// SPDX-License-Identifier: GPL-2.0/* * bsg.c - block layer implementation of the sg v4 interface */#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 <linux/io_uring/cmd.h> #include <scsi/scsi.h>#include <scsi/scsi_ioctl.h>#include <scsi/sg.h> #define BSG_DESCRIPTION	"Block layer SCSI generic (bsg) driver"#define BSG_VERSION	"0.4" struct bsg_device {	struct request_queue *queue;	struct device device;	struct cdev cdev;	int max_queue;	unsigned int timeout;	unsigned int reserved_size;	bsg_sg_io_fn *sg_io_fn;	bsg_uring_cmd_fn *uring_cmd_fn;}; 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		(1 << MINORBITS) static DEFINE_IDA(bsg_minor_ida);static const struct class bsg_class;static int bsg_major; static unsigned int bsg_timeout(struct bsg_device *bd, struct sg_io_v4 *hdr){	unsigned int timeout = BLK_DEFAULT_SG_TIMEOUT; 	if (hdr->timeout)		timeout = msecs_to_jiffies(hdr->timeout);	else if (bd->timeout)		timeout = bd->timeout; 	return max_t(unsigned int, timeout, BLK_MIN_SG_TIMEOUT);} static int bsg_sg_io(struct bsg_device *bd, bool open_for_write,		     void __user *uarg){	struct sg_io_v4 hdr;	int ret; 	if (copy_from_user(&hdr, uarg, sizeof(hdr)))		return -EFAULT;	if (hdr.guard != 'Q')		return -EINVAL;	ret = bd->sg_io_fn(bd->queue, &hdr, open_for_write,			   bsg_timeout(bd, &hdr));	if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))		return -EFAULT;	return ret;} static int bsg_open(struct inode *inode, struct file *file){	if (!blk_get_queue(to_bsg_device(inode)->queue))		return -ENXIO;	return 0;} static int bsg_release(struct inode *inode, struct file *file){	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(READ_ONCE(bd->max_queue), uarg);} static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg){	int max_queue; 	if (get_user(max_queue, uarg))		return -EFAULT;	if (max_queue < 1)		return -EINVAL;	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 = to_bsg_device(file_inode(file));	struct request_queue *q = bd->queue;	void __user *uarg = (void __user *) arg;	int __user *intp = uarg;	int val; 	switch (cmd) {	/*	 * Our own ioctls	 */	case SG_GET_COMMAND_Q:		return bsg_get_command_q(bd, uarg);	case SG_SET_COMMAND_Q:		return bsg_set_command_q(bd, uarg); 	/*	 * SCSI/sg ioctls	 */	case SG_GET_VERSION_NUM:		return put_user(30527, intp);	case SCSI_IOCTL_GET_IDLUN:		return put_user(0, intp);	case SCSI_IOCTL_GET_BUS_NUMBER:		return put_user(0, intp);	case SG_SET_TIMEOUT:		if (get_user(val, intp))			return -EFAULT;		bd->timeout = clock_t_to_jiffies(val);		return 0;	case SG_GET_TIMEOUT:		return jiffies_to_clock_t(bd->timeout);	case SG_GET_RESERVED_SIZE:		return put_user(min(bd->reserved_size, queue_max_bytes(q)),				intp);	case SG_SET_RESERVED_SIZE:		if (get_user(val, intp))			return -EFAULT;		if (val < 0)			return -EINVAL;		bd->reserved_size =			min_t(unsigned int, val, queue_max_bytes(q));		return 0;	case SG_EMULATED_HOST:		return put_user(1, intp);	case SG_IO:		return bsg_sg_io(bd, file->f_mode & FMODE_WRITE, uarg);	case SCSI_IOCTL_SEND_COMMAND:		pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",				current->comm);		return -EINVAL;	default:		return -ENOTTY;	}} static int bsg_check_uring_features(unsigned int issue_flags){	/* BSG passthrough requires big SQE/CQE support */	if ((issue_flags & (IO_URING_F_SQE128|IO_URING_F_CQE32)) !