From 3d6392cfbd7dc11f23058e3493683afab4ac13a3 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Jul 2007 12:38:05 +0200 Subject: bsg: support for full generic block layer SG v3 Signed-off-by: Jens Axboe --- block/bsg.c | 997 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 997 insertions(+) create mode 100644 block/bsg.c (limited to 'block/bsg.c') diff --git a/block/bsg.c b/block/bsg.c new file mode 100644 index 0000000..724b693 --- /dev/null +++ b/block/bsg.c @@ -0,0 +1,997 @@ +/* + * bsg.c - block layer implementation of the sg v3 interface + * + * Copyright (C) 2004 Jens Axboe SUSE Labs + * Copyright (C) 2004 Peter M. Jones + * + * 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. + * + */ +/* + * TODO + * - Should this get merged, block/scsi_ioctl.c will be migrated into + * this file. To keep maintenance down, it's easier to have them + * seperated right now. + * + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static char bsg_version[] = "block layer sg (bsg) 0.4"; + +struct bsg_command; + +struct bsg_device { + struct gendisk *disk; + request_queue_t *queue; + spinlock_t lock; + struct list_head busy_list; + struct list_head done_list; + struct hlist_node dev_list; + atomic_t ref_count; + int minor; + int queued_cmds; + int done_cmds; + unsigned long *cmd_bitmap; + struct bsg_command *cmd_map; + wait_queue_head_t wq_done; + wait_queue_head_t wq_free; + char name[BDEVNAME_SIZE]; + int max_queue; + unsigned long flags; +}; + +enum { + BSG_F_BLOCK = 1, + BSG_F_WRITE_PERM = 2, +}; + +/* + * command allocation bitmap defines + */ +#define BSG_CMDS_PAGE_ORDER (1) +#define BSG_CMDS_PER_LONG (sizeof(unsigned long) * 8) +#define BSG_CMDS_MASK (BSG_CMDS_PER_LONG - 1) +#define BSG_CMDS_BYTES (PAGE_SIZE * (1 << BSG_CMDS_PAGE_ORDER)) +#define BSG_CMDS (BSG_CMDS_BYTES / sizeof(struct bsg_command)) + +#undef BSG_DEBUG + +#ifdef BSG_DEBUG +#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __FUNCTION__, ##args) +#else +#define dprintk(fmt, args...) +#endif + +#define list_entry_bc(entry) list_entry((entry), struct bsg_command, list) + +/* + * just for testing + */ +#define BSG_MAJOR (240) + +static DEFINE_MUTEX(bsg_mutex); +static int bsg_device_nr; + +#define BSG_LIST_SIZE (8) +#define bsg_list_idx(minor) ((minor) & (BSG_LIST_SIZE - 1)) +static struct hlist_head bsg_device_list[BSG_LIST_SIZE]; + +static struct class *bsg_class; +static LIST_HEAD(bsg_class_list); + +/* + * our internal command type + */ +struct bsg_command { + struct bsg_device *bd; + struct list_head list; + struct request *rq; + struct bio *bio; + int err; + struct sg_io_hdr hdr; + struct sg_io_hdr __user *uhdr; + char sense[SCSI_SENSE_BUFFERSIZE]; +}; + +static void bsg_free_command(struct bsg_command *bc) +{ + struct bsg_device *bd = bc->bd; + unsigned long bitnr = bc - bd->cmd_map; + unsigned long flags; + + dprintk("%s: command bit offset %lu\n", bd->name, bitnr); + + spin_lock_irqsave(&bd->lock, flags); + bd->queued_cmds--; + __clear_bit(bitnr, bd->cmd_bitmap); + 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 = NULL; + unsigned long *map; + int free_nr; + + spin_lock_irq(&bd->lock); + + if (bd->queued_cmds >= bd->max_queue) + goto out; + + for (free_nr = 0, map = bd->cmd_bitmap; *map == ~0UL; map++) + free_nr += BSG_CMDS_PER_LONG; + + BUG_ON(*map == ~0UL); + + bd->queued_cmds++; + free_nr += ffz(*map); + __set_bit(free_nr, bd->cmd_bitmap); + spin_unlock_irq(&bd->lock); + + bc = bd->cmd_map + free_nr; + memset(bc, 0, sizeof(*bc)); + bc->bd = bd; + INIT_LIST_HEAD(&bc->list); + dprintk("%s: returning free cmd %p (bit %d)\n", bd->name, bc, free_nr); + return bc; +out: + dprintk("%s: failed (depth %d)\n", bd->name, bd->queued_cmds); + spin_unlock_irq(&bd->lock); + return bc; +} + +static inline void +bsg_del_done_cmd(struct bsg_device *bd, struct bsg_command *bc) +{ + bd->done_cmds--; + list_del(&bc->list); +} + +static inline void +bsg_add_done_cmd(struct bsg_device *bd, struct bsg_command *bc) +{ + bd->done_cmds++; + list_add_tail(&bc->list, &bd->done_list); + wake_up(&bd->wq_done); +} + +static inline int bsg_io_schedule(struct bsg_device *bd, int state) +{ + 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, state); + spin_unlock_irq(&bd->lock); + io_schedule(); + finish_wait(&bd->wq_done, &wait); + + if ((state == TASK_INTERRUPTIBLE) && signal_pending(current)) + ret = -ERESTARTSYS; + + return ret; +unlock: + spin_unlock_irq(&bd->lock); + return ret; +} + +/* + * get a new free command, blocking if needed and specified + */ +static struct bsg_command *bsg_get_command(struct bsg_device *bd) +{ + struct bsg_command *bc; + int ret; + + do { + bc = __bsg_alloc_command(bd); + if (bc) + break; + + ret = bsg_io_schedule(bd, TASK_INTERRUPTIBLE); + if (ret) { + bc = ERR_PTR(ret); + break; + } + + } while (1); + + return bc; +} + +/* + * Check if sg_io_hdr from user is allowed and valid + */ +static int +bsg_validate_sghdr(request_queue_t *q, struct sg_io_hdr *hdr, int *rw) +{ + if (hdr->interface_id != 'S') + return -EINVAL; + if (hdr->cmd_len > BLK_MAX_CDB) + return -EINVAL; + if (hdr->dxfer_len > (q->max_sectors << 9)) + return -EIO; + + /* + * looks sane, if no data then it should be fine from our POV + */ + if (!hdr->dxfer_len) + return 0; + + switch (hdr->dxfer_direction) { + case SG_DXFER_TO_FROM_DEV: + case SG_DXFER_FROM_DEV: + *rw = READ; + break; + case SG_DXFER_TO_DEV: + *rw = WRITE; + break; + default: + return -EINVAL; + } + + return 0; +} + +/* + * map sg_io_hdr to a request. for scatter-gather sg_io_hdr, we map + * each segment to a bio and string multiple bio's to the request + */ +static struct request * +bsg_map_hdr(struct bsg_device *bd, int rw, struct sg_io_hdr *hdr) +{ + request_queue_t *q = bd->queue; + struct sg_iovec iov; + struct sg_iovec __user *u_iov; + struct request *rq; + int ret, i = 0; + + dprintk("map hdr %p/%d/%d\n", hdr->dxferp, hdr->dxfer_len, + hdr->iovec_count); + + ret = bsg_validate_sghdr(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); + ret = blk_fill_sghdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM, + &bd->flags)); + if (ret) { + blk_put_request(rq); + return ERR_PTR(ret); + } + + if (!hdr->iovec_count) { + ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len); + if (ret) + goto out; + } + + u_iov = hdr->dxferp; + for (ret = 0, i = 0; i < hdr->iovec_count; i++, u_iov++) { + if (copy_from_user(&iov, u_iov, sizeof(iov))) { + ret = -EFAULT; + break; + } + + if (!iov.iov_len || !iov.iov_base) { + ret = -EINVAL; + break; + } + + ret = blk_rq_map_user(q, rq, iov.iov_base, iov.iov_len); + if (ret) + break; + } + + /* + * bugger, cleanup + */ + if (ret) { +out: + dprintk("failed map at %d: %d\n", i, ret); + blk_unmap_sghdr_rq(rq, hdr); + rq = ERR_PTR(ret); + } + + return rq; +} + +/* + * 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 bio %p, bc %p offset %ld stat %d\n", + bd->name, rq, bc, bc->bio, bc - bd->cmd_map, uptodate); + + bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); + + spin_lock_irqsave(&bd->lock, flags); + list_del(&bc->list); + bsg_add_done_cmd(bd, bc); + spin_unlock_irqrestore(&bd->lock, flags); +} + +/* + * 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, request_queue_t *q, + struct bsg_command *bc, struct request *rq) +{ + rq->sense = bc->sense; + rq->sense_len = 0; + + /* + * add bc command to busy queue and submit rq for io + */ + bc->rq = rq; + bc->bio = 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, bd->disk, rq, 1, bsg_rq_end_io); +} + +static inline 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_entry_bc(bd->done_list.next); + bsg_del_done_cmd(bd, bc); + } + 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, int state) +{ + struct bsg_command *bc; + int ret; + + do { + bc = bsg_next_done_cmd(bd); + if (bc) + break; + + ret = bsg_io_schedule(bd, state); + if (ret) { + bc = ERR_PTR(ret); + break; + } + } while (1); + + dprintk("%s: returning done %p\n", bd->name, bc); + + return bc; +} + +static struct bsg_command * +bsg_get_done_cmd(struct bsg_device *bd, const struct iovec *iov) +{ + return __bsg_get_done_cmd(bd, TASK_INTERRUPTIBLE); +} + +static struct bsg_command * +bsg_get_done_cmd_nosignals(struct bsg_device *bd) +{ + return __bsg_get_done_cmd(bd, TASK_UNINTERRUPTIBLE); +} + +static int bsg_complete_all_commands(struct bsg_device *bd) +{ + struct bsg_command *bc; + int ret, tret; + + dprintk("%s: entered\n", bd->name); + + set_bit(BSG_F_BLOCK, &bd->flags); + + /* + * wait for all commands to complete + */ + ret = 0; + do { + ret = bsg_io_schedule(bd, TASK_UNINTERRUPTIBLE); + /* + * 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 { + bc = bsg_get_done_cmd_nosignals(bd); + + /* + * we _must_ complete before restarting, because + * bsg_release can't handle this failing. + */ + if (PTR_ERR(bc) == -ERESTARTSYS) + continue; + if (IS_ERR(bc)) { + ret = PTR_ERR(bc); + break; + } + + tret = blk_complete_sghdr_rq(bc->rq, &bc->hdr, bc->bio); + if (!ret) + ret = tret; + + bsg_free_command(bc); + } while (1); + + return ret; +} + +typedef struct bsg_command *(*bsg_command_callback)(struct bsg_device *bd, const struct iovec *iov); + +static ssize_t +__bsg_read(char __user *buf, size_t count, bsg_command_callback get_bc, + 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_hdr)) + return -EINVAL; + + ret = 0; + nr_commands = count / sizeof(struct sg_io_hdr); + while (nr_commands) { + bc = get_bc(bd, iov); + 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_sghdr_rq(bc->rq, &bc->hdr, bc->bio); + + if (copy_to_user(buf, (char *) &bc->hdr, sizeof(bc->hdr))) + ret = -EFAULT; + + bsg_free_command(bc); + + if (ret) + break; + + buf += sizeof(struct sg_io_hdr); + *bytes_read += sizeof(struct sg_io_hdr); + 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); +} + +static inline void bsg_set_write_perm(struct bsg_device *bd, struct file *file) +{ + if (file->f_mode & FMODE_WRITE) + set_bit(BSG_F_WRITE_PERM, &bd->flags); + else + clear_bit(BSG_F_WRITE_PERM, &bd->flags); +} + +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 %lu bytes\n", bd->name, count); + + bsg_set_block(bd, file); + bytes_read = 0; + ret = __bsg_read(buf, count, bsg_get_done_cmd, + bd, NULL, &bytes_read); + *ppos = bytes_read; + + if (!bytes_read || (bytes_read && err_block_err(ret))) + bytes_read = ret; + + return bytes_read; +} + +static ssize_t __bsg_write(struct