/* * 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/poll.h> #include <linux/cdev.h> #include <linux/percpu.h> #include <linux/uio.h> #include <linux/idr.h> #include <linux/bsg.h> #include <linux/smp_lock.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" struct bsg_device { struct request_queue *queue; spinlock_t lock; struct list_head busy_list; struct list_head done_list; struct hlist_node dev_list; atomic_t ref_count; int queued_cmds; int done_cmds; wait_queue_head_t wq_done; wait_queue_head_t wq_free; char name[20]; int max_queue; unsigned long flags; }; enum { BSG_F_BLOCK = 1, }; #define BSG_DEFAULT_CMDS 64 #define BSG_MAX_DEVS 32768 #undef BSG_DEBUG #ifdef BSG_DEBUG #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) #else #define dprintk(fmt, args...) #endif 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 struct kmem_cache *bsg_cmd_cachep; /* * our internal command type */ struct bsg_command { struct bsg_device *bd; struct list_head list; struct request *rq; struct bio *bio; struct bio *bidi_bio; int err; struct sg_io_v4 hdr; char sense[SCSI_SENSE_BUFFERSIZE]; }; static void bsg_free_command(struct bsg_command *bc) { struct bsg_device *bd = bc->bd; unsigned long flags; kmem_cache_free(bsg_cmd_cachep, bc); spin_lock_irqsave(&bd->lock, flags); bd->queued_cmds--; spin_unlock_irqrestore(&bd->lock, flags); wake_up(&bd->wq_free); } static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) { struct bsg_command *bc = ERR_PTR(-EINVAL); spin_lock_irq(&bd->lock); if (bd->queued_cmds >= bd->max_queue) goto out; bd->queued_cmds++; spin_unlock_irq(&bd->lock); bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); if (unlikely(!bc)) { spin_lock_irq(&bd->lock); bd->queued_cmds--; bc = ERR_PTR(-ENOMEM); goto out; } bc->bd = bd; INIT_LIST_HEAD(&bc->list); dprintk("%s: returning free cmd %p\n", bd->name, bc); return bc; out: spin_unlock_irq(&bd->lock); return bc; } static inline struct hlist_head *bsg_dev_idx_hash(int index) { return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; } static int bsg_io_schedule(struct bsg_device *bd) { DEFINE_WAIT(wait); int ret = 0; spin_lock_irq(&bd->lock); BUG_ON(bd->done_cmds > bd->queued_cmds); /* * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no * work to do", even though we return -ENOSPC after this same test * during bsg_write() -- there, it means our buffer can't have more * bsg_commands added to it, thus has no space left. */ if (bd->done_cmds == bd->queued_cmds) { ret = -ENODATA; goto unlock; } if (!test_bit(BSG_F_BLOCK, &bd->flags)) { ret = -EAGAIN; goto unlock; } prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&bd->lock); io_schedule(); finish_wait(&bd->wq_done, &wait); return ret; unlock: spin_unlock_irq(&bd->lock); return ret; } static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, struct sg_io_v4 *hdr, struct bsg_device *bd, fmode_t has_write_perm) { if (hdr->request_len > BLK_MAX_CDB) { rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); if (!rq->cmd) return -ENOMEM; } if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, hdr->request_len)) return -EFAULT; if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { if (blk_verify_command(rq->cmd, has_write_perm)) return -EPERM; } else if (!capable(CAP_SYS_RAWIO)) return -EPERM; /* * fill in request structure */ rq->cmd_len = hdr->request_len; rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->timeout = (hdr->timeout * HZ) / 1000; 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; return 0; } /* * Check if sg_io_v4 from user is allowed and valid */ static int bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) { int ret = 0; if (hdr->guard != 'Q') return -EINVAL; switch (hdr->protocol) { case BSG_PROTOCOL_SCSI: