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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bsg.c - block layer implementation of the sg v4 interface
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/sg.h>
19
20#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
21#define BSG_VERSION "0.4"
22
23struct bsg_device {
24 struct request_queue *queue;
25 struct device device;
26 struct cdev cdev;
27 int max_queue;
28 unsigned int timeout;
29 unsigned int reserved_size;
30 bsg_sg_io_fn *sg_io_fn;
31};
32
33static inline struct bsg_device *to_bsg_device(struct inode *inode)
34{
35 return container_of(inode->i_cdev, struct bsg_device, cdev);
36}
37
38#define BSG_DEFAULT_CMDS 64
39#define BSG_MAX_DEVS 32768
40
41static DEFINE_IDA(bsg_minor_ida);
42static struct class *bsg_class;
43static int bsg_major;
44
45static unsigned int bsg_timeout(struct bsg_device *bd, struct sg_io_v4 *hdr)
46{
47 unsigned int timeout = BLK_DEFAULT_SG_TIMEOUT;
48
49 if (hdr->timeout)
50 timeout = msecs_to_jiffies(hdr->timeout);
51 else if (bd->timeout)
52 timeout = bd->timeout;
53
54 return max_t(unsigned int, timeout, BLK_MIN_SG_TIMEOUT);
55}
56
57static int bsg_sg_io(struct bsg_device *bd, fmode_t mode, void __user *uarg)
58{
59 struct sg_io_v4 hdr;
60 int ret;
61
62 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
63 return -EFAULT;
64 if (hdr.guard != 'Q')
65 return -EINVAL;
66 ret = bd->sg_io_fn(bd->queue, &hdr, mode, bsg_timeout(bd, &hdr));
67 if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
68 return -EFAULT;
69 return ret;
70}
71
72static int bsg_open(struct inode *inode, struct file *file)
73{
74 if (!blk_get_queue(to_bsg_device(inode)->queue))
75 return -ENXIO;
76 return 0;
77}
78
79static int bsg_release(struct inode *inode, struct file *file)
80{
81 blk_put_queue(to_bsg_device(inode)->queue);
82 return 0;
83}
84
85static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
86{
87 return put_user(READ_ONCE(bd->max_queue), uarg);
88}
89
90static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
91{
92 int max_queue;
93
94 if (get_user(max_queue, uarg))
95 return -EFAULT;
96 if (max_queue < 1)
97 return -EINVAL;
98 WRITE_ONCE(bd->max_queue, max_queue);
99 return 0;
100}
101
102static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
103{
104 struct bsg_device *bd = to_bsg_device(file_inode(file));
105 struct request_queue *q = bd->queue;
106 void __user *uarg = (void __user *) arg;
107 int __user *intp = uarg;
108 int val;
109
110 switch (cmd) {
111 /*
112 * Our own ioctls
113 */
114 case SG_GET_COMMAND_Q:
115 return bsg_get_command_q(bd, uarg);
116 case SG_SET_COMMAND_Q:
117 return bsg_set_command_q(bd, uarg);
118
119 /*
120 * SCSI/sg ioctls
121 */
122 case SG_GET_VERSION_NUM:
123 return put_user(30527, intp);
124 case SCSI_IOCTL_GET_IDLUN:
125 return put_user(0, intp);
126 case SCSI_IOCTL_GET_BUS_NUMBER:
127 return put_user(0, intp);
128 case SG_SET_TIMEOUT:
129 if (get_user(val, intp))
130 return -EFAULT;
131 bd->timeout = clock_t_to_jiffies(val);
132 return 0;
133 case SG_GET_TIMEOUT:
134 return jiffies_to_clock_t(bd->timeout);
135 case SG_GET_RESERVED_SIZE:
136 return put_user(min(bd->reserved_size, queue_max_bytes(q)),
137 intp);
138 case SG_SET_RESERVED_SIZE:
139 if (get_user(val, intp))
140 return -EFAULT;
141 if (val < 0)
142 return -EINVAL;
143 bd->reserved_size =
144 min_t(unsigned int, val, queue_max_bytes(q));
145 return 0;
146 case SG_EMULATED_HOST:
147 return put_user(1, intp);
