1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
4  * Copyright (C) 2014 Red Hat, Inc.
5  * Copyright (C) 2015 Arrikto, Inc.
6  * Copyright (C) 2017 Chinamobile, Inc.
7  */
8 
9 #include <linux/spinlock.h>
10 #include <linux/module.h>
11 #include <linux/idr.h>
12 #include <linux/kernel.h>
13 #include <linux/timer.h>
14 #include <linux/parser.h>
15 #include <linux/vmalloc.h>
16 #include <linux/uio_driver.h>
17 #include <linux/radix-tree.h>
18 #include <linux/stringify.h>
19 #include <linux/bitops.h>
20 #include <linux/highmem.h>
21 #include <linux/configfs.h>
22 #include <linux/mutex.h>
23 #include <linux/workqueue.h>
24 #include <net/genetlink.h>
25 #include <scsi/scsi_common.h>
26 #include <scsi/scsi_proto.h>
27 #include <target/target_core_base.h>
28 #include <target/target_core_fabric.h>
29 #include <target/target_core_backend.h>
30 
31 #include <linux/target_core_user.h>
32 
33 /**
34  * DOC: Userspace I/O
35  * Userspace I/O
36  * -------------
37  *
38  * Define a shared-memory interface for LIO to pass SCSI commands and
39  * data to userspace for processing. This is to allow backends that
40  * are too complex for in-kernel support to be possible.
41  *
42  * It uses the UIO framework to do a lot of the device-creation and
43  * introspection work for us.
44  *
45  * See the .h file for how the ring is laid out. Note that while the
46  * command ring is defined, the particulars of the data area are
47  * not. Offset values in the command entry point to other locations
48  * internal to the mmap-ed area. There is separate space outside the
49  * command ring for data buffers. This leaves maximum flexibility for
50  * moving buffer allocations, or even page flipping or other
51  * allocation techniques, without altering the command ring layout.
52  *
53  * SECURITY:
54  * The user process must be assumed to be malicious. There's no way to
55  * prevent it breaking the command ring protocol if it wants, but in
56  * order to prevent other issues we must only ever read *data* from
57  * the shared memory area, not offsets or sizes. This applies to
58  * command ring entries as well as the mailbox. Extra code needed for
59  * this may have a 'UAM' comment.
60  */
61 
62 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
63 
64 /* For cmd area, the size is fixed 8MB */
65 #define CMDR_SIZE (8 * 1024 * 1024)
66 
67 /*
68  * For data area, the block size is PAGE_SIZE and
69  * the total size is 256K * PAGE_SIZE.
70  */
71 #define DATA_BLOCK_SIZE PAGE_SIZE
72 #define DATA_BLOCK_SHIFT PAGE_SHIFT
73 #define DATA_BLOCK_BITS_DEF (256 * 1024)
74 
75 #define TCMU_MBS_TO_BLOCKS(_mbs) (_mbs << (20 - DATA_BLOCK_SHIFT))
76 #define TCMU_BLOCKS_TO_MBS(_blocks) (_blocks >> (20 - DATA_BLOCK_SHIFT))
77 
78 /*
79  * Default number of global data blocks(512K * PAGE_SIZE)
80  * when the unmap thread will be started.
81  */
82 #define TCMU_GLOBAL_MAX_BLOCKS_DEF (512 * 1024)
83 
84 static u8 tcmu_kern_cmd_reply_supported;
85 static u8 tcmu_netlink_blocked;
86 
87 static struct device *tcmu_root_device;
88 
89 struct tcmu_hba {
90 	u32 host_id;
91 };
92 
93 #define TCMU_CONFIG_LEN 256
94 
95 static DEFINE_MUTEX(tcmu_nl_cmd_mutex);
96 static LIST_HEAD(tcmu_nl_cmd_list);
97 
98 struct tcmu_dev;
99 
100 struct tcmu_nl_cmd {
101 	/* wake up thread waiting for reply */
102 	struct completion complete;
103 	struct list_head nl_list;
104 	struct tcmu_dev *udev;
105 	int cmd;
106 	int status;
107 };
108 
109 struct tcmu_dev {
110 	struct list_head node;
111 	struct kref kref;
112 
113 	struct se_device se_dev;
114 
115 	char *name;
116 	struct se_hba *hba;
117 
118 #define TCMU_DEV_BIT_OPEN 0
119 #define TCMU_DEV_BIT_BROKEN 1
120 #define TCMU_DEV_BIT_BLOCKED 2
121 #define TCMU_DEV_BIT_TMR_NOTIFY 3
122 	unsigned long flags;
123 
124 	struct uio_info uio_info;
125 
126 	struct inode *inode;
127 
128 	struct tcmu_mailbox *mb_addr;
129 	uint64_t dev_size;
130 	u32 cmdr_size;
131 	u32 cmdr_last_cleaned;
132 	/* Offset of data area from start of mb */
133 	/* Must add data_off and mb_addr to get the address */
134 	size_t data_off;
135 	size_t data_size;
136 	uint32_t max_blocks;
137 	size_t ring_size;
138 
139 	struct mutex cmdr_lock;
140 	struct list_head qfull_queue;
141 	struct list_head tmr_queue;
142 
143 	uint32_t dbi_max;
144 	uint32_t dbi_thresh;
145 	unsigned long *data_bitmap;
146 	struct radix_tree_root data_blocks;
147 
148 	struct idr commands;
149 
150 	struct timer_list cmd_timer;
151 	unsigned int cmd_time_out;
152 	struct list_head inflight_queue;
153 
154 	struct timer_list qfull_timer;
155 	int qfull_time_out;
156 
157 	struct list_head timedout_entry;
158 
159 	struct tcmu_nl_cmd curr_nl_cmd;
160 
161 	char dev_config[TCMU_CONFIG_LEN];
162 
163 	int nl_reply_supported;
164 };
165 
166 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
167 
168 #define CMDR_OFF sizeof(struct tcmu_mailbox)
169 
170 struct tcmu_cmd {
171 	struct se_cmd *se_cmd;
172 	struct tcmu_dev *tcmu_dev;
173 	struct list_head queue_entry;
174 
175 	uint16_t cmd_id;
176 
177 	/* Can't use se_cmd when cleaning up expired cmds, because if
178 	   cmd has been completed then accessing se_cmd is off limits */
179 	uint32_t dbi_cnt;
180 	uint32_t dbi_bidi_cnt;
181 	uint32_t dbi_cur;
182 	uint32_t *dbi;
183 
184 	uint32_t data_len_bidi;
185 
186 	unsigned long deadline;
187 
188 #define TCMU_CMD_BIT_EXPIRED 0
189 	unsigned long flags;
190 };
191 
192 struct tcmu_tmr {
193 	struct list_head queue_entry;
194 
195 	uint8_t tmr_type;
196 	uint32_t tmr_cmd_cnt;
197 	int16_t tmr_cmd_ids[];
198 };
199 
200 /*
201  * To avoid dead lock the mutex lock order should always be:
202  *
203  * mutex_lock(&root_udev_mutex);
204  * ...
205  * mutex_lock(&tcmu_dev->cmdr_lock);
206  * mutex_unlock(&tcmu_dev->cmdr_lock);
207  * ...
208  * mutex_unlock(&root_udev_mutex);
209  */
210 static DEFINE_MUTEX(root_udev_mutex);
211 static LIST_HEAD(root_udev);
212 
213 static DEFINE_SPINLOCK(timed_out_udevs_lock);
214 static LIST_HEAD(timed_out_udevs);
215 
216 static struct kmem_cache *tcmu_cmd_cache;
217 
218 static atomic_t global_db_count = ATOMIC_INIT(0);
219 static struct delayed_work tcmu_unmap_work;
220 static int tcmu_global_max_blocks = TCMU_GLOBAL_MAX_BLOCKS_DEF;
221 
222 static int tcmu_set_global_max_data_area(const char *str,
223 					 const struct kernel_param *kp)
224 {
225 	int ret, max_area_mb;
226 
227 	ret = kstrtoint(str, 10, &max_area_mb);
228 	if (ret)
229 		return -EINVAL;
230 
231 	if (max_area_mb <= 0) {
232 		pr_err("global_max_data_area must be larger than 0.\n");
233 		return -EINVAL;
234 	}
235 
236 	tcmu_global_max_blocks = TCMU_MBS_TO_BLOCKS(max_area_mb);
237 	if (atomic_read(&global_db_count) > tcmu_global_max_blocks)
238 		schedule_delayed_work(&tcmu_unmap_work, 0);
239 	else
240 		cancel_delayed_work_sync(&tcmu_unmap_work);
241 
242 	return 0;
243 }
244 
245 static int tcmu_get_global_max_data_area(char *buffer,
246 					 const struct kernel_param *kp)
247 {
248 	return sprintf(buffer, "%d\n", TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
249 }
250 
251 static const struct kernel_param_ops tcmu_global_max_data_area_op = {
252 	.set = tcmu_set_global_max_data_area,
253 	.get = tcmu_get_global_max_data_area,
254 };
255 
256 module_param_cb(global_max_data_area_mb, &tcmu_global_max_data_area_op, NULL,
257 		S_IWUSR | S_IRUGO);
258 MODULE_PARM_DESC(global_max_data_area_mb,
259 		 "Max MBs allowed to be allocated to all the tcmu device's "
260 		 "data areas.");
261 
262 static int tcmu_get_block_netlink(char *buffer,
263 				  const struct kernel_param *kp)
264 {
265 	return sprintf(buffer, "%s\n", tcmu_netlink_blocked ?
266 		       "blocked" : "unblocked");
267 }
268 
269 static int tcmu_set_block_netlink(const char *str,
270 				  const struct kernel_param *kp)
271 {
272 	int ret;
273 	u8 val;
274 
275 	ret = kstrtou8(str, 0, &val);
276 	if (ret < 0)
277 		return ret;
278 
279 	if (val > 1) {
280 		pr_err("Invalid block netlink value %u\n", val);
281 		return -EINVAL;
282 	}
283 
284 	tcmu_netlink_blocked = val;
285 	return 0;
286 }
287 
288 static const struct kernel_param_ops tcmu_block_netlink_op = {
289 	.set = tcmu_set_block_netlink,
290 	.get = tcmu_get_block_netlink,
291 };
292 
293 module_param_cb(block_netlink, &tcmu_block_netlink_op, NULL, S_IWUSR | S_IRUGO);
294 MODULE_PARM_DESC(block_netlink, "Block new netlink commands.");
295 
296 static int tcmu_fail_netlink_cmd(struct tcmu_nl_cmd *nl_cmd)
297 {
298 	struct tcmu_dev *udev = nl_cmd->udev;
299 
300 	if (!tcmu_netlink_blocked) {
301 		pr_err("Could not reset device's netlink interface. Netlink is not blocked.\n");
302 		return -EBUSY;
303 	}
304 
305 	if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
306 		pr_debug("Aborting nl cmd %d on %s\n", nl_cmd->cmd, udev->name);
307 		nl_cmd->status = -EINTR;
308 		list_del(&nl_cmd->nl_list);
309 		complete(&nl_cmd->complete);
310 	}
311 	return 0;
312 }
313 
314 static int tcmu_set_reset_netlink(const char *str,
315 				  const struct kernel_param *kp)
316 {
317 	struct tcmu_nl_cmd *nl_cmd, *tmp_cmd;
318 	int ret;
319 	u8 val;
320 
321 	ret = kstrtou8(str, 0, &val);
322 	if (ret < 0)
323 		return ret;
324 
325 	if (val != 1) {
326 		pr_err("Invalid reset netlink value %u\n", val);
327 		return -EINVAL;
328 	}
329 
330 	mutex_lock(&tcmu_nl_cmd_mutex);
331 	list_for_each_entry_safe(nl_cmd, tmp_cmd, &tcmu_nl_cmd_list, nl_list) {
332 		ret = tcmu_fail_netlink_cmd(nl_cmd);
333 		if (ret)
334 			break;
335 	}
336 	mutex_unlock(&tcmu_nl_cmd_mutex);
337 
338 	return ret;
339 }
340 
341 static const struct kernel_param_ops tcmu_reset_netlink_op = {
342 	.set = tcmu_set_reset_netlink,
343 };
344 
345 module_param_cb(reset_netlink, &tcmu_reset_netlink_op, NULL, S_IWUSR);
346 MODULE_PARM_DESC(reset_netlink, "Reset netlink commands.");
347 
348 /* multicast group */
349 enum tcmu_multicast_groups {
350 	TCMU_MCGRP_CONFIG,
351 };
352 
353 static const struct genl_multicast_group tcmu_mcgrps[] = {
354 	[TCMU_MCGRP_CONFIG] = { .name = "config", },
355 };
356 
357 static struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX+1] = {
358 	[TCMU_ATTR_DEVICE]	= { .type = NLA_STRING },
359 	[TCMU_ATTR_MINOR]	= { .type = NLA_U32 },
360 	[TCMU_ATTR_CMD_STATUS]	= { .type = NLA_S32 },
361 	[TCMU_ATTR_DEVICE_ID]	= { .type = NLA_U32 },
362 	[TCMU_ATTR_SUPP_KERN_CMD_REPLY] = { .type = NLA_U8 },
363 };
364 
365 static int tcmu_genl_cmd_done(struct genl_info *info, int completed_cmd)
366 {
367 	struct tcmu_dev *udev = NULL;
368 	struct tcmu_nl_cmd *nl_cmd;
369 	int dev_id, rc, ret = 0;
370 
371 	if (!info->attrs[TCMU_ATTR_CMD_STATUS] ||
372 	    !info->attrs[TCMU_ATTR_DEVICE_ID]) {
373 		printk(KERN_ERR "TCMU_ATTR_CMD_STATUS or TCMU_ATTR_DEVICE_ID not set, doing nothing\n");
374 		return -EINVAL;
375         }
376 
377 	dev_id = nla_get_u32(info->attrs[TCMU_ATTR_DEVICE_ID]);
378 	rc = nla_get_s32(info->attrs[TCMU_ATTR_CMD_STATUS]);
379 
380 	mutex_lock(&tcmu_nl_cmd_mutex);
381 	list_for_each_entry(nl_cmd, &tcmu_nl_cmd_list, nl_list) {
382 		if (nl_cmd->udev->se_dev.dev_index == dev_id) {
383 			udev = nl_cmd->udev;
384 			break;
385 		}
386 	}
387 
388 	if (!udev) {
