_fill_hdr,
+	.complete_rq		= bsg_scsi_complete_rq,
+	.free_rq		= bsg_scsi_free_rq,
+};
+
+static struct request *
+bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
+{
+	struct request *rq, *next_rq = NULL;
+	int ret;
+
+	if (!q->bsg_dev.class_dev)
+		return ERR_PTR(-ENXIO);
+
+	if (hdr->guard != 'Q')
+		return ERR_PTR(-EINVAL);
+
+	ret = q->bsg_dev.ops->check_proto(hdr);
+	if (ret)
+		return ERR_PTR(ret);
+
+	rq = blk_get_request(q, hdr->dout_xfer_len ?
+			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
+	if (IS_ERR(rq))
+		return rq;
+
+	ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode);
+	if (ret)
+		goto out;
+
+	rq->timeout = msecs_to_jiffies(hdr->timeout);
+	if (!rq->timeout)
+		rq->timeout = q->sg_timeout;
+	if (!rq->timeout)
+		rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
+	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
+		rq->timeout = BLK_MIN_SG_TIMEOUT;
+
+	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+		if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
+			ret = -EOPNOTSUPP;
+			goto out;
+		}
+
+		next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
+		if (IS_ERR(next_rq)) {
+			ret = PTR_ERR(next_rq);
+			goto out;
+		}
+
+		rq->next_rq = next_rq;
+		ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp),
+				       hdr->din_xfer_len, GFP_KERNEL);
+		if (ret)
+			goto out_free_nextrq;
+	}
+
+	if (hdr->dout_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp),
+				hdr->dout_xfer_len, GFP_KERNEL);
+	} else if (hdr->din_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp),
+				hdr->din_xfer_len, GFP_KERNEL);
+	}
+
+	if (ret)
+		goto out_unmap_nextrq;
+	return rq;
+
+out_unmap_nextrq:
+	if (rq->next_rq)
+		blk_rq_unmap_user(rq->next_rq->bio);
+out_free_nextrq:
+	if (rq->next_rq)
+		blk_put_request(rq->next_rq);
+out:
+	q->bsg_dev.ops->free_rq(rq);
+	blk_put_request(rq);
+	return ERR_PTR(ret);
+}
+
+static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
+				    struct bio *bio, struct bio *bidi_bio)
+{
+	int ret;
+
+	ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr);
+
+	if (rq->next_rq) {
+		blk_rq_unmap_user(bidi_bio);
+		blk_put_request(rq->next_rq);
+	}
+
+	blk_rq_unmap_user(bio);
+	rq->q->bsg_dev.ops->free_rq(rq);
+	blk_put_request(rq);
+	return ret;
+}
+
+static struct bsg_device *bsg_alloc_device(void)
+{
+	struct bsg_device *bd;
+
+	bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
+	if (unlikely(!bd))
+		return NULL;
+
+	spin_lock_init(&bd->lock);
+	bd->max_queue = BSG_DEFAULT_CMDS;
+	INIT_HLIST_NODE(&bd->dev_list);
+	return bd;
+}
+
+static int bsg_put_device(struct bsg_device *bd)
+{
+	struct request_queue *q = bd->queue;
+
+	mutex_lock(&bsg_mutex);
+
+	if (!refcount_dec_and_test(&bd->ref_count)) {
+		mutex_unlock(&bsg_mutex);
+		return 0;
+	}
+
+	hlist_del(&bd->dev_list);
+	mutex_unlock(&bsg_mutex);
+
+	bsg_dbg(bd, "tearing down\n");
+
+	/*
+	 * close can always block
+	 */
+	kfree(bd);
+	blk_put_queue(q);
+	return 0;
+}
+
+static struct bsg_device *bsg_add_device(struct inode *inode,
+					 struct request_queue *rq,
+					 struct file *file)
+{
+	struct bsg_device *bd;
+	unsigned char buf[32];
+
+	lockdep_assert_held(&bsg_mutex);