148 case SG_IO:
149 return bsg_sg_io(bd, file->f_mode, uarg);
150 case SCSI_IOCTL_SEND_COMMAND:
151 pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",
152 current->comm);
153 return -EINVAL;
154 default:
155 return -ENOTTY;
156 }
157}
158
159static const struct file_operations bsg_fops = {
160 .open = bsg_open,
161 .release = bsg_release,
162 .unlocked_ioctl = bsg_ioctl,
163 .compat_ioctl = compat_ptr_ioctl,
164 .owner = THIS_MODULE,
165 .llseek = default_llseek,
166};
167
168static void bsg_device_release(struct device *dev)
169{
170 struct bsg_device *bd = container_of(dev, struct bsg_device, device);
171
172 ida_free(&bsg_minor_ida, MINOR(bd->device.devt));
173 kfree(bd);
174}
175
176void bsg_unregister_queue(struct bsg_device *bd)
177{
178 struct gendisk *disk = bd->queue->disk;
179
180 if (disk && disk->queue_kobj.sd)
181 sysfs_remove_link(&disk->queue_kobj, "bsg");
182 cdev_device_del(&bd->cdev, &bd->device);
183 put_device(&bd->device);
184}
185EXPORT_SYMBOL_GPL(bsg_unregister_queue);
186
187struct bsg_device *bsg_register_queue(struct request_queue *q,
188 struct device *parent, const char *name, bsg_sg_io_fn *sg_io_fn)
189{
190 struct bsg_device *bd;
191 int ret;
192
193 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
194 if (!bd)
195 return ERR_PTR(-ENOMEM);
196 bd->max_queue = BSG_DEFAULT_CMDS;
197 bd->reserved_size = INT_MAX;
198 bd->queue = q;
199 bd->sg_io_fn = sg_io_fn;
200
201 ret = ida_alloc_max(&bsg_minor_ida, BSG_MAX_DEVS - 1, GFP_KERNEL);
202 if (ret < 0) {
203 if (ret == -ENOSPC)
204 dev_err(parent, "bsg: too many bsg devices\n");
205 kfree(bd);
206 return ERR_PTR(ret);
207 }
208 bd->device.devt = MKDEV(bsg_major, ret);
209 bd->device.class = bsg_class;
210 bd->device.parent = parent;
211 bd->device.release = bsg_device_release;
212 dev_set_name(&bd->device, "%s", name);
213 device_initialize(&bd->device);
214
215 cdev_init(&bd->cdev, &bsg_fops);
216 bd->cdev.owner = THIS_MODULE;
217 ret = cdev_device_add(&bd->cdev, &bd->device);
218 if (ret)
219 goto out_put_device;
220
221 if (q->disk && q->disk->queue_kobj.sd) {
222 ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj,
223 "bsg");
224 if (ret)
225 goto out_device_del;
226 }
227
228 return bd;
229
230out_device_del:
231 cdev_device_del(&bd->cdev, &bd->device);
232out_put_device:
233 put_device(&bd->device);
234 return ERR_PTR(ret);
235}
236EXPORT_SYMBOL_GPL(bsg_register_queue);
237
238static char *bsg_devnode(const struct device *dev, umode_t *mode)
239{
240 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
241}
242
243static int __init bsg_init(void)
244{
245 dev_t devid;
246 int ret;
247
248 bsg_class = class_create(THIS_MODULE, "bsg");
249 if (IS_ERR(bsg_class))
250 return PTR_ERR(bsg_class);
251 bsg_class->devnode = bsg_devnode;
252
253 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
254 if (ret)
255 goto destroy_bsg_class;
256 bsg_major = MAJOR(devid);
257
258 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
259 " loaded (major %d)\n", bsg_major);
260 return 0;
261
262destroy_bsg_class:
263 class_destroy(bsg_class);
264 return ret;
265}
266
267MODULE_AUTHOR("Jens Axboe");
268MODULE_DESCRIPTION(BSG_DESCRIPTION);
269MODULE_LICENSE("GPL");
270
271device_initcall(bsg_init);
1/*
2 * bsg.c - block layer implementation of the sg v4 interface
3 *
4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License version 2. See the file "COPYING" in the main directory of this
9 * archive for more details.