389 		pr_err("tcmu nl cmd %u/%d completion could not find device with dev id %u.\n",
390 		       completed_cmd, rc, dev_id);
391 		ret = -ENODEV;
392 		goto unlock;
393 	}
394 	list_del(&nl_cmd->nl_list);
395 
396 	pr_debug("%s genl cmd done got id %d curr %d done %d rc %d stat %d\n",
397 		 udev->name, dev_id, nl_cmd->cmd, completed_cmd, rc,
398 		 nl_cmd->status);
399 
400 	if (nl_cmd->cmd != completed_cmd) {
401 		pr_err("Mismatched commands on %s (Expecting reply for %d. Current %d).\n",
402 		       udev->name, completed_cmd, nl_cmd->cmd);
403 		ret = -EINVAL;
404 		goto unlock;
405 	}
406 
407 	nl_cmd->status = rc;
408 	complete(&nl_cmd->complete);
409 unlock:
410 	mutex_unlock(&tcmu_nl_cmd_mutex);
411 	return ret;
412 }
413 
414 static int tcmu_genl_rm_dev_done(struct sk_buff *skb, struct genl_info *info)
415 {
416 	return tcmu_genl_cmd_done(info, TCMU_CMD_REMOVED_DEVICE);
417 }
418 
419 static int tcmu_genl_add_dev_done(struct sk_buff *skb, struct genl_info *info)
420 {
421 	return tcmu_genl_cmd_done(info, TCMU_CMD_ADDED_DEVICE);
422 }
423 
424 static int tcmu_genl_reconfig_dev_done(struct sk_buff *skb,
425 				       struct genl_info *info)
426 {
427 	return tcmu_genl_cmd_done(info, TCMU_CMD_RECONFIG_DEVICE);
428 }
429 
430 static int tcmu_genl_set_features(struct sk_buff *skb, struct genl_info *info)
431 {
432 	if (info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]) {
433 		tcmu_kern_cmd_reply_supported  =
434 			nla_get_u8(info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]);
435 		printk(KERN_INFO "tcmu daemon: command reply support %u.\n",
436 		       tcmu_kern_cmd_reply_supported);
437 	}
438 
439 	return 0;
440 }
441 
442 static const struct genl_small_ops tcmu_genl_ops[] = {
443 	{
444 		.cmd	= TCMU_CMD_SET_FEATURES,
445 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
446 		.flags	= GENL_ADMIN_PERM,
447 		.doit	= tcmu_genl_set_features,
448 	},
449 	{
450 		.cmd	= TCMU_CMD_ADDED_DEVICE_DONE,
451 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
452 		.flags	= GENL_ADMIN_PERM,
453 		.doit	= tcmu_genl_add_dev_done,
454 	},
455 	{
456 		.cmd	= TCMU_CMD_REMOVED_DEVICE_DONE,
457 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
458 		.flags	= GENL_ADMIN_PERM,
459 		.doit	= tcmu_genl_rm_dev_done,
460 	},
461 	{
462 		.cmd	= TCMU_CMD_RECONFIG_DEVICE_DONE,
463 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
464 		.flags	= GENL_ADMIN_PERM,
465 		.doit	= tcmu_genl_reconfig_dev_done,
466 	},
467 };
468 
469 /* Our generic netlink family */
470 static struct genl_family tcmu_genl_family __ro_after_init = {
471 	.module = THIS_MODULE,
472 	.hdrsize = 0,
473 	.name = "TCM-USER",
474 	.version = 2,
475 	.maxattr = TCMU_ATTR_MAX,
476 	.policy = tcmu_attr_policy,
477 	.mcgrps = tcmu_mcgrps,
478 	.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
479 	.netnsok = true,
480 	.small_ops = tcmu_genl_ops,
481 	.n_small_ops = ARRAY_SIZE(tcmu_genl_ops),
482 };
483 
484 #define tcmu_cmd_set_dbi_cur(cmd, index) ((cmd)->dbi_cur = (index))
485 #define tcmu_cmd_reset_dbi_cur(cmd) tcmu_cmd_set_dbi_cur(cmd, 0)
486 #define tcmu_cmd_set_dbi(cmd, index) ((cmd)->dbi[(cmd)->dbi_cur++] = (index))
487 #define tcmu_cmd_get_dbi(cmd) ((cmd)->dbi[(cmd)->dbi_cur++])
488 
489 static void tcmu_cmd_free_data(struct tcmu_cmd *tcmu_cmd, uint32_t len)
490 {
491 	struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
492 	uint32_t i;
493 
494 	for (i = 0; i < len; i++)
495 		clear_bit(tcmu_cmd->dbi[i], udev->data_bitmap);
496 }
497 
498 static inline int tcmu_get_empty_block(struct tcmu_dev *udev,
499 				       struct tcmu_cmd *tcmu_cmd,
500 				       int prev_dbi, int *iov_cnt)
501 {
502 	struct page *page;
503 	int ret, dbi;
504 
505 	dbi = find_first_zero_bit(udev->data_bitmap, udev->dbi_thresh);
506 	if (dbi == udev->dbi_thresh)
507 		return -1;
508 
509 	page = radix_tree_lookup(&udev->data_blocks, dbi);
510 	if (!page) {
511 		if (atomic_add_return(1, &global_db_count) >
512 				      tcmu_global_max_blocks)
513 			schedule_delayed_work(&tcmu_unmap_work, 0);
514 
515 		/* try to get new page from the mm */
516 		page = alloc_page(GFP_NOIO);
517 		if (!page)
518 			goto err_alloc;
519 
520 		ret = radix_tree_insert(&udev->data_blocks, dbi, page);
521 		if (ret)
522 			goto err_insert;
523 	}
524 
525 	if (dbi > udev->dbi_max)
526 		udev->dbi_max = dbi;
527 
528 	set_bit(dbi, udev->data_bitmap);
529 	tcmu_cmd_set_dbi(tcmu_cmd, dbi);
530 
531 	if (dbi != prev_dbi + 1)
532 		*iov_cnt += 1;
533 
534 	return dbi;
535 err_insert:
536 	__free_page(page);
537 err_alloc:
538 	atomic_dec(&global_db_count);
539 	return -1;
540 }
541 
542 static int tcmu_get_empty_blocks(struct tcmu_dev *udev,
543 				 struct tcmu_cmd *tcmu_cmd, int dbi_cnt)
544 {
545 	/* start value of dbi + 1 must not be a valid dbi */
546 	int dbi = -2;
547 	int i, iov_cnt = 0;
548 
549 	for (i = 0; i < dbi_cnt; i++) {
550 		dbi = tcmu_get_empty_block(udev, tcmu_cmd, dbi, &iov_cnt);
551 		if (dbi < 0)
552 			return -1;
553 	}
554 	return iov_cnt;
555 }
556 
557 static inline struct page *
558 tcmu_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
559 {
560 	return radix_tree_lookup(&udev->data_blocks, dbi);
561 }
562 
563 static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd)
564 {
565 	if (tcmu_cmd->se_cmd)
566 		tcmu_cmd->se_cmd->priv = NULL;
567 	kfree(tcmu_cmd->dbi);
568 	kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
569 }
570 
571 static inline void tcmu_cmd_set_block_cnts(struct tcmu_cmd *cmd)
572 {
573 	int i, len;
574 	struct se_cmd *se_cmd = cmd->se_cmd;
575 
576 	cmd->dbi_cnt = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
577 
578 	if (se_cmd->se_cmd_flags & SCF_BIDI) {
579 		BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
580 		for (i = 0, len = 0; i < se_cmd->t_bidi_data_nents; i++)
581 			len += se_cmd->t_bidi_data_sg[i].length;
582 		cmd->dbi_bidi_cnt = DIV_ROUND_UP(len, DATA_BLOCK_SIZE);
583 		cmd->dbi_cnt += cmd->dbi_bidi_cnt;
584 		cmd->data_len_bidi = len;
585 	}
586 }
587 
588 static int new_block_to_iov(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
589 			    struct iovec **iov, int prev_dbi, int *remain)
590 {
591 	/* Get the next dbi */
592 	int dbi = tcmu_cmd_get_dbi(cmd);
593 	/* Do not add more than DATA_BLOCK_SIZE to iov */
594 	int len = min_t(int, DATA_BLOCK_SIZE, *remain);
595 
596 	*remain -= len;
597 	/*
598 	 * The following code will gather and map the blocks to the same iovec
599 	 * when the blocks are all next to each other.
600 	 */
601 	if (dbi != prev_dbi + 1) {
602 		/* dbi is not next to previous dbi, so start new iov */
603 		if (prev_dbi >= 0)
604 			(*iov)++;
605 		/* write offset relative to mb_addr */
606 		(*iov)->iov_base = (void __user *)
607 				(udev->data_off + dbi * DATA_BLOCK_SIZE);
608 	}
609 	(*iov)->iov_len += len;
610 
611 	return dbi;
612 }
613 
614 static void tcmu_setup_iovs(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
615 			    struct iovec **iov, int data_length)
616 {
617 	/* start value of dbi + 1 must not be a valid dbi */
618 	int dbi = -2;
619 
620 	/* We prepare the IOVs for DMA_FROM_DEVICE transfer direction */
621 	while (data_length > 0)
622 		dbi = new_block_to_iov(udev, cmd, iov, dbi, &data_length);
623 }
624 
625 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
626 {
627 	struct se_device *se_dev = se_cmd->se_dev;
628 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
629 	struct tcmu_cmd *tcmu_cmd;
630 
631 	tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_NOIO);
632 	if (!tcmu_cmd)
633 		return NULL;
634 
635 	INIT_LIST_HEAD(&tcmu_cmd->queue_entry);
636 	tcmu_cmd->se_cmd = se_cmd;
637 	tcmu_cmd->tcmu_dev = udev;
638 
639 	tcmu_cmd_set_block_cnts(tcmu_cmd);
640 	tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
641 				GFP_NOIO);
642 	if (!tcmu_cmd->dbi) {
643 		kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
644 		return NULL;
645 	}
646 
647 	return tcmu_cmd;
648 }
649 
650 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
651 {
652 	unsigned long offset = offset_in_page(vaddr);
653 	void *start = vaddr - offset;
654 
655 	size = round_up(size+offset, PAGE_SIZE);
656 
657 	while (size) {
658 		flush_dcache_page(vmalloc_to_page(start));
659 		start += PAGE_SIZE;
660 		size -= PAGE_SIZE;
661 	}
662 }
663 
664 /*
665  * Some ring helper functions. We don't assume size is a power of 2 so
666  * we can't use circ_buf.h.
667  */
668 static inline size_t spc_used(size_t head, size_t tail, size_t size)
669 {
670 	int diff = head - tail;
671 
672 	if (diff >= 0)
673 		return diff;
674 	else
675 		return size + diff;
676 }
677 
678 static inline size_t spc_free(size_t head, size_t tail, size_t size)
679 {
680 	/* Keep 1 byte unused or we can't tell full from empty */
681 	return (size - spc_used(head, tail, size) - 1);
682 }
683 
684 static inline size_t head_to_end(size_t head, size_t size)
685 {
686 	return size - head;
687 }
688 
689 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
690 
691 static void scatter_data_area(struct tcmu_dev *udev, struct tcmu_cmd *tcmu_cmd,
692 			      struct iovec **iov)
693 {
694 	struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
695 	/* start value of dbi + 1 must not be a valid dbi */
696 	int i, dbi = -2;
697 	int block_remaining = 0;
698 	int data_len = se_cmd->data_length;
699 	void *from, *to = NULL;
700 	size_t copy_bytes, offset;
701 	struct scatterlist *sg;
702 	struct page *page = NULL;
703 
704 	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
705 		int sg_remaining = sg->length;
706 		from = kmap_atomic(sg_page(sg)) + sg->offset;
707 		while (sg_remaining > 0) {
708 			if (block_remaining == 0) {
709 				if (to) {
710 					flush_dcache_page(page);
711 					kunmap_atomic(to);
712 				}
713 
714 				/* get next dbi and add to IOVs */
715 				dbi = new_block_to_iov(udev, tcmu_cmd, iov, dbi,
716 						       &data_len);
717 				page = tcmu_get_block_page(udev, dbi);
718 				to = kmap_atomic(page);
719 				block_remaining = DATA_BLOCK_SIZE;
720 			}
721 
722 			copy_bytes = min_t(size_t, sg_remaining,
723 					block_remaining);
724 			offset = DATA_BLOCK_SIZE - block_remaining;
725 			memcpy(to + offset, from + sg->length - sg_remaining,
726 			       copy_bytes);
727 
728 			sg_remaining -= copy_bytes;
729 			block_remaining -= copy_bytes;
730 		}
731 		kunmap_atomic(from - sg->offset);
732 	}
733 
734 	if (to) {
735 		flush_dcache_page(page);
736 		kunmap_atomic(to);
737 	}
738 }
739 
740 static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
741 			     bool bidi, uint32_t read_len)
742 {
743 	struct se_cmd *se_cmd = cmd->se_cmd;
744 	int i, dbi;
745 	int block_remaining = 0;
746 	void *from = NULL, *to;
747 	size_t copy_bytes, offset;
748 	struct scatterlist *sg, *data_sg;
749 	struct page *page;
750 	unsigned int data_nents;
751 	uint32_t count = 0;
752 
753 	if (!bidi) {
754 		data_sg = se_cmd->t_data_sg;
755 		data_nents = se_cmd->t_data_nents;
756 	} else {
757 		/*
758 		 * For bidi case, the first count blocks are for Data-Out
759 		 * buffer blocks, and before gathering the Data-In buffer
760 		 * the Data-Out buffer blocks should be skipped.
