Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target...
[muen/linux.git] / drivers / target / target_core_user.c
1 /*
2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
3  * Copyright (C) 2014 Red Hat, Inc.
4  * Copyright (C) 2015 Arrikto, Inc.
5  * Copyright (C) 2017 Chinamobile, Inc.
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms and conditions of the GNU General Public License,
9  * version 2, as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  *
16  * You should have received a copy of the GNU General Public License along with
17  * this program; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19  */
20
21 #include <linux/spinlock.h>
22 #include <linux/module.h>
23 #include <linux/idr.h>
24 #include <linux/kernel.h>
25 #include <linux/timer.h>
26 #include <linux/parser.h>
27 #include <linux/vmalloc.h>
28 #include <linux/uio_driver.h>
29 #include <linux/radix-tree.h>
30 #include <linux/stringify.h>
31 #include <linux/bitops.h>
32 #include <linux/highmem.h>
33 #include <linux/configfs.h>
34 #include <linux/mutex.h>
35 #include <linux/kthread.h>
36 #include <net/genetlink.h>
37 #include <scsi/scsi_common.h>
38 #include <scsi/scsi_proto.h>
39 #include <target/target_core_base.h>
40 #include <target/target_core_fabric.h>
41 #include <target/target_core_backend.h>
42
43 #include <linux/target_core_user.h>
44
45 /*
46  * Define a shared-memory interface for LIO to pass SCSI commands and
47  * data to userspace for processing. This is to allow backends that
48  * are too complex for in-kernel support to be possible.
49  *
50  * It uses the UIO framework to do a lot of the device-creation and
51  * introspection work for us.
52  *
53  * See the .h file for how the ring is laid out. Note that while the
54  * command ring is defined, the particulars of the data area are
55  * not. Offset values in the command entry point to other locations
56  * internal to the mmap()ed area. There is separate space outside the
57  * command ring for data buffers. This leaves maximum flexibility for
58  * moving buffer allocations, or even page flipping or other
59  * allocation techniques, without altering the command ring layout.
60  *
61  * SECURITY:
62  * The user process must be assumed to be malicious. There's no way to
63  * prevent it breaking the command ring protocol if it wants, but in
64  * order to prevent other issues we must only ever read *data* from
65  * the shared memory area, not offsets or sizes. This applies to
66  * command ring entries as well as the mailbox. Extra code needed for
67  * this may have a 'UAM' comment.
68  */
69
70 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
71
72 /* For cmd area, the size is fixed 8MB */
73 #define CMDR_SIZE (8 * 1024 * 1024)
74
75 /*
76  * For data area, the block size is PAGE_SIZE and
77  * the total size is 256K * PAGE_SIZE.
78  */
79 #define DATA_BLOCK_SIZE PAGE_SIZE
80 #define DATA_BLOCK_BITS (256 * 1024)
81 #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
82 #define DATA_BLOCK_INIT_BITS 128
83
84 /* The total size of the ring is 8M + 256K * PAGE_SIZE */
85 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
86
87 /* Default maximum of the global data blocks(512K * PAGE_SIZE) */
88 #define TCMU_GLOBAL_MAX_BLOCKS (512 * 1024)
89
90 static u8 tcmu_kern_cmd_reply_supported;
91
92 static struct device *tcmu_root_device;
93
94 struct tcmu_hba {
95         u32 host_id;
96 };
97
98 #define TCMU_CONFIG_LEN 256
99
100 struct tcmu_nl_cmd {
101         /* wake up thread waiting for reply */
102         struct completion complete;
103         int cmd;
104         int status;
105 };
106
107 struct tcmu_dev {
108         struct list_head node;
109         struct kref kref;
110         struct se_device se_dev;
111
112         char *name;
113         struct se_hba *hba;
114
115 #define TCMU_DEV_BIT_OPEN 0
116 #define TCMU_DEV_BIT_BROKEN 1
117         unsigned long flags;
118
119         struct uio_info uio_info;
120
121         struct inode *inode;
122
123         struct tcmu_mailbox *mb_addr;
124         size_t dev_size;
125         u32 cmdr_size;
126         u32 cmdr_last_cleaned;
127         /* Offset of data area from start of mb */
128         /* Must add data_off and mb_addr to get the address */
129         size_t data_off;
130         size_t data_size;
131
132         wait_queue_head_t wait_cmdr;
133         struct mutex cmdr_lock;
134
135         bool waiting_global;
136         uint32_t dbi_max;
137         uint32_t dbi_thresh;
138         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
139         struct radix_tree_root data_blocks;
140
141         struct idr commands;
142         spinlock_t commands_lock;
143
144         struct timer_list timeout;
145         unsigned int cmd_time_out;
146
147         spinlock_t nl_cmd_lock;
148         struct tcmu_nl_cmd curr_nl_cmd;
149         /* wake up threads waiting on curr_nl_cmd */
150         wait_queue_head_t nl_cmd_wq;
151
152         char dev_config[TCMU_CONFIG_LEN];
153
154         int nl_reply_supported;
155 };
156
157 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
158
159 #define CMDR_OFF sizeof(struct tcmu_mailbox)
160
161 struct tcmu_cmd {
162         struct se_cmd *se_cmd;
163         struct tcmu_dev *tcmu_dev;
164
165         uint16_t cmd_id;
166
167         /* Can't use se_cmd when cleaning up expired cmds, because if
168            cmd has been completed then accessing se_cmd is off limits */
169         uint32_t dbi_cnt;
170         uint32_t dbi_cur;
171         uint32_t *dbi;
172
173         unsigned long deadline;
174
175 #define TCMU_CMD_BIT_EXPIRED 0
176         unsigned long flags;
177 };
178
179 static struct task_struct *unmap_thread;
180 static wait_queue_head_t unmap_wait;
181 static DEFINE_MUTEX(root_udev_mutex);
182 static LIST_HEAD(root_udev);
183
184 static atomic_t global_db_count = ATOMIC_INIT(0);
185
186 static struct kmem_cache *tcmu_cmd_cache;
187
188 /* multicast group */
189 enum tcmu_multicast_groups {
190         TCMU_MCGRP_CONFIG,
191 };
192
193 static const struct genl_multicast_group tcmu_mcgrps[] = {
194         [TCMU_MCGRP_CONFIG] = { .name = "config", },
195 };
196
197 static struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX+1] = {
198         [TCMU_ATTR_DEVICE]      = { .type = NLA_STRING },
199         [TCMU_ATTR_MINOR]       = { .type = NLA_U32 },
200         [TCMU_ATTR_CMD_STATUS]  = { .type = NLA_S32 },
201         [TCMU_ATTR_DEVICE_ID]   = { .type = NLA_U32 },
202         [TCMU_ATTR_SUPP_KERN_CMD_REPLY] = { .type = NLA_U8 },
203 };
204
205 static int tcmu_genl_cmd_done(struct genl_info *info, int completed_cmd)
206 {
207         struct se_device *dev;
208         struct tcmu_dev *udev;
209         struct tcmu_nl_cmd *nl_cmd;
210         int dev_id, rc, ret = 0;
211         bool is_removed = (completed_cmd == TCMU_CMD_REMOVED_DEVICE);
212
213         if (!info->attrs[TCMU_ATTR_CMD_STATUS] ||
214             !info->attrs[TCMU_ATTR_DEVICE_ID]) {
215                 printk(KERN_ERR "TCMU_ATTR_CMD_STATUS or TCMU_ATTR_DEVICE_ID not set, doing nothing\n");
216                 return -EINVAL;
217         }
218
219         dev_id = nla_get_u32(info->attrs[TCMU_ATTR_DEVICE_ID]);
220         rc = nla_get_s32(info->attrs[TCMU_ATTR_CMD_STATUS]);
221
222         dev = target_find_device(dev_id, !is_removed);
223         if (!dev) {
224                 printk(KERN_ERR "tcmu nl cmd %u/%u completion could not find device with dev id %u.\n",
225                        completed_cmd, rc, dev_id);
226                 return -ENODEV;
227         }
228         udev = TCMU_DEV(dev);
229
230         spin_lock(&udev->nl_cmd_lock);
231         nl_cmd = &udev->curr_nl_cmd;
232
233         pr_debug("genl cmd done got id %d curr %d done %d rc %d\n", dev_id,
234                  nl_cmd->cmd, completed_cmd, rc);
235
236         if (nl_cmd->cmd != completed_cmd) {
237                 printk(KERN_ERR "Mismatched commands (Expecting reply for %d. Current %d).\n",