10 *
11 */
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/file.h>
15#include <linux/blkdev.h>
16#include <linux/poll.h>
17#include <linux/cdev.h>
18#include <linux/jiffies.h>
19#include <linux/percpu.h>
20#include <linux/uio.h>
21#include <linux/idr.h>
22#include <linux/bsg.h>
23#include <linux/slab.h>
24
25#include <scsi/scsi.h>
26#include <scsi/scsi_ioctl.h>
27#include <scsi/scsi_cmnd.h>
28#include <scsi/scsi_device.h>
29#include <scsi/scsi_driver.h>
30#include <scsi/sg.h>
31
32#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
33#define BSG_VERSION "0.4"
34
35#define bsg_dbg(bd, fmt, ...) \
36 pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
37
38struct bsg_device {
39 struct request_queue *queue;
40 spinlock_t lock;
41 struct list_head busy_list;
42 struct list_head done_list;
43 struct hlist_node dev_list;
44 atomic_t ref_count;
45 int queued_cmds;
46 int done_cmds;
47 wait_queue_head_t wq_done;
48 wait_queue_head_t wq_free;
49 char name[20];
50 int max_queue;
51 unsigned long flags;
52};
53
54enum {
55 BSG_F_BLOCK = 1,
56};
57
58#define BSG_DEFAULT_CMDS 64
59#define BSG_MAX_DEVS 32768
60
61static DEFINE_MUTEX(bsg_mutex);
62static DEFINE_IDR(bsg_minor_idr);
63
64#define BSG_LIST_ARRAY_SIZE 8
65static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
66
67static struct class *bsg_class;
68static int bsg_major;
69
70static struct kmem_cache *bsg_cmd_cachep;
71
72/*
73 * our internal command type
74 */
75struct bsg_command {
76 struct bsg_device *bd;
77 struct list_head list;
78 struct request *rq;
79 struct bio *bio;
80 struct bio *bidi_bio;
81 int err;
82 struct sg_io_v4 hdr;
83};
84
85static void bsg_free_command(struct bsg_command *bc)
86{
87 struct bsg_device *bd = bc->bd;
88 unsigned long flags;
89
90 kmem_cache_free(bsg_cmd_cachep, bc);
91
92 spin_lock_irqsave(&bd->lock, flags);
93 bd->queued_cmds--;
94 spin_unlock_irqrestore(&bd->lock, flags);
95
96 wake_up(&bd->wq_free);
97}
98
99static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
100{
101 struct bsg_command *bc = ERR_PTR(-EINVAL);
102
103 spin_lock_irq(&bd->lock);
104
105 if (bd->queued_cmds >= bd->max_queue)
106 goto out;
107
108 bd->queued_cmds++;
109 spin_unlock_irq(&bd->lock);
110
111 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
112 if (unlikely(!bc)) {
113 spin_lock_irq(&bd->lock);
114 bd->queued_cmds--;
115 bc = ERR_PTR(-ENOMEM);
116 goto out;
117 }
118
119 bc->bd = bd;
120 INIT_LIST_HEAD(&bc->list);
121 bsg_dbg(bd, "returning free cmd %p\n", bc);
122 return bc;
123out:
124 spin_unlock_irq(&bd->lock);
125 return bc;
126}
127
128static inline struct hlist_head *bsg_dev_idx_hash(int index)
129{
130 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
131}
132
133#define uptr64(val) ((void __user *)(uintptr_t)(val))
134
135static int bsg_scsi_check_proto(struct sg_io_v4 *hdr)
136{
137 if (hdr->protocol != BSG_PROTOCOL_SCSI ||
138 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
139 return -EINVAL;
140 return 0;
141}
142
143static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
144 fmode_t mode)
145{
146 struct scsi_request *sreq = scsi_req(rq);
147
148 sreq->cmd_len = hdr->request_len;
149 if (sreq->cmd_len > BLK_MAX_CDB) {
150 sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
151 if (!sreq->cmd)
152 return -ENOMEM;
153 }
154
155 if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
156 return -EFAULT;
157 if (blk_verify_command(sreq->cmd, mode))
158 return -EPERM;
159 return 0;
160}
161
162static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
163{
164 struct scsi_request *sreq = scsi_req(rq);
165 int ret = 0;
166
167 /*
168 * fill in all the output members
169 */
170 hdr->device_status = sreq->result & 0xff;
171 hdr->transport_status = host_byte(sreq->result);
172 hdr->driver_status = driver_byte(sreq->result);
173 hdr->info = 0;
174 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
175 hdr->info |= SG_INFO_CHECK;
176 hdr->response_len = 0;
177
178 if (sreq->sense_len && hdr->response) {
179 int len = min_t(unsigned int, hdr->max_response_len,
180 sreq->sense_len);
181
182 if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
183 ret = -EFAULT;
184 else
185 hdr->response_len = len;
186 }
187
188 if (rq->next_rq) {
189 hdr->dout_resid = sreq->resid_len;
190 hdr->din_resid = scsi_req(rq->next_rq)->resid_len;
191 } else if (rq_data_dir(rq) == READ) {
192 hdr->din_resid = sreq->resid_len;
193 } else {
194 hdr->dout_resid = sreq->resid_len;
195 }
196
197 return ret;
198}
199
200static void bsg_scsi_free_rq(struct request *rq)
201{
202 scsi_req_free_cmd(scsi_req(rq));
203}
204
205static const struct bsg_ops bsg_scsi_ops = {
206 .check_proto = bsg_scsi_check_proto,
207 .fill_hdr = bsg_scsi_fill_hdr,
208 .complete_rq = bsg_scsi_complete_rq,
209 .free_rq = bsg_scsi_free_rq,
210};
211
212static struct request *
213bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
214{
215 struct request *rq, *next_rq = NULL;
216 int ret;
217
218 if (!q->bsg_dev.class_dev)
219 return ERR_PTR(-ENXIO);
220
221 if (hdr->guard != 'Q')
222 return ERR_PTR(-EINVAL);
223
224 ret = q->bsg_dev.ops->check_proto(hdr);
225 if (ret)
226 return ERR_PTR(ret);
227
228 rq = blk_get_request(q, hdr->dout_xfer_len ?
