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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 (1 << MINORBITS)
40
41static DEFINE_IDA(bsg_minor_ida);
42static const 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, bool open_for_write,
58 void __user *uarg)
59{
60 struct sg_io_v4 hdr;
61 int ret;
62
63 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
64 return -EFAULT;
65 if (hdr.guard != 'Q')
66 return -EINVAL;
67 ret = bd->sg_io_fn(bd->queue, &hdr, open_for_write,
68 bsg_timeout(bd, &hdr));
69 if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
70 return -EFAULT;
71 return ret;
72}
73
74static int bsg_open(struct inode *inode, struct file *file)
75{
76 if (!blk_get_queue(to_bsg_device(inode)->queue))
77 return -ENXIO;
78 return 0;
79}
80
81static int bsg_release(struct inode *inode, struct file *file)
82{
83 blk_put_queue(to_bsg_device(inode)->queue);
84 return 0;
85}
86
87static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
88{
89 return put_user(READ_ONCE(bd->max_queue), uarg);
90}
91
92static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
93{
94 int max_queue;
95
96 if (get_user(max_queue, uarg))
97 return -EFAULT;
98 if (max_queue < 1)
99 return -EINVAL;
100 WRITE_ONCE(bd->max_queue, max_queue);
101 return 0;
102}
103
104static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
105{
106 struct bsg_device *bd = to_bsg_device(file_inode(file));
107 struct request_queue *q = bd->queue;
108 void __user *uarg = (void __user *) arg;
109 int __user *intp = uarg;
110 int val;
111
112 switch (cmd) {
113 /*
114 * Our own ioctls
115 */
116 case SG_GET_COMMAND_Q:
117 return bsg_get_command_q(bd, uarg);
118 case SG_SET_COMMAND_Q:
119 return bsg_set_command_q(bd, uarg);
120
121 /*
122 * SCSI/sg ioctls
123 */
124 case SG_GET_VERSION_NUM:
125 return put_user(30527, intp);
126 case SCSI_IOCTL_GET_IDLUN:
127 return put_user(0, intp);
128 case SCSI_IOCTL_GET_BUS_NUMBER:
129 return put_user(0, intp);
130 case SG_SET_TIMEOUT:
131 if (get_user(val, intp))
132 return -EFAULT;
133 bd->timeout = clock_t_to_jiffies(val);
134 return 0;
135 case SG_GET_TIMEOUT:
136 return jiffies_to_clock_t(bd->timeout);
137 case SG_GET_RESERVED_SIZE:
138 return put_user(min(bd->reserved_size, queue_max_bytes(q)),
139 intp);
140 case SG_SET_RESERVED_SIZE:
141 if (get_user(val, intp))
142 return -EFAULT;
143 if (val < 0)
144 return -EINVAL;
145 bd->reserved_size =
146 min_t(unsigned int, val, queue_max_bytes(q));
147 return 0;
148 case SG_EMULATED_HOST:
149 return put_user(1, intp);
150 case SG_IO:
151 return bsg_sg_io(bd, file->f_mode & FMODE_WRITE, uarg);
152 case SCSI_IOCTL_SEND_COMMAND:
153 pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",
154 current->comm);
155 return -EINVAL;
156 default:
157 return -ENOTTY;
158 }
159}
160
161static const struct file_operations bsg_fops = {
162 .open = bsg_open,
163 .release = bsg_release,
164 .unlocked_ioctl = bsg_ioctl,
165 .compat_ioctl = compat_ptr_ioctl,
166 .owner = THIS_MODULE,
167 .llseek = default_llseek,
168};
169
170static void bsg_device_release(struct device *dev)
171{
172 struct bsg_device *bd = container_of(dev, struct bsg_device, device);
173
174 ida_free(&bsg_minor_ida, MINOR(bd->device.devt));
