Commit ead09dd3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Martin K. Petersen
Browse files

scsi: bsg: Simplify device registration 

Use the per-device cdev_device_interface to store the bsg data in the char
device inode, and thus remove the need to embedd the bsg_class_device
structure in the request_queue.

Link: https://lore.kernel.org/r/20210729064845.1044147-2-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent ba51bdaf

block/bsg-lib.c

+6 −5
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 *  Copyright (C) 2011   Red Hat, Inc.  All rights reserved.

 *  Copyright (C) 2011   Mike Christie

 */

#include <linux/bsg.h>

#include <linux/slab.h>

#include <linux/blk-mq.h>

#include <linux/delay.h>
@@ -19,6 +20,7 @@ 


struct bsg_set {

	struct blk_mq_tag_set	tag_set;

	struct bsg_device	*bd;

	bsg_job_fn		*job_fn;

	bsg_timeout_fn		*timeout_fn;

};
@@ -327,7 +329,7 @@ void bsg_remove_queue(struct request_queue *q) 
		struct bsg_set *bset =

			container_of(q->tag_set, struct bsg_set, tag_set);



		bsg_unregister_queue(q);

		bsg_unregister_queue(bset->bd);

		blk_cleanup_queue(q);

		blk_mq_free_tag_set(&bset->tag_set);

		kfree(bset);
@@ -396,10 +398,9 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name, 
	q->queuedata = dev;

	blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);



	ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);

	if (ret) {

		printk(KERN_ERR "%s: bsg interface failed to "

		       "initialize - register queue\n", dev->kobj.name);

	bset->bd = bsg_register_queue(q, dev, name, &bsg_transport_ops);

	if (IS_ERR(bset->bd)) {

		ret = PTR_ERR(bset->bd);

		goto out_cleanup_queue;

	}

block/bsg.c

+72 −232
Original line number Diff line number Diff line
@@ -20,38 +20,29 @@ 
#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];

	const struct bsg_ops *ops;

	struct device device;

	struct cdev cdev;

	int max_queue;

};



static inline struct bsg_device *to_bsg_device(struct inode *inode)

{

	return container_of(inode->i_cdev, struct bsg_device, cdev);

}



#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 DEFINE_IDA(bsg_minor_ida);

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_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)

static int bsg_sg_io(struct bsg_device *bd, fmode_t mode, void __user *uarg)

{

	struct request *rq;

	struct bio *bio;
@@ -61,21 +52,18 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg) 
	if (copy_from_user(&hdr, uarg, sizeof(hdr)))

		return -EFAULT;



	if (!q->bsg_dev.class_dev)

		return -ENXIO;



	if (hdr.guard != 'Q')

		return -EINVAL;

	ret = q->bsg_dev.ops->check_proto(&hdr);

	ret = bd->ops->check_proto(&hdr);

	if (ret)

		return ret;



	rq = blk_get_request(q, hdr.dout_xfer_len ?

	rq = blk_get_request(bd->queue, hdr.dout_xfer_len ?

			REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);

	if (IS_ERR(rq))

		return PTR_ERR(rq);



	ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);

	ret = bd->ops->fill_hdr(rq, &hdr, mode);

	if (ret) {

		blk_put_request(rq);

		return ret;
@@ -83,17 +71,17 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg) 


	rq->timeout = msecs_to_jiffies(hdr.timeout);

	if (!rq->timeout)

		rq->timeout = q->sg_timeout;

		rq->timeout = rq->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) {

		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),

		ret = blk_rq_map_user(rq->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),

		ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr.din_xferp),

				hdr.din_xfer_len, GFP_KERNEL);

	}
@@ -103,171 +91,50 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg) 
	bio = rq->bio;



	blk_execute_rq(NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));

	ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);

	ret = bd->ops->complete_rq(rq, &hdr);

	blk_rq_unmap_user(bio);



out_free_rq:

	rq->q->bsg_dev.ops->free_rq(rq);

	bd->ops->free_rq(rq);

	blk_put_request(rq);

	if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))

		return -EFAULT;