229 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
230 GFP_KERNEL);
231 if (IS_ERR(rq))
232 return rq;
233
234 ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode);
235 if (ret)
236 goto out;
237
238 rq->timeout = msecs_to_jiffies(hdr->timeout);
239 if (!rq->timeout)
240 rq->timeout = q->sg_timeout;
241 if (!rq->timeout)
242 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
243 if (rq->timeout < BLK_MIN_SG_TIMEOUT)
244 rq->timeout = BLK_MIN_SG_TIMEOUT;
245
246 if (hdr->dout_xfer_len && hdr->din_xfer_len) {
247 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
248 ret = -EOPNOTSUPP;
249 goto out;
250 }
251
252 next_rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL);
253 if (IS_ERR(next_rq)) {
254 ret = PTR_ERR(next_rq);
255 goto out;
256 }
257
258 rq->next_rq = next_rq;
259 ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp),
260 hdr->din_xfer_len, GFP_KERNEL);
261 if (ret)
262 goto out_free_nextrq;
263 }
264
265 if (hdr->dout_xfer_len) {
266 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp),
267 hdr->dout_xfer_len, GFP_KERNEL);
268 } else if (hdr->din_xfer_len) {
269 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp),
270 hdr->din_xfer_len, GFP_KERNEL);
271 } else {
272 ret = blk_rq_map_user(q, rq, NULL, NULL, 0, GFP_KERNEL);
273 }
274
275 if (ret)
276 goto out_unmap_nextrq;
277 return rq;
278
279out_unmap_nextrq:
280 if (rq->next_rq)
281 blk_rq_unmap_user(rq->next_rq->bio);
282out_free_nextrq:
283 if (rq->next_rq)
284 blk_put_request(rq->next_rq);
285out:
286 q->bsg_dev.ops->free_rq(rq);
287 blk_put_request(rq);
288 return ERR_PTR(ret);
289}
290
291/*
292 * async completion call-back from the block layer, when scsi/ide/whatever
293 * calls end_that_request_last() on a request
294 */
295static void bsg_rq_end_io(struct request *rq, blk_status_t status)
296{
297 struct bsg_command *bc = rq->end_io_data;
298 struct bsg_device *bd = bc->bd;
299 unsigned long flags;
300
301 bsg_dbg(bd, "finished rq %p bc %p, bio %p\n",
302 rq, bc, bc->bio);
303
304 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
305
306 spin_lock_irqsave(&bd->lock, flags);
307 list_move_tail(&bc->list, &bd->done_list);
308 bd->done_cmds++;
309 spin_unlock_irqrestore(&bd->lock, flags);
310
311 wake_up(&bd->wq_done);
312}
313
314/*
315 * do final setup of a 'bc' and submit the matching 'rq' to the block
316 * layer for io
317 */
318static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
319 struct bsg_command *bc, struct request *rq)
320{
321 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));
322
323 /*
324 * add bc command to busy queue and submit rq for io
325 */
326 bc->rq = rq;
327 bc->bio = rq->bio;
328 if (rq->next_rq)
329 bc->bidi_bio = rq->next_rq->bio;
330 bc->hdr.duration = jiffies;
331 spin_lock_irq(&bd->lock);
332 list_add_tail(&bc->list, &bd->busy_list);
333 spin_unlock_irq(&bd->lock);
334
335 bsg_dbg(bd, "queueing rq %p, bc %p\n", rq, bc);
336
337 rq->end_io_data = bc;
338 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io);
339}
340
341static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
342{
343 struct bsg_command *bc = NULL;
344
345 spin_lock_irq(&bd->lock);
346 if (bd->done_cmds) {
347 bc = list_first_entry(&bd->done_list, struct bsg_command, list);
348 list_del(&bc->list);
349 bd->done_cmds--;
350 }
351 spin_unlock_irq(&bd->lock);
352
353 return bc;
354}
355
356/*
357 * Get a finished command from the done list
358 */
359static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
360{
361 struct bsg_command *bc;
362 int ret;
363
364 do {
365 bc = bsg_next_done_cmd(bd);
366 if (bc)
367 break;
368
369 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
370 bc = ERR_PTR(-EAGAIN);
371 break;
372 }
373
374 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
375 if (ret) {
376 bc = ERR_PTR(-ERESTARTSYS);
377 break;
378 }
379 } while (1);
380
381 bsg_dbg(bd, "returning done %p\n", bc);
382
383 return bc;
384}
385
386static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
387 struct bio *bio, struct bio *bidi_bio)
388{
389 int ret;
390
391 ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr);
392
393 if (rq->next_rq) {
394 blk_rq_unmap_user(bidi_bio);
395 blk_put_request(rq->next_rq);
396 }
397
398 blk_rq_unmap_user(bio);
399 rq->q->bsg_dev.ops->free_rq(rq);
400 blk_put_request(rq);
401 return ret;
402}
403
404static bool bsg_complete(struct bsg_device *bd)
405{
406 bool ret = false;
407 bool spin;
408
409 do {
410 spin_lock_irq(&bd->lock);
411
412 BUG_ON(bd->done_cmds > bd->queued_cmds);
413
414 /*
415 * All commands consumed.