175 kfree(bd);
176}
177
178void bsg_unregister_queue(struct bsg_device *bd)
179{
180 struct gendisk *disk = bd->queue->disk;
181
182 if (disk && disk->queue_kobj.sd)
183 sysfs_remove_link(&disk->queue_kobj, "bsg");
184 cdev_device_del(&bd->cdev, &bd->device);
185 put_device(&bd->device);
186}
187EXPORT_SYMBOL_GPL(bsg_unregister_queue);
188
189struct bsg_device *bsg_register_queue(struct request_queue *q,
190 struct device *parent, const char *name, bsg_sg_io_fn *sg_io_fn)
191{
192 struct bsg_device *bd;
193 int ret;
194
195 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
196 if (!bd)
197 return ERR_PTR(-ENOMEM);
198 bd->max_queue = BSG_DEFAULT_CMDS;
199 bd->reserved_size = INT_MAX;
200 bd->queue = q;
201 bd->sg_io_fn = sg_io_fn;
202
203 ret = ida_alloc_max(&bsg_minor_ida, BSG_MAX_DEVS - 1, GFP_KERNEL);
204 if (ret < 0) {
205 if (ret == -ENOSPC)
206 dev_err(parent, "bsg: too many bsg devices\n");
207 kfree(bd);
208 return ERR_PTR(ret);
209 }
210 bd->device.devt = MKDEV(bsg_major, ret);
211 bd->device.class = &bsg_class;
212 bd->device.parent = parent;
213 bd->device.release = bsg_device_release;
214 dev_set_name(&bd->device, "%s", name);
215 device_initialize(&bd->device);
216
217 cdev_init(&bd->cdev, &bsg_fops);
218 bd->cdev.owner = THIS_MODULE;
219 ret = cdev_device_add(&bd->cdev, &bd->device);
220 if (ret)
221 goto out_put_device;
222
223 if (q->disk && q->disk->queue_kobj.sd) {
224 ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj,
225 "bsg");
226 if (ret)
227 goto out_device_del;
228 }
229
230 return bd;
231
232out_device_del:
233 cdev_device_del(&bd->cdev, &bd->device);
234out_put_device:
235 put_device(&bd->device);
236 return ERR_PTR(ret);
237}
238EXPORT_SYMBOL_GPL(bsg_register_queue);
239
240static char *bsg_devnode(const struct device *dev, umode_t *mode)
241{
242 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
243}
244
245static const struct class bsg_class = {
246 .name = "bsg",
247 .devnode = bsg_devnode,
248};
249
250static int __init bsg_init(void)
251{
252 dev_t devid;
253 int ret;
254
255 ret = class_register(&bsg_class);
256 if (ret)
257 return ret;
258
259 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
260 if (ret)
261 goto destroy_bsg_class;
262 bsg_major = MAJOR(devid);
263
264 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
265 " loaded (major %d)\n", bsg_major);
266 return 0;
267
268destroy_bsg_class:
269 class_unregister(&bsg_class);
270 return ret;
271}
272
273MODULE_AUTHOR("Jens Axboe");
274MODULE_DESCRIPTION(BSG_DESCRIPTION);
275MODULE_LICENSE("GPL");
276
277device_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
35struct bsg_device {
36 struct request_queue *queue;
37 spinlock_t lock;
38 struct list_head busy_list;
39 struct list_head done_list;
40 struct hlist_node dev_list;
41 atomic_t ref_count;
42 int queued_cmds;
43 int done_cmds;
44 wait_queue_head_t wq_done;
45 wait_queue_head_t wq_free;
46 char name[20];
47 int max_queue;
48 unsigned long flags;
49};
50
51enum {
52 BSG_F_BLOCK = 1,
53};
54
55#define BSG_DEFAULT_CMDS 64
56#define BSG_MAX_DEVS 32768
57
58#undef BSG_DEBUG
59
60#ifdef BSG_DEBUG
61#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
62#else
63#define dprintk(fmt, args...)