238                        completed_cmd, nl_cmd->cmd);
239                 ret = -EINVAL;
240         } else {
241                 nl_cmd->status = rc;
242         }
243
244         spin_unlock(&udev->nl_cmd_lock);
245         if (!is_removed)
246                  target_undepend_item(&dev->dev_group.cg_item);
247         if (!ret)
248                 complete(&nl_cmd->complete);
249         return ret;
250 }
251
252 static int tcmu_genl_rm_dev_done(struct sk_buff *skb, struct genl_info *info)
253 {
254         return tcmu_genl_cmd_done(info, TCMU_CMD_REMOVED_DEVICE);
255 }
256
257 static int tcmu_genl_add_dev_done(struct sk_buff *skb, struct genl_info *info)
258 {
259         return tcmu_genl_cmd_done(info, TCMU_CMD_ADDED_DEVICE);
260 }
261
262 static int tcmu_genl_reconfig_dev_done(struct sk_buff *skb,
263                                        struct genl_info *info)
264 {
265         return tcmu_genl_cmd_done(info, TCMU_CMD_RECONFIG_DEVICE);
266 }
267
268 static int tcmu_genl_set_features(struct sk_buff *skb, struct genl_info *info)
269 {
270         if (info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]) {
271                 tcmu_kern_cmd_reply_supported  =
272                         nla_get_u8(info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]);
273                 printk(KERN_INFO "tcmu daemon: command reply support %u.\n",
274                        tcmu_kern_cmd_reply_supported);
275         }
276
277         return 0;
278 }
279
280 static const struct genl_ops tcmu_genl_ops[] = {
281         {
282                 .cmd    = TCMU_CMD_SET_FEATURES,
283                 .flags  = GENL_ADMIN_PERM,
284                 .policy = tcmu_attr_policy,
285                 .doit   = tcmu_genl_set_features,
286         },
287         {
288                 .cmd    = TCMU_CMD_ADDED_DEVICE_DONE,
289                 .flags  = GENL_ADMIN_PERM,
290                 .policy = tcmu_attr_policy,
291                 .doit   = tcmu_genl_add_dev_done,
292         },
293         {
294                 .cmd    = TCMU_CMD_REMOVED_DEVICE_DONE,
295                 .flags  = GENL_ADMIN_PERM,
296                 .policy = tcmu_attr_policy,
297                 .doit   = tcmu_genl_rm_dev_done,
298         },
299         {
300                 .cmd    = TCMU_CMD_RECONFIG_DEVICE_DONE,
301                 .flags  = GENL_ADMIN_PERM,
302                 .policy = tcmu_attr_policy,
303                 .doit   = tcmu_genl_reconfig_dev_done,
304         },
305 };
306
307 /* Our generic netlink family */
308 static struct genl_family tcmu_genl_family __ro_after_init = {
309         .module = THIS_MODULE,
310         .hdrsize = 0,
311         .name = "TCM-USER",
312         .version = 2,
313         .maxattr = TCMU_ATTR_MAX,
314         .mcgrps = tcmu_mcgrps,
315         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
316         .netnsok = true,
317         .ops = tcmu_genl_ops,
318         .n_ops = ARRAY_SIZE(tcmu_genl_ops),
319 };
320
321 #define tcmu_cmd_set_dbi_cur(cmd, index) ((cmd)->dbi_cur = (index))
322 #define tcmu_cmd_reset_dbi_cur(cmd) tcmu_cmd_set_dbi_cur(cmd, 0)
323 #define tcmu_cmd_set_dbi(cmd, index) ((cmd)->dbi[(cmd)->dbi_cur++] = (index))
324 #define tcmu_cmd_get_dbi(cmd) ((cmd)->dbi[(cmd)->dbi_cur++])
325
326 static void tcmu_cmd_free_data(struct tcmu_cmd *tcmu_cmd, uint32_t len)
327 {
328         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
329         uint32_t i;
330
331         for (i = 0; i < len; i++)
332                 clear_bit(tcmu_cmd->dbi[i], udev->data_bitmap);
333 }
334
335 static inline bool tcmu_get_empty_block(struct tcmu_dev *udev,
336                                         struct tcmu_cmd *tcmu_cmd)
337 {
338         struct page *page;
339         int ret, dbi;
340
341         dbi = find_first_zero_bit(udev->data_bitmap, udev->dbi_thresh);
342         if (dbi == udev->dbi_thresh)
343                 return false;
344
345         page = radix_tree_lookup(&udev->data_blocks, dbi);
346         if (!page) {
347                 if (atomic_add_return(1, &global_db_count) >
348                                         TCMU_GLOBAL_MAX_BLOCKS) {
349                         atomic_dec(&global_db_count);
350                         return false;
351                 }
352
353                 /* try to get new page from the mm */
354                 page = alloc_page(GFP_KERNEL);
355                 if (!page)
356                         goto err_alloc;
357
358                 ret = radix_tree_insert(&udev->data_blocks, dbi, page);
359                 if (ret)
360                         goto err_insert;
361         }
362
363         if (dbi > udev->dbi_max)
364                 udev->dbi_max = dbi;
365
366         set_bit(dbi, udev->data_bitmap);
367         tcmu_cmd_set_dbi(tcmu_cmd, dbi);
368
369         return true;
370 err_insert:
371         __free_page(page);
372 err_alloc:
373         atomic_dec(&global_db_count);
374         return false;
375 }
376
377 static bool tcmu_get_empty_blocks(struct tcmu_dev *udev,
378                                   struct tcmu_cmd *tcmu_cmd)
379 {
380         int i;
381
382         udev->waiting_global = false;
383
384         for (i = tcmu_cmd->dbi_cur; i < tcmu_cmd->dbi_cnt; i++) {
385                 if (!tcmu_get_empty_block(udev, tcmu_cmd))
386                         goto err;
387         }
388         return true;
389
390 err:
391         udev->waiting_global = true;
392         /* Try to wake up the unmap thread */
393         wake_up(&unmap_wait);
394         return false;
395 }
396
397 static inline struct page *
398 tcmu_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
399 {
400         return radix_tree_lookup(&udev->data_blocks, dbi);
401 }
402
403 static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd)
404 {
405         kfree(tcmu_cmd->dbi);
406         kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
407 }
408
409 static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
410 {
411         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
412         size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
413
414         if (se_cmd->se_cmd_flags & SCF_BIDI) {
415                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
416                 data_length += round_up(se_cmd->t_bidi_data_sg->length,
417                                 DATA_BLOCK_SIZE);
418         }
419
420         return data_length;
421 }
422
423 static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
424 {
425         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
426
427         return data_length / DATA_BLOCK_SIZE;
428 }
429
430 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
431 {
432         struct se_device *se_dev = se_cmd->se_dev;
433         struct tcmu_dev *udev = TCMU_DEV(se_dev);
434         struct tcmu_cmd *tcmu_cmd;
435
436         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
437         if (!tcmu_cmd)
438                 return NULL;
439
440         tcmu_cmd->se_cmd = se_cmd;
441         tcmu_cmd->tcmu_dev = udev;
442
443         tcmu_cmd_reset_dbi_cur(tcmu_cmd);
444         tcmu_cmd->dbi_cnt = tcmu_cmd_get_block_cnt(tcmu_cmd);
445         tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
446                                 GFP_KERNEL);
447         if (!tcmu_cmd->dbi) {
448                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
449                 return NULL;
450         }
451
452         return tcmu_cmd;
453 }
454
455 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
456 {
457         unsigned long offset = offset_in_page(vaddr);
458
459         size = round_up(size+offset, PAGE_SIZE);
460         vaddr -= offset;
461
462         while (size) {
463                 flush_dcache_page(virt_to_page(vaddr));
464                 size -= PAGE_SIZE;
465         }
466 }
467
468 /*
469  * Some ring helper functions. We don't assume size is a power of 2 so
470  * we can't use circ_buf.h.