761 		 */
762 		count = cmd->dbi_cnt - cmd->dbi_bidi_cnt;
763 
764 		data_sg = se_cmd->t_bidi_data_sg;
765 		data_nents = se_cmd->t_bidi_data_nents;
766 	}
767 
768 	tcmu_cmd_set_dbi_cur(cmd, count);
769 
770 	for_each_sg(data_sg, sg, data_nents, i) {
771 		int sg_remaining = sg->length;
772 		to = kmap_atomic(sg_page(sg)) + sg->offset;
773 		while (sg_remaining > 0 && read_len > 0) {
774 			if (block_remaining == 0) {
775 				if (from)
776 					kunmap_atomic(from);
777 
778 				block_remaining = DATA_BLOCK_SIZE;
779 				dbi = tcmu_cmd_get_dbi(cmd);
780 				page = tcmu_get_block_page(udev, dbi);
781 				from = kmap_atomic(page);
782 				flush_dcache_page(page);
783 			}
784 			copy_bytes = min_t(size_t, sg_remaining,
785 					block_remaining);
786 			if (read_len < copy_bytes)
787 				copy_bytes = read_len;
788 			offset = DATA_BLOCK_SIZE - block_remaining;
789 			memcpy(to + sg->length - sg_remaining, from + offset,
790 					copy_bytes);
791 
792 			sg_remaining -= copy_bytes;
793 			block_remaining -= copy_bytes;
794 			read_len -= copy_bytes;
795 		}
796 		kunmap_atomic(to - sg->offset);
797 		if (read_len == 0)
798 			break;
799 	}
800 	if (from)
801 		kunmap_atomic(from);
802 }
803 
804 static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
805 {
806 	return thresh - bitmap_weight(bitmap, thresh);
807 }
808 
809 /*
810  * We can't queue a command until we have space available on the cmd ring.
811  *
812  * Called with ring lock held.
813  */
814 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size)
815 {
816 	struct tcmu_mailbox *mb = udev->mb_addr;
817 	size_t space, cmd_needed;
818 	u32 cmd_head;
819 
820 	tcmu_flush_dcache_range(mb, sizeof(*mb));
821 
822 	cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
823 
824 	/*
825 	 * If cmd end-of-ring space is too small then we need space for a NOP plus
826 	 * original cmd - cmds are internally contiguous.
827 	 */
828 	if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
829 		cmd_needed = cmd_size;
830 	else
831 		cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
832 
833 	space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
834 	if (space < cmd_needed) {
835 		pr_debug("no cmd space: %u %u %u\n", cmd_head,
836 		       udev->cmdr_last_cleaned, udev->cmdr_size);
837 		return false;
838 	}
839 	return true;
840 }
841 
842 /*
843  * We have to allocate data buffers before we can queue a command.
844  * Returns -1 on error (not enough space) or number of needed iovs on success
845  *
846  * Called with ring lock held.
847  */
848 static int tcmu_alloc_data_space(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
849 				  int *iov_bidi_cnt)
850 {
851 	int space, iov_cnt = 0, ret = 0;
852 
853 	if (!cmd->dbi_cnt)
854 		goto wr_iov_cnts;
855 
856 	/* try to check and get the data blocks as needed */
857 	space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
858 	if (space < cmd->dbi_cnt) {
859 		unsigned long blocks_left =
860 				(udev->max_blocks - udev->dbi_thresh) + space;
861 
862 		if (blocks_left < cmd->dbi_cnt) {
863 			pr_debug("no data space: only %lu available, but ask for %lu\n",
864 					blocks_left * DATA_BLOCK_SIZE,
865 					cmd->dbi_cnt * DATA_BLOCK_SIZE);
866 			return -1;
867 		}
868 
869 		udev->dbi_thresh += cmd->dbi_cnt;
870 		if (udev->dbi_thresh > udev->max_blocks)
871 			udev->dbi_thresh = udev->max_blocks;
872 	}
873 
874 	iov_cnt = tcmu_get_empty_blocks(udev, cmd,
875 					cmd->dbi_cnt - cmd->dbi_bidi_cnt);
876 	if (iov_cnt < 0)
877 		return -1;
878 
879 	if (cmd->dbi_bidi_cnt) {
880 		ret = tcmu_get_empty_blocks(udev, cmd, cmd->dbi_bidi_cnt);
881 		if (ret < 0)
882 			return -1;
883 	}
884 wr_iov_cnts:
885 	*iov_bidi_cnt = ret;
886 	return iov_cnt + ret;
887 }
888 
889 static inline size_t tcmu_cmd_get_base_cmd_size(size_t iov_cnt)
890 {
891 	return max(offsetof(struct tcmu_cmd_entry, req.iov[iov_cnt]),
892 			sizeof(struct tcmu_cmd_entry));
893 }
894 
895 static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
896 					   size_t base_command_size)
897 {
898 	struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
899 	size_t command_size;
900 
901 	command_size = base_command_size +
902 		round_up(scsi_command_size(se_cmd->t_task_cdb),
903 				TCMU_OP_ALIGN_SIZE);
904 
905 	WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
906 
907 	return command_size;
908 }
909 
910 static void tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo,
911 				 struct timer_list *timer)
912 {
913 	if (!tmo)
914 		return;
915 
916 	tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
917 	if (!timer_pending(timer))
918 		mod_timer(timer, tcmu_cmd->deadline);
919 
920 	pr_debug("Timeout set up for cmd %p, dev = %s, tmo = %lu\n", tcmu_cmd,
921 		 tcmu_cmd->tcmu_dev->name, tmo / MSEC_PER_SEC);
922 }
923 
924 static int add_to_qfull_queue(struct tcmu_cmd *tcmu_cmd)
925 {
926 	struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
927 	unsigned int tmo;
928 
929 	/*
930 	 * For backwards compat if qfull_time_out is not set use
931 	 * cmd_time_out and if that's not set use the default time out.
932 	 */
933 	if (!udev->qfull_time_out)
934 		return -ETIMEDOUT;
935 	else if (udev->qfull_time_out > 0)
936 		tmo = udev->qfull_time_out;
937 	else if (udev->cmd_time_out)
938 		tmo = udev->cmd_time_out;
939 	else
940 		tmo = TCMU_TIME_OUT;
941 
942 	tcmu_setup_cmd_timer(tcmu_cmd, tmo, &udev->qfull_timer);
943 
944 	list_add_tail(&tcmu_cmd->queue_entry, &udev->qfull_queue);
945 	pr_debug("adding cmd %p on dev %s to ring space wait queue\n",
946 		 tcmu_cmd, udev->name);
947 	return 0;
948 }
949 
950 static uint32_t ring_insert_padding(struct tcmu_dev *udev, size_t cmd_size)
951 {
952 	struct tcmu_cmd_entry_hdr *hdr;
953 	struct tcmu_mailbox *mb = udev->mb_addr;
954 	uint32_t cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
955 
956 	/* Insert a PAD if end-of-ring space is too small */
957 	if (head_to_end(cmd_head, udev->cmdr_size) < cmd_size) {
958 		size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
959 
960 		hdr = (void *) mb + CMDR_OFF + cmd_head;
961 		tcmu_hdr_set_op(&hdr->len_op, TCMU_OP_PAD);
962 		tcmu_hdr_set_len(&hdr->len_op, pad_size);
963 		hdr->cmd_id = 0; /* not used for PAD */
964 		hdr->kflags = 0;
965 		hdr->uflags = 0;
966 		tcmu_flush_dcache_range(hdr, sizeof(*hdr));
967 
968 		UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
969 		tcmu_flush_dcache_range(mb, sizeof(*mb));
970 
971 		cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
972 		WARN_ON(cmd_head != 0);
973 	}
974 
975 	return cmd_head;
976 }
977 
978 /**
979  * queue_cmd_ring - queue cmd to ring or internally
980  * @tcmu_cmd: cmd to queue
981  * @scsi_err: TCM error code if failure (-1) returned.
982  *
983  * Returns:
984  * -1 we cannot queue internally or to the ring.
985  *  0 success
986  *  1 internally queued to wait for ring memory to free.
987  */
988 static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
989 {
990 	struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
991 	struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
992 	size_t base_command_size, command_size;
993 	struct tcmu_mailbox *mb = udev->mb_addr;
994 	struct tcmu_cmd_entry *entry;
995 	struct iovec *iov;
996 	int iov_cnt, iov_bidi_cnt, cmd_id;
997 	uint32_t cmd_head;
998 	uint64_t cdb_off;
999 	/* size of data buffer needed */
1000 	size_t data_length = (size_t)tcmu_cmd->dbi_cnt * DATA_BLOCK_SIZE;
1001 
1002 	*scsi_err = TCM_NO_SENSE;
1003 
1004 	if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags)) {
1005 		*scsi_err = TCM_LUN_BUSY;
1006 		return -1;
1007 	}
1008 
1009 	if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
1010 		*scsi_err = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1011 		return -1;
1012 	}
1013 
1014 	if (!list_empty(&udev->qfull_queue))
1015 		goto queue;
1016 
1017 	if (data_length > udev->data_size) {
1018 		pr_warn("TCMU: Request of size %zu is too big for %zu data area\n",
1019 			data_length, udev->data_size);
1020 		*scsi_err = TCM_INVALID_CDB_FIELD;
1021 		return -1;
1022 	}
1023 
1024 	iov_cnt = tcmu_alloc_data_space(udev, tcmu_cmd, &iov_bidi_cnt);
1025 	if (iov_cnt < 0)
1026 		goto free_and_queue;
1027 
1028 	/*
1029 	 * Must be a certain minimum size for response sense info, but
1030 	 * also may be larger if the iov array is large.
1031 	 */
1032 	base_command_size = tcmu_cmd_get_base_cmd_size(iov_cnt);
1033 	command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
1034 
1035 	if (command_size > (udev->cmdr_size / 2)) {
1036 		pr_warn("TCMU: Request of size %zu is too big for %u cmd ring\n",
1037 			command_size, udev->cmdr_size);
1038 		tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur);
1039 		*scsi_err = TCM_INVALID_CDB_FIELD;
1040 		return -1;
1041 	}
1042 
1043 	if (!is_ring_space_avail(udev, command_size))
1044 		/*
1045 		 * Don't leave commands partially setup because the unmap
1046 		 * thread might need the blocks to make forward progress.
1047 		 */
1048 		goto free_and_queue;
1049 
1050 	cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
1051 	if (cmd_id < 0) {
1052 		pr_err("tcmu: Could not allocate cmd id.\n");
1053 
1054 		tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
1055 		*scsi_err = TCM_OUT_OF_RESOURCES;
1056 		return -1;
1057 	}
1058 	tcmu_cmd->cmd_id = cmd_id;
1059 
1060 	pr_debug("allocated cmd id %u for cmd %p dev %s\n", tcmu_cmd->cmd_id,
1061 		 tcmu_cmd, udev->name);
1062 
1063 	cmd_head = ring_insert_padding(udev, command_size);
1064 
1065 	entry = (void *) mb + CMDR_OFF + cmd_head;
1066 	memset(entry, 0, command_size);
1067 	tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
1068 
1069 	/* prepare iov list and copy data to data area if necessary */
1070 	tcmu_cmd_reset_dbi_cur(tcmu_cmd);
1071 	iov = &entry->req.iov[0];
1072 
1073 	if (se_cmd->data_direction == DMA_TO_DEVICE ||
1074 	    se_cmd->se_cmd_flags & SCF_BIDI)
1075 		scatter_data_area(udev, tcmu_cmd, &iov);
1076 	else
1077 		tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
1078 
1079 	entry->req.iov_cnt = iov_cnt - iov_bidi_cnt;
1080 
1081 	/* Handle BIDI commands */
1082 	if (se_cmd->se_cmd_flags & SCF_BIDI) {
1083 		iov++;
1084 		tcmu_setup_iovs(udev, tcmu_cmd, &iov, tcmu_cmd->data_len_bidi);
1085 		entry->req.iov_bidi_cnt = iov_bidi_cnt;
1086 	}
1087 
1088 	tcmu_setup_cmd_timer(tcmu_cmd, udev->cmd_time_out, &udev->cmd_timer);
1089 
1090 	entry->hdr.cmd_id = tcmu_cmd->cmd_id;
1091 
1092 	tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
1093 
1094 	/* All offsets relative to mb_addr, not start of entry! */
1095 	cdb_off = CMDR_OFF + cmd_head + base_command_size;
1096 	memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
1097 	entry->req.cdb_off = cdb_off;
1098 	tcmu_flush_dcache_range(entry, command_size);
1099 
1100 	UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
1101 	tcmu_flush_dcache_range(mb, sizeof(*mb));
1102 
1103 	list_add_tail(&tcmu_cmd->queue_entry, &udev->inflight_queue);
1104 
1105 	/* TODO: only if FLUSH and FUA? */
1106 	uio_event_notify(&udev->uio_info);
1107 
1108 	return 0;
1109 
1110 free_and_queue:
1111 	tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur);
1112 	tcmu_cmd_reset_dbi_cur(tcmu_cmd);
1113 
1114 queue:
1115 	if (add_to_qfull_queue(tcmu_cmd)) {
1116 		*scsi_err = TCM_OUT_OF_RESOURCES;
1117 		return -1;
1118 	}
1119 
1120 	return 1;
1121 }
1122 
1123 /**
1124  * queue_tmr_ring - queue tmr info to ring or internally
1125  * @udev: related tcmu_dev
1126  * @tmr: tcmu_tmr containing tmr info to queue
1127  *
1128  * Returns:
1129  *  0 success
1130  *  1 internally queued to wait for ring memory to free.