64#endif
65
66static DEFINE_MUTEX(bsg_mutex);
67static DEFINE_IDR(bsg_minor_idr);
68
69#define BSG_LIST_ARRAY_SIZE 8
70static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
71
72static struct class *bsg_class;
73static int bsg_major;
74
75static struct kmem_cache *bsg_cmd_cachep;
76
77/*
78 * our internal command type
79 */
80struct bsg_command {
81 struct bsg_device *bd;
82 struct list_head list;
83 struct request *rq;
84 struct bio *bio;
85 struct bio *bidi_bio;
86 int err;
87 struct sg_io_v4 hdr;
88 char sense[SCSI_SENSE_BUFFERSIZE];
89};
90
91static void bsg_free_command(struct bsg_command *bc)
92{
93 struct bsg_device *bd = bc->bd;
94 unsigned long flags;
95
96 kmem_cache_free(bsg_cmd_cachep, bc);
97
98 spin_lock_irqsave(&bd->lock, flags);
99 bd->queued_cmds--;
100 spin_unlock_irqrestore(&bd->lock, flags);
101
102 wake_up(&bd->wq_free);
103}
104
105static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
106{
107 struct bsg_command *bc = ERR_PTR(-EINVAL);
108
109 spin_lock_irq(&bd->lock);
110
111 if (bd->queued_cmds >= bd->max_queue)
112 goto out;
113
114 bd->queued_cmds++;
115 spin_unlock_irq(&bd->lock);
116
117 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
118 if (unlikely(!bc)) {
119 spin_lock_irq(&bd->lock);
120 bd->queued_cmds--;
121 bc = ERR_PTR(-ENOMEM);
122 goto out;
123 }
124
125 bc->bd = bd;
126 INIT_LIST_HEAD(&bc->list);
127 dprintk("%s: returning free cmd %p\n", bd->name, bc);
128 return bc;
129out:
130 spin_unlock_irq(&bd->lock);
131 return bc;
132}
133
134static inline struct hlist_head *bsg_dev_idx_hash(int index)
135{
136 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
137}
138
139static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
140 struct sg_io_v4 *hdr, struct bsg_device *bd,
141 fmode_t has_write_perm)
142{
143 if (hdr->request_len > BLK_MAX_CDB) {
144 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
145 if (!rq->cmd)
146 return -ENOMEM;
147 }
148
149 if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request,
150 hdr->request_len))
151 return -EFAULT;
152
153 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
154 if (blk_verify_command(rq->cmd, has_write_perm))
155 return -EPERM;
156 } else if (!capable(CAP_SYS_RAWIO))
157 return -EPERM;
158
159 /*
160 * fill in request structure
161 */
162 rq->cmd_len = hdr->request_len;
163
164 rq->timeout = msecs_to_jiffies(hdr->timeout);
165 if (!rq->timeout)
166 rq->timeout = q->sg_timeout;
167 if (!rq->timeout)
168 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
169 if (rq->timeout < BLK_MIN_SG_TIMEOUT)
170 rq->timeout = BLK_MIN_SG_TIMEOUT;
171
172 return 0;
173}
174
175/*
176 * Check if sg_io_v4 from user is allowed and valid
177 */
178static int
179bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
180{
181 int ret = 0;
182
183 if (hdr->guard != 'Q')
184 return -EINVAL;
185
186 switch (hdr->protocol) {
187 case BSG_PROTOCOL_SCSI:
188 switch (hdr->subprotocol) {
189 case BSG_SUB_PROTOCOL_SCSI_CMD:
190 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
191 break;
192 default:
193 ret = -EINVAL;
194 }
195 break;
196 default:
197 ret = -EINVAL;
198 }
199
200 *rw = hdr->dout_xfer_len ? WRITE : READ;
201 return ret;
202}
203
204/*
205 * map sg_io_v4 to a request.
206 */
207static struct request *
208bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
209 u8 *sense)
210{
211 struct request_queue *q = bd->queue;
212 struct request *rq, *next_rq = NULL;
213 int ret, rw;
214 unsigned int dxfer_len;
215 void __user *dxferp = NULL;
216 struct bsg_class_device *bcd = &q->bsg_dev;
217
218 /* if the LLD has been removed then the bsg_unregister_queue will
219 * eventually be called and the class_dev was freed, so we can no
220 * longer use this request_queue. Return no such address.
221 */
222 if (!bcd->class_dev)
223 return ERR_PTR(-ENXIO);
224
225 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
226 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
227 hdr->din_xfer_len);
228
229 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
230 if (ret)
231 return ERR_PTR(ret);
232
233 /*
234 * map scatter-gather elements separately and string them to request
235 */
236 rq = blk_get_request(q, rw, GFP_KERNEL);
237 if (IS_ERR(rq))
238 return rq;
239 blk_rq_set_block_pc(rq);
240
241 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
242 if (ret)
243 goto out;
244
245 if (rw == WRITE && hdr->din_xfer_len) {
246 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
247 ret = -EOPNOTSUPP;
248 goto out;
249 }
250
251 next_rq = blk_get_request(q, READ, GFP_KERNEL);
252 if (IS_ERR(next_rq)) {
253 ret = PTR_ERR(next_rq);
254 next_rq = NULL;
255 goto out;
256 }