switch (hdr->subprotocol) { case BSG_SUB_PROTOCOL_SCSI_CMD: case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: break; default: ret = -EINVAL; } break; default: ret = -EINVAL; } *rw = hdr->dout_xfer_len ? WRITE : READ; return ret; } /* * map sg_io_v4 to a request. */ static struct request * bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm, u8 *sense) { struct request_queue *q = bd->queue; struct request *rq, *next_rq = NULL; int ret, rw; unsigned int dxfer_len; void *dxferp = NULL; dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, hdr->din_xfer_len); ret = bsg_validate_sgv4_hdr(q, hdr, &rw); if (ret) return ERR_PTR(ret); /* * map scatter-gather elements seperately and string them to request */ rq = blk_get_request(q, rw, GFP_KERNEL); if (!rq) return ERR_PTR(-ENOMEM); ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); if (ret) goto out; if (rw == WRITE && hdr->din_xfer_len) { if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { ret = -EOPNOTSUPP; goto out; } next_rq = blk_get_request(q, READ, GFP_KERNEL); if (!next_rq) { ret = -ENOMEM; goto out; } rq->next_rq = next_rq; next_rq->cmd_type = rq->cmd_type; dxferp = (void*)(unsigned long)hdr->din_xferp; ret = blk_rq_map_user(q, next_rq, NULL, dxferp, hdr->din_xfer_len, GFP_KERNEL); if (ret) goto out; } if (hdr->dout_xfer_len) { dxfer_len = hdr->dout_xfer_len; dxferp = (void*)(unsigned long)hdr->dout_xferp; } else if (hdr->din_xfer_len) { dxfer_len = hdr->din_xfer_len; dxferp = (void*)(unsigned long)hdr->din_xferp; } else dxfer_len = 0; if (dxfer_len) { ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, GFP_KERNEL); if (ret) goto out; } rq->sense = sense; rq->sense_len = 0; return rq; out: if (rq->cmd != rq->__cmd) kfree(rq->cmd); blk_put_request(rq); if (next_rq) { blk_rq_unmap_user(next_rq->bio); blk_put_request(next_rq); } return ERR_PTR(ret); } /* * async completion call-back from the block layer, when scsi/ide/whatever * calls end_that_request_last() on a request */ static void bsg_rq_end_io(struct request *rq, int uptodate) { struct bsg_command *bc = rq->end_io_data; struct bsg_device *bd = bc->bd; unsigned long flags; dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", bd->name, rq, bc, bc->bio, uptodate); bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); spin_lock_irqsave(&bd->lock, flags); list_move_tail(&bc->list, &bd->done_list); bd->done_cmds++; spin_unlock_irqrestore(&bd->lock, flags); wake_up(&bd->wq_done); } /* * do final setup of a 'bc' and submit the matching 'rq' to the block * layer for io */ static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, struct bsg_command *bc, struct request *rq) { int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); /* * add bc command to busy queue and submit rq for io */ bc->rq = rq; bc->bio = rq->bio; if (rq->next_rq) bc->bidi_bio = rq->next_rq->bio; bc->hdr.duration = jiffies; spin_lock_irq(&bd->lock); list_add_tail(&bc->list, &bd->busy_list); spin_unlock_irq(&bd->lock); dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); rq->end_io_data = bc; blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); } static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) { struct bsg_command *bc = NULL; spin_lock_irq(&bd->lock); if (bd->done_cmds) { bc = list_first_entry(&bd->done_list, struct bsg_command, list); list_del(&bc->list); bd->done_cmds--; } spin_unlock_irq(&bd->lock); return bc; } /* * Get a finished command from the done list */ static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) { struct bsg_command *bc; int ret; do { bc = bsg_next_done_cmd(bd); if (bc) break; if (!test_bit(BSG_F_BLOCK, &bd->flags)) { bc = ERR_PTR(-EAGAIN); break; } ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); if (ret) { bc = ERR_PTR(-ERESTARTSYS); break; } } while (1); dprintk("%s: returning done %p\n", bd->name, bc); return bc; } static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, struct bio *bio, struct bio *bidi_bio) { int ret = 0; dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); /* * fill in all the output members */ hdr->device_status = status_byte(rq->errors); hdr->transport_status = host_byte(rq->errors); hdr->driver_status = driver_byte(rq->errors); hdr->info = 0; if (hdr->device_status || hdr->transport_status || hdr->driver_status) hdr->info |= SG_INFO_CHECK; hdr->response_len = 0; if (rq->sense_len && hdr->response) { int len = min_t(unsigned int, hdr->max_response_len, rq->sense_len); ret = copy_to_user((void*)(unsigned long)hdr->response, rq->sense, len); if (!ret) hdr->response_len = len; else ret = -EFAULT; } if (rq->next_rq) { hdr->dout_resid = rq->resid_len; hdr->din_resid = rq->next_rq->resid_len; blk_rq_unmap_user(bidi_bio); blk_put_request(rq->next_rq); } else if (rq_data_dir(rq) == READ) hdr->din_resid = rq->resid_len; else hdr->dout_resid = rq->resid_len; /* * If the request generated a negative error number, return it * (providing we aren't already returning an error); if it's * just a protocol response (i.e. non negative), that gets * processed above. */ if (!ret && rq->errors < 0) ret = rq->errors; blk_rq_unmap_user(bio); if (rq->cmd != rq->__cmd) kfree(rq->cmd); blk_put_request(rq); return ret; } static int bsg_complete_all_commands(struct bsg_device *bd) { struct bsg_command *bc; int ret, tret; dprintk("%s: entered\n", bd->name); /* * wait for all commands to complete */ ret = 0; do { ret = bsg_io_schedule(bd); /* * look for -ENODATA specifically -- we'll sometimes get * -ERESTARTSYS when we've taken a signal, but we can't * return until we're done freeing the queue, so ignore * it. The signal will get handled when we're done freeing * the bsg_device. */ } while (ret != -ENODATA); /* * discard done commands */ ret = 0; do { spin_lock_irq(&bd->lock); if (!bd->queued_cmds) { spin_unlock_irq(&bd->lock); break; } spin_unlock_irq(&bd->lock); bc = bsg_get_done_cmd(bd); if (IS_ERR(bc)) break; tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, bc->bidi_bio); if (!ret) ret = tret; bsg_free_command(bc); } while (1); return ret; } static int __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, const struct iovec *iov, ssize_t *bytes_read) { struct bsg_command *bc; int nr_commands, ret; if (count % sizeof(struct sg_io_v4)) return -EINVAL; ret = 0; nr_commands = count / sizeof(struct sg_io_v4); while (nr_commands) { bc = bsg_get_done_cmd(bd); if (IS_ERR(bc)) { ret = PTR_ERR(bc); break; } /* * this is the only case where we need to copy data back * after completing the request. so do that here, * bsg_complete_work() cannot do that for us */ ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, bc->bidi_bio); if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) ret = -EFAULT; bsg_free_command(bc); if (ret) break; buf += sizeof(struct sg_io_v4); *bytes_read += sizeof(struct sg_io_v4); nr_commands--; } return ret; } static inline void bsg_set_block(struct bsg_device *bd, struct file *file) { if (file->f_flags & O_NONBLOCK) clear_bit(BSG_F_BLOCK, &bd->flags); else set_bit(BSG_F_BLOCK, &bd->flags); } /* * Check if the error is a "real" error that we should return. */ static inline int err_block_err(int ret) { if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) return 1; return 0; } static ssize_t bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct bsg_device *bd = file->private_data; int ret; ssize_t bytes_read; dprintk("%s: read %Zd bytes\n", bd->name, count); bsg_set_block(bd, file); bytes_read = 0; ret = __bsg_read(buf, count, bd, NULL, &bytes_read); *ppos = bytes_read; if (!bytes_read || (bytes_read && err_block_err(ret))) bytes_read = ret; return bytes_read; } static int __bsg_write(struct bsg_device *bd, const char __user *buf, size_t count, ssize_t *bytes_written, fmode_t has_write_perm) { struct bsg_command *bc; struct request *rq; int ret, nr_commands; if (count % sizeof(struct sg_io_v4)) return -EINVAL; nr_commands = count / sizeof(struct sg_io_v4); rq = NULL; bc = NULL; ret = 0; while (nr_commands) { struct request_queue *q = bd->queue; bc = bsg_alloc_command(bd); if (IS_ERR(bc)) { ret = PTR_ERR(bc); bc = NULL; break; } if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { ret = -EFAULT; break; } /* * get a request, fill in the blanks, and add to request queue */ rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); if (IS_ERR(rq)) { ret = PTR_ERR(rq); rq = NULL; break; } bsg_add_command(bd, q, bc, rq); bc = NULL; rq = NULL; nr_commands--; buf += sizeof(struct sg_io_v4); *bytes_written += sizeof(struct sg_io_v4); } if (bc) bsg_free_command(bc); return ret; } static ssize_t bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct bsg_device *bd = file->private_data; ssize_t bytes_written; int ret; dprintk("%s: write %Zd bytes\n", bd->name, count); bsg_set_block(bd, file); bytes_written = 0; ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode & FMODE_WRITE); *ppos = bytes_written; /* * return bytes written on non-fatal errors */ if (!bytes_written || (bytes_written && err_block_err(ret))) bytes_written = ret; dprintk("%s: returning %Zd\n", bd->name, bytes_written); return bytes_written; } 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_LIST_HEAD(&bd->busy_list); INIT_LIST_HEAD(&bd->done_list); INIT_HLIST_NODE(&bd->dev_list); init_waitqueue_head(&bd->wq_free); init_waitqueue_head(&bd->wq_done); return bd; } static void bsg_kref_release_function(struct kref *kref) { struct bsg_class_device *bcd = container_of(kref, struct bsg_class_device, ref); struct device *parent = bcd->parent; if (bcd->release) bcd->release(bcd->parent); put_device(parent); } static int bsg_put_device(struct bsg_device *bd) { int ret = 0, do_free; struct request_queue *q = bd->queue; mutex_lock(&bsg_mutex); do_free = atomic_dec_and_test(&bd->ref_count); if (!do_free) { mutex_unlock(&bsg_mutex); goto out; } hlist_del(&bd->dev_list); mutex_unlock(&bsg_mutex); dprintk("%s: tearing down\n", bd->name); /* * close can always block */ set_bit(BSG_F_BLOCK, &bd->flags); /* * correct error detection baddies here again. it's the responsibility * of the app to properly reap commands before close() if it wants * fool-proof error detection */ ret = bsg_complete_all_commands(bd); kfree(bd); out: kref_put(&q->bsg_dev.ref, bsg_kref_release_function); if (do_free) blk_put_queue(q); return ret; } static struct bsg_device *bsg_add_device(struct inode *inode, struct request_queue *rq, struct file *file) { struct bsg_device *bd; int ret; #ifdef BSG_DEBUG unsigned char buf[32]; #endif ret = blk_get_queue(rq); if (ret) return ERR_PTR(-ENXIO); bd = bsg_alloc_device(); if (!bd) { blk_put_queue(rq); return ERR_PTR(-ENOMEM); } bd->queue = rq; bsg_set_block(bd, file); atomic_set(&bd->ref_count, 1); mutex_lock(&bsg_mutex); 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); dprintk("bound to <%s>, max queue %d\n", format_dev_t(buf, inode->i_rdev), bd->max_queue); mutex_unlock(&bsg_mutex); return bd; } static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) { struct bsg_device *bd; struct hlist_node *entry; mutex_lock(&bsg_mutex); hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { if (bd->queue == q) { atomic_inc(&bd->ref_count); goto found; } } bd = NULL; found: mutex_unlock(&bsg_mutex); 