1131  */
1132 static int
1133 queue_tmr_ring(struct tcmu_dev *udev, struct tcmu_tmr *tmr)
1134 {
1135 	struct tcmu_tmr_entry *entry;
1136 	int cmd_size;
1137 	int id_list_sz;
1138 	struct tcmu_mailbox *mb = udev->mb_addr;
1139 	uint32_t cmd_head;
1140 
1141 	if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
1142 		goto out_free;
1143 
1144 	id_list_sz = sizeof(tmr->tmr_cmd_ids[0]) * tmr->tmr_cmd_cnt;
1145 	cmd_size = round_up(sizeof(*entry) + id_list_sz, TCMU_OP_ALIGN_SIZE);
1146 
1147 	if (!list_empty(&udev->tmr_queue) ||
1148 	    !is_ring_space_avail(udev, cmd_size)) {
1149 		list_add_tail(&tmr->queue_entry, &udev->tmr_queue);
1150 		pr_debug("adding tmr %p on dev %s to TMR ring space wait queue\n",
1151 			 tmr, udev->name);
1152 		return 1;
1153 	}
1154 
1155 	cmd_head = ring_insert_padding(udev, cmd_size);
1156 
1157 	entry = (void *)mb + CMDR_OFF + cmd_head;
1158 	memset(entry, 0, cmd_size);
1159 	tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_TMR);
1160 	tcmu_hdr_set_len(&entry->hdr.len_op, cmd_size);
1161 	entry->tmr_type = tmr->tmr_type;
1162 	entry->cmd_cnt = tmr->tmr_cmd_cnt;
1163 	memcpy(&entry->cmd_ids[0], &tmr->tmr_cmd_ids[0], id_list_sz);
1164 	tcmu_flush_dcache_range(entry, cmd_size);
1165 
1166 	UPDATE_HEAD(mb->cmd_head, cmd_size, udev->cmdr_size);
1167 	tcmu_flush_dcache_range(mb, sizeof(*mb));
1168 
1169 	uio_event_notify(&udev->uio_info);
1170 
1171 out_free:
1172 	kfree(tmr);
1173 
1174 	return 0;
1175 }
1176 
1177 static sense_reason_t
1178 tcmu_queue_cmd(struct se_cmd *se_cmd)
1179 {
1180 	struct se_device *se_dev = se_cmd->se_dev;
1181 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
1182 	struct tcmu_cmd *tcmu_cmd;
1183 	sense_reason_t scsi_ret = TCM_CHECK_CONDITION_ABORT_CMD;
1184 	int ret = -1;
1185 
1186 	tcmu_cmd = tcmu_alloc_cmd(se_cmd);
1187 	if (!tcmu_cmd)
1188 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1189 
1190 	mutex_lock(&udev->cmdr_lock);
1191 	se_cmd->priv = tcmu_cmd;
1192 	if (!(se_cmd->transport_state & CMD_T_ABORTED))
1193 		ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
1194 	if (ret < 0)
1195 		tcmu_free_cmd(tcmu_cmd);
1196 	mutex_unlock(&udev->cmdr_lock);
1197 	return scsi_ret;
1198 }
1199 
1200 static void tcmu_set_next_deadline(struct list_head *queue,
1201 				   struct timer_list *timer)
1202 {
1203 	struct tcmu_cmd *cmd;
1204 
1205 	if (!list_empty(queue)) {
1206 		cmd = list_first_entry(queue, struct tcmu_cmd, queue_entry);
1207 		mod_timer(timer, cmd->deadline);
1208 	} else
1209 		del_timer(timer);
1210 }
1211 
1212 static int
1213 tcmu_tmr_type(enum tcm_tmreq_table tmf)
1214 {
1215 	switch (tmf) {
1216 	case TMR_ABORT_TASK:		return TCMU_TMR_ABORT_TASK;
1217 	case TMR_ABORT_TASK_SET:	return TCMU_TMR_ABORT_TASK_SET;
1218 	case TMR_CLEAR_ACA:		return TCMU_TMR_CLEAR_ACA;
1219 	case TMR_CLEAR_TASK_SET:	return TCMU_TMR_CLEAR_TASK_SET;
1220 	case TMR_LUN_RESET:		return TCMU_TMR_LUN_RESET;
1221 	case TMR_TARGET_WARM_RESET:	return TCMU_TMR_TARGET_WARM_RESET;
1222 	case TMR_TARGET_COLD_RESET:	return TCMU_TMR_TARGET_COLD_RESET;
1223 	case TMR_LUN_RESET_PRO:		return TCMU_TMR_LUN_RESET_PRO;
1224 	default:			return TCMU_TMR_UNKNOWN;
1225 	}
1226 }
1227 
1228 static void
1229 tcmu_tmr_notify(struct se_device *se_dev, enum tcm_tmreq_table tmf,
1230 		struct list_head *cmd_list)
1231 {
1232 	int i = 0, cmd_cnt = 0;
1233 	bool unqueued = false;
1234 	uint16_t *cmd_ids = NULL;
1235 	struct tcmu_cmd *cmd;
1236 	struct se_cmd *se_cmd;
1237 	struct tcmu_tmr *tmr;
1238 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
1239 
1240 	mutex_lock(&udev->cmdr_lock);
1241 
1242 	/* First we check for aborted commands in qfull_queue */
1243 	list_for_each_entry(se_cmd, cmd_list, state_list) {
1244 		i++;
1245 		if (!se_cmd->priv)
1246 			continue;
1247 		cmd = se_cmd->priv;
1248 		/* Commands on qfull queue have no id yet */
1249 		if (cmd->cmd_id) {
1250 			cmd_cnt++;
1251 			continue;
1252 		}
1253 		pr_debug("Removing aborted command %p from queue on dev %s.\n",
1254 			 cmd, udev->name);
1255 
1256 		list_del_init(&cmd->queue_entry);
1257 		tcmu_free_cmd(cmd);
1258 		target_complete_cmd(se_cmd, SAM_STAT_TASK_ABORTED);
1259 		unqueued = true;
1260 	}
1261 	if (unqueued)
1262 		tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
1263 
1264 	if (!test_bit(TCMU_DEV_BIT_TMR_NOTIFY, &udev->flags))
1265 		goto unlock;
1266 
1267 	pr_debug("TMR event %d on dev %s, aborted cmds %d, afflicted cmd_ids %d\n",
1268 		 tcmu_tmr_type(tmf), udev->name, i, cmd_cnt);
1269 
1270 	tmr = kmalloc(sizeof(*tmr) + cmd_cnt * sizeof(*cmd_ids), GFP_KERNEL);
1271 	if (!tmr)
1272 		goto unlock;
1273 
1274 	tmr->tmr_type = tcmu_tmr_type(tmf);
1275 	tmr->tmr_cmd_cnt = cmd_cnt;
1276 
1277 	if (cmd_cnt != 0) {
1278 		cmd_cnt = 0;
1279 		list_for_each_entry(se_cmd, cmd_list, state_list) {
1280 			if (!se_cmd->priv)
1281 				continue;
1282 			cmd = se_cmd->priv;
1283 			if (cmd->cmd_id)
1284 				tmr->tmr_cmd_ids[cmd_cnt++] = cmd->cmd_id;
1285 		}
1286 	}
1287 
1288 	queue_tmr_ring(udev, tmr);
1289 
1290 unlock:
1291 	mutex_unlock(&udev->cmdr_lock);
1292 }
1293 
1294 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
1295 {
1296 	struct se_cmd *se_cmd = cmd->se_cmd;
1297 	struct tcmu_dev *udev = cmd->tcmu_dev;
1298 	bool read_len_valid = false;
1299 	uint32_t read_len;
1300 
1301 	/*
1302 	 * cmd has been completed already from timeout, just reclaim
1303 	 * data area space and free cmd
1304 	 */
1305 	if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1306 		WARN_ON_ONCE(se_cmd);
1307 		goto out;
1308 	}
1309 
1310 	list_del_init(&cmd->queue_entry);
1311 
1312 	tcmu_cmd_reset_dbi_cur(cmd);
1313 
1314 	if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
1315 		pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
1316 			cmd->se_cmd);
1317 		entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
1318 		goto done;
1319 	}
1320 
1321 	read_len = se_cmd->data_length;
1322 	if (se_cmd->data_direction == DMA_FROM_DEVICE &&
1323 	    (entry->hdr.uflags & TCMU_UFLAG_READ_LEN) && entry->rsp.read_len) {
1324 		read_len_valid = true;
1325 		if (entry->rsp.read_len < read_len)
1326 			read_len = entry->rsp.read_len;
1327 	}
1328 
1329 	if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
1330 		transport_copy_sense_to_cmd(se_cmd, entry->rsp.sense_buffer);
1331 		if (!read_len_valid )
1332 			goto done;
1333 		else
1334 			se_cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
1335 	}
1336 	if (se_cmd->se_cmd_flags & SCF_BIDI) {
1337 		/* Get Data-In buffer before clean up */
1338 		gather_data_area(udev, cmd, true, read_len);
1339 	} else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
1340 		gather_data_area(udev, cmd, false, read_len);
1341 	} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
1342 		/* TODO: */
1343 	} else if (se_cmd->data_direction != DMA_NONE) {
1344 		pr_warn("TCMU: data direction was %d!\n",
1345 			se_cmd->data_direction);
1346 	}
1347 
1348 done:
1349 	if (read_len_valid) {
1350 		pr_debug("read_len = %d\n", read_len);
1351 		target_complete_cmd_with_length(cmd->se_cmd,
1352 					entry->rsp.scsi_status, read_len);
1353 	} else
1354 		target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
1355 
1356 out:
1357 	tcmu_cmd_free_data(cmd, cmd->dbi_cnt);
1358 	tcmu_free_cmd(cmd);
1359 }
1360 
1361 static int tcmu_run_tmr_queue(struct tcmu_dev *udev)
1362 {
1363 	struct tcmu_tmr *tmr, *tmp;
1364 	LIST_HEAD(tmrs);
1365 
1366 	if (list_empty(&udev->tmr_queue))
1367 		return 1;
1368 
1369 	pr_debug("running %s's tmr queue\n", udev->name);
1370 
1371 	list_splice_init(&udev->tmr_queue, &tmrs);
1372 
1373 	list_for_each_entry_safe(tmr, tmp, &tmrs, queue_entry) {
1374 		list_del_init(&tmr->queue_entry);
1375 
1376 		pr_debug("removing tmr %p on dev %s from queue\n",
1377 			 tmr, udev->name);
1378 
1379 		if (queue_tmr_ring(udev, tmr)) {
1380 			pr_debug("ran out of space during tmr queue run\n");
1381 			/*
1382 			 * tmr was requeued, so just put all tmrs back in
1383 			 * the queue
1384 			 */
1385 			list_splice_tail(&tmrs, &udev->tmr_queue);
1386 			return 0;
1387 		}
1388 	}
1389 
1390 	return 1;
1391 }
1392 
1393 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
1394 {
1395 	struct tcmu_mailbox *mb;
1396 	struct tcmu_cmd *cmd;
1397 	bool free_space = false;
1398 
1399 	if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
1400 		pr_err("ring broken, not handling completions\n");
1401 		return 0;
1402 	}
1403 
1404 	mb = udev->mb_addr;
1405 	tcmu_flush_dcache_range(mb, sizeof(*mb));
1406 
1407 	while (udev->cmdr_last_cleaned != READ_ONCE(mb->cmd_tail)) {
1408 
1409 		struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
1410 
1411 		/*
1412 		 * Flush max. up to end of cmd ring since current entry might
1413 		 * be a padding that is shorter than sizeof(*entry)
1414 		 */
1415 		size_t ring_left = head_to_end(udev->cmdr_last_cleaned,
1416 					       udev->cmdr_size);
1417 		tcmu_flush_dcache_range(entry, ring_left < sizeof(*entry) ?
1418 					ring_left : sizeof(*entry));
1419 
1420 		free_space = true;
1421 
1422 		if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD ||
1423 		    tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_TMR) {
1424 			UPDATE_HEAD(udev->cmdr_last_cleaned,
1425 				    tcmu_hdr_get_len(entry->hdr.len_op),
1426 				    udev->cmdr_size);
1427 			continue;
1428 		}
1429 		WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
1430 
1431 		cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
1432 		if (!cmd) {
1433 			pr_err("cmd_id %u not found, ring is broken\n",
1434 			       entry->hdr.cmd_id);
1435 			set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
1436 			break;
1437 		}
1438 
1439 		tcmu_handle_completion(cmd, entry);
1440 
1441 		UPDATE_HEAD(udev->cmdr_last_cleaned,
1442 			    tcmu_hdr_get_len(entry->hdr.len_op),
1443 			    udev->cmdr_size);
1444 	}
1445 	if (free_space)
1446 		free_space = tcmu_run_tmr_queue(udev);
1447 
1448 	if (atomic_read(&global_db_count) > tcmu_global_max_blocks &&
1449 	    idr_is_empty(&udev->commands) && list_empty(&udev->qfull_queue)) {
1450 		/*
1451 		 * Allocated blocks exceeded global block limit, currently no
1452 		 * more pending or waiting commands so try to reclaim blocks.