257 rq->next_rq = next_rq;
258 next_rq->cmd_type = rq->cmd_type;
259
260 dxferp = (void __user *)(unsigned long)hdr->din_xferp;
261 ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
262 hdr->din_xfer_len, GFP_KERNEL);
263 if (ret)
264 goto out;
265 }
266
267 if (hdr->dout_xfer_len) {
268 dxfer_len = hdr->dout_xfer_len;
269 dxferp = (void __user *)(unsigned long)hdr->dout_xferp;
270 } else if (hdr->din_xfer_len) {
271 dxfer_len = hdr->din_xfer_len;
272 dxferp = (void __user *)(unsigned long)hdr->din_xferp;
273 } else
274 dxfer_len = 0;
275
276 if (dxfer_len) {
277 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
278 GFP_KERNEL);
279 if (ret)
280 goto out;
281 }
282
283 rq->sense = sense;
284 rq->sense_len = 0;
285
286 return rq;
287out:
288 if (rq->cmd != rq->__cmd)
289 kfree(rq->cmd);
290 blk_put_request(rq);
291 if (next_rq) {
292 blk_rq_unmap_user(next_rq->bio);
293 blk_put_request(next_rq);
294 }
295 return ERR_PTR(ret);
296}
297
298/*
299 * async completion call-back from the block layer, when scsi/ide/whatever
300 * calls end_that_request_last() on a request
301 */
302static void bsg_rq_end_io(struct request *rq, int uptodate)
303{
304 struct bsg_command *bc = rq->end_io_data;
305 struct bsg_device *bd = bc->bd;
306 unsigned long flags;
307
308 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
309 bd->name, rq, bc, bc->bio, uptodate);
310
311 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
312
313 spin_lock_irqsave(&bd->lock, flags);
314 list_move_tail(&bc->list, &bd->done_list);
315 bd->done_cmds++;
316 spin_unlock_irqrestore(&bd->lock, flags);
317
318 wake_up(&bd->wq_done);
319}
320
321/*
322 * do final setup of a 'bc' and submit the matching 'rq' to the block
323 * layer for io
324 */
325static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
326 struct bsg_command *bc, struct request *rq)
327{
328 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));
329
330 /*
331 * add bc command to busy queue and submit rq for io
332 */
333 bc->rq = rq;
334 bc->bio = rq->bio;
335 if (rq->next_rq)
336 bc->bidi_bio = rq->next_rq->bio;
337 bc->hdr.duration = jiffies;
338 spin_lock_irq(&bd->lock);
339 list_add_tail(&bc->list, &bd->busy_list);
340 spin_unlock_irq(&bd->lock);
341
342 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
343
344 rq->end_io_data = bc;
345 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io);
346}
347
348static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
349{
350 struct bsg_command *bc = NULL;
351
352 spin_lock_irq(&bd->lock);
353 if (bd->done_cmds) {
354 bc = list_first_entry(&bd->done_list, struct bsg_command, list);
355 list_del(&bc->list);
356 bd->done_cmds--;
357 }
358 spin_unlock_irq(&bd->lock);
359
360 return bc;
361}
362
363/*
364 * Get a finished command from the done list
365 */
366static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
367{
368 struct bsg_command *bc;
369 int ret;
370
371 do {
372 bc = bsg_next_done_cmd(bd);
373 if (bc)
374 break;
375
376 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
377 bc = ERR_PTR(-EAGAIN);
378 break;
379 }
380
381 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
382 if (ret) {
383 bc = ERR_PTR(-ERESTARTSYS);
384 break;
385 }
386 } while (1);
387
388 dprintk("%s: returning done %p\n", bd->name, bc);
389
390 return bc;
391}
392
393static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
394 struct bio *bio, struct bio *bidi_bio)
395{
396 int ret = 0;
397
398 dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);
399 /*
400 * fill in all the output members
401 */
402 hdr->device_status = rq->errors & 0xff;
403 hdr->transport_status = host_byte(rq->errors);
404 hdr->driver_status = driver_byte(rq->errors);
405 hdr->info = 0;
406 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
407 hdr->info |= SG_INFO_CHECK;
408 hdr->response_len = 0;
409
410 if (rq->sense_len && hdr->response) {
411 int len = min_t(unsigned int, hdr->max_response_len,
412 rq->sense_len);
413
414 ret = copy_to_user((void __user *)(unsigned long)hdr->response,
415 rq->sense, len);
416 if (!ret)
417 hdr->response_len = len;
418 else
419 ret = -EFAULT;
420 }
421
422 if (rq->next_rq) {
423 hdr->dout_resid = rq->resid_len;
424 hdr->din_resid = rq->next_rq->resid_len;
425 blk_rq_unmap_user(bidi_bio);
426 blk_put_request(rq->next_rq);
427 } else if (rq_data_dir(rq) == READ)
428 hdr->din_resid = rq->resid_len;
429 else
430 hdr->dout_resid = rq->resid_len;
431
432 /*
433 * If the request generated a negative error number, return it
434 * (providing we aren't already returning an error); if it's
435 * just a protocol response (i.e. non negative), that gets
436 * processed above.