	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;

	if (!blk_get_queue(to_bsg_device(inode)->queue))

		return -ENXIO;

	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);

	blk_put_queue(to_bsg_device(inode)->queue);

	return 0;

}



static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)

{

	return put_user(bd->max_queue, uarg);

	return put_user(READ_ONCE(bd->max_queue), uarg);

}



static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)

{

	int queue;

	int max_queue;



	if (get_user(queue, uarg))

	if (get_user(max_queue, uarg))

		return -EFAULT;

	if (queue < 1)

	if (max_queue < 1)

		return -EINVAL;



	spin_lock_irq(&bd->lock);

	bd->max_queue = queue;

	spin_unlock_irq(&bd->lock);

	WRITE_ONCE(bd->max_queue, max_queue);

	return 0;

}



static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	struct bsg_device *bd = file->private_data;

	struct bsg_device *bd = to_bsg_device(file_inode(file));

	struct request_queue *q = bd->queue;

	void __user *uarg = (void __user *) arg;

	int __user *intp = uarg;
@@ -312,7 +179,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	case SG_EMULATED_HOST:

		return put_user(1, intp);

	case SG_IO:

		return bsg_sg_io(q, file->f_mode, uarg);

		return bsg_sg_io(bd, file->f_mode, uarg);

	case SCSI_IOCTL_SEND_COMMAND:

		pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",

				current->comm);
@@ -331,83 +198,66 @@ static const struct file_operations bsg_fops = { 
	.llseek		=	default_llseek,

};



void bsg_unregister_queue(struct request_queue *q)

void bsg_unregister_queue(struct bsg_device *bd)

{

	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);

	if (bd->queue->kobj.sd)

		sysfs_remove_link(&bd->queue->kobj, "bsg");

	cdev_device_del(&bd->cdev, &bd->device);

	ida_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt));

	kfree(bd);

}

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_device *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;

	struct bsg_device *bd;

	int ret;

	struct device *class_dev = NULL;



	/*

	 * we need a proper transport to send commands, not a stacked device

	 */

	if (!queue_is_mq(q))

		return 0;



	bcd = &q->bsg_dev;

	memset(bcd, 0, sizeof(*bcd));



	mutex_lock(&bsg_mutex);

	bd = kzalloc(sizeof(*bd), GFP_KERNEL);

	if (!bd)

		return ERR_PTR(-ENOMEM);

	bd->max_queue = BSG_DEFAULT_CMDS;

	bd->queue = q;

	bd->ops = ops;



	ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);

	ret = ida_simple_get(&bsg_minor_ida, 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;

		if (ret == -ENOSPC)

			dev_err(parent, "bsg: too many bsg devices\n");

		goto out_kfree;

	}

	bcd->class_dev = class_dev;

	bd->device.devt = MKDEV(bsg_major, ret);

	bd->device.class = bsg_class;

	bd->device.parent = parent;

	dev_set_name(&bd->device, "%s", name);

	device_initialize(&bd->device);



	cdev_init(&bd->cdev, &bsg_fops);

	bd->cdev.owner = THIS_MODULE;

	ret = cdev_device_add(&bd->cdev, &bd->device);

	if (ret)

		goto out_ida_remove;



	if (q->kobj.sd) {

		ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");

		ret = sysfs_create_link(&q->kobj, &bd->device.kobj, "bsg");

		if (ret)

			goto unregister_class_dev;

			goto out_device_del;

	}



	mutex_unlock(&bsg_mutex);

	return 0;

	return bd;



unregister_class_dev:

	device_unregister(class_dev);

idr_remove:

	idr_remove(&bsg_minor_idr, bcd->minor);

unlock:

	mutex_unlock(&bsg_mutex);

	return ret;

out_device_del:

	cdev_device_del(&bd->cdev, &bd->device);

out_ida_remove:

	ida_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt));

out_kfree:

	kfree(bd);

	return ERR_PTR(ret);