471  */
472 static inline size_t spc_used(size_t head, size_t tail, size_t size)
473 {
474         int diff = head - tail;
475
476         if (diff >= 0)
477                 return diff;
478         else
479                 return size + diff;
480 }
481
482 static inline size_t spc_free(size_t head, size_t tail, size_t size)
483 {
484         /* Keep 1 byte unused or we can't tell full from empty */
485         return (size - spc_used(head, tail, size) - 1);
486 }
487
488 static inline size_t head_to_end(size_t head, size_t size)
489 {
490         return size - head;
491 }
492
493 static inline void new_iov(struct iovec **iov, int *iov_cnt,
494                            struct tcmu_dev *udev)
495 {
496         struct iovec *iovec;
497
498         if (*iov_cnt != 0)
499                 (*iov)++;
500         (*iov_cnt)++;
501
502         iovec = *iov;
503         memset(iovec, 0, sizeof(struct iovec));
504 }
505
506 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
507
508 /* offset is relative to mb_addr */
509 static inline size_t get_block_offset_user(struct tcmu_dev *dev,
510                 int dbi, int remaining)
511 {
512         return dev->data_off + dbi * DATA_BLOCK_SIZE +
513                 DATA_BLOCK_SIZE - remaining;
514 }
515
516 static inline size_t iov_tail(struct iovec *iov)
517 {
518         return (size_t)iov->iov_base + iov->iov_len;
519 }
520
521 static int scatter_data_area(struct tcmu_dev *udev,
522         struct tcmu_cmd *tcmu_cmd, struct scatterlist *data_sg,
523         unsigned int data_nents, struct iovec **iov,
524         int *iov_cnt, bool copy_data)
525 {
526         int i, dbi;
527         int block_remaining = 0;
528         void *from, *to = NULL;
529         size_t copy_bytes, to_offset, offset;
530         struct scatterlist *sg;
531         struct page *page;
532
533         for_each_sg(data_sg, sg, data_nents, i) {
534                 int sg_remaining = sg->length;
535                 from = kmap_atomic(sg_page(sg)) + sg->offset;
536                 while (sg_remaining > 0) {
537                         if (block_remaining == 0) {
538                                 if (to)
539                                         kunmap_atomic(to);
540
541                                 block_remaining = DATA_BLOCK_SIZE;
542                                 dbi = tcmu_cmd_get_dbi(tcmu_cmd);
543                                 page = tcmu_get_block_page(udev, dbi);
544                                 to = kmap_atomic(page);
545                         }
546
547                         copy_bytes = min_t(size_t, sg_remaining,
548                                         block_remaining);
549                         to_offset = get_block_offset_user(udev, dbi,
550                                         block_remaining);
551
552                         if (*iov_cnt != 0 &&
553                             to_offset == iov_tail(*iov)) {
554                                 (*iov)->iov_len += copy_bytes;
555                         } else {
556                                 new_iov(iov, iov_cnt, udev);
557                                 (*iov)->iov_base = (void __user *)to_offset;
558                                 (*iov)->iov_len = copy_bytes;
559                         }
560                         if (copy_data) {
561                                 offset = DATA_BLOCK_SIZE - block_remaining;
562                                 memcpy(to + offset,
563                                        from + sg->length - sg_remaining,
564                                        copy_bytes);
565                                 tcmu_flush_dcache_range(to, copy_bytes);
566                         }
567                         sg_remaining -= copy_bytes;
568                         block_remaining -= copy_bytes;
569                 }
570                 kunmap_atomic(from - sg->offset);
571         }
572         if (to)
573                 kunmap_atomic(to);
574
575         return 0;
576 }
577
578 static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
579                              bool bidi)
580 {
581         struct se_cmd *se_cmd = cmd->se_cmd;
582         int i, dbi;
583         int block_remaining = 0;
584         void *from = NULL, *to;
585         size_t copy_bytes, offset;
586         struct scatterlist *sg, *data_sg;
587         struct page *page;
588         unsigned int data_nents;
589         uint32_t count = 0;
590
591         if (!bidi) {
592                 data_sg = se_cmd->t_data_sg;
593                 data_nents = se_cmd->t_data_nents;
594         } else {
595
596                 /*
597                  * For bidi case, the first count blocks are for Data-Out
598                  * buffer blocks, and before gathering the Data-In buffer
599                  * the Data-Out buffer blocks should be discarded.
600                  */
601                 count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
602
603                 data_sg = se_cmd->t_bidi_data_sg;
604                 data_nents = se_cmd->t_bidi_data_nents;
605         }
606
607         tcmu_cmd_set_dbi_cur(cmd, count);
608
609         for_each_sg(data_sg, sg, data_nents, i) {
610                 int sg_remaining = sg->length;
611                 to = kmap_atomic(sg_page(sg)) + sg->offset;
612                 while (sg_remaining > 0) {
613                         if (block_remaining == 0) {
614                                 if (from)
615                                         kunmap_atomic(from);
616
617                                 block_remaining = DATA_BLOCK_SIZE;
618                                 dbi = tcmu_cmd_get_dbi(cmd);
619                                 page = tcmu_get_block_page(udev, dbi);
620                                 from = kmap_atomic(page);
621                         }
622                         copy_bytes = min_t(size_t, sg_remaining,
623                                         block_remaining);
624                         offset = DATA_BLOCK_SIZE - block_remaining;
625                         tcmu_flush_dcache_range(from, copy_bytes);
626                         memcpy(to + sg->length - sg_remaining, from + offset,
627                                         copy_bytes);
628
629                         sg_remaining -= copy_bytes;
630                         block_remaining -= copy_bytes;
631                 }
632                 kunmap_atomic(to - sg->offset);
633         }
634         if (from)
635                 kunmap_atomic(from);
636 }
637
638 static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
639 {
640         return DATA_BLOCK_SIZE * (thresh - bitmap_weight(bitmap, thresh));
641 }
642
643 /*
644  * We can't queue a command until we have space available on the cmd ring *and*
645  * space available on the data area.
646  *
647  * Called with ring lock held.
648  */
649 static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
650                 size_t cmd_size, size_t data_needed)
651 {
652         struct tcmu_mailbox *mb = udev->mb_addr;
653         uint32_t blocks_needed = (data_needed + DATA_BLOCK_SIZE - 1)
654                                 / DATA_BLOCK_SIZE;
655         size_t space, cmd_needed;
656         u32 cmd_head;
657
658         tcmu_flush_dcache_range(mb, sizeof(*mb));
659
660         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
661
662         /*
663          * If cmd end-of-ring space is too small then we need space for a NOP plus
664          * original cmd - cmds are internally contiguous.
665          */
666         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
667                 cmd_needed = cmd_size;
668         else
669                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
670
671         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
672         if (space < cmd_needed) {
673                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
674                        udev->cmdr_last_cleaned, udev->cmdr_size);
675                 return false;
676         }
677
678         /* try to check and get the data blocks as needed */
679         space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
680         if (space < data_needed) {
681                 unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh;
682                 unsigned long grow;
683
684                 if (blocks_left < blocks_needed) {
685                         pr_debug("no data space: only %lu available, but ask for %zu\n",
686                                         blocks_left * DATA_BLOCK_SIZE,
687                                         data_needed);
688                         return false;
689                 }
690
691                 /* Try to expand the thresh */
692                 if (!udev->dbi_thresh) {
693                         /* From idle state */
694                         uint32_t init_thresh = DATA_BLOCK_INIT_BITS;
695
696                         udev->dbi_thresh = max(blocks_needed, init_thresh);
697                 } else {
698                         /*
699                          * Grow the data area by max(blocks needed,
700                          * dbi_thresh / 2), but limited to the max
701                          * DATA_BLOCK_BITS size.
702                          */
703                         grow = max(blocks_needed, udev->dbi_thresh / 2);
704                         udev->dbi_thresh += grow;
705                         if (udev->dbi_thresh > DATA_BLOCK_BITS)
706                                 udev->dbi_thresh = DATA_BLOCK_BITS;
707                 }
708         }
709
710         return tcmu_get_empty_blocks(udev, cmd);
711 }
712
713 static inline size_t tcmu_cmd_get_base_cmd_size(size_t iov_cnt)
714 {
715         return max(offsetof(struct tcmu_cmd_entry, req.iov[iov_cnt]),
716                         sizeof(struct tcmu_cmd_entry));
717 }
718
719 static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
720                                            size_t base_command_size)
721 {
722         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
723         size_t command_size;
724
725         command_size = base_command_size +
726                 round_up(scsi_command_size(se_cmd->t_task_cdb),
727                                 TCMU_OP_ALIGN_SIZE);
728
729         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
730
731         return command_size;
732 }
733
734 static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
735 {
736         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
737         unsigned long tmo = udev->cmd_time_out;
738         int cmd_id;
739
740         if (tcmu_cmd->cmd_id)
741                 return 0;
742
743         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
744         if (cmd_id < 0) {
745                 pr_err("tcmu: Could not allocate cmd id.\n");
746                 return cmd_id;
747         }
748         tcmu_cmd->cmd_id = cmd_id;
749
750         if (!tmo)
751                 return 0;
752
753         tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
754         mod_timer(&udev->timeout, tcmu_cmd->deadline);
755         return 0;
756 }
757
758 static sense_reason_t
759 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
760 {
761         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
762         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
763         size_t base_command_size, command_size;
764         struct tcmu_mailbox *mb;
765         struct tcmu_cmd_entry *entry;
766         struct iovec *iov;
767         int iov_cnt, ret;
768         uint32_t cmd_head;
769         uint64_t cdb_off;
770         bool copy_to_data_area;
771         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
772
773         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
774                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
775
776         /*
777          * Must be a certain minimum size for response sense info, but
778          * also may be larger if the iov array is large.
779          *
780          * We prepare as many iovs as possbile for potential uses here,
781          * because it's expensive to tell how many regions are freed in
782          * the bitmap & global data pool, as the size calculated here
783          * will only be used to do the checks.
784          *
785          * The size will be recalculated later as actually needed to save
786          * cmd area memories.