437 */
438 if (!ret && rq->errors < 0)
439 ret = rq->errors;
440
441 blk_rq_unmap_user(bio);
442 if (rq->cmd != rq->__cmd)
443 kfree(rq->cmd);
444 blk_put_request(rq);
445
446 return ret;
447}
448
449static bool bsg_complete(struct bsg_device *bd)
450{
451 bool ret = false;
452 bool spin;
453
454 do {
455 spin_lock_irq(&bd->lock);
456
457 BUG_ON(bd->done_cmds > bd->queued_cmds);
458
459 /*
460 * All commands consumed.
461 */
462 if (bd->done_cmds == bd->queued_cmds)
463 ret = true;
464
465 spin = !test_bit(BSG_F_BLOCK, &bd->flags);
466
467 spin_unlock_irq(&bd->lock);
468 } while (!ret && spin);
469
470 return ret;
471}
472
473static int bsg_complete_all_commands(struct bsg_device *bd)
474{
475 struct bsg_command *bc;
476 int ret, tret;
477
478 dprintk("%s: entered\n", bd->name);
479
480 /*
481 * wait for all commands to complete
482 */
483 io_wait_event(bd->wq_done, bsg_complete(bd));
484
485 /*
486 * discard done commands
487 */
488 ret = 0;
489 do {
490 spin_lock_irq(&bd->lock);
491 if (!bd->queued_cmds) {
492 spin_unlock_irq(&bd->lock);
493 break;
494 }
495 spin_unlock_irq(&bd->lock);
496
497 bc = bsg_get_done_cmd(bd);
498 if (IS_ERR(bc))
499 break;
500
501 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
502 bc->bidi_bio);
503 if (!ret)
504 ret = tret;
505
506 bsg_free_command(bc);
507 } while (1);
508
509 return ret;
510}
511
512static int
513__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
514 const struct iovec *iov, ssize_t *bytes_read)
515{
516 struct bsg_command *bc;
517 int nr_commands, ret;
518
519 if (count % sizeof(struct sg_io_v4))
520 return -EINVAL;
521
522 ret = 0;
523 nr_commands = count / sizeof(struct sg_io_v4);
524 while (nr_commands) {
525 bc = bsg_get_done_cmd(bd);
526 if (IS_ERR(bc)) {
527 ret = PTR_ERR(bc);
528 break;
529 }
530
531 /*
532 * this is the only case where we need to copy data back
533 * after completing the request. so do that here,
534 * bsg_complete_work() cannot do that for us
535 */
536 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
537 bc->bidi_bio);
538
539 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
540 ret = -EFAULT;
541
542 bsg_free_command(bc);
543
544 if (ret)
545 break;
546
547 buf += sizeof(struct sg_io_v4);
548 *bytes_read += sizeof(struct sg_io_v4);
549 nr_commands--;
550 }
551
552 return ret;
553}
554
555static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
556{
557 if (file->f_flags & O_NONBLOCK)
558 clear_bit(BSG_F_BLOCK, &bd->flags);
559 else
560 set_bit(BSG_F_BLOCK, &bd->flags);
561}
562
563/*
564 * Check if the error is a "real" error that we should return.