1453 		 */
1454 		schedule_delayed_work(&tcmu_unmap_work, 0);
1455 	}
1456 	if (udev->cmd_time_out)
1457 		tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer);
1458 
1459 	return free_space;
1460 }
1461 
1462 static void tcmu_check_expired_ring_cmd(struct tcmu_cmd *cmd)
1463 {
1464 	struct se_cmd *se_cmd;
1465 
1466 	if (!time_after_eq(jiffies, cmd->deadline))
1467 		return;
1468 
1469 	set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
1470 	list_del_init(&cmd->queue_entry);
1471 	se_cmd = cmd->se_cmd;
1472 	se_cmd->priv = NULL;
1473 	cmd->se_cmd = NULL;
1474 
1475 	pr_debug("Timing out inflight cmd %u on dev %s.\n",
1476 		 cmd->cmd_id, cmd->tcmu_dev->name);
1477 
1478 	target_complete_cmd(se_cmd, SAM_STAT_CHECK_CONDITION);
1479 }
1480 
1481 static void tcmu_check_expired_queue_cmd(struct tcmu_cmd *cmd)
1482 {
1483 	struct se_cmd *se_cmd;
1484 
1485 	if (!time_after_eq(jiffies, cmd->deadline))
1486 		return;
1487 
1488 	pr_debug("Timing out queued cmd %p on dev %s.\n",
1489 		  cmd, cmd->tcmu_dev->name);
1490 
1491 	list_del_init(&cmd->queue_entry);
1492 	se_cmd = cmd->se_cmd;
1493 	tcmu_free_cmd(cmd);
1494 
1495 	target_complete_cmd(se_cmd, SAM_STAT_TASK_SET_FULL);
1496 }
1497 
1498 static void tcmu_device_timedout(struct tcmu_dev *udev)
1499 {
1500 	spin_lock(&timed_out_udevs_lock);
1501 	if (list_empty(&udev->timedout_entry))
1502 		list_add_tail(&udev->timedout_entry, &timed_out_udevs);
1503 	spin_unlock(&timed_out_udevs_lock);
1504 
1505 	schedule_delayed_work(&tcmu_unmap_work, 0);
1506 }
1507 
1508 static void tcmu_cmd_timedout(struct timer_list *t)
1509 {
1510 	struct tcmu_dev *udev = from_timer(udev, t, cmd_timer);
1511 
1512 	pr_debug("%s cmd timeout has expired\n", udev->name);
1513 	tcmu_device_timedout(udev);
1514 }
1515 
1516 static void tcmu_qfull_timedout(struct timer_list *t)
1517 {
1518 	struct tcmu_dev *udev = from_timer(udev, t, qfull_timer);
1519 
1520 	pr_debug("%s qfull timeout has expired\n", udev->name);
1521 	tcmu_device_timedout(udev);
1522 }
1523 
1524 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
1525 {
1526 	struct tcmu_hba *tcmu_hba;
1527 
1528 	tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
1529 	if (!tcmu_hba)
1530 		return -ENOMEM;
1531 
1532 	tcmu_hba->host_id = host_id;
1533 	hba->hba_ptr = tcmu_hba;
1534 
1535 	return 0;
1536 }
1537 
1538 static void tcmu_detach_hba(struct se_hba *hba)
1539 {
1540 	kfree(hba->hba_ptr);
1541 	hba->hba_ptr = NULL;
1542 }
1543 
1544 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
1545 {
1546 	struct tcmu_dev *udev;
1547 
1548 	udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
1549 	if (!udev)
1550 		return NULL;
1551 	kref_init(&udev->kref);
1552 
1553 	udev->name = kstrdup(name, GFP_KERNEL);
1554 	if (!udev->name) {
1555 		kfree(udev);
1556 		return NULL;
1557 	}
1558 
1559 	udev->hba = hba;
1560 	udev->cmd_time_out = TCMU_TIME_OUT;
1561 	udev->qfull_time_out = -1;
1562 
1563 	udev->max_blocks = DATA_BLOCK_BITS_DEF;
1564 	mutex_init(&udev->cmdr_lock);
1565 
1566 	INIT_LIST_HEAD(&udev->node);
1567 	INIT_LIST_HEAD(&udev->timedout_entry);
1568 	INIT_LIST_HEAD(&udev->qfull_queue);
1569 	INIT_LIST_HEAD(&udev->tmr_queue);
1570 	INIT_LIST_HEAD(&udev->inflight_queue);
1571 	idr_init(&udev->commands);
1572 
1573 	timer_setup(&udev->qfull_timer, tcmu_qfull_timedout, 0);
1574 	timer_setup(&udev->cmd_timer, tcmu_cmd_timedout, 0);
1575 
1576 	INIT_RADIX_TREE(&udev->data_blocks, GFP_KERNEL);
1577 
1578 	return &udev->se_dev;
1579 }
1580 
1581 static void run_qfull_queue(struct tcmu_dev *udev, bool fail)
1582 {
1583 	struct tcmu_cmd *tcmu_cmd, *tmp_cmd;
1584 	LIST_HEAD(cmds);
1585 	sense_reason_t scsi_ret;
1586 	int ret;
1587 
1588 	if (list_empty(&udev->qfull_queue))
1589 		return;
1590 
1591 	pr_debug("running %s's cmdr queue forcefail %d\n", udev->name, fail);
1592 
1593 	list_splice_init(&udev->qfull_queue, &cmds);
1594 
1595 	list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, queue_entry) {
1596 		list_del_init(&tcmu_cmd->queue_entry);
1597 
1598 		pr_debug("removing cmd %p on dev %s from queue\n",
1599 			 tcmu_cmd, udev->name);
1600 
1601 		if (fail) {
1602 			/*
1603 			 * We were not able to even start the command, so
1604 			 * fail with busy to allow a retry in case runner
1605 			 * was only temporarily down. If the device is being
1606 			 * removed then LIO core will do the right thing and
1607 			 * fail the retry.
1608 			 */
1609 			target_complete_cmd(tcmu_cmd->se_cmd, SAM_STAT_BUSY);
1610 			tcmu_free_cmd(tcmu_cmd);
1611 			continue;
1612 		}
1613 
1614 		ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
1615 		if (ret < 0) {
1616 			pr_debug("cmd %p on dev %s failed with %u\n",
1617 				 tcmu_cmd, udev->name, scsi_ret);
1618 			/*
1619 			 * Ignore scsi_ret for now. target_complete_cmd
1620 			 * drops it.
1621 			 */
1622 			target_complete_cmd(tcmu_cmd->se_cmd,
1623 					    SAM_STAT_CHECK_CONDITION);
1624 			tcmu_free_cmd(tcmu_cmd);
1625 		} else if (ret > 0) {
1626 			pr_debug("ran out of space during cmdr queue run\n");
1627 			/*
1628 			 * cmd was requeued, so just put all cmds back in
1629 			 * the queue
1630 			 */
1631 			list_splice_tail(&cmds, &udev->qfull_queue);
1632 			break;
1633 		}
1634 	}
1635 
1636 	tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
1637 }
1638 
1639 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
1640 {
1641 	struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1642 
1643 	mutex_lock(&udev->cmdr_lock);
1644 	if (tcmu_handle_completions(udev))
1645 		run_qfull_queue(udev, false);
1646 	mutex_unlock(&udev->cmdr_lock);
1647 
1648 	return 0;
1649 }
1650 
1651 /*
1652  * mmap code from uio.c. Copied here because we want to hook mmap()
1653  * and this stuff must come along.
1654  */
1655 static int tcmu_find_mem_index(struct vm_area_struct *vma)
1656 {
1657 	struct tcmu_dev *udev = vma->vm_private_data;
1658 	struct uio_info *info = &udev->uio_info;
1659 
1660 	if (vma->vm_pgoff < MAX_UIO_MAPS) {
1661 		if (info->mem[vma->vm_pgoff].size == 0)
1662 			return -1;
1663 		return (int)vma->vm_pgoff;
1664 	}
1665 	return -1;
1666 }
1667 
1668 static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
1669 {
1670 	struct page *page;
1671 
1672 	mutex_lock(&udev->cmdr_lock);
1673 	page = tcmu_get_block_page(udev, dbi);
1674 	if (likely(page)) {
1675 		mutex_unlock(&udev->cmdr_lock);
1676 		return page;
1677 	}
1678 
1679 	/*
1680 	 * Userspace messed up and passed in a address not in the
1681 	 * data iov passed to it.
1682 	 */
1683 	pr_err("Invalid addr to data block mapping  (dbi %u) on device %s\n",
1684 	       dbi, udev->name);
1685 	page = NULL;
1686 	mutex_unlock(&udev->cmdr_lock);
1687 
1688 	return page;
1689 }
1690 
1691 static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
1692 {
1693 	struct tcmu_dev *udev = vmf->vma->vm_private_data;
1694 	struct uio_info *info = &udev->uio_info;
1695 	struct page *page;
1696 	unsigned long offset;
1697 	void *addr;
1698 
1699 	int mi = tcmu_find_mem_index(vmf->vma);
1700 	if (mi < 0)
1701 		return VM_FAULT_SIGBUS;
1702 
1703 	/*
1704 	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
1705 	 * to use mem[N].
1706 	 */
1707 	offset = (vmf->pgoff - mi) << PAGE_SHIFT;
1708 
1709 	if (offset < udev->data_off) {
1710 		/* For the vmalloc()ed cmd area pages */
1711 		addr = (void *)(unsigned long)info->mem[mi].addr + offset;
1712 		page = vmalloc_to_page(addr);
1713 	} else {
1714 		uint32_t dbi;
1715 
1716 		/* For the dynamically growing data area pages */
1717 		dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
1718 		page = tcmu_try_get_block_page(udev, dbi);
1719 		if (!page)
1720 			return VM_FAULT_SIGBUS;
1721 	}
1722 
1723 	get_page(page);
1724 	vmf->page = page;
1725 	return 0;
1726 }
1727 
1728 static const struct vm_operations_struct tcmu_vm_ops = {
1729 	.fault = tcmu_vma_fault,
1730 };
1731 
1732 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
1733 {
1734 	struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1735 
1736 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1737 	vma->vm_ops = &tcmu_vm_ops;
1738 
1739 	vma->vm_private_data = udev;
1740 
1741 	/* Ensure the mmap is exactly the right size */
1742 	if (vma_pages(vma) != (udev->ring_size >> PAGE_SHIFT))
1743 		return -EINVAL;
1744 
1745 	return 0;
1746 }
1747 
1748 static int tcmu_open(struct uio_info *info, struct inode *inode)
1749 {
1750 	struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1751 
1752 	/* O_EXCL not supported for char devs, so fake it? */
1753 	if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
1754 		return -EBUSY;
1755 
1756 	udev->inode = inode;
1757 	kref_get(&udev->kref);
1758 
1759 	pr_debug("open\n");
1760 
1761 	return 0;
1762 }
1763 
1764 static void tcmu_dev_call_rcu(struct rcu_head *p)
1765 {
1766 	struct se_device *dev = container_of(p, struct se_device, rcu_head);
1767 	struct tcmu_dev *udev = TCMU_DEV(dev);
1768 
1769 	kfree(udev->uio_info.name);
1770 	kfree(udev->name);
1771 	kfree(udev);
1772 }
1773 
1774 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1775 {
1776 	if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1777 		kmem_cache_free(tcmu_cmd_cache, cmd);
1778 		return 0;
1779 	}
1780 	return -EINVAL;
1781 }
1782 
1783 static void tcmu_blocks_release(struct radix_tree_root *blocks,
1784 				int start, int end)
1785 {
1786 	int i;
1787 	struct page *page;
1788 
1789 	for (i = start; i < end; i++) {
1790 		page = radix_tree_delete(blocks, i);
1791 		if (page) {
1792 			__free_page(page);
1793 			atomic_dec(&global_db_count);
1794 		}
1795 	}
1796 }
1797 
1798 static void tcmu_remove_all_queued_tmr(struct tcmu_dev *udev)
1799 {
1800 	struct tcmu_tmr *tmr, *tmp;
1801 
1802 	list_for_each_entry_safe(tmr, tmp, &udev->tmr_queue, queue_entry) {
1803 		list_del_init(&tmr->queue_entry);
1804 		kfree(tmr);
1805 	}
1806 }
1807 
1808 static void tcmu_dev_kref_release(struct kref *kref)
1809 {
1810 	struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref);
1811 	struct se_device *dev = &udev->se_dev;
1812 	struct tcmu_cmd *cmd;
1813 	bool all_expired = true;
1814 	int i;
1815 
1816 	vfree(udev->mb_addr);
1817 	udev->mb_addr = NULL;
1818 
1819 	spin_lock_bh(&timed_out_udevs_lock);
1820 	if (!list_empty(&udev->timedout_entry))
1821 		list_del(&udev->timedout_entry);
1822 	spin_unlock_bh(&timed_out_udevs_lock);
1823 
1824 	/* Upper layer should drain all requests before calling this */
1825 	mutex_lock(&udev->cmdr_lock);
1826 	idr_for_each_entry(&udev->commands, cmd, i) {
1827 		if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1828 			all_expired = false;
1829 	}
1830 	/* There can be left over TMR cmds. Remove them. */
1831 	tcmu_remove_all_queued_tmr(udev);
1832 	if (!list_empty(&udev->qfull_queue))
1833 		all_expired = false;
1834 	idr_destroy(&udev->commands);
1835 	WARN_ON(!all_expired);
1836 
1837 	tcmu_blocks_release(&udev->data_blocks, 0, udev->dbi_max + 1);
1838 	bitmap_free(udev->data_bitmap);
1839 	mutex_unlock(&udev->cmdr_lock);
1840 
1841 	call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1842 }
1843 
1844 static int tcmu_release(struct uio_info *info, struct inode *inode)
1845 {
1846 	struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1847 
1848 	clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
1849 
1850 	pr_debug("close\n");
1851 	/* release ref from open */
1852 	kref_put(&udev->kref, tcmu_dev_kref_release);
1853 	return 0;
1854 }
1855 
1856 static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
1857 {
1858 	struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1859 
1860 	if (!tcmu_kern_cmd_reply_supported)
1861 		return 0;
1862 
