272 строки
6.2 KiB
C
272 строки
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* bsg.c - block layer implementation of the sg v4 interface
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/file.h>
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#include <linux/blkdev.h>
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#include <linux/cdev.h>
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#include <linux/jiffies.h>
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#include <linux/percpu.h>
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#include <linux/idr.h>
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#include <linux/bsg.h>
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#include <linux/slab.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_ioctl.h>
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#include <scsi/sg.h>
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#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
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#define BSG_VERSION "0.4"
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struct bsg_device {
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struct request_queue *queue;
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struct device device;
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struct cdev cdev;
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int max_queue;
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unsigned int timeout;
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unsigned int reserved_size;
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bsg_sg_io_fn *sg_io_fn;
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};
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static inline struct bsg_device *to_bsg_device(struct inode *inode)
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{
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return container_of(inode->i_cdev, struct bsg_device, cdev);
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}
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#define BSG_DEFAULT_CMDS 64
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#define BSG_MAX_DEVS 32768
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static DEFINE_IDA(bsg_minor_ida);
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static struct class *bsg_class;
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static int bsg_major;
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static unsigned int bsg_timeout(struct bsg_device *bd, struct sg_io_v4 *hdr)
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{
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unsigned int timeout = BLK_DEFAULT_SG_TIMEOUT;
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if (hdr->timeout)
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timeout = msecs_to_jiffies(hdr->timeout);
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else if (bd->timeout)
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timeout = bd->timeout;
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return max_t(unsigned int, timeout, BLK_MIN_SG_TIMEOUT);
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}
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static int bsg_sg_io(struct bsg_device *bd, fmode_t mode, void __user *uarg)
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{
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struct sg_io_v4 hdr;
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int ret;
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if (copy_from_user(&hdr, uarg, sizeof(hdr)))
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return -EFAULT;
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if (hdr.guard != 'Q')
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return -EINVAL;
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ret = bd->sg_io_fn(bd->queue, &hdr, mode, bsg_timeout(bd, &hdr));
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if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
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return -EFAULT;
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return ret;
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}
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static int bsg_open(struct inode *inode, struct file *file)
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{
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if (!blk_get_queue(to_bsg_device(inode)->queue))
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return -ENXIO;
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return 0;
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}
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static int bsg_release(struct inode *inode, struct file *file)
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{
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blk_put_queue(to_bsg_device(inode)->queue);
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return 0;
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}
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static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
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{
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return put_user(READ_ONCE(bd->max_queue), uarg);
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}
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static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
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{
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int max_queue;
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if (get_user(max_queue, uarg))
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return -EFAULT;
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if (max_queue < 1)
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return -EINVAL;
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WRITE_ONCE(bd->max_queue, max_queue);
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return 0;
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}
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static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct bsg_device *bd = to_bsg_device(file_inode(file));
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struct request_queue *q = bd->queue;
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void __user *uarg = (void __user *) arg;
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int __user *intp = uarg;
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int val;
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switch (cmd) {
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/*
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* Our own ioctls
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*/
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case SG_GET_COMMAND_Q:
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return bsg_get_command_q(bd, uarg);
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case SG_SET_COMMAND_Q:
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return bsg_set_command_q(bd, uarg);
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/*
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* SCSI/sg ioctls
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*/
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case SG_GET_VERSION_NUM:
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return put_user(30527, intp);
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case SCSI_IOCTL_GET_IDLUN:
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return put_user(0, intp);
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case SCSI_IOCTL_GET_BUS_NUMBER:
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return put_user(0, intp);
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case SG_SET_TIMEOUT:
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if (get_user(val, intp))
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return -EFAULT;
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bd->timeout = clock_t_to_jiffies(val);
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return 0;
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case SG_GET_TIMEOUT:
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return jiffies_to_clock_t(bd->timeout);
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case SG_GET_RESERVED_SIZE:
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return put_user(min(bd->reserved_size, queue_max_bytes(q)),
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intp);