565 */
566static inline int err_block_err(int ret)
567{
568 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
569 return 1;
570
571 return 0;
572}
573
574static ssize_t
575bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
576{
577 struct bsg_device *bd = file->private_data;
578 int ret;
579 ssize_t bytes_read;
580
581 dprintk("%s: read %Zd bytes\n", bd->name, count);
582
583 bsg_set_block(bd, file);
584
585 bytes_read = 0;
586 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
587 *ppos = bytes_read;
588
589 if (!bytes_read || err_block_err(ret))
590 bytes_read = ret;
591
592 return bytes_read;
593}
594
595static int __bsg_write(struct bsg_device *bd, const char __user *buf,
596 size_t count, ssize_t *bytes_written,
597 fmode_t has_write_perm)
598{
599 struct bsg_command *bc;
600 struct request *rq;
601 int ret, nr_commands;
602
603 if (count % sizeof(struct sg_io_v4))
604 return -EINVAL;
605
606 nr_commands = count / sizeof(struct sg_io_v4);
607 rq = NULL;
608 bc = NULL;
609 ret = 0;
610 while (nr_commands) {
611 struct request_queue *q = bd->queue;
612
613 bc = bsg_alloc_command(bd);
614 if (IS_ERR(bc)) {
615 ret = PTR_ERR(bc);
616 bc = NULL;
617 break;
618 }
619
620 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
621 ret = -EFAULT;
622 break;
623 }
624
625 /*
626 * get a request, fill in the blanks, and add to request queue
627 */
628 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);
629 if (IS_ERR(rq)) {
630 ret = PTR_ERR(rq);
631 rq = NULL;
632 break;
633 }
634
635 bsg_add_command(bd, q, bc, rq);
636 bc = NULL;
637 rq = NULL;
638 nr_commands--;
639 buf += sizeof(struct sg_io_v4);
640 *bytes_written += sizeof(struct sg_io_v4);
641 }
642
643 if (bc)
644 bsg_free_command(bc);
645
646 return ret;
647}
648
649static ssize_t
650bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
651{
652 struct bsg_device *bd = file->private_data;
653 ssize_t bytes_written;
654 int ret;
655
656 dprintk("%s: write %Zd bytes\n", bd->name, count);
657
658 bsg_set_block(bd, file);
659
660 bytes_written = 0;
661 ret = __bsg_write(bd, buf, count, &bytes_written,
662 file->f_mode & FMODE_WRITE);
663
664 *ppos = bytes_written;
665
666 /*
667 * return bytes written on non-fatal errors
668 */
669 if (!bytes_written || err_block_err(ret))
670 bytes_written = ret;
671
672 dprintk("%s: returning %Zd\n", bd->name, bytes_written);
673 return bytes_written;
674}
675
676static struct bsg_device *bsg_alloc_device(void)
677{
678 struct bsg_device *bd;
679
680 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
681 if (unlikely(!bd))
682 return NULL;
683
684 spin_lock_init(&bd->lock);
685
686 bd->max_queue = BSG_DEFAULT_CMDS;
687
688 INIT_LIST_HEAD(&bd->busy_list);
689 INIT_LIST_HEAD(&bd->done_list);
690 INIT_HLIST_NODE(&bd->dev_list);
691
692 init_waitqueue_head(&bd->wq_free);
693 init_waitqueue_head(&bd->wq_done);
694 return bd;
695}
696
697static void bsg_kref_release_function(struct kref *kref)
698{
699 struct bsg_class_device *bcd =
700 container_of(kref, struct bsg_class_device, ref);
701 struct device *parent = bcd->parent;
702
703 if (bcd->release)
704 bcd->release(bcd->parent);
705
706 put_device(parent);
707}
708
709static int bsg_put_device(struct bsg_device *bd)
710{
711 int ret = 0, do_free;
712 struct request_queue *q = bd->queue;
713
714 mutex_lock(&bsg_mutex);
715
716 do_free = atomic_dec_and_test(&bd->ref_count);
717 if (!do_free) {
718 mutex_unlock(&bsg_mutex);
719 goto out;
720 }
721
722 hlist_del(&bd->dev_list);
723 mutex_unlock(&bsg_mutex);
724
725 dprintk("%s: tearing down\n", bd->name);
726
727 /*
728 * close can always block
729 */
730 set_bit(BSG_F_BLOCK, &bd->flags);
731
732 /*
733 * correct error detection baddies here again. it's the responsibility
734 * of the app to properly reap commands before close() if it wants
735 * fool-proof error detection
736 */
737 ret = bsg_complete_all_commands(bd);
738
739 kfree(bd);
740out:
741 kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
742 if (do_free)
743 blk_put_queue(q);
744 return ret;
745}
746
747static struct bsg_device *bsg_add_device(struct inode *inode,
748 struct request_queue *rq,
