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-rw-r--r--block/bsg.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/block/bsg.c b/block/bsg.c
new file mode 100644
index 000000000..2ab1351eb
--- /dev/null
+++ b/block/bsg.c
@@ -0,0 +1,268 @@
+// 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_free(&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_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->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);