1863 	if (udev->nl_reply_supported <= 0)
1864 		return 0;
1865 
1866 	mutex_lock(&tcmu_nl_cmd_mutex);
1867 
1868 	if (tcmu_netlink_blocked) {
1869 		mutex_unlock(&tcmu_nl_cmd_mutex);
1870 		pr_warn("Failing nl cmd %d on %s. Interface is blocked.\n", cmd,
1871 			udev->name);
1872 		return -EAGAIN;
1873 	}
1874 
1875 	if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
1876 		mutex_unlock(&tcmu_nl_cmd_mutex);
1877 		pr_warn("netlink cmd %d already executing on %s\n",
1878 			 nl_cmd->cmd, udev->name);
1879 		return -EBUSY;
1880 	}
1881 
1882 	memset(nl_cmd, 0, sizeof(*nl_cmd));
1883 	nl_cmd->cmd = cmd;
1884 	nl_cmd->udev = udev;
1885 	init_completion(&nl_cmd->complete);
1886 	INIT_LIST_HEAD(&nl_cmd->nl_list);
1887 
1888 	list_add_tail(&nl_cmd->nl_list, &tcmu_nl_cmd_list);
1889 
1890 	mutex_unlock(&tcmu_nl_cmd_mutex);
1891 	return 0;
1892 }
1893 
1894 static void tcmu_destroy_genl_cmd_reply(struct tcmu_dev *udev)
1895 {
1896 	struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1897 
1898 	if (!tcmu_kern_cmd_reply_supported)
1899 		return;
1900 
1901 	if (udev->nl_reply_supported <= 0)
1902 		return;
1903 
1904 	mutex_lock(&tcmu_nl_cmd_mutex);
1905 
1906 	list_del(&nl_cmd->nl_list);
1907 	memset(nl_cmd, 0, sizeof(*nl_cmd));
1908 
1909 	mutex_unlock(&tcmu_nl_cmd_mutex);
1910 }
1911 
1912 static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
1913 {
1914 	struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1915 	int ret;
1916 
1917 	if (!tcmu_kern_cmd_reply_supported)
1918 		return 0;
1919 
1920 	if (udev->nl_reply_supported <= 0)
1921 		return 0;
1922 
1923 	pr_debug("sleeping for nl reply\n");
1924 	wait_for_completion(&nl_cmd->complete);
1925 
1926 	mutex_lock(&tcmu_nl_cmd_mutex);
1927 	nl_cmd->cmd = TCMU_CMD_UNSPEC;
1928 	ret = nl_cmd->status;
1929 	mutex_unlock(&tcmu_nl_cmd_mutex);
1930 
1931 	return ret;
1932 }
1933 
1934 static int tcmu_netlink_event_init(struct tcmu_dev *udev,
1935 				   enum tcmu_genl_cmd cmd,
1936 				   struct sk_buff **buf, void **hdr)
1937 {
1938 	struct sk_buff *skb;
1939 	void *msg_header;
1940 	int ret = -ENOMEM;
1941 
1942 	skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1943 	if (!skb)
1944 		return ret;
1945 
1946 	msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
1947 	if (!msg_header)
1948 		goto free_skb;
1949 
1950 	ret = nla_put_string(skb, TCMU_ATTR_DEVICE, udev->uio_info.name);
1951 	if (ret < 0)
1952 		goto free_skb;
1953 
1954 	ret = nla_put_u32(skb, TCMU_ATTR_MINOR, udev->uio_info.uio_dev->minor);
1955 	if (ret < 0)
1956 		goto free_skb;
1957 
1958 	ret = nla_put_u32(skb, TCMU_ATTR_DEVICE_ID, udev->se_dev.dev_index);
1959 	if (ret < 0)
1960 		goto free_skb;
1961 
1962 	*buf = skb;
1963 	*hdr = msg_header;
1964 	return ret;
1965 
1966 free_skb:
1967 	nlmsg_free(skb);
1968 	return ret;
1969 }
1970 
1971 static int tcmu_netlink_event_send(struct tcmu_dev *udev,
1972 				   enum tcmu_genl_cmd cmd,
1973 				   struct sk_buff *skb, void *msg_header)
1974 {
1975 	int ret;
1976 
1977 	genlmsg_end(skb, msg_header);
1978 
1979 	ret = tcmu_init_genl_cmd_reply(udev, cmd);
1980 	if (ret) {
1981 		nlmsg_free(skb);
1982 		return ret;
1983 	}
1984 
1985 	ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
1986 				      TCMU_MCGRP_CONFIG, GFP_KERNEL);
1987 
1988 	/* Wait during an add as the listener may not be up yet */
1989 	if (ret == 0 ||
1990 	   (ret == -ESRCH && cmd == TCMU_CMD_ADDED_DEVICE))
1991 		return tcmu_wait_genl_cmd_reply(udev);
1992 	else
1993 		tcmu_destroy_genl_cmd_reply(udev);
1994 
1995 	return ret;
1996 }
1997 
1998 static int tcmu_send_dev_add_event(struct tcmu_dev *udev)
1999 {
2000 	struct sk_buff *skb = NULL;
2001 	void *msg_header = NULL;
2002 	int ret = 0;
2003 
2004 	ret = tcmu_netlink_event_init(udev, TCMU_CMD_ADDED_DEVICE, &skb,
2005 				      &msg_header);
2006 	if (ret < 0)
2007 		return ret;
2008 	return tcmu_netlink_event_send(udev, TCMU_CMD_ADDED_DEVICE, skb,
2009 				       msg_header);
2010 }
2011 
2012 static int tcmu_send_dev_remove_event(struct tcmu_dev *udev)
2013 {
2014 	struct sk_buff *skb = NULL;
2015 	void *msg_header = NULL;
2016 	int ret = 0;
2017 
2018 	ret = tcmu_netlink_event_init(udev, TCMU_CMD_REMOVED_DEVICE,
2019 				      &skb, &msg_header);
2020 	if (ret < 0)
2021 		return ret;
2022 	return tcmu_netlink_event_send(udev, TCMU_CMD_REMOVED_DEVICE,
2023 				       skb, msg_header);
2024 }
2025 
2026 static int tcmu_update_uio_info(struct tcmu_dev *udev)
2027 {
2028 	struct tcmu_hba *hba = udev->hba->hba_ptr;
2029 	struct uio_info *info;
2030 	char *str;
2031 
2032 	info = &udev->uio_info;
2033 
2034 	if (udev->dev_config[0])
2035 		str = kasprintf(GFP_KERNEL, "tcm-user/%u/%s/%s", hba->host_id,
2036 				udev->name, udev->dev_config);
2037 	else
2038 		str = kasprintf(GFP_KERNEL, "tcm-user/%u/%s", hba->host_id,
2039 				udev->name);
2040 	if (!str)
2041 		return -ENOMEM;
2042 
2043 	/* If the old string exists, free it */
2044 	kfree(info->name);
2045 	info->name = str;
2046 
2047 	return 0;
2048 }
2049 
2050 static int tcmu_configure_device(struct se_device *dev)
2051 {
2052 	struct tcmu_dev *udev = TCMU_DEV(dev);
2053 	struct uio_info *info;
2054 	struct tcmu_mailbox *mb;
2055 	int ret = 0;
2056 
2057 	ret = tcmu_update_uio_info(udev);
2058 	if (ret)
2059 		return ret;
2060 
2061 	info = &udev->uio_info;
2062 
2063 	mutex_lock(&udev->cmdr_lock);
2064 	udev->data_bitmap = bitmap_zalloc(udev->max_blocks, GFP_KERNEL);
2065 	mutex_unlock(&udev->cmdr_lock);
2066 	if (!udev->data_bitmap) {
2067 		ret = -ENOMEM;
2068 		goto err_bitmap_alloc;
2069 	}
2070 
2071 	udev->mb_addr = vzalloc(CMDR_SIZE);
2072 	if (!udev->mb_addr) {
2073 		ret = -ENOMEM;
2074 		goto err_vzalloc;
2075 	}
2076 
2077 	/* mailbox fits in first part of CMDR space */
2078 	udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
2079 	udev->data_off = CMDR_SIZE;
2080 	udev->data_size = udev->max_blocks * DATA_BLOCK_SIZE;
2081 	udev->dbi_thresh = 0; /* Default in Idle state */
2082 
2083 	/* Initialise the mailbox of the ring buffer */
2084 	mb = udev->mb_addr;
2085 	mb->version = TCMU_MAILBOX_VERSION;
2086 	mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC |
2087 		    TCMU_MAILBOX_FLAG_CAP_READ_LEN |
2088 		    TCMU_MAILBOX_FLAG_CAP_TMR;
2089 	mb->cmdr_off = CMDR_OFF;
2090 	mb->cmdr_size = udev->cmdr_size;
2091 
2092 	WARN_ON(!PAGE_ALIGNED(udev->data_off));
2093 	WARN_ON(udev->data_size % PAGE_SIZE);
2094 	WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
2095 
2096 	info->version = __stringify(TCMU_MAILBOX_VERSION);
2097 
2098 	info->mem[0].name = "tcm-user command & data buffer";
2099 	info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
2100 	info->mem[0].size = udev->ring_size = udev->data_size + CMDR_SIZE;
2101 	info->mem[0].memtype = UIO_MEM_NONE;
2102 
2103 	info->irqcontrol = tcmu_irqcontrol;
2104 	info->irq = UIO_IRQ_CUSTOM;
2105 
2106 	info->mmap = tcmu_mmap;
2107 	info->open = tcmu_open;
2108 	info->release = tcmu_release;
2109 
2110 	ret = uio_register_device(tcmu_root_device, info);
2111 	if (ret)
2112 		goto err_register;
2113 
2114 	/* User can set hw_block_size before enable the device */
2115 	if (dev->dev_attrib.hw_block_size == 0)
2116 		dev->dev_attrib.hw_block_size = 512;
2117 	/* Other attributes can be configured in userspace */
2118 	if (!dev->dev_attrib.hw_max_sectors)
2119 		dev->dev_attrib.hw_max_sectors = 128;
2120 	if (!dev->dev_attrib.emulate_write_cache)
2121 		dev->dev_attrib.emulate_write_cache = 0;
2122 	dev->dev_attrib.hw_queue_depth = 128;
2123 
2124 	/* If user didn't explicitly disable netlink reply support, use
2125 	 * module scope setting.
2126 	 */
2127 	if (udev->nl_reply_supported >= 0)
2128 		udev->nl_reply_supported = tcmu_kern_cmd_reply_supported;
2129 
2130 	/*
2131 	 * Get a ref incase userspace does a close on the uio device before
2132 	 * LIO has initiated tcmu_free_device.
2133 	 */
2134 	kref_get(&udev->kref);
2135 
2136 	ret = tcmu_send_dev_add_event(udev);
2137 	if (ret)
2138 		goto err_netlink;
2139 
2140 	mutex_lock(&root_udev_mutex);
2141 	list_add(&udev->node, &root_udev);
2142 	mutex_unlock(&root_udev_mutex);
2143 
2144 	return 0;
2145 
2146 err_netlink:
2147 	kref_put(&udev->kref, tcmu_dev_kref_release);
2148 	uio_unregister_device(&udev->uio_info);
2149 err_register:
2150 	vfree(udev->mb_addr);
2151 	udev->mb_addr = NULL;
2152 err_vzalloc:
2153 	bitmap_free(udev->data_bitmap);
2154 	udev->data_bitmap = NULL;
2155 err_bitmap_alloc:
2156 	kfree(info->name);
2157 	info->name = NULL;
2158 
2159 	return ret;
2160 }
2161 
2162 static void tcmu_free_device(struct se_device *dev)
2163 {
2164 	struct tcmu_dev *udev = TCMU_DEV(dev);
2165 
2166 	/* release ref from init */
2167 	kref_put(&udev->kref, tcmu_dev_kref_release);
2168 }
2169 
2170 static void tcmu_destroy_device(struct se_device *dev)
2171 {
2172 	struct tcmu_dev *udev = TCMU_DEV(dev);
2173 
2174 	del_timer_sync(&udev->cmd_timer);
2175 	del_timer_sync(&udev->qfull_timer);
2176 
2177 	mutex_lock(&root_udev_mutex);
2178 	list_del(&udev->node);
2179 	mutex_unlock(&root_udev_mutex);
2180 
2181 	tcmu_send_dev_remove_event(udev);
2182 
2183 	uio_unregister_device(&udev->uio_info);
2184 
2185 	/* release ref from configure */
2186 	kref_put(&udev->kref, tcmu_dev_kref_release);
2187 }
2188 
2189 static void tcmu_unblock_dev(struct tcmu_dev *udev)
2190 {
2191 	mutex_lock(&udev->cmdr_lock);
2192 	clear_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags);
2193 	mutex_unlock(&udev->cmdr_lock);
2194 }
2195 
2196 static void tcmu_block_dev(struct tcmu_dev *udev)
2197 {
2198 	mutex_lock(&udev->cmdr_lock);
2199 
2200 	if (test_and_set_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))
2201 		goto unlock;
2202 
2203 	/* complete IO that has executed successfully */
2204 	tcmu_handle_completions(udev);
2205 	/* fail IO waiting to be queued */
2206 	run_qfull_queue(udev, true);
2207 
2208 unlock:
2209 	mutex_unlock(&udev->cmdr_lock);
2210 }
2211 
2212 static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level)
2213 {
2214 	struct tcmu_mailbox *mb;
2215 	struct tcmu_cmd *cmd;
2216 	int i;
2217 
2218 	mutex_lock(&udev->cmdr_lock);
2219 
2220 	idr_for_each_entry(&udev->commands, cmd, i) {
2221 		pr_debug("removing cmd %u on dev %s from ring (is expired %d)\n",
2222 			  cmd->cmd_id, udev->name,
2223 			  test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags));
2224 
2225 		idr_remove(&udev->commands, i);
2226 		if (!test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
2227 			WARN_ON(!cmd->se_cmd);
2228 			list_del_init(&cmd->queue_entry);
2229 			if (err_level == 1) {
2230 				/*
2231 				 * Userspace was not able to start the
2232 				 * command or it is retryable.
2233 				 */
2234 				target_complete_cmd(cmd->se_cmd, SAM_STAT_BUSY);
2235 			} else {
2236 				/* hard failure */
2237 				target_complete_cmd(cmd->se_cmd,
2238 						    SAM_STAT_CHECK_CONDITION);
2239 			}
2240 		}
2241 		tcmu_cmd_free_data(cmd, cmd->dbi_cnt);
2242 		tcmu_free_cmd(cmd);
2243 	}
2244 
2245 	mb = udev->mb_addr;
2246 	tcmu_flush_dcache_range(mb, sizeof(*mb));
2247 	pr_debug("mb last %u head %u tail %u\n", udev->cmdr_last_cleaned,
2248 		 mb->cmd_tail, mb->cmd_head);
2249 
2250 	udev->cmdr_last_cleaned = 0;
2251 	mb->cmd_tail = 0;
2252 	mb->cmd_head = 0;
2253 	tcmu_flush_dcache_range(mb, sizeof(*mb));
2254 	clear_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
2255 
2256 	del_timer(&udev->cmd_timer);
2257 
2258 	/*
2259 	 * ring is empty and qfull queue never contains aborted commands.
2260 	 * So TMRs in tmr queue do not contain relevant cmd_ids.
2261 	 * After a ring reset userspace should do a fresh start, so
2262 	 * even LUN RESET message is no longer relevant.