749 struct file *file)
750{
751 struct bsg_device *bd;
752#ifdef BSG_DEBUG
753 unsigned char buf[32];
754#endif
755 if (!blk_get_queue(rq))
756 return ERR_PTR(-ENXIO);
757
758 bd = bsg_alloc_device();
759 if (!bd) {
760 blk_put_queue(rq);
761 return ERR_PTR(-ENOMEM);
762 }
763
764 bd->queue = rq;
765
766 bsg_set_block(bd, file);
767
768 atomic_set(&bd->ref_count, 1);
769 mutex_lock(&bsg_mutex);
770 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
771
772 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
773 dprintk("bound to <%s>, max queue %d\n",
774 format_dev_t(buf, inode->i_rdev), bd->max_queue);
775
776 mutex_unlock(&bsg_mutex);
777 return bd;
778}
779
780static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
781{
782 struct bsg_device *bd;
783
784 mutex_lock(&bsg_mutex);
785
786 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
787 if (bd->queue == q) {
788 atomic_inc(&bd->ref_count);
789 goto found;
790 }
791 }
792 bd = NULL;
793found:
794 mutex_unlock(&bsg_mutex);
795 return bd;
796}
797
798static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
799{
800 struct bsg_device *bd;
801 struct bsg_class_device *bcd;
802
803 /*
804 * find the class device
805 */
806 mutex_lock(&bsg_mutex);
807 bcd = idr_find(&bsg_minor_idr, iminor(inode));
808 if (bcd)
809 kref_get(&bcd->ref);
810 mutex_unlock(&bsg_mutex);
811
812 if (!bcd)
813 return ERR_PTR(-ENODEV);
814
815 bd = __bsg_get_device(iminor(inode), bcd->queue);
816 if (bd)
817 return bd;
818
819 bd = bsg_add_device(inode, bcd->queue, file);
820 if (IS_ERR(bd))
821 kref_put(&bcd->ref, bsg_kref_release_function);
822
823 return bd;
824}
825
826static int bsg_open(struct inode *inode, struct file *file)
827{
828 struct bsg_device *bd;
829
830 bd = bsg_get_device(inode, file);
831
832 if (IS_ERR(bd))
833 return PTR_ERR(bd);
834
835 file->private_data = bd;
836 return 0;
837}
838
839static int bsg_release(struct inode *inode, struct file *file)
840{
841 struct bsg_device *bd = file->private_data;
842
843 file->private_data = NULL;
844 return bsg_put_device(bd);
845}
846
847static unsigned int bsg_poll(struct file *file, poll_table *wait)
848{
849 struct bsg_device *bd = file->private_data;
850 unsigned int mask = 0;
851
852 poll_wait(file, &bd->wq_done, wait);
853 poll_wait(file, &bd->wq_free, wait);
854
855 spin_lock_irq(&bd->lock);
856 if (!list_empty(&bd->done_list))
857 mask |= POLLIN | POLLRDNORM;
858 if (bd->queued_cmds < bd->max_queue)
859 mask |= POLLOUT;
860 spin_unlock_irq(&bd->lock);
861
862 return mask;
863}
864
865static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
866{
867 struct bsg_device *bd = file->private_data;
868 int __user *uarg = (int __user *) arg;
869 int ret;
870
871 switch (cmd) {
872 /*
873 * our own ioctls
874 */
875 case SG_GET_COMMAND_Q:
876 return put_user(bd->max_queue, uarg);
877 case SG_SET_COMMAND_Q: {
878 int queue;
879
880 if (get_user(queue, uarg))
881 return -EFAULT;
882 if (queue < 1)
883 return -EINVAL;
884
885 spin_lock_irq(&bd->lock);
886 bd->max_queue = queue;
887 spin_unlock_irq(&bd->lock);
888 return 0;
889 }
890
891 /*
892 * SCSI/sg ioctls
893 */
894 case SG_GET_VERSION_NUM:
895 case SCSI_IOCTL_GET_IDLUN:
896 case SCSI_IOCTL_GET_BUS_NUMBER:
897 case SG_SET_TIMEOUT:
898 case SG_GET_TIMEOUT:
899 case SG_GET_RESERVED_SIZE:
900 case SG_SET_RESERVED_SIZE:
901 case SG_EMULATED_HOST:
902 case SCSI_IOCTL_SEND_COMMAND: {
903 void __user *uarg = (void __user *) arg;
904 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
905 }
906 case SG_IO: {
907 struct request *rq;
908 struct bio *bio, *bidi_bio = NULL;
909 struct sg_io_v4 hdr;
910 int at_head;
911 u8 sense[SCSI_SENSE_BUFFERSIZE];
912
913 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
914 return -EFAULT;
915
916 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
917 if (IS_ERR(rq))
918 return PTR_ERR(rq);
919
920 bio = rq->bio;
921 if (rq->next_rq)
922 bidi_bio = rq->next_rq->bio;
923
924 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
925 blk_execute_rq(bd->queue, NULL, rq, at_head);
926 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
927
928 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