bsg_device *bd, const char __user *buf, + size_t count, ssize_t *bytes_read) +{ + struct bsg_command *bc; + struct request *rq; + int ret, nr_commands; + + if (count % sizeof(struct sg_io_hdr)) + return -EINVAL; + + nr_commands = count / sizeof(struct sg_io_hdr); + rq = NULL; + bc = NULL; + ret = 0; + while (nr_commands) { + request_queue_t *q = bd->queue; + int rw = READ; + + bc = bsg_get_command(bd); + if (!bc) + break; + if (IS_ERR(bc)) { + ret = PTR_ERR(bc); + bc = NULL; + break; + } + + bc->uhdr = (struct sg_io_hdr __user *) buf; + 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, rw, &bc->hdr); + 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_hdr); + *bytes_read += sizeof(struct sg_io_hdr); + } + + if (rq) + blk_unmap_sghdr_rq(rq, &bc->hdr); + 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_read; + int ret; + + dprintk("%s: write %lu bytes\n", bd->name, count); + + bsg_set_block(bd, file); + bsg_set_write_perm(bd, file); + + bytes_read = 0; + ret = __bsg_write(bd, buf, count, &bytes_read); + *ppos = bytes_read; + + /* + * return bytes written on non-fatal errors + */ + if (!bytes_read || (bytes_read && err_block_err(ret))) + bytes_read = ret; + + dprintk("%s: returning %lu\n", bd->name, bytes_read); + return bytes_read; +} + +static void bsg_free_device(struct bsg_device *bd) +{ + if (bd->cmd_map) + free_pages((unsigned long) bd->cmd_map, BSG_CMDS_PAGE_ORDER); + + kfree(bd->cmd_bitmap); + kfree(bd); +} + +static struct bsg_device *bsg_alloc_device(void) +{ + struct bsg_command *cmd_map; + unsigned long *cmd_bitmap; + struct bsg_device *bd; + int bits; + + bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); + if (unlikely(!bd)) + return NULL; + + spin_lock_init(&bd->lock); + + bd->max_queue = BSG_CMDS; + + bits = (BSG_CMDS / BSG_CMDS_PER_LONG) + 1; + cmd_bitmap = kzalloc(bits * sizeof(unsigned long), GFP_KERNEL); + if (!cmd_bitmap) + goto out_free_bd; + bd->cmd_bitmap = cmd_bitmap; + + cmd_map = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, + BSG_CMDS_PAGE_ORDER); + if (!cmd_map) + goto out_free_bitmap; + bd->cmd_map = cmd_map; + + 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; + +out_free_bitmap: + kfree(cmd_bitmap); +out_free_bd: + kfree(bd); + return NULL; +} + +static int bsg_put_device(struct bsg_device *bd) +{ + int ret = 0; + + mutex_lock(&bsg_mutex); + + if (!atomic_dec_and_test(&bd->ref_count)) + goto out; + + 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); + + blk_put_queue(bd->queue); + hlist_del(&bd->dev_list); + bsg_free_device(bd); +out: + mutex_unlock(&bsg_mutex); + return ret; +} + +static struct bsg_device *bsg_add_device(struct inode *inode, + struct gendisk *disk, + struct file *file) +{ + struct bsg_device *bd = NULL; +#ifdef BSG_DEBUG + unsigned char buf[32]; +#endif + + bd = bsg_alloc_device(); + if (!bd) + return ERR_PTR(-ENOMEM); + + bd->disk = disk; + bd->queue = disk->queue; + kobject_get(&disk->queue->kobj); + bsg_set_block(bd, file); + + atomic_set(&bd->ref_count, 1); + bd->minor = iminor(inode); + mutex_lock(&bsg_mutex); + hlist_add_head(&bd->dev_list,&bsg_device_list[bsg_list_idx(bd->minor)]); + + strncpy(bd->name, disk->disk_name, sizeof(bd->name) - 1); + dprintk("bound to <%s>, max queue %d\n", + format_dev_t(buf, i->i_rdev), bd->max_queue); + + mutex_unlock(&bsg_mutex); + return bd; +} + +static struct bsg_device *__bsg_get_device(int minor) +{ + struct hlist_head *list = &bsg_device_list[bsg_list_idx(minor)]; + struct bsg_device *bd = NULL; + struct hlist_node *entry; + + mutex_lock(&bsg_mutex); + + hlist_for_each(entry, list) { + bd = hlist_entry(entry, struct bsg_device, dev_list); + if (bd->minor == minor) { + atomic_inc(&bd->ref_count); + break; + } + + bd = NULL; + } + + mutex_unlock(&bsg_mutex); + return bd; +} + +static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) +{ + struct bsg_device *bd = __bsg_get_device(iminor(inode)); + struct bsg_class_device *bcd, *__bcd; + + if (bd) + return bd; + + /* + * find the class device + */ + bcd = NULL; + mutex_lock(&bsg_mutex); + list_for_each_entry(__bcd, &bsg_class_list, list) { + if (__bcd->minor == iminor(inode)) { + bcd = __bcd; + break; + } + } + mutex_unlock(&bsg_mutex); + + if (!bcd) + return ERR_PTR(-ENODEV); + + return bsg_add_device(inode, bcd->disk, file); +} + +static int bsg_open(struct inode *inode, struct file *file) +{ + struct bsg_device *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 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 int +bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct bsg_device *bd = file->private_data; + int __user *uarg = (int __user *) arg; + + if (!bd) + return -ENXIO; + + 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 > BSG_CMDS || queue < 1) + return -EINVAL; + + bd->max_queue = queue; + 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 SG_IO: + case SCSI_IOCTL_SEND_COMMAND: { + void __user *uarg = (void __user *) arg; + return scsi_cmd_ioctl(file, bd->disk, cmd, uarg); + } + /* + * block device ioctls + */ + default: +#if 0 + return ioctl_by_bdev(bd->bdev, cmd, arg); +#else + return -ENOTTY; +#endif + } +} + +static struct file_operations bsg_fops = { + .read = bsg_read, + .write = bsg_write, + .poll = bsg_poll, + .open = bsg_open, + .release = bsg_release, + .ioctl = bsg_ioctl, + .owner = THIS_MODULE, +}; + +void bsg_unregister_disk(struct gendisk *disk) +{ + struct bsg_class_device *bcd = &disk->bsg_dev; + + if (!bcd->class_dev) + return; + + mutex_lock(&bsg_mutex); + sysfs_remove_link(&bcd->disk->queue->kobj, "bsg"); + class_device_destroy(bsg_class, MKDEV(BSG_MAJOR, bcd->minor)); + bcd->class_dev = NULL; + list_del_init(&bcd->list); + mutex_unlock(&bsg_mutex); +} + +int bsg_register_disk(struct gendisk *disk) +{ + request_queue_t *q = disk->queue; + struct bsg_class_device *bcd; + dev_t dev; + + /* + * we need a proper transport to send commands, not a stacked device + */ + if (!q->request_fn) + return 0; + + bcd = &disk->bsg_dev; + memset(bcd, 0, sizeof(*bcd)); + INIT_LIST_HEAD(&bcd->list); + + mutex_lock(&bsg_mutex); + dev = MKDEV(BSG_MAJOR, bsg_device_nr); + bcd->minor = bsg_device_nr; + bsg_device_nr++; + bcd->disk = disk; + bcd->class_dev = class_device_create(bsg_class, NULL, dev, bcd->dev, "%s", disk->disk_name); + list_add_tail(&bcd->list, &bsg_class_list); + sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); + mutex_unlock(&bsg_mutex); + return 0; +} + +static int __init bsg_init(void) +{ + int ret, i; + + for (i = 0; i < BSG_LIST_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); + + ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops); + if (ret) { + class_destroy(bsg_class); + return ret; + } + + printk(KERN_INFO "%s loaded\n", bsg_version); + return 0; +} + +MODULE_AUTHOR("Jens Axboe"); +MODULE_DESCRIPTION("Block layer SGSI generic (sg) driver"); +MODULE_LICENSE("GPL"); + +subsys_initcall(bsg_init); -- cgit v1.1