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4
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/file.h>
8#include <linux/blkdev.h>
9#include <linux/cdev.h>
10#include <linux/jiffies.h>
11#include <linux/percpu.h>
12#include <linux/idr.h>
13#include <linux/bsg.h>
14#include <linux/slab.h>
15
16#include <scsi/scsi.h>
17#include <scsi/scsi_ioctl.h>
18#include <scsi/scsi_cmnd.h>
19#include <scsi/scsi_device.h>
20#include <scsi/scsi_driver.h>
21#include <scsi/sg.h>
22
23#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
24#define BSG_VERSION "0.4"
25
26#define bsg_dbg(bd, fmt, ...) \
27 pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
28
29struct bsg_device {
30 struct request_queue *queue;
31 spinlock_t lock;
32 struct hlist_node dev_list;
33 refcount_t ref_count;
34 char name[20];
35 int max_queue;
36};
37
38#define BSG_DEFAULT_CMDS 64
39#define BSG_MAX_DEVS 32768
40
41static DEFINE_MUTEX(bsg_mutex);
42static DEFINE_IDR(bsg_minor_idr);
43
44#define BSG_LIST_ARRAY_SIZE 8
45static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
46
47static struct class *bsg_class;
48static int bsg_major;
49
50static inline struct hlist_head *bsg_dev_idx_hash(int index)
51{
52 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
53}
54
55#define uptr64(val) ((void __user *)(uintptr_t)(val))
56
57static int bsg_scsi_check_proto(struct sg_io_v4 *hdr)
58{
59 if (hdr->protocol != BSG_PROTOCOL_SCSI ||
60 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
61 return -EINVAL;
62 return 0;
63}
64
65static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
66 fmode_t mode)
67{
68 struct scsi_request *sreq = scsi_req(rq);
69
70 if (hdr->dout_xfer_len && hdr->din_xfer_len) {
71 pr_warn_once("BIDI support in bsg has been removed.\n");
72 return -EOPNOTSUPP;
73 }
74
75 sreq->cmd_len = hdr->request_len;
76 if (sreq->cmd_len > BLK_MAX_CDB) {
77 sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
78 if (!sreq->cmd)
79 return -ENOMEM;
80 }
81
82 if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
83 return -EFAULT;
84 if (blk_verify_command(sreq->cmd, mode))
85 return -EPERM;
86 return 0;
87}
88
89static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
90{
91 struct scsi_request *sreq = scsi_req(rq);
92 int ret = 0;
93
94
95
96
97 hdr->device_status = sreq->result & 0xff;
98 hdr->transport_status = host_byte(sreq->result);
99 hdr->driver_status = driver_byte(sreq->result);
100 hdr->info = 0;
101 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
102 hdr->info |= SG_INFO_CHECK;
103 hdr->response_len = 0;
104
105 if (sreq->sense_len && hdr->response) {
106 int len = min_t(unsigned int, hdr->max_response_len,
107 sreq->sense_len);
108
109 if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
110 ret = -EFAULT;
111 else
112 hdr->response_len = len;
113 }
114
115 if (rq_data_dir(rq) == READ)
116 hdr->din_resid = sreq->resid_len;
117 else
118 hdr->dout_resid = sreq->resid_len;
119
120 return ret;
121}
122
123static void bsg_scsi_free_rq(struct request *rq)
124{
125 scsi_req_free_cmd(scsi_req(rq));
126}
127
128static const struct bsg_ops bsg_scsi_ops = {
129 .check_proto = bsg_scsi_check_proto,
130 .fill_hdr = bsg_scsi_fill_hdr,
131 .complete_rq = bsg_scsi_complete_rq,
132 .free_rq = bsg_scsi_free_rq,
133};
134
135static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
136{
137 struct request *rq;
138 struct bio *bio;
139 struct sg_io_v4 hdr;
140 int ret;
141
142 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
143 return -EFAULT;
144
145 if (!q->bsg_dev.class_dev)
146 return -ENXIO;
147
148 if (hdr.guard != 'Q')
149 return -EINVAL;
150 ret = q->bsg_dev.ops->check_proto(&hdr);
151 if (ret)
152 return ret;
153
154 rq = blk_get_request(q, hdr.dout_xfer_len ?