+
+	if (!blk_get_queue(rq))
+		return ERR_PTR(-ENXIO);
+
+	bd = bsg_alloc_device();
+	if (!bd) {
+		blk_put_queue(rq);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	bd->queue = rq;
+
+	refcount_set(&bd->ref_count, 1);
+	hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
+
+	strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
+	bsg_dbg(bd, "bound to <%s>, max queue %d\n",
+		format_dev_t(buf, inode->i_rdev), bd->max_queue);
+
+	return bd;
+}
+
+static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
+{
+	struct bsg_device *bd;
+
+	lockdep_assert_held(&bsg_mutex);
+
+	hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
+		if (bd->queue == q) {
+			refcount_inc(&bd->ref_count);
+			goto found;
+		}
+	}
+	bd = NULL;
+found:
+	return bd;
+}
+
+static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
+{
+	struct bsg_device *bd;
+	struct bsg_class_device *bcd;
+
+	/*
+	 * find the class device
+	 */
+	mutex_lock(&bsg_mutex);
+	bcd = idr_find(&bsg_minor_idr, iminor(inode));
+
+	if (!bcd) {
+		bd = ERR_PTR(-ENODEV);
+		goto out_unlock;
+	}
+
+	bd = __bsg_get_device(iminor(inode), bcd->queue);
+	if (!bd)
+		bd = bsg_add_device(inode, bcd->queue, file);
+
+out_unlock:
+	mutex_unlock(&bsg_mutex);
+	return bd;
+}
+
+static int bsg_open(struct inode *inode, struct file *file)
+{
+	struct bsg_device *bd;
+
+	bd = bsg_get_device(inode, file);
+
+	if (IS_ERR(bd))
+		return PTR_ERR(bd);
+
+	file->private_data = bd;
+	return 0;
+}
+
+static int bsg_release(struct inode *inode, struct file *file)
+{
+	struct bsg_device *bd = file->private_data;
+
+	file->private_data = NULL;
+	return bsg_put_device(bd);
+}
+
+static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct bsg_device *bd = file->private_data;
+	int __user *uarg = (int __user *) arg;
+	int ret;
+
+	switch (cmd) {
+		/*
+		 * our own ioctls
+		 */
+	case SG_GET_COMMAND_Q:
+		return put_user(bd->max_queue, uarg);
+	case SG_SET_COMMAND_Q: {
+		int queue;
+
+		if (get_user(queue, uarg))
+			return -EFAULT;
+		if (queue < 1)
+			return -EINVAL;
+
+		spin_lock_irq(&bd->lock);
+		bd->max_queue = queue;
+		spin_unlock_irq(&bd->lock);
+		return 0;
+	}
+
+	/*
+	 * SCSI/sg ioctls
+	 */
+	case SG_GET_VERSION_NUM:
+	case SCSI_IOCTL_GET_IDLUN:
+	case SCSI_IOCTL_GET_BUS_NUMBER:
+	case SG_SET_TIMEOUT:
+	case SG_GET_TIMEOUT:
+	case SG_GET_RESERVED_SIZE:
+	case SG_SET_RESERVED_SIZE:
+	case SG_EMULATED_HOST:
+	case SCSI_IOCTL_SEND_COMMAND: {
+		void __user *uarg = (void __user *) arg;
+		return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
+	}
+	case SG_IO: {
+		struct request *rq;
+		struct bio *bio, *bidi_bio = NULL;
+		struct sg_io_v4 hdr;
+		int at_head;
+
+		if (copy_from_user(&hdr, uarg, sizeof(hdr)))
+			return -EFAULT;
+
+		rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode);
+		if (IS_ERR(rq))
+			return PTR_ERR(rq);
+
+		bio = rq->bio;
+		if (rq->next_rq)
+			bidi_bio = rq->next_rq->bio;
+
+		at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
+		blk_execute_rq(bd->queue, NULL, rq, at_head);
+		ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
+
+		if (copy_to_user(uarg, &hdr, sizeof(hdr)))
+			return -EFAULT;
+
+		return ret;
+	}