=	    (IO_URING_F_SQE128|IO_URING_F_CQE32))		return -EOPNOTSUPP;	return 0;} static int bsg_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags){	struct bsg_device *bd = to_bsg_device(file_inode(ioucmd->file));	bool open_for_write = ioucmd->file->f_mode & FMODE_WRITE;	struct request_queue *q = bd->queue;	int ret; 	ret = bsg_check_uring_features(issue_flags);	if (ret)		return ret; 	if (!bd->uring_cmd_fn)		return -EOPNOTSUPP; 	return bd->uring_cmd_fn(q, ioucmd, issue_flags, open_for_write);} static const struct file_operations bsg_fops = {	.open		=	bsg_open,	.release	=	bsg_release,	.unlocked_ioctl	=	bsg_ioctl,	.compat_ioctl	=	compat_ptr_ioctl,	.uring_cmd	=	bsg_uring_cmd,	.owner		=	THIS_MODULE,	.llseek		=	default_llseek,}; static void bsg_device_release(struct device *dev){	struct bsg_device *bd = container_of(dev, struct bsg_device, device); 	ida_free(&bsg_minor_ida, MINOR(bd->device.devt));	kfree(bd);} void bsg_unregister_queue(struct bsg_device *bd){	struct gendisk *disk = bd->queue->disk; 	if (disk && disk->queue_kobj.sd)		sysfs_remove_link(&disk->queue_kobj, "bsg");	cdev_device_del(&bd->cdev, &bd->device);	put_device(&bd->device);}EXPORT_SYMBOL_GPL(bsg_unregister_queue); struct bsg_device *bsg_register_queue(struct request_queue *q,		struct device *parent, const char *name, bsg_sg_io_fn *sg_io_fn,		bsg_uring_cmd_fn *uring_cmd_fn){	struct bsg_device *bd;	int ret; 	bd = kzalloc_obj(*bd);	if (!bd)		return ERR_PTR(-ENOMEM);	bd->max_queue = BSG_DEFAULT_CMDS;	bd->reserved_size = INT_MAX;	bd->queue = q;	bd->sg_io_fn = sg_io_fn;	bd->uring_cmd_fn = uring_cmd_fn; 	ret = ida_alloc_max(&bsg_minor_ida, BSG_MAX_DEVS - 1, GFP_KERNEL);	if (ret < 0) {		if (ret == -ENOSPC)			dev_err(parent, "bsg: too many bsg devices\n");		kfree(bd);		return ERR_PTR(ret);	}	bd->device.devt = MKDEV(bsg_major, ret);	bd->device.class = &bsg_class;	bd->device.parent = parent;	bd->device.release = bsg_device_release;	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_put_device; 	if (q->disk && q->disk->queue_kobj.sd) {		ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj,					"bsg");		if (ret)			goto out_device_del;	} 	return bd; out_device_del:	cdev_device_del(&bd->cdev, &bd->device);out_put_device:	put_device(&bd->device);	return ERR_PTR(ret);}EXPORT_SYMBOL_GPL(bsg_register_queue); static char *bsg_devnode(const struct device *dev, umode_t *mode){	return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));} static const struct class bsg_class = {	.name		= "bsg",	.devnode	= bsg_devnode,}; static int __init bsg_init(void){	dev_t devid;	int ret; 	ret = class_register(&bsg_class);	if (ret)		return ret; 	ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");	if (ret)		goto destroy_bsg_class;	bsg_major = MAJOR(devid); 	printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION	       " loaded (major %d)\n", bsg_major);	return 0; destroy_bsg_class:	class_unregister(&bsg_class);	return ret;} MODULE_AUTHOR("Jens Axboe");MODULE_DESCRIPTION(BSG_DESCRIPTION);MODULE_LICENSE("GPL"); device_initcall(bsg_init);