2263 	 * Therefore remove all TMRs from qfull queue
2264 	 */
2265 	tcmu_remove_all_queued_tmr(udev);
2266 
2267 	run_qfull_queue(udev, false);
2268 
2269 	mutex_unlock(&udev->cmdr_lock);
2270 }
2271 
2272 enum {
2273 	Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
2274 	Opt_nl_reply_supported, Opt_max_data_area_mb, Opt_err,
2275 };
2276 
2277 static match_table_t tokens = {
2278 	{Opt_dev_config, "dev_config=%s"},
2279 	{Opt_dev_size, "dev_size=%s"},
2280 	{Opt_hw_block_size, "hw_block_size=%d"},
2281 	{Opt_hw_max_sectors, "hw_max_sectors=%d"},
2282 	{Opt_nl_reply_supported, "nl_reply_supported=%d"},
2283 	{Opt_max_data_area_mb, "max_data_area_mb=%d"},
2284 	{Opt_err, NULL}
2285 };
2286 
2287 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
2288 {
2289 	int val, ret;
2290 
2291 	ret = match_int(arg, &val);
2292 	if (ret < 0) {
2293 		pr_err("match_int() failed for dev attrib. Error %d.\n",
2294 		       ret);
2295 		return ret;
2296 	}
2297 
2298 	if (val <= 0) {
2299 		pr_err("Invalid dev attrib value %d. Must be greater than zero.\n",
2300 		       val);
2301 		return -EINVAL;
2302 	}
2303 	*dev_attrib = val;
2304 	return 0;
2305 }
2306 
2307 static int tcmu_set_max_blocks_param(struct tcmu_dev *udev, substring_t *arg)
2308 {
2309 	int val, ret;
2310 
2311 	ret = match_int(arg, &val);
2312 	if (ret < 0) {
2313 		pr_err("match_int() failed for max_data_area_mb=. Error %d.\n",
2314 		       ret);
2315 		return ret;
2316 	}
2317 
2318 	if (val <= 0) {
2319 		pr_err("Invalid max_data_area %d.\n", val);
2320 		return -EINVAL;
2321 	}
2322 
2323 	mutex_lock(&udev->cmdr_lock);
2324 	if (udev->data_bitmap) {
2325 		pr_err("Cannot set max_data_area_mb after it has been enabled.\n");
2326 		ret = -EINVAL;
2327 		goto unlock;
2328 	}
2329 
2330 	udev->max_blocks = TCMU_MBS_TO_BLOCKS(val);
2331 	if (udev->max_blocks > tcmu_global_max_blocks) {
2332 		pr_err("%d is too large. Adjusting max_data_area_mb to global limit of %u\n",
2333 		       val, TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
2334 		udev->max_blocks = tcmu_global_max_blocks;
2335 	}
2336 
2337 unlock:
2338 	mutex_unlock(&udev->cmdr_lock);
2339 	return ret;
2340 }
2341 
2342 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
2343 		const char *page, ssize_t count)
2344 {
2345 	struct tcmu_dev *udev = TCMU_DEV(dev);
2346 	char *orig, *ptr, *opts;
2347 	substring_t args[MAX_OPT_ARGS];
2348 	int ret = 0, token;
2349 
2350 	opts = kstrdup(page, GFP_KERNEL);
2351 	if (!opts)
2352 		return -ENOMEM;
2353 
2354 	orig = opts;
2355 
2356 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
2357 		if (!*ptr)
2358 			continue;
2359 
2360 		token = match_token(ptr, tokens, args);
2361 		switch (token) {
2362 		case Opt_dev_config:
2363 			if (match_strlcpy(udev->dev_config, &args[0],
2364 					  TCMU_CONFIG_LEN) == 0) {
2365 				ret = -EINVAL;
2366 				break;
2367 			}
2368 			pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
2369 			break;
2370 		case Opt_dev_size:
2371 			ret = match_u64(&args[0], &udev->dev_size);
2372 			if (ret < 0)
2373 				pr_err("match_u64() failed for dev_size=. Error %d.\n",
2374 				       ret);
2375 			break;
2376 		case Opt_hw_block_size:
2377 			ret = tcmu_set_dev_attrib(&args[0],
2378 					&(dev->dev_attrib.hw_block_size));
2379 			break;
2380 		case Opt_hw_max_sectors:
2381 			ret = tcmu_set_dev_attrib(&args[0],
2382 					&(dev->dev_attrib.hw_max_sectors));
2383 			break;
2384 		case Opt_nl_reply_supported:
2385 			ret = match_int(&args[0], &udev->nl_reply_supported);
2386 			if (ret < 0)
2387 				pr_err("match_int() failed for nl_reply_supported=. Error %d.\n",
2388 				       ret);
2389 			break;
2390 		case Opt_max_data_area_mb:
2391 			ret = tcmu_set_max_blocks_param(udev, &args[0]);
2392 			break;
2393 		default:
2394 			break;
2395 		}
2396 
2397 		if (ret)
2398 			break;
2399 	}
2400 
2401 	kfree(orig);
2402 	return (!ret) ? count : ret;
2403 }
2404 
2405 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
2406 {
2407 	struct tcmu_dev *udev = TCMU_DEV(dev);
2408 	ssize_t bl = 0;
2409 
2410 	bl = sprintf(b + bl, "Config: %s ",
2411 		     udev->dev_config[0] ? udev->dev_config : "NULL");
2412 	bl += sprintf(b + bl, "Size: %llu ", udev->dev_size);
2413 	bl += sprintf(b + bl, "MaxDataAreaMB: %u\n",
2414 		      TCMU_BLOCKS_TO_MBS(udev->max_blocks));
2415 
2416 	return bl;
2417 }
2418 
2419 static sector_t tcmu_get_blocks(struct se_device *dev)
2420 {
2421 	struct tcmu_dev *udev = TCMU_DEV(dev);
2422 
2423 	return div_u64(udev->dev_size - dev->dev_attrib.block_size,
2424 		       dev->dev_attrib.block_size);
2425 }
2426 
2427 static sense_reason_t
2428 tcmu_parse_cdb(struct se_cmd *cmd)
2429 {
2430 	return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
2431 }
2432 
2433 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
2434 {
2435 	struct se_dev_attrib *da = container_of(to_config_group(item),
2436 					struct se_dev_attrib, da_group);
2437 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2438 
2439 	return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
2440 }
2441 
2442 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
2443 				       size_t count)
2444 {
2445 	struct se_dev_attrib *da = container_of(to_config_group(item),
2446 					struct se_dev_attrib, da_group);
2447 	struct tcmu_dev *udev = container_of(da->da_dev,
2448 					struct tcmu_dev, se_dev);
2449 	u32 val;
2450 	int ret;
2451 
2452 	if (da->da_dev->export_count) {
2453 		pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
2454 		return -EINVAL;
2455 	}
2456 
2457 	ret = kstrtou32(page, 0, &val);
2458 	if (ret < 0)
2459 		return ret;
2460 
2461 	udev->cmd_time_out = val * MSEC_PER_SEC;
2462 	return count;
2463 }
2464 CONFIGFS_ATTR(tcmu_, cmd_time_out);
2465 
2466 static ssize_t tcmu_qfull_time_out_show(struct config_item *item, char *page)
2467 {
2468 	struct se_dev_attrib *da = container_of(to_config_group(item),
2469 						struct se_dev_attrib, da_group);
2470 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2471 
2472 	return snprintf(page, PAGE_SIZE, "%ld\n", udev->qfull_time_out <= 0 ?
2473 			udev->qfull_time_out :
2474 			udev->qfull_time_out / MSEC_PER_SEC);
2475 }
2476 
2477 static ssize_t tcmu_qfull_time_out_store(struct config_item *item,
2478 					 const char *page, size_t count)
2479 {
2480 	struct se_dev_attrib *da = container_of(to_config_group(item),
2481 					struct se_dev_attrib, da_group);
2482 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2483 	s32 val;
2484 	int ret;
2485 
2486 	ret = kstrtos32(page, 0, &val);
2487 	if (ret < 0)
2488 		return ret;
2489 
2490 	if (val >= 0) {
2491 		udev->qfull_time_out = val * MSEC_PER_SEC;
2492 	} else if (val == -1) {
2493 		udev->qfull_time_out = val;
2494 	} else {
2495 		printk(KERN_ERR "Invalid qfull timeout value %d\n", val);
2496 		return -EINVAL;
2497 	}
2498 	return count;
2499 }
2500 CONFIGFS_ATTR(tcmu_, qfull_time_out);
2501 
2502 static ssize_t tcmu_max_data_area_mb_show(struct config_item *item, char *page)
2503 {
2504 	struct se_dev_attrib *da = container_of(to_config_group(item),
2505 						struct se_dev_attrib, da_group);
2506 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2507 
2508 	return snprintf(page, PAGE_SIZE, "%u\n",
2509 			TCMU_BLOCKS_TO_MBS(udev->max_blocks));
2510 }
2511 CONFIGFS_ATTR_RO(tcmu_, max_data_area_mb);
2512 
2513 static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
2514 {
2515 	struct se_dev_attrib *da = container_of(to_config_group(item),
2516 						struct se_dev_attrib, da_group);
2517 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2518 
2519 	return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
2520 }
2521 
2522 static int tcmu_send_dev_config_event(struct tcmu_dev *udev,
2523 				      const char *reconfig_data)
2524 {
2525 	struct sk_buff *skb = NULL;
2526 	void *msg_header = NULL;
2527 	int ret = 0;
2528 
2529 	ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2530 				      &skb, &msg_header);
2531 	if (ret < 0)
2532 		return ret;
2533 	ret = nla_put_string(skb, TCMU_ATTR_DEV_CFG, reconfig_data);
2534 	if (ret < 0) {
2535 		nlmsg_free(skb);
2536 		return ret;
2537 	}
2538 	return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2539 				       skb, msg_header);
2540 }
2541 
2542 
2543 static ssize_t tcmu_dev_config_store(struct config_item *item, const char *page,
2544 				     size_t count)
2545 {
2546 	struct se_dev_attrib *da = container_of(to_config_group(item),
2547 						struct se_dev_attrib, da_group);
2548 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2549 	int ret, len;
2550 
2551 	len = strlen(page);
2552 	if (!len || len > TCMU_CONFIG_LEN - 1)
2553 		return -EINVAL;
2554 
2555 	/* Check if device has been configured before */
2556 	if (target_dev_configured(&udev->se_dev)) {
2557 		ret = tcmu_send_dev_config_event(udev, page);
2558 		if (ret) {
2559 			pr_err("Unable to reconfigure device\n");
2560 			return ret;
2561 		}
2562 		strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
2563 
2564 		ret = tcmu_update_uio_info(udev);
2565 		if (ret)
2566 			return ret;
2567 		return count;
2568 	}
2569 	strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
2570 
2571 	return count;
2572 }
2573 CONFIGFS_ATTR(tcmu_, dev_config);
2574 
2575 static ssize_t tcmu_dev_size_show(struct config_item *item, char *page)
2576 {
2577 	struct se_dev_attrib *da = container_of(to_config_group(item),
2578 						struct se_dev_attrib, da_group);
2579 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2580 
2581 	return snprintf(page, PAGE_SIZE, "%llu\n", udev->dev_size);
2582 }
2583 
2584 static int tcmu_send_dev_size_event(struct tcmu_dev *udev, u64 size)
2585 {
2586 	struct sk_buff *skb = NULL;
2587 	void *msg_header = NULL;
2588 	int ret = 0;
2589 
2590 	ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2591 				      &skb, &msg_header);
2592 	if (ret < 0)
2593 		return ret;
2594 	ret = nla_put_u64_64bit(skb, TCMU_ATTR_DEV_SIZE,
2595 				size, TCMU_ATTR_PAD);
2596 	if (ret < 0) {
2597 		nlmsg_free(skb);
2598 		return ret;
2599 	}
2600 	return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2601 				       skb, msg_header);
2602 }
2603 
2604 static ssize_t tcmu_dev_size_store(struct config_item *item, const char *page,
2605 				   size_t count)
2606 {
2607 	struct se_dev_attrib *da = container_of(to_config_group(item),
2608 						struct se_dev_attrib, da_group);
2609 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2610 	u64 val;
2611 	int ret;
2612 
2613 	ret = kstrtou64(page, 0, &val);
2614 	if (ret < 0)
2615 		return ret;
2616 
2617 	/* Check if device has been configured before */
2618 	if (target_dev_configured(&udev->se_dev)) {
2619 		ret = tcmu_send_dev_size_event(udev, val);
2620 		if (ret) {
2621 			pr_err("Unable to reconfigure device\n");
2622 			return ret;
2623 		}
2624 	}
2625 	udev->dev_size = val;
2626 	return count;
2627 }
2628 CONFIGFS_ATTR(tcmu_, dev_size);
2629 
2630 static ssize_t tcmu_nl_reply_supported_show(struct config_item *item,
2631 		char *page)
2632 {
2633 	struct se_dev_attrib *da = container_of(to_config_group(item),
2634 						struct se_dev_attrib, da_group);
2635 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2636 
2637 	return snprintf(page, PAGE_SIZE, "%d\n", udev->nl_reply_supported);
2638 }
2639 
2640 static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
2641 		const char *page, size_t count)
2642 {
2643 	struct se_dev_attrib *da = container_of(to_config_group(item),
2644 						struct se_dev_attrib, da_group);
2645 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2646 	s8 val;
2647 	int ret;
2648 
2649 	ret = kstrtos8(page, 0, &val);
2650 	if (ret < 0)
2651 		return ret;
2652 
2653 	udev->nl_reply_supported = val;
2654 	return count;
2655 }
2656 CONFIGFS_ATTR(tcmu_, nl_reply_supported);
2657 
2658 static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
2659 					     char *page)
2660 {
2661 	struct se_dev_attrib *da = container_of(to_config_group(item),
2662 					struct se_dev_attrib, da_group);
2663 