787          */
788         base_command_size = tcmu_cmd_get_base_cmd_size(tcmu_cmd->dbi_cnt);
789         command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
790
791         mutex_lock(&udev->cmdr_lock);
792
793         mb = udev->mb_addr;
794         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
795         if ((command_size > (udev->cmdr_size / 2)) ||
796             data_length > udev->data_size) {
797                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
798                         "cmd ring/data area\n", command_size, data_length,
799                         udev->cmdr_size, udev->data_size);
800                 mutex_unlock(&udev->cmdr_lock);
801                 return TCM_INVALID_CDB_FIELD;
802         }
803
804         while (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) {
805                 int ret;
806                 DEFINE_WAIT(__wait);
807
808                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
809
810                 pr_debug("sleeping for ring space\n");
811                 mutex_unlock(&udev->cmdr_lock);
812                 if (udev->cmd_time_out)
813                         ret = schedule_timeout(
814                                         msecs_to_jiffies(udev->cmd_time_out));
815                 else
816                         ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
817                 finish_wait(&udev->wait_cmdr, &__wait);
818                 if (!ret) {
819                         pr_warn("tcmu: command timed out\n");
820                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
821                 }
822
823                 mutex_lock(&udev->cmdr_lock);
824
825                 /* We dropped cmdr_lock, cmd_head is stale */
826                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
827         }
828
829         /* Insert a PAD if end-of-ring space is too small */
830         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
831                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
832
833                 entry = (void *) mb + CMDR_OFF + cmd_head;
834                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
835                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
836                 entry->hdr.cmd_id = 0; /* not used for PAD */
837                 entry->hdr.kflags = 0;
838                 entry->hdr.uflags = 0;
839                 tcmu_flush_dcache_range(entry, sizeof(*entry));
840
841                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
842                 tcmu_flush_dcache_range(mb, sizeof(*mb));
843
844                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
845                 WARN_ON(cmd_head != 0);
846         }
847
848         entry = (void *) mb + CMDR_OFF + cmd_head;
849         memset(entry, 0, command_size);
850         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
851
852         /* Handle allocating space from the data area */
853         tcmu_cmd_reset_dbi_cur(tcmu_cmd);
854         iov = &entry->req.iov[0];
855         iov_cnt = 0;
856         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
857                 || se_cmd->se_cmd_flags & SCF_BIDI);
858         ret = scatter_data_area(udev, tcmu_cmd, se_cmd->t_data_sg,
859                                 se_cmd->t_data_nents, &iov, &iov_cnt,
860                                 copy_to_data_area);
861         if (ret) {
862                 tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
863                 mutex_unlock(&udev->cmdr_lock);
864
865                 pr_err("tcmu: alloc and scatter data failed\n");
866                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
867         }
868         entry->req.iov_cnt = iov_cnt;
869
870         /* Handle BIDI commands */
871         iov_cnt = 0;
872         if (se_cmd->se_cmd_flags & SCF_BIDI) {
873                 iov++;
874                 ret = scatter_data_area(udev, tcmu_cmd,
875                                         se_cmd->t_bidi_data_sg,
876                                         se_cmd->t_bidi_data_nents,
877                                         &iov, &iov_cnt, false);
878                 if (ret) {
879                         tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
880                         mutex_unlock(&udev->cmdr_lock);
881
882                         pr_err("tcmu: alloc and scatter bidi data failed\n");
883                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
884                 }
885         }
886         entry->req.iov_bidi_cnt = iov_cnt;
887
888         ret = tcmu_setup_cmd_timer(tcmu_cmd);
889         if (ret) {
890                 tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
891                 mutex_unlock(&udev->cmdr_lock);
892                 return TCM_OUT_OF_RESOURCES;
893         }
894         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
895
896         /*
897          * Recalaulate the command's base size and size according
898          * to the actual needs
899          */
900         base_command_size = tcmu_cmd_get_base_cmd_size(entry->req.iov_cnt +
901                                                        entry->req.iov_bidi_cnt);
902         command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
903
904         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
905
906         /* All offsets relative to mb_addr, not start of entry! */
907         cdb_off = CMDR_OFF + cmd_head + base_command_size;
908         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
909         entry->req.cdb_off = cdb_off;
910         tcmu_flush_dcache_range(entry, sizeof(*entry));
911
912         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
913         tcmu_flush_dcache_range(mb, sizeof(*mb));
914         mutex_unlock(&udev->cmdr_lock);
915
916         /* TODO: only if FLUSH and FUA? */
917         uio_event_notify(&udev->uio_info);
918
919         if (udev->cmd_time_out)
920                 mod_timer(&udev->timeout, round_jiffies_up(jiffies +
921                           msecs_to_jiffies(udev->cmd_time_out)));
922
923         return TCM_NO_SENSE;
924 }
925
926 static sense_reason_t
927 tcmu_queue_cmd(struct se_cmd *se_cmd)
928 {
929         struct tcmu_cmd *tcmu_cmd;
930         sense_reason_t ret;
931
932         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
933         if (!tcmu_cmd)
934                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
935
936         ret = tcmu_queue_cmd_ring(tcmu_cmd);
937         if (ret != TCM_NO_SENSE) {
938                 pr_err("TCMU: Could not queue command\n");
939
940                 tcmu_free_cmd(tcmu_cmd);
941         }
942
943         return ret;
944 }
945
946 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
947 {
948         struct se_cmd *se_cmd = cmd->se_cmd;
949         struct tcmu_dev *udev = cmd->tcmu_dev;
950
951         /*
952          * cmd has been completed already from timeout, just reclaim
953          * data area space and free cmd
954          */
955         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
956                 goto out;
957
958         tcmu_cmd_reset_dbi_cur(cmd);
959
960         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
961                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
962                         cmd->se_cmd);
963                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
964         } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
965                 transport_copy_sense_to_cmd(se_cmd, entry->rsp.sense_buffer);
966         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
967                 /* Get Data-In buffer before clean up */
968                 gather_data_area(udev, cmd, true);
969         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
970                 gather_data_area(udev, cmd, false);
971         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
972                 /* TODO: */
973         } else if (se_cmd->data_direction != DMA_NONE) {
974                 pr_warn("TCMU: data direction was %d!\n",
975                         se_cmd->data_direction);
976         }
977
978         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
979
980 out:
981         cmd->se_cmd = NULL;
982         tcmu_cmd_free_data(cmd, cmd->dbi_cnt);
983         tcmu_free_cmd(cmd);
984 }
985
986 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
987 {
988         struct tcmu_mailbox *mb;
989         int handled = 0;
990
991         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
992                 pr_err("ring broken, not handling completions\n");
993                 return 0;
994         }
995
996         mb = udev->mb_addr;
997         tcmu_flush_dcache_range(mb, sizeof(*mb));
998
999         while (udev->cmdr_last_cleaned != READ_ONCE(mb->cmd_tail)) {
1000
1001                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
1002                 struct tcmu_cmd *cmd;
1003
1004                 tcmu_flush_dcache_range(entry, sizeof(*entry));
1005
1006                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
1007                         UPDATE_HEAD(udev->cmdr_last_cleaned,
1008                                     tcmu_hdr_get_len(entry->hdr.len_op),
1009                                     udev->cmdr_size);
1010                         continue;
1011                 }
1012                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
1013
1014                 spin_lock(&udev->commands_lock);
1015                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
1016                 spin_unlock(&udev->commands_lock);
1017
1018                 if (!cmd) {
1019                         pr_err("cmd_id not found, ring is broken\n");
1020                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
1021                         break;
1022                 }
1023
1024                 tcmu_handle_completion(cmd, entry);
1025
1026                 UPDATE_HEAD(udev->cmdr_last_cleaned,
1027                             tcmu_hdr_get_len(entry->hdr.len_op),
1028                             udev->cmdr_size);
1029
1030                 handled++;
1031         }
1032
1033         if (mb->cmd_tail == mb->cmd_head)
1034                 del_timer(&udev->timeout); /* no more pending cmds */
1035
1036         wake_up(&udev->wait_cmdr);
1037
1038         return handled;
1039 }
1040
1041 static int tcmu_check_expired_cmd(int id, void *p, void *data)
1042 {
1043         struct tcmu_cmd *cmd = p;
1044
1045         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
1046                 return 0;
1047
1048         if (!time_after(jiffies, cmd->deadline))
1049                 return 0;
1050
1051         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
1052         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
1053         cmd->se_cmd = NULL;
1054
1055         return 0;
1056 }
1057
1058 static void tcmu_device_timedout(unsigned long data)
1059 {
1060         struct tcmu_dev *udev = (struct tcmu_dev *)data;
1061         unsigned long flags;
1062
1063         spin_lock_irqsave(&udev->commands_lock, flags);
1064         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
1065         spin_unlock_irqrestore(&udev->commands_lock, flags);
1066
1067         /* Try to wake up the ummap thread */
1068         wake_up(&unmap_wait);
1069
1070         /*
1071          * We don't need to wakeup threads on wait_cmdr since they have their
1072          * own timeout.