929 return -EFAULT;
930
931 return ret;
932 }
933 /*
934 * block device ioctls
935 */
936 default:
937#if 0
938 return ioctl_by_bdev(bd->bdev, cmd, arg);
939#else
940 return -ENOTTY;
941#endif
942 }
943}
944
945static const struct file_operations bsg_fops = {
946 .read = bsg_read,
947 .write = bsg_write,
948 .poll = bsg_poll,
949 .open = bsg_open,
950 .release = bsg_release,
951 .unlocked_ioctl = bsg_ioctl,
952 .owner = THIS_MODULE,
953 .llseek = default_llseek,
954};
955
956void bsg_unregister_queue(struct request_queue *q)
957{
958 struct bsg_class_device *bcd = &q->bsg_dev;
959
960 if (!bcd->class_dev)
961 return;
962
963 mutex_lock(&bsg_mutex);
964 idr_remove(&bsg_minor_idr, bcd->minor);
965 if (q->kobj.sd)
966 sysfs_remove_link(&q->kobj, "bsg");
967 device_unregister(bcd->class_dev);
968 bcd->class_dev = NULL;
969 kref_put(&bcd->ref, bsg_kref_release_function);
970 mutex_unlock(&bsg_mutex);
971}
972EXPORT_SYMBOL_GPL(bsg_unregister_queue);
973
974int bsg_register_queue(struct request_queue *q, struct device *parent,
975 const char *name, void (*release)(struct device *))
976{
977 struct bsg_class_device *bcd;
978 dev_t dev;
979 int ret;
980 struct device *class_dev = NULL;
981 const char *devname;
982
983 if (name)
984 devname = name;
985 else
986 devname = dev_name(parent);
987
988 /*
989 * we need a proper transport to send commands, not a stacked device
990 */
991 if (!queue_is_rq_based(q))
992 return 0;
993
994 bcd = &q->bsg_dev;
995 memset(bcd, 0, sizeof(*bcd));
996
997 mutex_lock(&bsg_mutex);
998
999 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
1000 if (ret < 0) {
1001 if (ret == -ENOSPC) {
1002 printk(KERN_ERR "bsg: too many bsg devices\n");
1003 ret = -EINVAL;
1004 }
1005 goto unlock;
1006 }
1007
1008 bcd->minor = ret;
1009 bcd->queue = q;
1010 bcd->parent = get_device(parent);
1011 bcd->release = release;
1012 kref_init(&bcd->ref);
1013 dev = MKDEV(bsg_major, bcd->minor);
1014 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
1015 if (IS_ERR(class_dev)) {
1016 ret = PTR_ERR(class_dev);
1017 goto put_dev;
1018 }
1019 bcd->class_dev = class_dev;
1020
1021 if (q->kobj.sd) {
1022 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
1023 if (ret)
1024 goto unregister_class_dev;
1025 }
1026
1027 mutex_unlock(&bsg_mutex);
1028 return 0;
1029
1030unregister_class_dev:
1031 device_unregister(class_dev);
1032put_dev:
1033 put_device(parent);
1034 idr_remove(&bsg_minor_idr, bcd->minor);
1035unlock:
1036 mutex_unlock(&bsg_mutex);
1037 return ret;
1038}
1039EXPORT_SYMBOL_GPL(bsg_register_queue);
1040
1041static struct cdev bsg_cdev;
1042
1043static char *bsg_devnode(struct device *dev, umode_t *mode)
1044{
1045 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
1046}
1047
1048static int __init bsg_init(void)
1049{
1050 int ret, i;
1051 dev_t devid;
1052
1053 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
1054 sizeof(struct bsg_command), 0, 0, NULL);
1055 if (!bsg_cmd_cachep) {
1056 printk(KERN_ERR "bsg: failed creating slab cache\n");
1057 return -ENOMEM;
1058 }
1059
1060 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
1061 INIT_HLIST_HEAD(&bsg_device_list[i]);
1062
1063 bsg_class = class_create(THIS_MODULE, "bsg");
1064 if (IS_ERR(bsg_class)) {
1065 ret = PTR_ERR(bsg_class);
1066 goto destroy_kmemcache;
1067 }
1068 bsg_class->devnode = bsg_devnode;
1069
1070 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
1071 if (ret)
1072 goto destroy_bsg_class;
1073
1074 bsg_major = MAJOR(devid);
1075
1076 cdev_init(&bsg_cdev, &bsg_fops);
1077 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1078 if (ret)
1079 goto unregister_chrdev;
1080
1081 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
1082 " loaded (major %d)\n", bsg_major);
1083 return 0;
1084unregister_chrdev:
1085 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1086destroy_bsg_class:
1087 class_destroy(bsg_class);
1088destroy_kmemcache:
1089 kmem_cache_destroy(bsg_cmd_cachep);
1090 return ret;
1091}
1092
1093MODULE_AUTHOR("Jens Axboe");
1094MODULE_DESCRIPTION(BSG_DESCRIPTION);
1095MODULE_LICENSE("GPL");
1096
1097device_initcall(bsg_init);