416 */
417 if (bd->done_cmds == bd->queued_cmds)
418 ret = true;
419
420 spin = !test_bit(BSG_F_BLOCK, &bd->flags);
421
422 spin_unlock_irq(&bd->lock);
423 } while (!ret && spin);
424
425 return ret;
426}
427
428static int bsg_complete_all_commands(struct bsg_device *bd)
429{
430 struct bsg_command *bc;
431 int ret, tret;
432
433 bsg_dbg(bd, "entered\n");
434
435 /*
436 * wait for all commands to complete
437 */
438 io_wait_event(bd->wq_done, bsg_complete(bd));
439
440 /*
441 * discard done commands
442 */
443 ret = 0;
444 do {
445 spin_lock_irq(&bd->lock);
446 if (!bd->queued_cmds) {
447 spin_unlock_irq(&bd->lock);
448 break;
449 }
450 spin_unlock_irq(&bd->lock);
451
452 bc = bsg_get_done_cmd(bd);
453 if (IS_ERR(bc))
454 break;
455
456 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
457 bc->bidi_bio);
458 if (!ret)
459 ret = tret;
460
461 bsg_free_command(bc);
462 } while (1);
463
464 return ret;
465}
466
467static int
468__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
469 const struct iovec *iov, ssize_t *bytes_read)
470{
471 struct bsg_command *bc;
472 int nr_commands, ret;
473
474 if (count % sizeof(struct sg_io_v4))
475 return -EINVAL;
476
477 ret = 0;
478 nr_commands = count / sizeof(struct sg_io_v4);
479 while (nr_commands) {
480 bc = bsg_get_done_cmd(bd);
481 if (IS_ERR(bc)) {
482 ret = PTR_ERR(bc);
483 break;
484 }
485
486 /*
487 * this is the only case where we need to copy data back
488 * after completing the request. so do that here,
489 * bsg_complete_work() cannot do that for us
490 */
491 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
492 bc->bidi_bio);
493
494 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
495 ret = -EFAULT;
496
497 bsg_free_command(bc);
498
499 if (ret)
500 break;
501
502 buf += sizeof(struct sg_io_v4);
503 *bytes_read += sizeof(struct sg_io_v4);
504 nr_commands--;
505 }
506
507 return ret;
508}
509
510static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
511{
512 if (file->f_flags & O_NONBLOCK)
513 clear_bit(BSG_F_BLOCK, &bd->flags);
514 else
515 set_bit(BSG_F_BLOCK, &bd->flags);
516}
517
518/*
519 * Check if the error is a "real" error that we should return.
