linux/block/bsg.c
Anatoliy Glagolev d6c73964f1 bsg: fix race of bsg_open and bsg_unregister
The existing implementation allows races between bsg_unregister and
bsg_open paths. bsg_unregister and request_queue cleanup and deletion
may start and complete right after bsg_get_device (in bsg_open path)
retrieves bsg_class_device and releases the mutex. Then bsg_open path
touches freed memory of bsg_class_device and request_queue.

One possible fix is to hold the mutex all the way through bsg_get_device
instead of releasing it after bsg_class_device retrieval.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-Off-By: Anatoliy Glagolev <glagolig@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-15 08:15:37 -06:00

1027 lines
21 KiB
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"
#define bsg_dbg(bd, fmt, ...) \
pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
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
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;
};
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);
bsg_dbg(bd, "returning free cmd %p\n", 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)];
}
#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;
}
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);
} else {
ret = blk_rq_map_user(q, rq, NULL, NULL, 0, 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);
}
/*
* 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, blk_status_t status)
{
struct bsg_command *bc = rq->end_io_data;
struct bsg_device *bd = bc->bd;
unsigned long flags;
bsg_dbg(bd, "finished rq %p bc %p, bio %p\n",
rq, bc, bc->bio);
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);
bsg_dbg(bd, "queueing rq %p, bc %p\n", 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);
bsg_dbg(bd, "returning done %p\n", 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;
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 bool bsg_complete(struct bsg_device *bd)
{
bool ret = false;
bool spin;
do {
spin_lock_irq(&bd->lock);
BUG_ON(bd->done_cmds > bd->queued_cmds);
/*
* All commands consumed.
*/
if (bd->done_cmds == bd->queued_cmds)
ret = true;
spin = !test_bit(BSG_F_BLOCK, &bd->flags);
spin_unlock_irq(&bd->lock);
} while (!ret && spin);
return ret;
}
static int bsg_complete_all_commands(struct bsg_device *bd)
{
struct bsg_command *bc;
int ret, tret;
bsg_dbg(bd, "entered\n");
/*
* wait for all commands to complete
*/
io_wait_event(bd->wq_done, bsg_complete(bd));
/*
* 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;
bsg_dbg(bd, "read %zd bytes\n", 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 mode)
{
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->queue, &bc->hdr, mode);
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;
bsg_dbg(bd, "write %zd bytes\n", count);
if (unlikely(uaccess_kernel()))
return -EINVAL;
bsg_set_block(bd, file);
bytes_written = 0;
ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode);
*ppos = bytes_written;
/*
* return bytes written on non-fatal errors
*/
if (!bytes_written || err_block_err(ret))
bytes_written = ret;
bsg_dbg(bd, "returning %zd\n", 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 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);
bsg_dbg(bd, "tearing down\n");
/*
* 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:
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;
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;
bsg_set_block(bd, file);
atomic_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) {
atomic_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 __poll_t bsg_poll(struct file *file, poll_table *wait)
{
struct bsg_device *bd = file->private_data;
__poll_t 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 |= EPOLLIN | EPOLLRDNORM;
if (bd->queued_cmds < bd->max_queue)
mask |= EPOLLOUT;
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;
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 = {
.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;
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_rq_based(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;
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);