1073          */
1074 }
1075
1076 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
1077 {
1078         struct tcmu_hba *tcmu_hba;
1079
1080         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
1081         if (!tcmu_hba)
1082                 return -ENOMEM;
1083
1084         tcmu_hba->host_id = host_id;
1085         hba->hba_ptr = tcmu_hba;
1086
1087         return 0;
1088 }
1089
1090 static void tcmu_detach_hba(struct se_hba *hba)
1091 {
1092         kfree(hba->hba_ptr);
1093         hba->hba_ptr = NULL;
1094 }
1095
1096 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
1097 {
1098         struct tcmu_dev *udev;
1099
1100         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
1101         if (!udev)
1102                 return NULL;
1103         kref_init(&udev->kref);
1104
1105         udev->name = kstrdup(name, GFP_KERNEL);
1106         if (!udev->name) {
1107                 kfree(udev);
1108                 return NULL;
1109         }
1110
1111         udev->hba = hba;
1112         udev->cmd_time_out = TCMU_TIME_OUT;
1113
1114         init_waitqueue_head(&udev->wait_cmdr);
1115         mutex_init(&udev->cmdr_lock);
1116
1117         idr_init(&udev->commands);
1118         spin_lock_init(&udev->commands_lock);
1119
1120         setup_timer(&udev->timeout, tcmu_device_timedout,
1121                 (unsigned long)udev);
1122
1123         init_waitqueue_head(&udev->nl_cmd_wq);
1124         spin_lock_init(&udev->nl_cmd_lock);
1125
1126         INIT_RADIX_TREE(&udev->data_blocks, GFP_KERNEL);
1127
1128         return &udev->se_dev;
1129 }
1130
1131 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
1132 {
1133         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
1134
1135         mutex_lock(&tcmu_dev->cmdr_lock);
1136         tcmu_handle_completions(tcmu_dev);
1137         mutex_unlock(&tcmu_dev->cmdr_lock);
1138
1139         return 0;
1140 }
1141
1142 /*
1143  * mmap code from uio.c. Copied here because we want to hook mmap()
1144  * and this stuff must come along.
1145  */
1146 static int tcmu_find_mem_index(struct vm_area_struct *vma)
1147 {
1148         struct tcmu_dev *udev = vma->vm_private_data;
1149         struct uio_info *info = &udev->uio_info;
1150
1151         if (vma->vm_pgoff < MAX_UIO_MAPS) {
1152                 if (info->mem[vma->vm_pgoff].size == 0)
1153                         return -1;
1154                 return (int)vma->vm_pgoff;
1155         }
1156         return -1;
1157 }
1158
1159 static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
1160 {
1161         struct page *page;
1162         int ret;
1163
1164         mutex_lock(&udev->cmdr_lock);
1165         page = tcmu_get_block_page(udev, dbi);
1166         if (likely(page)) {
1167                 mutex_unlock(&udev->cmdr_lock);
1168                 return page;
1169         }
1170
1171         /*
1172          * Normally it shouldn't be here:
1173          * Only when the userspace has touched the blocks which
1174          * are out of the tcmu_cmd's data iov[], and will return
1175          * one zeroed page.
1176          */
1177         pr_warn("Block(%u) out of cmd's iov[] has been touched!\n", dbi);
1178         pr_warn("Mostly it will be a bug of userspace, please have a check!\n");
1179
1180         if (dbi >= udev->dbi_thresh) {
1181                 /* Extern the udev->dbi_thresh to dbi + 1 */
1182                 udev->dbi_thresh = dbi + 1;
1183                 udev->dbi_max = dbi;
1184         }
1185
1186         page = radix_tree_lookup(&udev->data_blocks, dbi);
1187         if (!page) {
1188                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
1189                 if (!page) {
1190                         mutex_unlock(&udev->cmdr_lock);
1191                         return NULL;
1192                 }
1193
1194                 ret = radix_tree_insert(&udev->data_blocks, dbi, page);
1195                 if (ret) {
1196                         mutex_unlock(&udev->cmdr_lock);
1197                         __free_page(page);
1198                         return NULL;
1199                 }
1200
1201                 /*
1202                  * Since this case is rare in page fault routine, here we
1203                  * will allow the global_db_count >= TCMU_GLOBAL_MAX_BLOCKS
1204                  * to reduce possible page fault call trace.
1205                  */
1206                 atomic_inc(&global_db_count);
1207         }
1208         mutex_unlock(&udev->cmdr_lock);
1209
1210         return page;
1211 }
1212
1213 static int tcmu_vma_fault(struct vm_fault *vmf)
1214 {
1215         struct tcmu_dev *udev = vmf->vma->vm_private_data;
1216         struct uio_info *info = &udev->uio_info;
1217         struct page *page;
1218         unsigned long offset;
1219         void *addr;
1220
1221         int mi = tcmu_find_mem_index(vmf->vma);
1222         if (mi < 0)
1223                 return VM_FAULT_SIGBUS;
1224
1225         /*
1226          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
1227          * to use mem[N].
1228          */
1229         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
1230
1231         if (offset < udev->data_off) {
1232                 /* For the vmalloc()ed cmd area pages */
1233                 addr = (void *)(unsigned long)info->mem[mi].addr + offset;
1234                 page = vmalloc_to_page(addr);
1235         } else {
1236                 uint32_t dbi;
1237
1238                 /* For the dynamically growing data area pages */
1239                 dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
1240                 page = tcmu_try_get_block_page(udev, dbi);
1241                 if (!page)
1242                         return VM_FAULT_NOPAGE;
1243         }
1244
1245         get_page(page);
1246         vmf->page = page;
1247         return 0;
1248 }
1249
1250 static const struct vm_operations_struct tcmu_vm_ops = {
1251         .fault = tcmu_vma_fault,
1252 };
1253
1254 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
1255 {
1256         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1257
1258         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1259         vma->vm_ops = &tcmu_vm_ops;
1260
1261         vma->vm_private_data = udev;
1262
1263         /* Ensure the mmap is exactly the right size */
1264         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
1265                 return -EINVAL;
1266
1267         return 0;
1268 }
1269
1270 static int tcmu_open(struct uio_info *info, struct inode *inode)
1271 {
1272         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1273
1274         /* O_EXCL not supported for char devs, so fake it? */
1275         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
1276                 return -EBUSY;
1277
1278         udev->inode = inode;
1279         kref_get(&udev->kref);
1280
1281         pr_debug("open\n");
1282
1283         return 0;
1284 }
1285
1286 static void tcmu_dev_call_rcu(struct rcu_head *p)
1287 {
1288         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1289         struct tcmu_dev *udev = TCMU_DEV(dev);
1290
1291         kfree(udev->uio_info.name);
1292         kfree(udev->name);
1293         kfree(udev);
1294 }
1295
1296 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1297 {
1298         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1299                 kmem_cache_free(tcmu_cmd_cache, cmd);
1300                 return 0;
1301         }
1302         return -EINVAL;
1303 }
1304
1305 static void tcmu_blocks_release(struct tcmu_dev *udev)
1306 {
1307         int i;
1308         struct page *page;
1309
1310         /* Try to release all block pages */
1311         mutex_lock(&udev->cmdr_lock);
1312         for (i = 0; i <= udev->dbi_max; i++) {
1313                 page = radix_tree_delete(&udev->data_blocks, i);
1314                 if (page) {
1315                         __free_page(page);
1316                         atomic_dec(&global_db_count);
1317                 }
1318         }
1319         mutex_unlock(&udev->cmdr_lock);
1320 }
1321
1322 static void tcmu_dev_kref_release(struct kref *kref)
1323 {
1324         struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref);
1325         struct se_device *dev = &udev->se_dev;
1326         struct tcmu_cmd *cmd;
1327         bool all_expired = true;
1328         int i;
1329
1330         vfree(udev->mb_addr);
1331         udev->mb_addr = NULL;
1332
1333         /* Upper layer should drain all requests before calling this */
1334         spin_lock_irq(&udev->commands_lock);
1335         idr_for_each_entry(&udev->commands, cmd, i) {
1336                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1337                         all_expired = false;