520 */
521static inline int err_block_err(int ret)
522{
523 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
524 return 1;
525
526 return 0;
527}
528
529static ssize_t
530bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
531{
532 struct bsg_device *bd = file->private_data;
533 int ret;
534 ssize_t bytes_read;
535
536 bsg_dbg(bd, "read %zd bytes\n", count);
537
538 bsg_set_block(bd, file);
539
540 bytes_read = 0;
541 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
542 *ppos = bytes_read;
543
544 if (!bytes_read || err_block_err(ret))
545 bytes_read = ret;
546
547 return bytes_read;
548}
549
550static int __bsg_write(struct bsg_device *bd, const char __user *buf,
551 size_t count, ssize_t *bytes_written, fmode_t mode)
552{
553 struct bsg_command *bc;
554 struct request *rq;
555 int ret, nr_commands;
556
557 if (count % sizeof(struct sg_io_v4))
558 return -EINVAL;
559
560 nr_commands = count / sizeof(struct sg_io_v4);
561 rq = NULL;
562 bc = NULL;
563 ret = 0;
564 while (nr_commands) {
565 struct request_queue *q = bd->queue;
566
567 bc = bsg_alloc_command(bd);
568 if (IS_ERR(bc)) {
569 ret = PTR_ERR(bc);
570 bc = NULL;
571 break;
572 }
573
574 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
575 ret = -EFAULT;
576 break;
577 }
578
579 /*
580 * get a request, fill in the blanks, and add to request queue
581 */
582 rq = bsg_map_hdr(bd->queue, &bc->hdr, mode);
583 if (IS_ERR(rq)) {
584 ret = PTR_ERR(rq);
585 rq = NULL;
586 break;
587 }
588
589 bsg_add_command(bd, q, bc, rq);
590 bc = NULL;
591 rq = NULL;
592 nr_commands--;
593 buf += sizeof(struct sg_io_v4);
594 *bytes_written += sizeof(struct sg_io_v4);
595 }
596
597 if (bc)
598 bsg_free_command(bc);
599
600 return ret;
601}
602
603static ssize_t
604bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
605{
606 struct bsg_device *bd = file->private_data;
607 ssize_t bytes_written;
608 int ret;
609
610 bsg_dbg(bd, "write %zd bytes\n", count);
611
612 if (unlikely(uaccess_kernel()))
613 return -EINVAL;
614
615 bsg_set_block(bd, file);
616
617 bytes_written = 0;
618 ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode);
619
620 *ppos = bytes_written;
621
622 /*
623 * return bytes written on non-fatal errors
624 */
625 if (!bytes_written || err_block_err(ret))
626 bytes_written = ret;
627
628 bsg_dbg(bd, "returning %zd\n", bytes_written);
629 return bytes_written;
630}
631
632static struct bsg_device *bsg_alloc_device(void)
633{
634 struct bsg_device *bd;
635
636 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
637 if (unlikely(!bd))
638 return NULL;
639
640 spin_lock_init(&bd->lock);
641
642 bd->max_queue = BSG_DEFAULT_CMDS;
643
644 INIT_LIST_HEAD(&bd->busy_list);
645 INIT_LIST_HEAD(&bd->done_list);
646 INIT_HLIST_NODE(&bd->dev_list);
647
648 init_waitqueue_head(&bd->wq_free);
649 init_waitqueue_head(&bd->wq_done);
650 return bd;
651}
652
653static void bsg_kref_release_function(struct kref *kref)
654{
655 struct bsg_class_device *bcd =
656 container_of(kref, struct bsg_class_device, ref);
657 struct device *parent = bcd->parent;
658
659 if (bcd->release)
660 bcd->release(bcd->parent);
661
662 put_device(parent);
663}
664
665static int bsg_put_device(struct bsg_device *bd)
666{
667 int ret = 0, do_free;
668 struct request_queue *q = bd->queue;
669
670 mutex_lock(&bsg_mutex);
671
672 do_free = atomic_dec_and_test(&bd->ref_count);
673 if (!do_free) {
674 mutex_unlock(&bsg_mutex);
675 goto out;
676 }
677
678 hlist_del(&bd->dev_list);
679 mutex_unlock(&bsg_mutex);
680
681 bsg_dbg(bd, "tearing down\n");
682
683 /*
684 * close can always block
685 */
686 set_bit(BSG_F_BLOCK, &bd->flags);
687
688 /*
689 * correct error detection baddies here again. it's the responsibility
690 * of the app to properly reap commands before close() if it wants
691 * fool-proof error detection
692 */
693 ret = bsg_complete_all_commands(bd);
694
695 kfree(bd);
696out:
697 kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
698 if (do_free)
699 blk_put_queue(q);
700 return ret;
701}
702
703static struct bsg_device *bsg_add_device(struct inode *inode,
704 struct request_queue *rq,
705 struct file *file)
706{
707 struct bsg_device *bd;