155 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
156 if (IS_ERR(rq))
157 return PTR_ERR(rq);
158
159 ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
160 if (ret) {
161 blk_put_request(rq);
162 return ret;
163 }
164
165 rq->timeout = msecs_to_jiffies(hdr.timeout);
166 if (!rq->timeout)
167 rq->timeout = q->sg_timeout;
168 if (!rq->timeout)
169 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
170 if (rq->timeout < BLK_MIN_SG_TIMEOUT)
171 rq->timeout = BLK_MIN_SG_TIMEOUT;
172
173 if (hdr.dout_xfer_len) {
174 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
175 hdr.dout_xfer_len, GFP_KERNEL);
176 } else if (hdr.din_xfer_len) {
177 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp),
178 hdr.din_xfer_len, GFP_KERNEL);
179 }
180
181 if (ret)
182 goto out_free_rq;
183
184 bio = rq->bio;
185
186 blk_execute_rq(NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
187 ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
188 blk_rq_unmap_user(bio);
189
190out_free_rq:
191 rq->q->bsg_dev.ops->free_rq(rq);
192 blk_put_request(rq);
193 if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
194 return -EFAULT;
195 return ret;
196}
197
198static struct bsg_device *bsg_alloc_device(void)
199{
200 struct bsg_device *bd;
201
202 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
203 if (unlikely(!bd))
204 return NULL;
205
206 spin_lock_init(&bd->lock);
207 bd->max_queue = BSG_DEFAULT_CMDS;
208 INIT_HLIST_NODE(&bd->dev_list);
209 return bd;
210}
211
212static int bsg_put_device(struct bsg_device *bd)
213{
214 struct request_queue *q = bd->queue;
215
216 mutex_lock(&bsg_mutex);
217
218 if (!refcount_dec_and_test(&bd->ref_count)) {
219 mutex_unlock(&bsg_mutex);
220 return 0;
221 }
222
223 hlist_del(&bd->dev_list);
224 mutex_unlock(&bsg_mutex);
225
226 bsg_dbg(bd, "tearing down\n");
227
228
229
230
231 kfree(bd);
232 blk_put_queue(q);
233 return 0;
234}
235
236static struct bsg_device *bsg_add_device(struct inode *inode,
237 struct request_queue *rq,
238 struct file *file)
239{
240 struct bsg_device *bd;
241 unsigned char buf[32];
242
243 lockdep_assert_held(&bsg_mutex);
244
245 if (!blk_get_queue(rq))
246 return ERR_PTR(-ENXIO);
247
248 bd = bsg_alloc_device();
249 if (!bd) {
250 blk_put_queue(rq);
251 return ERR_PTR(-ENOMEM);
252 }
253
254 bd->queue = rq;
255
256 refcount_set(&bd->ref_count, 1);
257 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
258
259 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
260 bsg_dbg(bd, "bound to <%s>, max queue %d\n",
261 format_dev_t(buf, inode->i_rdev), bd->max_queue);
262
263 return bd;
264}
265
266static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
267{
268 struct bsg_device *bd;
269
270 lockdep_assert_held(&bsg_mutex);
271
272 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
273 if (bd->queue == q) {
274 refcount_inc(&bd->ref_count);
275 goto found;
276 }
277 }
278 bd = NULL;
279found:
280 return bd;
281}
282
283static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
284{
285 struct bsg_device *bd;
286 struct bsg_class_device *bcd;
287
288
289
290
291 mutex_lock(&bsg_mutex);
292 bcd = idr_find(&bsg_minor_idr, iminor(inode));
293
294 if (!bcd) {
295 bd = ERR_PTR(-ENODEV);
296 goto out_unlock;
297 }
298
299 bd = __bsg_get_device(iminor(inode), bcd->queue);
300 if (!bd)
301 bd = bsg_add_device(inode, bcd->queue, file);
302
303out_unlock:
304 mutex_unlock(&bsg_mutex);
305 return bd;
306}
307
308static int bsg_open(struct inode *inode, struct file *file)
309{
310 struct bsg_device *bd;
311
312 bd = bsg_get_device(inode, file);
313
314 if (IS_ERR(bd))
315 return PTR_ERR(bd);
316
317 file->private_data = bd;
318 return 0;
319}
320
321static int bsg_release(struct inode *inode, struct file *file)
322{
323 struct bsg_device *bd = file->private_data;
324
325 file->private_data = NULL;
326 return bsg_put_device(bd);
327}
328
329static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
330{
331 return put_user(bd->max_queue, uarg);
332}
333
334static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
335{
336 int queue;
337
338 if (get_user(queue, uarg))
339 return -EFAULT;
340 if (queue < 1)
341 return -EINVAL;
342
343 spin_lock_irq(&bd->lock);
344 bd->max_queue = queue;
345 spin_unlock_irq(&bd->lock);