1338         }
1339         idr_destroy(&udev->commands);
1340         spin_unlock_irq(&udev->commands_lock);
1341         WARN_ON(!all_expired);
1342
1343         tcmu_blocks_release(udev);
1344
1345         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1346 }
1347
1348 static int tcmu_release(struct uio_info *info, struct inode *inode)
1349 {
1350         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1351
1352         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
1353
1354         pr_debug("close\n");
1355         /* release ref from open */
1356         kref_put(&udev->kref, tcmu_dev_kref_release);
1357         return 0;
1358 }
1359
1360 static void tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
1361 {
1362         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1363
1364         if (!tcmu_kern_cmd_reply_supported)
1365                 return;
1366
1367         if (udev->nl_reply_supported <= 0)
1368                 return;
1369
1370 relock:
1371         spin_lock(&udev->nl_cmd_lock);
1372
1373         if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
1374                 spin_unlock(&udev->nl_cmd_lock);
1375                 pr_debug("sleeping for open nl cmd\n");
1376                 wait_event(udev->nl_cmd_wq, (nl_cmd->cmd == TCMU_CMD_UNSPEC));
1377                 goto relock;
1378         }
1379
1380         memset(nl_cmd, 0, sizeof(*nl_cmd));
1381         nl_cmd->cmd = cmd;
1382         init_completion(&nl_cmd->complete);
1383
1384         spin_unlock(&udev->nl_cmd_lock);
1385 }
1386
1387 static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
1388 {
1389         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1390         int ret;
1391         DEFINE_WAIT(__wait);
1392
1393         if (!tcmu_kern_cmd_reply_supported)
1394                 return 0;
1395
1396         if (udev->nl_reply_supported <= 0)
1397                 return 0;
1398
1399         pr_debug("sleeping for nl reply\n");
1400         wait_for_completion(&nl_cmd->complete);
1401
1402         spin_lock(&udev->nl_cmd_lock);
1403         nl_cmd->cmd = TCMU_CMD_UNSPEC;
1404         ret = nl_cmd->status;
1405         nl_cmd->status = 0;
1406         spin_unlock(&udev->nl_cmd_lock);
1407
1408         wake_up_all(&udev->nl_cmd_wq);
1409
1410         return ret;;
1411 }
1412
1413 static int tcmu_netlink_event(struct tcmu_dev *udev, enum tcmu_genl_cmd cmd,
1414                               int reconfig_attr, const void *reconfig_data)
1415 {
1416         struct sk_buff *skb;
1417         void *msg_header;
1418         int ret = -ENOMEM;
1419
1420         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1421         if (!skb)
1422                 return ret;
1423
1424         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
1425         if (!msg_header)
1426                 goto free_skb;
1427
1428         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, udev->uio_info.name);
1429         if (ret < 0)
1430                 goto free_skb;
1431
1432         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, udev->uio_info.uio_dev->minor);
1433         if (ret < 0)
1434                 goto free_skb;
1435
1436         ret = nla_put_u32(skb, TCMU_ATTR_DEVICE_ID, udev->se_dev.dev_index);
1437         if (ret < 0)
1438                 goto free_skb;
1439
1440         if (cmd == TCMU_CMD_RECONFIG_DEVICE) {
1441                 switch (reconfig_attr) {
1442                 case TCMU_ATTR_DEV_CFG:
1443                         ret = nla_put_string(skb, reconfig_attr, reconfig_data);
1444                         break;
1445                 case TCMU_ATTR_DEV_SIZE:
1446                         ret = nla_put_u64_64bit(skb, reconfig_attr,
1447                                                 *((u64 *)reconfig_data),
1448                                                 TCMU_ATTR_PAD);
1449                         break;
1450                 case TCMU_ATTR_WRITECACHE:
1451                         ret = nla_put_u8(skb, reconfig_attr,
1452                                           *((u8 *)reconfig_data));
1453                         break;
1454                 default:
1455                         BUG();
1456                 }
1457
1458                 if (ret < 0)
1459                         goto free_skb;
1460         }
1461
1462         genlmsg_end(skb, msg_header);
1463
1464         tcmu_init_genl_cmd_reply(udev, cmd);
1465
1466         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
1467                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
1468         /* We don't care if no one is listening */
1469         if (ret == -ESRCH)
1470                 ret = 0;
1471         if (!ret)
1472                 ret = tcmu_wait_genl_cmd_reply(udev);
1473
1474         return ret;
1475 free_skb:
1476         nlmsg_free(skb);
1477         return ret;
1478 }
1479
1480 static int tcmu_update_uio_info(struct tcmu_dev *udev)
1481 {
1482         struct tcmu_hba *hba = udev->hba->hba_ptr;
1483         struct uio_info *info;
1484         size_t size, used;
1485         char *str;
1486
1487         info = &udev->uio_info;
1488         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
1489                         udev->dev_config);
1490         size += 1; /* for \0 */
1491         str = kmalloc(size, GFP_KERNEL);
1492         if (!str)
1493                 return -ENOMEM;
1494
1495         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
1496         if (udev->dev_config[0])
1497                 snprintf(str + used, size - used, "/%s", udev->dev_config);
1498
1499         /* If the old string exists, free it */
1500         kfree(info->name);
1501         info->name = str;
1502
1503         return 0;
1504 }
1505
1506 static int tcmu_configure_device(struct se_device *dev)
1507 {
1508         struct tcmu_dev *udev = TCMU_DEV(dev);
1509         struct uio_info *info;
1510         struct tcmu_mailbox *mb;
1511         int ret = 0;
1512
1513         ret = tcmu_update_uio_info(udev);
1514         if (ret)
1515                 return ret;
1516
1517         info = &udev->uio_info;
1518
1519         udev->mb_addr = vzalloc(CMDR_SIZE);
1520         if (!udev->mb_addr) {
1521                 ret = -ENOMEM;
1522                 goto err_vzalloc;
1523         }
1524
1525         /* mailbox fits in first part of CMDR space */
1526         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
1527         udev->data_off = CMDR_SIZE;
1528         udev->data_size = DATA_SIZE;
1529         udev->dbi_thresh = 0; /* Default in Idle state */
1530         udev->waiting_global = false;
1531
1532         /* Initialise the mailbox of the ring buffer */
1533         mb = udev->mb_addr;
1534         mb->version = TCMU_MAILBOX_VERSION;
1535         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
1536         mb->cmdr_off = CMDR_OFF;
1537         mb->cmdr_size = udev->cmdr_size;
1538
1539         WARN_ON(!PAGE_ALIGNED(udev->data_off));
1540         WARN_ON(udev->data_size % PAGE_SIZE);
1541         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
1542
1543         info->version = __stringify(TCMU_MAILBOX_VERSION);
1544
1545         info->mem[0].name = "tcm-user command & data buffer";
1546         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
1547         info->mem[0].size = TCMU_RING_SIZE;
1548         info->mem[0].memtype = UIO_MEM_NONE;
1549
1550         info->irqcontrol = tcmu_irqcontrol;
1551         info->irq = UIO_IRQ_CUSTOM;
1552
1553         info->mmap = tcmu_mmap;
1554         info->open = tcmu_open;
1555         info->release = tcmu_release;
1556
1557         ret = uio_register_device(tcmu_root_device, info);
1558         if (ret)
1559                 goto err_register;
1560
1561         /* User can set hw_block_size before enable the device */
1562         if (dev->dev_attrib.hw_block_size == 0)
1563                 dev->dev_attrib.hw_block_size = 512;
1564         /* Other attributes can be configured in userspace */
1565         if (!dev->dev_attrib.hw_max_sectors)
1566                 dev->dev_attrib.hw_max_sectors = 128;
1567         if (!dev->dev_attrib.emulate_write_cache)
1568                 dev->dev_attrib.emulate_write_cache = 0;
1569         dev->dev_attrib.hw_queue_depth = 128;
1570
1571         /* If user didn't explicitly disable netlink reply support, use
1572          * module scope setting.
1573          */
1574         if (udev->nl_reply_supported >= 0)
1575                 udev->nl_reply_supported = tcmu_kern_cmd_reply_supported;
1576
1577         /*
1578          * Get a ref incase userspace does a close on the uio device before
1579          * LIO has initiated tcmu_free_device.