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case SG_SET_RESERVED_SIZE:
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if (get_user(val, intp))
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return -EFAULT;
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if (val < 0)
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return -EINVAL;
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bd->reserved_size =
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min_t(unsigned int, val, queue_max_bytes(q));
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return 0;
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case SG_EMULATED_HOST:
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return put_user(1, intp);
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case SG_IO:
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return bsg_sg_io(bd, file->f_mode, uarg);
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case SCSI_IOCTL_SEND_COMMAND:
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pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",
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current->comm);
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return -EINVAL;
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations bsg_fops = {
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.open = bsg_open,
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.release = bsg_release,
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.unlocked_ioctl = bsg_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.owner = THIS_MODULE,
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.llseek = default_llseek,
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};
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static void bsg_device_release(struct device *dev)
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{
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struct bsg_device *bd = container_of(dev, struct bsg_device, device);
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ida_free(&bsg_minor_ida, MINOR(bd->device.devt));
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kfree(bd);
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}
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void bsg_unregister_queue(struct bsg_device *bd)
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{
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struct gendisk *disk = bd->queue->disk;
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if (disk && disk->queue_kobj.sd)
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sysfs_remove_link(&disk->queue_kobj, "bsg");
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cdev_device_del(&bd->cdev, &bd->device);
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put_device(&bd->device);
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}
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EXPORT_SYMBOL_GPL(bsg_unregister_queue);
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struct bsg_device *bsg_register_queue(struct request_queue *q,
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struct device *parent, const char *name, bsg_sg_io_fn *sg_io_fn)
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{
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struct bsg_device *bd;
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int ret;
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bd = kzalloc(sizeof(*bd), GFP_KERNEL);
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if (!bd)
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return ERR_PTR(-ENOMEM);
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bd->max_queue = BSG_DEFAULT_CMDS;
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bd->reserved_size = INT_MAX;
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bd->queue = q;
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bd->sg_io_fn = sg_io_fn;
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ret = ida_alloc_max(&bsg_minor_ida, BSG_MAX_DEVS - 1, GFP_KERNEL);
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if (ret < 0) {
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if (ret == -ENOSPC)
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dev_err(parent, "bsg: too many bsg devices\n");
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kfree(bd);
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return ERR_PTR(ret);
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}
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bd->device.devt = MKDEV(bsg_major, ret);
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bd->device.class = bsg_class;
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bd->device.parent = parent;
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bd->device.release = bsg_device_release;
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dev_set_name(&bd->device, "%s", name);
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device_initialize(&bd->device);
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cdev_init(&bd->cdev, &bsg_fops);
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bd->cdev.owner = THIS_MODULE;
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ret = cdev_device_add(&bd->cdev, &bd->device);
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if (ret)
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goto out_put_device;
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if (q->disk && q->disk->queue_kobj.sd) {
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ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj,
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"bsg");
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if (ret)
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goto out_device_del;
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}
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return bd;
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out_device_del:
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cdev_device_del(&bd->cdev, &bd->device);
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out_put_device:
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put_device(&bd->device);
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return ERR_PTR(ret);
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}
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EXPORT_SYMBOL_GPL(bsg_register_queue);
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static char *bsg_devnode(const struct device *dev, umode_t *mode)
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{
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return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
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}
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static int __init bsg_init(void)
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{
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dev_t devid;
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int ret;
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bsg_class = class_create(THIS_MODULE, "bsg");
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if (IS_ERR(bsg_class))
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return PTR_ERR(bsg_class);
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bsg_class->devnode = bsg_devnode;
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ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
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if (ret)
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goto destroy_bsg_class;
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bsg_major = MAJOR(devid);
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printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
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" loaded (major %d)\n", bsg_major);
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return 0;
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destroy_bsg_class:
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class_destroy(bsg_class);
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return ret;
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}
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MODULE_AUTHOR("Jens Axboe");
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MODULE_DESCRIPTION(BSG_DESCRIPTION);
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MODULE_LICENSE("GPL");
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device_initcall(bsg_init);
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