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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309// 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);