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations bsg_fops = {
+	.open		=	bsg_open,
+	.release	=	bsg_release,
+	.unlocked_ioctl	=	bsg_ioctl,
+	.owner		=	THIS_MODULE,
+	.llseek		=	default_llseek,
+};
+
+void bsg_unregister_queue(struct request_queue *q)
+{
+	struct bsg_class_device *bcd = &q->bsg_dev;
+
+	if (!bcd->class_dev)
+		return;
+
+	mutex_lock(&bsg_mutex);
+	idr_remove(&bsg_minor_idr, bcd->minor);
+	if (q->kobj.sd)
+		sysfs_remove_link(&q->kobj, "bsg");
+	device_unregister(bcd->class_dev);
+	bcd->class_dev = NULL;
+	mutex_unlock(&bsg_mutex);
+}
+EXPORT_SYMBOL_GPL(bsg_unregister_queue);
+
+int bsg_register_queue(struct request_queue *q, struct device *parent,
+		const char *name, const struct bsg_ops *ops)
+{
+	struct bsg_class_device *bcd;
+	dev_t dev;
+	int ret;
+	struct device *class_dev = NULL;
+
+	/*
+	 * we need a proper transport to send commands, not a stacked device
+	 */
+	if (!queue_is_rq_based(q))
+		return 0;
+
+	bcd = &q->bsg_dev;
+	memset(bcd, 0, sizeof(*bcd));
+
+	mutex_lock(&bsg_mutex);
+
+	ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
+	if (ret < 0) {
+		if (ret == -ENOSPC) {
+			printk(KERN_ERR "bsg: too many bsg devices\n");
+			ret = -EINVAL;
+		}
+		goto unlock;
+	}
+
+	bcd->minor = ret;
+	bcd->queue = q;
+	bcd->ops = ops;
+	dev = MKDEV(bsg_major, bcd->minor);
+	class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
+	if (IS_ERR(class_dev)) {
+		ret = PTR_ERR(class_dev);
+		goto idr_remove;
+	}
+	bcd->class_dev = class_dev;
+
+	if (q->kobj.sd) {
+		ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
+		if (ret)
+			goto unregister_class_dev;
+	}
+
+	mutex_unlock(&bsg_mutex);
+	return 0;
+
+unregister_class_dev:
+	device_unregister(class_dev);
+idr_remove:
+	idr_remove(&bsg_minor_idr, bcd->minor);
+unlock:
+	mutex_unlock(&bsg_mutex);
+	return ret;
+}
+
+int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
+{
+	if (!blk_queue_scsi_passthrough(q)) {
+		WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
+		return -EINVAL;
+	}
+
+	return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
+}
+EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
+
+static struct cdev bsg_cdev;
+
+static char *bsg_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
+}
+
+static int __init bsg_init(void)
+{
+	int ret, i;
+	dev_t devid;
+
+	for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
+		INIT_HLIST_HEAD(&bsg_device_list[i]);
+
+	bsg_class = class_create(THIS_MODULE, "bsg");
+	if (IS_ERR(bsg_class))
+		return PTR_ERR(bsg_class);
+	bsg_class->devnode = bsg_devnode;
+
+	ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
+	if (ret)
+		goto destroy_bsg_class;
+
+	bsg_major = MAJOR(devid);
+
+	cdev_init(&bsg_cdev, &bsg_fops);
+	ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
+	if (ret)
+		goto unregister_chrdev;
+
+	printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
+	       " loaded (major %d)\n", bsg_major);
+	return 0;
+unregister_chrdev:
+	unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
+destroy_bsg_class:
+	class_destroy(bsg_class);
+	return ret;
+}
+
+MODULE_AUTHOR("Jens Axboe");
+MODULE_DESCRIPTION(BSG_DESCRIPTION);
+MODULE_LICENSE("GPL");
+
+device_initcall(bsg_init);