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) kref_get(&bcd->ref); mutex_unlock(&bsg_mutex); if (!bcd) return ERR_PTR(-ENODEV); bd = __bsg_get_device(iminor(inode), bcd->queue); if (bd) return bd; bd = bsg_add_device(inode, bcd->queue, file); if (IS_ERR(bd)) kref_put(&bcd->ref, bsg_kref_release_function); return bd; } static int bsg_open(struct inode *inode, struct file *file) { struct bsg_device *bd; lock_kernel(); bd = bsg_get_device(inode, file); unlock_kernel(); 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 unsigned int bsg_poll(struct file *file, poll_table *wait) { struct bsg_device *bd = file->private_data; unsigned int mask = 0; poll_wait(file, &bd->wq_done, wait); poll_wait(file, &bd->wq_free, wait); spin_lock_irq(&bd->lock); if (!list_empty(&bd->done_list)) mask |= POLLIN | POLLRDNORM; if (bd->queued_cmds >= bd->max_queue) mask |= POLLOUT; spin_unlock_irq(&bd->lock); return mask; } 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; u8 sense[SCSI_SENSE_BUFFERSIZE]; if (copy_from_user(&hdr, uarg, sizeof(hdr))) return -EFAULT; rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); 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; } /* * block device ioctls */ default: #if 0 return ioctl_by_bdev(bd->bdev, cmd, arg); #else return -ENOTTY; #endif } } static const struct file_operations bsg_fops = { .read = bsg_read, .write = bsg_write, .poll = bsg_poll, .open = bsg_open, .release = bsg_release, .unlocked_ioctl = bsg_ioctl, .owner = THIS_MODULE, }; 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); sysfs_remove_link(&q->kobj, "bsg"); device_unregister(bcd->class_dev); bcd->class_dev = NULL; kref_put(&bcd->ref, bsg_kref_release_function); mutex_unlock(&bsg_mutex); } EXPORT_SYMBOL_GPL(bsg_unregister_queue); int bsg_register_queue(struct request_queue *q, struct device *parent, const char *name, void (*release)(struct device *)) { struct bsg_class_device *bcd; dev_t dev; int ret, minor; struct device *class_dev = NULL; const char *devname; if (name) devname = name; else devname = dev_name(parent); /* * we need a proper transport to send commands, not a stacked device */ if (!q->request_fn) return 0; bcd = &q->bsg_dev; memset(bcd, 0, sizeof(*bcd)); mutex_lock(&bsg_mutex); ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); if (!ret) { ret = -ENOMEM; goto unlock; } ret = idr_get_new(&bsg_minor_idr, bcd, &minor); if (ret < 0) goto unlock; if (minor >= BSG_MAX_DEVS) { printk(KERN_ERR "bsg: too many bsg devices\n"); ret = -EINVAL; goto remove_idr; } bcd->minor = minor; bcd->queue = q; bcd->parent = get_device(parent); bcd->release = release; kref_init(&bcd->ref); dev = MKDEV(bsg_major, bcd->minor); class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); if (IS_ERR(class_dev)) { ret = PTR_ERR(class_dev); goto put_dev; } 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); put_dev: put_device(parent); remove_idr: idr_remove(&bsg_minor_idr, minor); unlock: mutex_unlock(&bsg_mutex); return ret; } EXPORT_SYMBOL_GPL(bsg_register_queue); static struct cdev bsg_cdev; static char *bsg_devnode(struct device *dev, mode_t *mode) { return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); } static int __init bsg_init(void) { int ret, i; dev_t devid; bsg_cmd_cachep = kmem_cache_create("bsg_cmd", sizeof(struct bsg_command), 0, 0, NULL); if (!bsg_cmd_cachep) { printk(KERN_ERR "bsg: failed creating slab cache\n"); return -ENOMEM; } 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)) { ret = PTR_ERR(bsg_class); goto destroy_kmemcache; } 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); destroy_kmemcache: kmem_cache_destroy(bsg_cmd_cachep); return ret; } MODULE_AUTHOR("Jens Axboe"); MODULE_DESCRIPTION(BSG_DESCRIPTION); MODULE_LICENSE("GPL"); device_initcall(bsg_init);