1580          */
1581         kref_get(&udev->kref);
1582
1583         ret = tcmu_netlink_event(udev, TCMU_CMD_ADDED_DEVICE, 0, NULL);
1584         if (ret)
1585                 goto err_netlink;
1586
1587         mutex_lock(&root_udev_mutex);
1588         list_add(&udev->node, &root_udev);
1589         mutex_unlock(&root_udev_mutex);
1590
1591         return 0;
1592
1593 err_netlink:
1594         kref_put(&udev->kref, tcmu_dev_kref_release);
1595         uio_unregister_device(&udev->uio_info);
1596 err_register:
1597         vfree(udev->mb_addr);
1598         udev->mb_addr = NULL;
1599 err_vzalloc:
1600         kfree(info->name);
1601         info->name = NULL;
1602
1603         return ret;
1604 }
1605
1606 static bool tcmu_dev_configured(struct tcmu_dev *udev)
1607 {
1608         return udev->uio_info.uio_dev ? true : false;
1609 }
1610
1611 static void tcmu_free_device(struct se_device *dev)
1612 {
1613         struct tcmu_dev *udev = TCMU_DEV(dev);
1614
1615         /* release ref from init */
1616         kref_put(&udev->kref, tcmu_dev_kref_release);
1617 }
1618
1619 static void tcmu_destroy_device(struct se_device *dev)
1620 {
1621         struct tcmu_dev *udev = TCMU_DEV(dev);
1622
1623         del_timer_sync(&udev->timeout);
1624
1625         mutex_lock(&root_udev_mutex);
1626         list_del(&udev->node);
1627         mutex_unlock(&root_udev_mutex);
1628
1629         tcmu_netlink_event(udev, TCMU_CMD_REMOVED_DEVICE, 0, NULL);
1630
1631         uio_unregister_device(&udev->uio_info);
1632
1633         /* release ref from configure */
1634         kref_put(&udev->kref, tcmu_dev_kref_release);
1635 }
1636
1637 enum {
1638         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
1639         Opt_nl_reply_supported, Opt_err,
1640 };
1641
1642 static match_table_t tokens = {
1643         {Opt_dev_config, "dev_config=%s"},
1644         {Opt_dev_size, "dev_size=%u"},
1645         {Opt_hw_block_size, "hw_block_size=%u"},
1646         {Opt_hw_max_sectors, "hw_max_sectors=%u"},
1647         {Opt_nl_reply_supported, "nl_reply_supported=%d"},
1648         {Opt_err, NULL}
1649 };
1650
1651 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
1652 {
1653         unsigned long tmp_ul;
1654         char *arg_p;
1655         int ret;
1656
1657         arg_p = match_strdup(arg);
1658         if (!arg_p)
1659                 return -ENOMEM;
1660
1661         ret = kstrtoul(arg_p, 0, &tmp_ul);
1662         kfree(arg_p);
1663         if (ret < 0) {
1664                 pr_err("kstrtoul() failed for dev attrib\n");
1665                 return ret;
1666         }
1667         if (!tmp_ul) {
1668                 pr_err("dev attrib must be nonzero\n");
1669                 return -EINVAL;
1670         }
1671         *dev_attrib = tmp_ul;
1672         return 0;
1673 }
1674
1675 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1676                 const char *page, ssize_t count)
1677 {
1678         struct tcmu_dev *udev = TCMU_DEV(dev);
1679         char *orig, *ptr, *opts, *arg_p;
1680         substring_t args[MAX_OPT_ARGS];
1681         int ret = 0, token;
1682
1683         opts = kstrdup(page, GFP_KERNEL);
1684         if (!opts)
1685                 return -ENOMEM;
1686
1687         orig = opts;
1688
1689         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1690                 if (!*ptr)
1691                         continue;
1692
1693                 token = match_token(ptr, tokens, args);
1694                 switch (token) {
1695                 case Opt_dev_config:
1696                         if (match_strlcpy(udev->dev_config, &args[0],
1697                                           TCMU_CONFIG_LEN) == 0) {
1698                                 ret = -EINVAL;
1699                                 break;
1700                         }
1701                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1702                         break;
1703                 case Opt_dev_size:
1704                         arg_p = match_strdup(&args[0]);
1705                         if (!arg_p) {
1706                                 ret = -ENOMEM;
1707                                 break;
1708                         }
1709                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1710                         kfree(arg_p);
1711                         if (ret < 0)
1712                                 pr_err("kstrtoul() failed for dev_size=\n");
1713                         break;
1714                 case Opt_hw_block_size:
1715                         ret = tcmu_set_dev_attrib(&args[0],
1716                                         &(dev->dev_attrib.hw_block_size));
1717                         break;
1718                 case Opt_hw_max_sectors:
1719                         ret = tcmu_set_dev_attrib(&args[0],
1720                                         &(dev->dev_attrib.hw_max_sectors));
1721                         break;
1722                 case Opt_nl_reply_supported:
1723                         arg_p = match_strdup(&args[0]);
1724                         if (!arg_p) {
1725                                 ret = -ENOMEM;
1726                                 break;
1727                         }
1728                         ret = kstrtoint(arg_p, 0, &udev->nl_reply_supported);
1729                         kfree(arg_p);
1730                         if (ret < 0)
1731                                 pr_err("kstrtoint() failed for nl_reply_supported=\n");
1732                         break;
1733                 default:
1734                         break;
1735                 }
1736
1737                 if (ret)
1738                         break;
1739         }
1740
1741         kfree(orig);
1742         return (!ret) ? count : ret;
1743 }
1744
1745 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1746 {
1747         struct tcmu_dev *udev = TCMU_DEV(dev);
1748         ssize_t bl = 0;
1749
1750         bl = sprintf(b + bl, "Config: %s ",
1751                      udev->dev_config[0] ? udev->dev_config : "NULL");
1752         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1753
1754         return bl;
1755 }
1756
1757 static sector_t tcmu_get_blocks(struct se_device *dev)
1758 {
1759         struct tcmu_dev *udev = TCMU_DEV(dev);
1760
1761         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1762                        dev->dev_attrib.block_size);
1763 }
1764
1765 static sense_reason_t
1766 tcmu_parse_cdb(struct se_cmd *cmd)
1767 {
1768         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1769 }
1770
1771 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
1772 {
1773         struct se_dev_attrib *da = container_of(to_config_group(item),
1774                                         struct se_dev_attrib, da_group);
1775         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1776
1777         return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
1778 }
1779
1780 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
1781                                        size_t count)
1782 {
1783         struct se_dev_attrib *da = container_of(to_config_group(item),
1784                                         struct se_dev_attrib, da_group);
1785         struct tcmu_dev *udev = container_of(da->da_dev,
1786                                         struct tcmu_dev, se_dev);
1787         u32 val;
1788         int ret;
1789
1790         if (da->da_dev->export_count) {
1791                 pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
1792                 return -EINVAL;
1793         }
1794
1795         ret = kstrtou32(page, 0, &val);
1796         if (ret < 0)
1797                 return ret;
1798
1799         udev->cmd_time_out = val * MSEC_PER_SEC;
1800         return count;
1801 }
1802 CONFIGFS_ATTR(tcmu_, cmd_time_out);
1803
1804 static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
1805 {
1806         struct se_dev_attrib *da = container_of(to_config_group(item),
1807                                                 struct se_dev_attrib, da_group);
1808         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1809
1810         return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
1811 }
1812
1813 static ssize_t tcmu_dev_config_store(struct config_item *item, const char *page,
1814                                      size_t count)
1815 {
1816         struct se_dev_attrib *da = container_of(to_config_group(item),
1817                                                 struct se_dev_attrib, da_group);
1818         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1819         int ret, len;
1820
1821         len = strlen(page);
1822         if (!len || len > TCMU_CONFIG_LEN - 1)
1823                 return -EINVAL;
1824
1825         /* Check if device has been configured before */
1826         if (tcmu_dev_configured(udev)) {
1827                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1828                                          TCMU_ATTR_DEV_CFG, page);
1829                 if (ret) {
1830                         pr_err("Unable to reconfigure device\n");
1831                         return ret;
1832                 }
1833                 strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
1834
1835                 ret = tcmu_update_uio_info(udev);
1836                 if (ret)
1837                         return ret;
1838                 return count;
1839         }
1840         strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
1841
1842         return count;
1843 }
1844 CONFIGFS_ATTR(tcmu_, dev_config);
1845
1846 static ssize_t tcmu_dev_size_show(struct config_item *item, char *page)
1847 {
1848         struct se_dev_attrib *da = container_of(to_config_group(item),
1849                                                 struct se_dev_attrib, da_group);
1850         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1851
1852         return snprintf(page, PAGE_SIZE, "%zu\n", udev->dev_size);
1853 }
1854
1855 static ssize_t tcmu_dev_size_store(struct config_item *item, const char *page,
1856                                    size_t count)
1857 {
1858         struct se_dev_attrib *da = container_of(to_config_group(item),
1859                                                 struct se_dev_attrib, da_group);
1860         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1861         u64 val;
1862         int ret;
1863
1864         ret = kstrtou64(page, 0, &val);
1865         if (ret < 0)
1866                 return ret;
1867
1868         /* Check if device has been configured before */
1869         if (tcmu_dev_configured(udev)) {
1870                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1871                                          TCMU_ATTR_DEV_SIZE, &val);
1872                 if (ret) {
