forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
268 lines
6.1 KiB
268 lines
6.1 KiB
// 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 <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; |
|
}; |
|
|
|
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_IDA(bsg_minor_ida); |
|
static 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, fmode_t mode, 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, mode, 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, 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 const struct file_operations bsg_fops = { |
|
.open = bsg_open, |
|
.release = bsg_release, |
|
.unlocked_ioctl = bsg_ioctl, |
|
.compat_ioctl = compat_ptr_ioctl, |
|
.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_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt)); |
|
kfree(bd); |
|
} |
|
|
|
void bsg_unregister_queue(struct bsg_device *bd) |
|
{ |
|
if (bd->queue->kobj.sd) |
|
sysfs_remove_link(&bd->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) |
|
{ |
|
struct bsg_device *bd; |
|
int ret; |
|
|
|
bd = kzalloc(sizeof(*bd), GFP_KERNEL); |
|
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; |
|
|
|
ret = ida_simple_get(&bsg_minor_ida, 0, BSG_MAX_DEVS, 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->kobj.sd) { |
|
ret = sysfs_create_link(&q->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(struct device *dev, umode_t *mode) |
|
{ |
|
return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); |
|
} |
|
|
|
static int __init bsg_init(void) |
|
{ |
|
dev_t devid; |
|
int ret; |
|
|
|
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); |
|
|
|
printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION |
|
" loaded (major %d)\n", bsg_major); |
|
return 0; |
|
|
|
destroy_bsg_class: |
|
class_destroy(bsg_class); |
|
return ret; |
|
} |
|
|
|
MODULE_AUTHOR("Jens Axboe"); |
|
MODULE_DESCRIPTION(BSG_DESCRIPTION); |
|
MODULE_LICENSE("GPL"); |
|
|
|
device_initcall(bsg_init);
|
|
|