346 return 0;
347}
348
349static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
350{
351 struct bsg_device *bd = file->private_data;
352 void __user *uarg = (void __user *) arg;
353
354 switch (cmd) {
355
356
357
358 case SG_GET_COMMAND_Q:
359 return bsg_get_command_q(bd, uarg);
360 case SG_SET_COMMAND_Q:
361 return bsg_set_command_q(bd, uarg);
362
363
364
365
366 case SG_GET_VERSION_NUM:
367 case SCSI_IOCTL_GET_IDLUN:
368 case SCSI_IOCTL_GET_BUS_NUMBER:
369 case SG_SET_TIMEOUT:
370 case SG_GET_TIMEOUT:
371 case SG_GET_RESERVED_SIZE:
372 case SG_SET_RESERVED_SIZE:
373 case SG_EMULATED_HOST:
374 case SCSI_IOCTL_SEND_COMMAND:
375 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
376 case SG_IO:
377 return bsg_sg_io(bd->queue, file->f_mode, uarg);
378 default:
379 return -ENOTTY;
380 }
381}
382
383static const struct file_operations bsg_fops = {
384 .open = bsg_open,
385 .release = bsg_release,
386 .unlocked_ioctl = bsg_ioctl,
387 .compat_ioctl = compat_ptr_ioctl,
388 .owner = THIS_MODULE,
389 .llseek = default_llseek,
390};
391
392void bsg_unregister_queue(struct request_queue *q)
393{
394 struct bsg_class_device *bcd = &q->bsg_dev;
395
396 if (!bcd->class_dev)
397 return;
398
399 mutex_lock(&bsg_mutex);
400 idr_remove(&bsg_minor_idr, bcd->minor);
401 if (q->kobj.sd)
402 sysfs_remove_link(&q->kobj, "bsg");
403 device_unregister(bcd->class_dev);
404 bcd->class_dev = NULL;
405 mutex_unlock(&bsg_mutex);
406}
407EXPORT_SYMBOL_GPL(bsg_unregister_queue);
408
409int bsg_register_queue(struct request_queue *q, struct device *parent,
410 const char *name, const struct bsg_ops *ops)
411{
412 struct bsg_class_device *bcd;
413 dev_t dev;
414 int ret;
415 struct device *class_dev = NULL;
416
417
418
419
420 if (!queue_is_mq(q))
421 return 0;
422
423 bcd = &q->bsg_dev;
424 memset(bcd, 0, sizeof(*bcd));
425
426 mutex_lock(&bsg_mutex);
427
428 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
429 if (ret < 0) {
430 if (ret == -ENOSPC) {
431 printk(KERN_ERR "bsg: too many bsg devices\n");
432 ret = -EINVAL;
433 }
434 goto unlock;
435 }
436
437 bcd->minor = ret;
438 bcd->queue = q;
439 bcd->ops = ops;
440 dev = MKDEV(bsg_major, bcd->minor);
441 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
442 if (IS_ERR(class_dev)) {
443 ret = PTR_ERR(class_dev);
444 goto idr_remove;
445 }
446 bcd->class_dev = class_dev;
447
448 if (q->kobj.sd) {
449 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
450 if (ret)
451 goto unregister_class_dev;
452 }
453
454 mutex_unlock(&bsg_mutex);
455 return 0;
456
457unregister_class_dev:
458 device_unregister(class_dev);
459idr_remove:
460 idr_remove(&bsg_minor_idr, bcd->minor);
461unlock:
462 mutex_unlock(&bsg_mutex);
463 return ret;
464}
465
466int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
467{
468 if (!blk_queue_scsi_passthrough(q)) {
469 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
470 return -EINVAL;
471 }
472
473 return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
474}
475EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
476
477static struct cdev bsg_cdev;
478
479static char *bsg_devnode(struct device *dev, umode_t *mode)
480{
481 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
482}
483
484static int __init bsg_init(void)
485{
486 int ret, i;
487 dev_t devid;
488
489 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
490 INIT_HLIST_HEAD(&bsg_device_list[i]);
491
492 bsg_class = class_create(THIS_MODULE, "bsg");
493 if (IS_ERR(bsg_class))
494 return PTR_ERR(bsg_class);
495 bsg_class->devnode = bsg_devnode;
496
497 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
498 if (ret)
499 goto destroy_bsg_class;
500
501 bsg_major = MAJOR(devid);
502
503 cdev_init(&bsg_cdev, &bsg_fops);
504 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
505 if (ret)
506 goto unregister_chrdev;
507
508 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
509 " loaded (major %d)\n", bsg_major);
510 return 0;
511unregister_chrdev:
512 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
513destroy_bsg_class:
514 class_destroy(bsg_class);
515 return ret;
516}
517
518MODULE_AUTHOR("Jens Axboe");
519MODULE_DESCRIPTION(BSG_DESCRIPTION);
520MODULE_LICENSE("GPL");
521
522device_initcall(bsg_init);
523