1873                         pr_err("Unable to reconfigure device\n");
1874                         return ret;
1875                 }
1876         }
1877         udev->dev_size = val;
1878         return count;
1879 }
1880 CONFIGFS_ATTR(tcmu_, dev_size);
1881
1882 static ssize_t tcmu_nl_reply_supported_show(struct config_item *item,
1883                 char *page)
1884 {
1885         struct se_dev_attrib *da = container_of(to_config_group(item),
1886                                                 struct se_dev_attrib, da_group);
1887         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1888
1889         return snprintf(page, PAGE_SIZE, "%d\n", udev->nl_reply_supported);
1890 }
1891
1892 static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
1893                 const char *page, size_t count)
1894 {
1895         struct se_dev_attrib *da = container_of(to_config_group(item),
1896                                                 struct se_dev_attrib, da_group);
1897         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1898         s8 val;
1899         int ret;
1900
1901         ret = kstrtos8(page, 0, &val);
1902         if (ret < 0)
1903                 return ret;
1904
1905         udev->nl_reply_supported = val;
1906         return count;
1907 }
1908 CONFIGFS_ATTR(tcmu_, nl_reply_supported);
1909
1910 static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
1911                                              char *page)
1912 {
1913         struct se_dev_attrib *da = container_of(to_config_group(item),
1914                                         struct se_dev_attrib, da_group);
1915
1916         return snprintf(page, PAGE_SIZE, "%i\n", da->emulate_write_cache);
1917 }
1918
1919 static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
1920                                               const char *page, size_t count)
1921 {
1922         struct se_dev_attrib *da = container_of(to_config_group(item),
1923                                         struct se_dev_attrib, da_group);
1924         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1925         u8 val;
1926         int ret;
1927
1928         ret = kstrtou8(page, 0, &val);
1929         if (ret < 0)
1930                 return ret;
1931
1932         /* Check if device has been configured before */
1933         if (tcmu_dev_configured(udev)) {
1934                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1935                                          TCMU_ATTR_WRITECACHE, &val);
1936                 if (ret) {
1937                         pr_err("Unable to reconfigure device\n");
1938                         return ret;
1939                 }
1940         }
1941
1942         da->emulate_write_cache = val;
1943         return count;
1944 }
1945 CONFIGFS_ATTR(tcmu_, emulate_write_cache);
1946
1947 static struct configfs_attribute *tcmu_attrib_attrs[] = {
1948         &tcmu_attr_cmd_time_out,
1949         &tcmu_attr_dev_config,
1950         &tcmu_attr_dev_size,
1951         &tcmu_attr_emulate_write_cache,
1952         &tcmu_attr_nl_reply_supported,
1953         NULL,
1954 };
1955
1956 static struct configfs_attribute **tcmu_attrs;
1957
1958 static struct target_backend_ops tcmu_ops = {
1959         .name                   = "user",
1960         .owner                  = THIS_MODULE,
1961         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1962         .attach_hba             = tcmu_attach_hba,
1963         .detach_hba             = tcmu_detach_hba,
1964         .alloc_device           = tcmu_alloc_device,
1965         .configure_device       = tcmu_configure_device,
1966         .destroy_device         = tcmu_destroy_device,
1967         .free_device            = tcmu_free_device,
1968         .parse_cdb              = tcmu_parse_cdb,
1969         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1970         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1971         .get_device_type        = sbc_get_device_type,
1972         .get_blocks             = tcmu_get_blocks,
1973         .tb_dev_attrib_attrs    = NULL,
1974 };
1975
1976 static int unmap_thread_fn(void *data)
1977 {
1978         struct tcmu_dev *udev;
1979         loff_t off;
1980         uint32_t start, end, block;
1981         struct page *page;
1982         int i;
1983
1984         while (!kthread_should_stop()) {
1985                 DEFINE_WAIT(__wait);
1986
1987                 prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
1988                 schedule();
1989                 finish_wait(&unmap_wait, &__wait);
1990
1991                 if (kthread_should_stop())
1992                         break;
1993
1994                 mutex_lock(&root_udev_mutex);
1995                 list_for_each_entry(udev, &root_udev, node) {
1996                         mutex_lock(&udev->cmdr_lock);
1997
1998                         /* Try to complete the finished commands first */
1999                         tcmu_handle_completions(udev);
2000
2001                         /* Skip the udevs waiting the global pool or in idle */
2002                         if (udev->waiting_global || !udev->dbi_thresh) {
2003                                 mutex_unlock(&udev->cmdr_lock);
2004                                 continue;
2005                         }
2006
2007                         end = udev->dbi_max + 1;
2008                         block = find_last_bit(udev->data_bitmap, end);
2009                         if (block == udev->dbi_max) {
2010                                 /*
2011                                  * The last bit is dbi_max, so there is
2012                                  * no need to shrink any blocks.
2013                                  */
2014                                 mutex_unlock(&udev->cmdr_lock);
2015                                 continue;
2016                         } else if (block == end) {
2017                                 /* The current udev will goto idle state */
2018                                 udev->dbi_thresh = start = 0;
2019                                 udev->dbi_max = 0;
2020                         } else {
2021                                 udev->dbi_thresh = start = block + 1;
2022                                 udev->dbi_max = block;
2023                         }
2024
2025                         /* Here will truncate the data area from off */
2026                         off = udev->data_off + start * DATA_BLOCK_SIZE;
2027                         unmap_mapping_range(udev->inode->i_mapping, off, 0, 1);
2028
2029                         /* Release the block pages */
2030                         for (i = start; i < end; i++) {
2031                                 page = radix_tree_delete(&udev->data_blocks, i);
2032                                 if (page) {
2033                                         __free_page(page);
2034                                         atomic_dec(&global_db_count);
2035                                 }
2036                         }
2037                         mutex_unlock(&udev->cmdr_lock);
2038                 }
2039
2040                 /*
2041                  * Try to wake up the udevs who are waiting
2042                  * for the global data pool.
2043                  */
2044                 list_for_each_entry(udev, &root_udev, node) {
2045                         if (udev->waiting_global)
2046                                 wake_up(&udev->wait_cmdr);
2047                 }
2048                 mutex_unlock(&root_udev_mutex);
2049         }
2050
2051         return 0;
2052 }
2053
2054 static int __init tcmu_module_init(void)
2055 {
2056         int ret, i, k, len = 0;
2057
2058         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
2059
2060         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
2061                                 sizeof(struct tcmu_cmd),
2062                                 __alignof__(struct tcmu_cmd),
2063                                 0, NULL);
2064         if (!tcmu_cmd_cache)
2065                 return -ENOMEM;
2066
2067         tcmu_root_device = root_device_register("tcm_user");
2068         if (IS_ERR(tcmu_root_device)) {
2069                 ret = PTR_ERR(tcmu_root_device);
2070                 goto out_free_cache;
2071         }
2072
2073         ret = genl_register_family(&tcmu_genl_family);
2074         if (ret < 0) {
2075                 goto out_unreg_device;
2076         }
2077
2078         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2079                 len += sizeof(struct configfs_attribute *);
2080         }
2081         for (i = 0; tcmu_attrib_attrs[i] != NULL; i++) {
2082                 len += sizeof(struct configfs_attribute *);
2083         }
2084         len += sizeof(struct configfs_attribute *);
2085
2086         tcmu_attrs = kzalloc(len, GFP_KERNEL);
2087         if (!tcmu_attrs) {
2088                 ret = -ENOMEM;
2089                 goto out_unreg_genl;
2090         }
2091
2092         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2093                 tcmu_attrs[i] = passthrough_attrib_attrs[i];
2094         }
2095         for (k = 0; tcmu_attrib_attrs[k] != NULL; k++) {
2096                 tcmu_attrs[i] = tcmu_attrib_attrs[k];
2097                 i++;
2098         }
2099         tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
2100
2101         ret = transport_backend_register(&tcmu_ops);
2102         if (ret)
2103                 goto out_attrs;
2104
2105         init_waitqueue_head(&unmap_wait);
2106         unmap_thread = kthread_run(unmap_thread_fn, NULL, "tcmu_unmap");
2107         if (IS_ERR(unmap_thread)) {
2108                 ret = PTR_ERR(unmap_thread);
2109                 goto out_unreg_transport;
2110         }
2111
2112         return 0;
2113
2114 out_unreg_transport:
2115         target_backend_unregister(&tcmu_ops);
2116 out_attrs:
2117         kfree(tcmu_attrs);
2118 out_unreg_genl:
2119         genl_unregister_family(&tcmu_genl_family);
2120 out_unreg_device:
2121         root_device_unregister(tcmu_root_device);
2122 out_free_cache:
2123         kmem_cache_destroy(tcmu_cmd_cache);
2124
2125         return ret;
2126 }
2127
2128 static void __exit tcmu_module_exit(void)
2129 {
2130         kthread_stop(unmap_thread);
2131         target_backend_unregister(&tcmu_ops);
2132         kfree(tcmu_attrs);
2133         genl_unregister_family(&tcmu_genl_family);
2134         root_device_unregister(tcmu_root_device);
2135         kmem_cache_destroy(tcmu_cmd_cache);
2136 }
2137
2138 MODULE_DESCRIPTION("TCM USER subsystem plugin");
2139 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
2140 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
2141 MODULE_LICENSE("GPL");
2142
2143 module_init(tcmu_module_init);
2144 module_exit(tcmu_module_exit);