2664 	return snprintf(page, PAGE_SIZE, "%i\n", da->emulate_write_cache);
2665 }
2666 
2667 static int tcmu_send_emulate_write_cache(struct tcmu_dev *udev, u8 val)
2668 {
2669 	struct sk_buff *skb = NULL;
2670 	void *msg_header = NULL;
2671 	int ret = 0;
2672 
2673 	ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2674 				      &skb, &msg_header);
2675 	if (ret < 0)
2676 		return ret;
2677 	ret = nla_put_u8(skb, TCMU_ATTR_WRITECACHE, val);
2678 	if (ret < 0) {
2679 		nlmsg_free(skb);
2680 		return ret;
2681 	}
2682 	return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2683 				       skb, msg_header);
2684 }
2685 
2686 static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
2687 					      const char *page, size_t count)
2688 {
2689 	struct se_dev_attrib *da = container_of(to_config_group(item),
2690 					struct se_dev_attrib, da_group);
2691 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2692 	u8 val;
2693 	int ret;
2694 
2695 	ret = kstrtou8(page, 0, &val);
2696 	if (ret < 0)
2697 		return ret;
2698 
2699 	/* Check if device has been configured before */
2700 	if (target_dev_configured(&udev->se_dev)) {
2701 		ret = tcmu_send_emulate_write_cache(udev, val);
2702 		if (ret) {
2703 			pr_err("Unable to reconfigure device\n");
2704 			return ret;
2705 		}
2706 	}
2707 
2708 	da->emulate_write_cache = val;
2709 	return count;
2710 }
2711 CONFIGFS_ATTR(tcmu_, emulate_write_cache);
2712 
2713 static ssize_t tcmu_tmr_notification_show(struct config_item *item, char *page)
2714 {
2715 	struct se_dev_attrib *da = container_of(to_config_group(item),
2716 					struct se_dev_attrib, da_group);
2717 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2718 
2719 	return snprintf(page, PAGE_SIZE, "%i\n",
2720 			test_bit(TCMU_DEV_BIT_TMR_NOTIFY, &udev->flags));
2721 }
2722 
2723 static ssize_t tcmu_tmr_notification_store(struct config_item *item,
2724 					   const char *page, size_t count)
2725 {
2726 	struct se_dev_attrib *da = container_of(to_config_group(item),
2727 					struct se_dev_attrib, da_group);
2728 	struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2729 	u8 val;
2730 	int ret;
2731 
2732 	ret = kstrtou8(page, 0, &val);
2733 	if (ret < 0)
2734 		return ret;
2735 	if (val > 1)
2736 		return -EINVAL;
2737 
2738 	if (val)
2739 		set_bit(TCMU_DEV_BIT_TMR_NOTIFY, &udev->flags);
2740 	else
2741 		clear_bit(TCMU_DEV_BIT_TMR_NOTIFY, &udev->flags);
2742 	return count;
2743 }
2744 CONFIGFS_ATTR(tcmu_, tmr_notification);
2745 
2746 static ssize_t tcmu_block_dev_show(struct config_item *item, char *page)
2747 {
2748 	struct se_device *se_dev = container_of(to_config_group(item),
2749 						struct se_device,
2750 						dev_action_group);
2751 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
2752 
2753 	if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))
2754 		return snprintf(page, PAGE_SIZE, "%s\n", "blocked");
2755 	else
2756 		return snprintf(page, PAGE_SIZE, "%s\n", "unblocked");
2757 }
2758 
2759 static ssize_t tcmu_block_dev_store(struct config_item *item, const char *page,
2760 				    size_t count)
2761 {
2762 	struct se_device *se_dev = container_of(to_config_group(item),
2763 						struct se_device,
2764 						dev_action_group);
2765 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
2766 	u8 val;
2767 	int ret;
2768 
2769 	if (!target_dev_configured(&udev->se_dev)) {
2770 		pr_err("Device is not configured.\n");
2771 		return -EINVAL;
2772 	}
2773 
2774 	ret = kstrtou8(page, 0, &val);
2775 	if (ret < 0)
2776 		return ret;
2777 
2778 	if (val > 1) {
2779 		pr_err("Invalid block value %d\n", val);
2780 		return -EINVAL;
2781 	}
2782 
2783 	if (!val)
2784 		tcmu_unblock_dev(udev);
2785 	else
2786 		tcmu_block_dev(udev);
2787 	return count;
2788 }
2789 CONFIGFS_ATTR(tcmu_, block_dev);
2790 
2791 static ssize_t tcmu_reset_ring_store(struct config_item *item, const char *page,
2792 				     size_t count)
2793 {
2794 	struct se_device *se_dev = container_of(to_config_group(item),
2795 						struct se_device,
2796 						dev_action_group);
2797 	struct tcmu_dev *udev = TCMU_DEV(se_dev);
2798 	u8 val;
2799 	int ret;
2800 
2801 	if (!target_dev_configured(&udev->se_dev)) {
2802 		pr_err("Device is not configured.\n");
2803 		return -EINVAL;
2804 	}
2805 
2806 	ret = kstrtou8(page, 0, &val);
2807 	if (ret < 0)
2808 		return ret;
2809 
2810 	if (val != 1 && val != 2) {
2811 		pr_err("Invalid reset ring value %d\n", val);
2812 		return -EINVAL;
2813 	}
2814 
2815 	tcmu_reset_ring(udev, val);
2816 	return count;
2817 }
2818 CONFIGFS_ATTR_WO(tcmu_, reset_ring);
2819 
2820 static struct configfs_attribute *tcmu_attrib_attrs[] = {
2821 	&tcmu_attr_cmd_time_out,
2822 	&tcmu_attr_qfull_time_out,
2823 	&tcmu_attr_max_data_area_mb,
2824 	&tcmu_attr_dev_config,
2825 	&tcmu_attr_dev_size,
2826 	&tcmu_attr_emulate_write_cache,
2827 	&tcmu_attr_tmr_notification,
2828 	&tcmu_attr_nl_reply_supported,
2829 	NULL,
2830 };
2831 
2832 static struct configfs_attribute **tcmu_attrs;
2833 
2834 static struct configfs_attribute *tcmu_action_attrs[] = {
2835 	&tcmu_attr_block_dev,
2836 	&tcmu_attr_reset_ring,
2837 	NULL,
2838 };
2839 
2840 static struct target_backend_ops tcmu_ops = {
2841 	.name			= "user",
2842 	.owner			= THIS_MODULE,
2843 	.transport_flags_default = TRANSPORT_FLAG_PASSTHROUGH,
2844 	.transport_flags_changeable = TRANSPORT_FLAG_PASSTHROUGH_PGR |
2845 				      TRANSPORT_FLAG_PASSTHROUGH_ALUA,
2846 	.attach_hba		= tcmu_attach_hba,
2847 	.detach_hba		= tcmu_detach_hba,
2848 	.alloc_device		= tcmu_alloc_device,
2849 	.configure_device	= tcmu_configure_device,
2850 	.destroy_device		= tcmu_destroy_device,
2851 	.free_device		= tcmu_free_device,
2852 	.parse_cdb		= tcmu_parse_cdb,
2853 	.tmr_notify		= tcmu_tmr_notify,
2854 	.set_configfs_dev_params = tcmu_set_configfs_dev_params,
2855 	.show_configfs_dev_params = tcmu_show_configfs_dev_params,
2856 	.get_device_type	= sbc_get_device_type,
2857 	.get_blocks		= tcmu_get_blocks,
2858 	.tb_dev_action_attrs	= tcmu_action_attrs,
2859 };
2860 
2861 static void find_free_blocks(void)
2862 {
2863 	struct tcmu_dev *udev;
2864 	loff_t off;
2865 	u32 start, end, block, total_freed = 0;
2866 
2867 	if (atomic_read(&global_db_count) <= tcmu_global_max_blocks)
2868 		return;
2869 
2870 	mutex_lock(&root_udev_mutex);
2871 	list_for_each_entry(udev, &root_udev, node) {
2872 		mutex_lock(&udev->cmdr_lock);
2873 
2874 		if (!target_dev_configured(&udev->se_dev)) {
2875 			mutex_unlock(&udev->cmdr_lock);
2876 			continue;
2877 		}
2878 
2879 		/* Try to complete the finished commands first */
2880 		if (tcmu_handle_completions(udev))
2881 			run_qfull_queue(udev, false);
2882 
2883 		/* Skip the udevs in idle */
2884 		if (!udev->dbi_thresh) {
2885 			mutex_unlock(&udev->cmdr_lock);
2886 			continue;
2887 		}
2888 
2889 		end = udev->dbi_max + 1;
2890 		block = find_last_bit(udev->data_bitmap, end);
2891 		if (block == udev->dbi_max) {
2892 			/*
2893 			 * The last bit is dbi_max, so it is not possible
2894 			 * reclaim any blocks.
2895 			 */
2896 			mutex_unlock(&udev->cmdr_lock);
2897 			continue;
2898 		} else if (block == end) {
2899 			/* The current udev will goto idle state */
2900 			udev->dbi_thresh = start = 0;
2901 			udev->dbi_max = 0;
2902 		} else {
2903 			udev->dbi_thresh = start = block + 1;
2904 			udev->dbi_max = block;
2905 		}
2906 
2907 		/* Here will truncate the data area from off */
2908 		off = udev->data_off + start * DATA_BLOCK_SIZE;
2909 		unmap_mapping_range(udev->inode->i_mapping, off, 0, 1);
2910 
2911 		/* Release the block pages */
2912 		tcmu_blocks_release(&udev->data_blocks, start, end);
2913 		mutex_unlock(&udev->cmdr_lock);
2914 
2915 		total_freed += end - start;
2916 		pr_debug("Freed %u blocks (total %u) from %s.\n", end - start,
2917 			 total_freed, udev->name);
2918 	}
2919 	mutex_unlock(&root_udev_mutex);
2920 
2921 	if (atomic_read(&global_db_count) > tcmu_global_max_blocks)
2922 		schedule_delayed_work(&tcmu_unmap_work, msecs_to_jiffies(5000));
2923 }
2924 
2925 static void check_timedout_devices(void)
2926 {
2927 	struct tcmu_dev *udev, *tmp_dev;
2928 	struct tcmu_cmd *cmd, *tmp_cmd;
2929 	LIST_HEAD(devs);
2930 
2931 	spin_lock_bh(&timed_out_udevs_lock);
2932 	list_splice_init(&timed_out_udevs, &devs);
2933 
2934 	list_for_each_entry_safe(udev, tmp_dev, &devs, timedout_entry) {
2935 		list_del_init(&udev->timedout_entry);
2936 		spin_unlock_bh(&timed_out_udevs_lock);
2937 
2938 		mutex_lock(&udev->cmdr_lock);
2939 
2940 		/*
2941 		 * If cmd_time_out is disabled but qfull is set deadline
2942 		 * will only reflect the qfull timeout. Ignore it.
2943 		 */
2944 		if (udev->cmd_time_out) {
2945 			list_for_each_entry_safe(cmd, tmp_cmd,
2946 						 &udev->inflight_queue,
2947 						 queue_entry) {
2948 				tcmu_check_expired_ring_cmd(cmd);
2949 			}
2950 			tcmu_set_next_deadline(&udev->inflight_queue,
2951 					       &udev->cmd_timer);
2952 		}
2953 		list_for_each_entry_safe(cmd, tmp_cmd, &udev->qfull_queue,
2954 					 queue_entry) {
2955 			tcmu_check_expired_queue_cmd(cmd);
2956 		}
2957 		tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
2958 
2959 		mutex_unlock(&udev->cmdr_lock);
2960 
2961 		spin_lock_bh(&timed_out_udevs_lock);
2962 	}
2963 
2964 	spin_unlock_bh(&timed_out_udevs_lock);
2965 }
2966 
2967 static void tcmu_unmap_work_fn(struct work_struct *work)
2968 {
2969 	check_timedout_devices();
2970 	find_free_blocks();
2971 }
2972 
2973 static int __init tcmu_module_init(void)
2974 {
2975 	int ret, i, k, len = 0;
2976 
2977 	BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
2978 
2979 	INIT_DELAYED_WORK(&tcmu_unmap_work, tcmu_unmap_work_fn);
2980 
2981 	tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
2982 				sizeof(struct tcmu_cmd),
2983 				__alignof__(struct tcmu_cmd),
2984 				0, NULL);
2985 	if (!tcmu_cmd_cache)
2986 		return -ENOMEM;
2987 
2988 	tcmu_root_device = root_device_register("tcm_user");
2989 	if (IS_ERR(tcmu_root_device)) {
2990 		ret = PTR_ERR(tcmu_root_device);
2991 		goto out_free_cache;
2992 	}
2993 
2994 	ret = genl_register_family(&tcmu_genl_family);
2995 	if (ret < 0) {
2996 		goto out_unreg_device;
2997 	}
2998 
2999 	for (i = 0; passthrough_attrib_attrs[i] != NULL; i++)
3000 		len += sizeof(struct configfs_attribute *);
3001 	for (i = 0; passthrough_pr_attrib_attrs[i] != NULL; i++)
3002 		len += sizeof(struct configfs_attribute *);
3003 	for (i = 0; tcmu_attrib_attrs[i] != NULL; i++)
3004 		len += sizeof(struct configfs_attribute *);
3005 	len += sizeof(struct configfs_attribute *);
3006 
3007 	tcmu_attrs = kzalloc(len, GFP_KERNEL);
3008 	if (!tcmu_attrs) {
3009 		ret = -ENOMEM;
3010 		goto out_unreg_genl;
3011 	}
3012 
3013 	for (i = 0; passthrough_attrib_attrs[i] != NULL; i++)
3014 		tcmu_attrs[i] = passthrough_attrib_attrs[i];
3015 	for (k = 0; passthrough_pr_attrib_attrs[k] != NULL; k++)
3016 		tcmu_attrs[i++] = passthrough_pr_attrib_attrs[k];
3017 	for (k = 0; tcmu_attrib_attrs[k] != NULL; k++)
3018 		tcmu_attrs[i++] = tcmu_attrib_attrs[k];
3019 	tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
3020 
3021 	ret = transport_backend_register(&tcmu_ops);
3022 	if (ret)
3023 		goto out_attrs;
3024 
3025 	return 0;
3026 
3027 out_attrs:
3028 	kfree(tcmu_attrs);
3029 out_unreg_genl:
3030 	genl_unregister_family(&tcmu_genl_family);
3031 out_unreg_device:
3032 	root_device_unregister(tcmu_root_device);
3033 out_free_cache:
3034 	kmem_cache_destroy(tcmu_cmd_cache);
3035 
3036 	return ret;
3037 }
3038 
3039 static void __exit tcmu_module_exit(void)
3040 {
3041 	cancel_delayed_work_sync(&tcmu_unmap_work);
3042 	target_backend_unregister(&tcmu_ops);
3043 	kfree(tcmu_attrs);
3044 	genl_unregister_family(&tcmu_genl_family);
3045 	root_device_unregister(tcmu_root_device);
3046 	kmem_cache_destroy(tcmu_cmd_cache);
3047 }
3048 
3049 MODULE_DESCRIPTION("TCM USER subsystem plugin");
3050 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
3051 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
3052 MODULE_LICENSE("GPL");
3053 
3054 module_init(tcmu_module_init);
3055 module_exit(tcmu_module_exit);
3056