- 根目录:
- block
- bsg.c
/*
* 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/jiffies.h>
#include <linux/percpu.h>
#include <linux/uio.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"
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 __user *)(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 = 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;
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 __user *dxferp = NULL;
struct bsg_class_device *bcd = &q->bsg_dev;
/* if the LLD has been removed then the bsg_unregister_queue will
* eventually be called and the class_dev was freed, so we can no
* longer use this request_queue. Return no such address.
*/
if (!bcd->class_dev)
return ERR_PTR(-ENXIO);
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 separately 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 __user *)(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 __user *)(unsigned long)hdr->dout_xferp;
} else if (hdr->din_xfer_len) {
dxfer_len = hdr->din_xfer_len;
dxferp = (void __user *)(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 = rq->errors & 0xff;
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 __user *)(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 || 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 || 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;
#ifdef BSG_DEBUG
unsigned char buf[32];
#endif
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;
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;
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 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,
.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;
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, umode_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);