/* * bsg.c - block layer implementation of the sg v4 interface * * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> * * This file is subject to the terms and conditions of the GNU General Public * License version 2. See the file "COPYING" in the main directory of this * archive for more details. * */ #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/scsi_cmnd.h> #include <scsi/scsi_device.h> #include <scsi/scsi_driver.h> #include <scsi/sg.h> #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" #define BSG_VERSION "0.4" #define bsg_dbg(bd, fmt, ...) \ pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__) struct bsg_device { struct request_queue *queue; spinlock_t lock; struct hlist_node dev_list; refcount_t ref_count; char name[20]; int max_queue; }; #define BSG_DEFAULT_CMDS 64 #define BSG_MAX_DEVS 32768 static DEFINE_MUTEX(bsg_mutex); static DEFINE_IDR(bsg_minor_idr); #define BSG_LIST_ARRAY_SIZE 8 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; static struct class *bsg_class; static int bsg_major; static inline struct hlist_head *bsg_dev_idx_hash(int index) { return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; } #define uptr64(val) ((void __user *)(uintptr_t)(val)) static int bsg_scsi_check_proto(struct sg_io_v4 *hdr) { if (hdr->protocol != BSG_PROTOCOL_SCSI || hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD) return -EINVAL; return 0; } static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, fmode_t mode) { struct scsi_request *sreq = scsi_req(rq); sreq->cmd_len = hdr->request_len; if (sreq->cmd_len > BLK_MAX_CDB) { sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL); if (!sreq->cmd) return -ENOMEM; } if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len)) return -EFAULT; if (blk_verify_command(sreq->cmd, mode)) return -EPERM; return 0; } static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr) { struct scsi_request *sreq = scsi_req(rq); int ret = 0; /* * fill in all the output members */ hdr->device_status = sreq->result & 0xff; hdr->transport_status = host_byte(sreq->result); hdr->driver_status = driver_byte(sreq->result); hdr->info = 0; if (hdr->device_status || hdr->transport_status || hdr->driver_status) hdr->info |= SG_INFO_CHECK; hdr->response_len = 0; if (sreq->sense_len && hdr->response) { int len = min_t(unsigned int, hdr->max_response_len, sreq->sense_len); if (copy_to_user(uptr64(hdr->response), sreq->sense, len)) ret = -EFAULT; else hdr->response_len = len; } if (rq->next_rq) { hdr->dout_resid = sreq->resid_len; hdr->din_resid = scsi_req(rq->next_rq)->resid_len; } else if (rq_data_dir(rq) == READ) { hdr->din_resid = sreq->resid_len; } else { hdr->dout_resid = sreq->resid_len; } return ret; } static void bsg_scsi_free_rq(struct request *rq) { scsi_req_free_cmd(scsi_req(rq)); } static const struct bsg_ops bsg_scsi_ops = { .check_proto = bsg_scsi_check_proto, .fill_hdr = bsg_scsi_fill_hdr, .complete_rq = bsg_scsi_complete_rq, .free_rq = bsg_scsi_free_rq, }; static struct request * bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode) { struct request *rq, *next_rq = NULL; int ret; if (!q->bsg_dev.class_dev) return ERR_PTR(-ENXIO); if (hdr->guard != 'Q') return ERR_PTR(-EINVAL); ret = q->bsg_dev.ops->check_proto(hdr); if (ret) return ERR_PTR(ret); rq = blk_get_request(q, hdr->dout_xfer_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0); if (IS_ERR(rq)) return rq; ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode); if (ret) goto out; rq->timeout = msecs_to_jiffies(hdr->timeout); if (!rq->timeout) rq->timeout = q->sg_timeout; if (!rq->timeout) rq->timeout = BLK_DEFAULT_SG_TIMEOUT; if (rq->timeout < BLK_MIN_SG_TIMEOUT) rq->timeout = BLK_MIN_SG_TIMEOUT; if (hdr->dout_xfer_len && hdr->din_xfer_len) { if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { ret = -EOPNOTSUPP; goto out; } pr_warn_once( "BIDI support in bsg has been deprecated and might be removed. " "Please report your use case to linux-scsi@vger.kernel.org\n"); next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0); if (IS_ERR(next_rq)) { ret = PTR_ERR(next_rq); goto out; } rq->next_rq = next_rq; ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp), hdr->din_xfer_len, GFP_KERNEL); if (ret) goto out_free_nextrq; } if (hdr->dout_xfer_len) { ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp), hdr->dout_xfer_len, GFP_KERNEL); } else if (hdr->din_xfer_len) { ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp), hdr->din_xfer_len, GFP_KERNEL); } if (ret) goto out_unmap_nextrq; return rq; out_unmap_nextrq: if (rq->next_rq) blk_rq_unmap_user(rq->next_rq->bio); out_free_nextrq: if (rq->next_rq) blk_put_request(rq->next_rq); out: q->bsg_dev.ops->free_rq(rq); blk_put_request(rq); return ERR_PTR(ret); } static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, struct bio *bio, struct bio *bidi_bio) { int ret; ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr); if (rq->next_rq) { blk_rq_unmap_user(bidi_bio); blk_put_request(rq->next_rq); } blk_rq_unmap_user(bio); rq->q->bsg_dev.ops->free_rq(rq); blk_put_request(rq); return ret; } static struct bsg_device *bsg_alloc_device(void) { struct bsg_device *bd; bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); if (unlikely(!bd)) return NULL; spin_lock_init(&bd->lock); bd->max_queue = BSG_DEFAULT_CMDS; INIT_HLIST_NODE(&bd->dev_list); return bd; } static int bsg_put_device(struct bsg_device *bd) { struct request_queue *q = bd->queue; mutex_lock(&bsg_mutex); if (!refcount_dec_and_test(&bd->ref_count)) { mutex_unlock(&bsg_mutex); return 0; } hlist_del(&bd->dev_list); mutex_unlock(&bsg_mutex); bsg_dbg(bd, "tearing down\n"); /* * close can always block */ kfree(bd); blk_put_queue(q); return 0; } static struct bsg_device *bsg_add_device(struct inode *inode, struct request_queue *rq, struct file *file) { struct bsg_device *bd; unsigned char buf[32]; lockdep_assert_held(&bsg_mutex); if (!blk_get_queue(rq)) return ERR_PTR(-ENXIO); bd = bsg_alloc_device(); if (!bd) { blk_put_queue(rq); return ERR_PTR(-ENOMEM); } bd->queue = rq; refcount_set(&bd->ref_count, 1); hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); bsg_dbg(bd, "bound to <%s>, max queue %d\n", format_dev_t(buf, inode->i_rdev), bd->max_queue); return bd; } static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) { struct bsg_device *bd; lockdep_assert_held(&bsg_mutex); hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { if (bd->queue == q) { refcount_inc(&bd->ref_count); goto found; } } bd = NULL; found: return bd; } static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) { struct bsg_device *bd; struct bsg_class_device *bcd; /* * find the class device */ mutex_lock(&bsg_mutex); bcd = idr_find(&bsg_minor_idr, iminor(inode)); if (!bcd) { bd = ERR_PTR(-ENODEV); goto out_unlock; } bd = __bsg_get_device(iminor(inode), bcd->queue); if (!bd) bd = bsg_add_device(inode, bcd->queue, file); out_unlock: mutex_unlock(&bsg_mutex); return bd; } static int bsg_open(struct inode *inode, struct file *file) { struct bsg_device *bd; bd = bsg_get_device(inode, file); if (IS_ERR(bd)) return PTR_ERR(bd); file->private_data = bd; return 0; } static int bsg_release(struct inode *inode, struct file *file) { struct bsg_device *bd = file->private_data; file->private_data = NULL; return bsg_put_device(bd); } static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct bsg_device *bd = file->private_data; int __user *uarg = (int __user *) arg; int ret; switch (cmd) { /* * our own ioctls */ case SG_GET_COMMAND_Q: return put_user(bd->max_queue, uarg); case SG_SET_COMMAND_Q: { int queue; if (get_user(queue, uarg)) return -EFAULT; if (queue < 1) return -EINVAL; spin_lock_irq(&bd->lock); bd->max_queue = queue; spin_unlock_irq(&bd->lock); return 0; } /* * SCSI/sg ioctls */ case SG_GET_VERSION_NUM: case SCSI_IOCTL_GET_IDLUN: case SCSI_IOCTL_GET_BUS_NUMBER: case SG_SET_TIMEOUT: case SG_GET_TIMEOUT: case SG_GET_RESERVED_SIZE: case SG_SET_RESERVED_SIZE: case SG_EMULATED_HOST: case SCSI_IOCTL_SEND_COMMAND: { void __user *uarg = (void __user *) arg; return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); } case SG_IO: { struct request *rq; struct bio *bio, *bidi_bio = NULL; struct sg_io_v4 hdr; int at_head; if (copy_from_user(&hdr, uarg, sizeof(hdr))) return -EFAULT; rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode); if (IS_ERR(rq)) return PTR_ERR(rq); bio = rq->bio; if (rq->next_rq) bidi_bio = rq->next_rq->bio; at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); blk_execute_rq(bd->queue, NULL, rq, at_head); ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); if (copy_to_user(uarg, &hdr, sizeof(hdr))) return -EFAULT; return ret; } default: return -ENOTTY; } } static const struct file_operations bsg_fops = { .open = bsg_open, .release = bsg_release, .unlocked_ioctl = bsg_ioctl, .owner = THIS_MODULE, .llseek = default_llseek, }; void bsg_unregister_queue(struct request_queue *q) { struct bsg_class_device *bcd = &q->bsg_dev; if (!bcd->class_dev) return; mutex_lock(&bsg_mutex); idr_remove(&bsg_minor_idr, bcd->minor); if (q->kobj.sd) sysfs_remove_link(&q->kobj, "bsg"); device_unregister(bcd->class_dev); bcd->class_dev = NULL; mutex_unlock(&bsg_mutex); } EXPORT_SYMBOL_GPL(bsg_unregister_queue); int bsg_register_queue(struct request_queue *q, struct device *parent, const char *name, const struct bsg_ops *ops) { struct bsg_class_device *bcd; dev_t dev; int ret; struct device *class_dev = NULL; /* * we need a proper transport to send commands, not a stacked device */ if (!queue_is_mq(q)) return 0; bcd = &q->bsg_dev; memset(bcd, 0, sizeof(*bcd)); mutex_lock(&bsg_mutex); ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); if (ret < 0) { if (ret == -ENOSPC) { printk(KERN_ERR "bsg: too many bsg devices\n"); ret = -EINVAL; } goto unlock; } bcd->minor = ret; bcd->queue = q; bcd->ops = ops; dev = MKDEV(bsg_major, bcd->minor); class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name); if (IS_ERR(class_dev)) { ret = PTR_ERR(class_dev); goto idr_remove; } bcd->class_dev = class_dev; if (q->kobj.sd) { ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); if (ret) goto unregister_class_dev; } mutex_unlock(&bsg_mutex); return 0; unregister_class_dev: device_unregister(class_dev); idr_remove: idr_remove(&bsg_minor_idr, bcd->minor); unlock: mutex_unlock(&bsg_mutex); return ret; } int bsg_scsi_register_queue(struct request_queue *q, struct device *parent) { if (!blk_queue_scsi_passthrough(q)) { WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); return -EINVAL; } return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops); } EXPORT_SYMBOL_GPL(bsg_scsi_register_queue); static struct cdev bsg_cdev; 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) { int ret, i; dev_t devid; for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) INIT_HLIST_HEAD(&bsg_device_list[i]); 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); cdev_init(&bsg_cdev, &bsg_fops); ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); if (ret) goto unregister_chrdev; printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION " loaded (major %d)\n", bsg_major); return 0; unregister_chrdev: unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); destroy_bsg_class: class_destroy(bsg_class); return ret; } MODULE_AUTHOR("Jens Axboe"); MODULE_DESCRIPTION(BSG_DESCRIPTION); MODULE_LICENSE("GPL"); device_initcall(bsg_init);