}

EXPORT_SYMBOL_GPL(bsg_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));
@@ -415,11 +265,8 @@ static char *bsg_devnode(struct device *dev, umode_t *mode) 


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]);

	int ret;



	bsg_class = class_create(THIS_MODULE, "bsg");

	if (IS_ERR(bsg_class))
@@ -429,19 +276,12 @@ static int __init bsg_init(void) 
	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;

drivers/scsi/scsi_bsg.c

+3 −2
Original line number Diff line number Diff line
@@ -89,7 +89,8 @@ static const struct bsg_ops scsi_bsg_ops = { 
	.free_rq		= scsi_bsg_free_rq,

};



int scsi_bsg_register_queue(struct request_queue *q, struct device *parent)

struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev)

{

	return bsg_register_queue(q, parent, dev_name(parent), &scsi_bsg_ops);

	return bsg_register_queue(sdev->request_queue, &sdev->sdev_gendev,

				  dev_name(&sdev->sdev_gendev), &scsi_bsg_ops);

}

drivers/scsi/scsi_priv.h

+2 −9
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <scsi/scsi_device.h>

#include <linux/sbitmap.h>



struct bsg_device;

struct request_queue;

struct request;

struct scsi_cmnd;
@@ -180,15 +181,7 @@ static inline void scsi_dh_add_device(struct scsi_device *sdev) { } 
static inline void scsi_dh_release_device(struct scsi_device *sdev) { }

#endif



#ifdef CONFIG_BLK_DEV_BSG

int scsi_bsg_register_queue(struct request_queue *q, struct device *parent);

#else

static inline int scsi_bsg_register_queue(struct request_queue *q,

		struct device *parent)

{

	return 0;

}

#endif

struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev);



extern int scsi_device_max_queue_depth(struct scsi_device *sdev);

drivers/scsi/scsi_sysfs.c

+16 −8
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/blkdev.h>

#include <linux/device.h>

#include <linux/pm_runtime.h>

#include <linux/bsg.h>



#include <scsi/scsi.h>

#include <scsi/scsi_device.h>
@@ -1327,7 +1328,6 @@ static int scsi_target_add(struct scsi_target *starget) 
int scsi_sysfs_add_sdev(struct scsi_device *sdev)

{

	int error, i;

	struct request_queue *rq = sdev->request_queue;

	struct scsi_target *starget = sdev->sdev_target;



	error = scsi_target_add(starget);
@@ -1366,12 +1366,19 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev) 
	transport_add_device(&sdev->sdev_gendev);

	sdev->is_visible = 1;



	error = scsi_bsg_register_queue(rq, &sdev->sdev_gendev);

	if (error)

		/* we're treating error on bsg register as non-fatal,

		 * so pretend nothing went wrong */

	if (IS_ENABLED(CONFIG_BLK_DEV_BSG)) {

		sdev->bsg_dev = scsi_bsg_register_queue(sdev);

		if (IS_ERR(sdev->bsg_dev)) {

			/*

			 * We're treating error on bsg register as non-fatal, so

			 * pretend nothing went wrong.

			 */

			sdev_printk(KERN_INFO, sdev,

			    "Failed to register bsg queue, errno=%d\n", error);

				    "Failed to register bsg queue, errno=%d\n",

				    error);

			sdev->bsg_dev = NULL;

		}

	}



	/* add additional host specific attributes */

	if (sdev->host->hostt->sdev_attrs) {
@@ -1433,7 +1440,8 @@ void __scsi_remove_device(struct scsi_device *sdev) 
			sysfs_remove_groups(&sdev->sdev_gendev.kobj,

					sdev->host->hostt->sdev_groups);



		bsg_unregister_queue(sdev->request_queue);

		if (IS_ENABLED(CONFIG_BLK_DEV_BSG) && sdev->bsg_dev)

			bsg_unregister_queue(sdev->bsg_dev);

		device_unregister(&sdev->sdev_dev);

		transport_remove_device(dev);

		device_del(dev);