708 unsigned char buf[32];
709
710 if (!blk_get_queue(rq))
711 return ERR_PTR(-ENXIO);
712
713 bd = bsg_alloc_device();
714 if (!bd) {
715 blk_put_queue(rq);
716 return ERR_PTR(-ENOMEM);
717 }
718
719 bd->queue = rq;
720
721 bsg_set_block(bd, file);
722
723 atomic_set(&bd->ref_count, 1);
724 mutex_lock(&bsg_mutex);
725 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
726
727 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
728 bsg_dbg(bd, "bound to <%s>, max queue %d\n",
729 format_dev_t(buf, inode->i_rdev), bd->max_queue);
730
731 mutex_unlock(&bsg_mutex);
732 return bd;
733}
734
735static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
736{
737 struct bsg_device *bd;
738
739 mutex_lock(&bsg_mutex);
740
741 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
742 if (bd->queue == q) {
743 atomic_inc(&bd->ref_count);
744 goto found;
745 }
746 }
747 bd = NULL;
748found:
749 mutex_unlock(&bsg_mutex);
750 return bd;
751}
752
753static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
754{
755 struct bsg_device *bd;
756 struct bsg_class_device *bcd;
757
758 /*
759 * find the class device
760 */
761 mutex_lock(&bsg_mutex);
762 bcd = idr_find(&bsg_minor_idr, iminor(inode));
763 if (bcd)
764 kref_get(&bcd->ref);
765 mutex_unlock(&bsg_mutex);
766
767 if (!bcd)
768 return ERR_PTR(-ENODEV);
769
770 bd = __bsg_get_device(iminor(inode), bcd->queue);
771 if (bd)
772 return bd;
773
774 bd = bsg_add_device(inode, bcd->queue, file);
775 if (IS_ERR(bd))
776 kref_put(&bcd->ref, bsg_kref_release_function);
777
778 return bd;
779}
780
781static int bsg_open(struct inode *inode, struct file *file)
782{
783 struct bsg_device *bd;
784
785 bd = bsg_get_device(inode, file);
786
787 if (IS_ERR(bd))
788 return PTR_ERR(bd);
789
790 file->private_data = bd;
791 return 0;
792}
793
794static int bsg_release(struct inode *inode, struct file *file)
795{
796 struct bsg_device *bd = file->private_data;
797
798 file->private_data = NULL;
799 return bsg_put_device(bd);
800}
801
802static __poll_t bsg_poll(struct file *file, poll_table *wait)
803{
804 struct bsg_device *bd = file->private_data;
805 __poll_t mask = 0;
806
807 poll_wait(file, &bd->wq_done, wait);
808 poll_wait(file, &bd->wq_free, wait);
809
810 spin_lock_irq(&bd->lock);
811 if (!list_empty(&bd->done_list))
812 mask |= EPOLLIN | EPOLLRDNORM;
813 if (bd->queued_cmds < bd->max_queue)
814 mask |= EPOLLOUT;
815 spin_unlock_irq(&bd->lock);
816
817 return mask;
818}
819
820static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
821{
822 struct bsg_device *bd = file->private_data;
823 int __user *uarg = (int __user *) arg;
824 int ret;
825
826 switch (cmd) {
827 /*
828 * our own ioctls
829 */
830 case SG_GET_COMMAND_Q:
831 return put_user(bd->max_queue, uarg);
832 case SG_SET_COMMAND_Q: {
833 int queue;
834
835 if (get_user(queue, uarg))
836 return -EFAULT;
837 if (queue < 1)
838 return -EINVAL;
839
840 spin_lock_irq(&bd->lock);
841 bd->max_queue = queue;
842 spin_unlock_irq(&bd->lock);
843 return 0;
844 }
845
846 /*
847 * SCSI/sg ioctls
848 */
849 case SG_GET_VERSION_NUM:
850 case SCSI_IOCTL_GET_IDLUN:
851 case SCSI_IOCTL_GET_BUS_NUMBER:
852 case SG_SET_TIMEOUT:
853 case SG_GET_TIMEOUT:
854 case SG_GET_RESERVED_SIZE:
855 case SG_SET_RESERVED_SIZE:
856 case SG_EMULATED_HOST:
857 case SCSI_IOCTL_SEND_COMMAND: {
858 void __user *uarg = (void __user *) arg;
859 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
860 }
861 case SG_IO: {
862 struct request *rq;
863 struct bio *bio, *bidi_bio = NULL;
864 struct sg_io_v4 hdr;
865 int at_head;
866
867 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
868 return -EFAULT;
869
870 rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode);
871 if (IS_ERR(rq))
872 return PTR_ERR(rq);
873
874 bio = rq->bio;
875 if (rq->next_rq)
876 bidi_bio = rq->next_rq->bio;
877
878 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
879 blk_execute_rq(bd->queue, NULL, rq, at_head);
880 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
881
882 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
883 return -EFAULT;
884
885 return ret;
886 }
887 default:
888 return -ENOTTY;
889 }
890}
891
892static const struct file_operations bsg_fops = {
893 .read = bsg_read,
894 .write = bsg_write,
895 .poll = bsg_poll,
896 .open = bsg_open,
897 .release = bsg_release,
898 .unlocked_ioctl = bsg_ioctl,
899 .owner = THIS_MODULE,
900 .llseek = default_llseek,
901};
902
903void bsg_unregister_queue(struct request_queue *q)
904{
905 struct bsg_class_device *bcd = &q->bsg_dev;
906
907 if (!bcd->class_dev)
908 return;
909
910 mutex_lock(&bsg_mutex);
911 idr_remove(&bsg_minor_idr, bcd->minor);
912 if (q->kobj.sd)
913 sysfs_remove_link(&q->kobj, "bsg");
914 device_unregister(bcd->class_dev);
915 bcd->class_dev = NULL;
916 kref_put(&bcd->ref, bsg_kref_release_function);
917 mutex_unlock(&bsg_mutex);
918}
919EXPORT_SYMBOL_GPL(bsg_unregister_queue);
920
921int bsg_register_queue(struct request_queue *q, struct device *parent,
922 const char *name, const struct bsg_ops *ops,
923 void (*release)(struct device *))
924{
925 struct bsg_class_device *bcd;
926 dev_t dev;
927 int ret;
928 struct device *class_dev = NULL;
929 const char *devname;
930
931 if (name)
932 devname = name;
933 else
934 devname = dev_name(parent);
935
936 /*
937 * we need a proper transport to send commands, not a stacked device
938 */
939 if (!queue_is_rq_based(q))
940 return 0;
941
942 bcd = &q->bsg_dev;
943 memset(bcd, 0, sizeof(*bcd));
944
945 mutex_lock(&bsg_mutex);
946
947 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
948 if (ret < 0) {
949 if (ret == -ENOSPC) {
950 printk(KERN_ERR "bsg: too many bsg devices\n");
951 ret = -EINVAL;
952 }
953 goto unlock;
954 }
955
956 bcd->minor = ret;
957 bcd->queue = q;
958 bcd->parent = get_device(parent);
959 bcd->release = release;
960 bcd->ops = ops;
961 kref_init(&bcd->ref);
962 dev = MKDEV(bsg_major, bcd->minor);
963 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
964 if (IS_ERR(class_dev)) {
965 ret = PTR_ERR(class_dev);
966 goto put_dev;
967 }
968 bcd->class_dev = class_dev;
969
970 if (q->kobj.sd) {
971 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
972 if (ret)
973 goto unregister_class_dev;
974 }
975
976 mutex_unlock(&bsg_mutex);
977 return 0;
978
979unregister_class_dev:
980 device_unregister(class_dev);
981put_dev:
982 put_device(parent);
983 idr_remove(&bsg_minor_idr, bcd->minor);
984unlock:
985 mutex_unlock(&bsg_mutex);
986 return ret;
987}
988
989int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
990{
991 if (!blk_queue_scsi_passthrough(q)) {
992 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
993 return -EINVAL;
994 }
995
996 return bsg_register_queue(q, parent, NULL, &bsg_scsi_ops, NULL);
997}
998EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
999
1000static struct cdev bsg_cdev;
1001
1002static char *bsg_devnode(struct device *dev, umode_t *mode)
1003{
1004 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
1005}
1006
1007static int __init bsg_init(void)
1008{
1009 int ret, i;
1010 dev_t devid;
1011
1012 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
1013 sizeof(struct bsg_command), 0, 0, NULL);
1014 if (!bsg_cmd_cachep) {
1015 printk(KERN_ERR "bsg: failed creating slab cache\n");
1016 return -ENOMEM;
1017 }
1018
1019 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
1020 INIT_HLIST_HEAD(&bsg_device_list[i]);
1021
1022 bsg_class = class_create(THIS_MODULE, "bsg");
1023 if (IS_ERR(bsg_class)) {
1024 ret = PTR_ERR(bsg_class);
1025 goto destroy_kmemcache;
1026 }
1027 bsg_class->devnode = bsg_devnode;
1028
1029 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
1030 if (ret)
1031 goto destroy_bsg_class;
1032
1033 bsg_major = MAJOR(devid);
1034
1035 cdev_init(&bsg_cdev, &bsg_fops);
1036 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1037 if (ret)
1038 goto unregister_chrdev;
1039
1040 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
1041 " loaded (major %d)\n", bsg_major);
1042 return 0;
1043unregister_chrdev:
1044 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1045destroy_bsg_class:
1046 class_destroy(bsg_class);
1047destroy_kmemcache:
1048 kmem_cache_destroy(bsg_cmd_cachep);
1049 return ret;
1050}
1051
1052MODULE_AUTHOR("Jens Axboe");
1053MODULE_DESCRIPTION(BSG_DESCRIPTION);
1054MODULE_LICENSE("GPL");
1055
1056device_initcall(bsg_init);