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(struct timer_list *t)
1059 {
1060         struct tcmu_dev *udev = from_timer(udev, t, timeout);
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         timer_setup(&udev->timeout, tcmu_device_timedout, 0);
1121
1122         init_waitqueue_head(&udev->nl_cmd_wq);
1123         spin_lock_init(&udev->nl_cmd_lock);
1124
1125         INIT_RADIX_TREE(&udev->data_blocks, GFP_KERNEL);
1126
1127         return &udev->se_dev;
1128 }
1129
1130 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
1131 {
1132         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
1133
1134         mutex_lock(&tcmu_dev->cmdr_lock);
1135         tcmu_handle_completions(tcmu_dev);
1136         mutex_unlock(&tcmu_dev->cmdr_lock);
1137
1138         return 0;
1139 }
1140
1141 /*
1142  * mmap code from uio.c. Copied here because we want to hook mmap()
1143  * and this stuff must come along.
1144  */
1145 static int tcmu_find_mem_index(struct vm_area_struct *vma)
1146 {
1147         struct tcmu_dev *udev = vma->vm_private_data;
1148         struct uio_info *info = &udev->uio_info;
1149
1150         if (vma->vm_pgoff < MAX_UIO_MAPS) {
1151                 if (info->mem[vma->vm_pgoff].size == 0)
1152                         return -1;
1153                 return (int)vma->vm_pgoff;
1154         }
1155         return -1;
1156 }
1157
1158 static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
1159 {
1160         struct page *page;
1161         int ret;
1162
1163         mutex_lock(&udev->cmdr_lock);
1164         page = tcmu_get_block_page(udev, dbi);
1165         if (likely(page)) {
1166                 mutex_unlock(&udev->cmdr_lock);
1167                 return page;
1168         }
1169
1170         /*
1171          * Normally it shouldn't be here:
1172          * Only when the userspace has touched the blocks which
1173          * are out of the tcmu_cmd's data iov[], and will return
1174          * one zeroed page.
1175          */
1176         pr_warn("Block(%u) out of cmd's iov[] has been touched!\n", dbi);
1177         pr_warn("Mostly it will be a bug of userspace, please have a check!\n");
1178
1179         if (dbi >= udev->dbi_thresh) {
1180                 /* Extern the udev->dbi_thresh to dbi + 1 */
1181                 udev->dbi_thresh = dbi + 1;
1182                 udev->dbi_max = dbi;
1183         }
1184
1185         page = radix_tree_lookup(&udev->data_blocks, dbi);
1186         if (!page) {
1187                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
1188                 if (!page) {
1189                         mutex_unlock(&udev->cmdr_lock);
1190                         return NULL;
1191                 }
1192
1193                 ret = radix_tree_insert(&udev->data_blocks, dbi, page);
1194                 if (ret) {
1195                         mutex_unlock(&udev->cmdr_lock);
1196                         __free_page(page);
1197                         return NULL;
1198                 }
1199
1200                 /*
1201                  * Since this case is rare in page fault routine, here we
1202                  * will allow the global_db_count >= TCMU_GLOBAL_MAX_BLOCKS
1203                  * to reduce possible page fault call trace.
1204                  */
1205                 atomic_inc(&global_db_count);
1206         }
1207         mutex_unlock(&udev->cmdr_lock);
1208
1209         return page;
1210 }
1211
1212 static int tcmu_vma_fault(struct vm_fault *vmf)
1213 {
1214         struct tcmu_dev *udev = vmf->vma->vm_private_data;
1215         struct uio_info *info = &udev->uio_info;
1216         struct page *page;
1217         unsigned long offset;
1218         void *addr;
1219
1220         int mi = tcmu_find_mem_index(vmf->vma);
1221         if (mi < 0)
1222                 return VM_FAULT_SIGBUS;
1223
1224         /*
1225          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
1226          * to use mem[N].
1227          */
1228         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
1229
1230         if (offset < udev->data_off) {
1231                 /* For the vmalloc()ed cmd area pages */
1232                 addr = (void *)(unsigned long)info->mem[mi].addr + offset;
1233                 page = vmalloc_to_page(addr);
1234         } else {
1235                 uint32_t dbi;
1236
1237                 /* For the dynamically growing data area pages */
1238                 dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
1239                 page = tcmu_try_get_block_page(udev, dbi);
1240                 if (!page)
1241                         return VM_FAULT_NOPAGE;
1242         }
1243
1244         get_page(page);
1245         vmf->page = page;
1246         return 0;
1247 }
1248
1249 static const struct vm_operations_struct tcmu_vm_ops = {
1250         .fault = tcmu_vma_fault,
1251 };
1252
1253 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
1254 {
1255         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1256
1257         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1258         vma->vm_ops = &tcmu_vm_ops;
1259
1260         vma->vm_private_data = udev;
1261
1262         /* Ensure the mmap is exactly the right size */
1263         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
1264                 return -EINVAL;
1265
1266         return 0;
1267 }
1268
1269 static int tcmu_open(struct uio_info *info, struct inode *inode)
1270 {
1271         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1272
1273         /* O_EXCL not supported for char devs, so fake it? */
1274         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
1275                 return -EBUSY;
1276
1277         udev->inode = inode;
1278         kref_get(&udev->kref);
1279
1280         pr_debug("open\n");
1281
1282         return 0;
1283 }
1284
1285 static void tcmu_dev_call_rcu(struct rcu_head *p)
1286 {
1287         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1288         struct tcmu_dev *udev = TCMU_DEV(dev);
1289
1290         kfree(udev->uio_info.name);
1291         kfree(udev->name);
1292         kfree(udev);
1293 }
1294
1295 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1296 {
1297         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1298                 kmem_cache_free(tcmu_cmd_cache, cmd);
1299                 return 0;
1300         }
1301         return -EINVAL;
1302 }
1303
1304 static void tcmu_blocks_release(struct tcmu_dev *udev)
1305 {
1306         int i;
1307         struct page *page;
1308
1309         /* Try to release all block pages */
1310         mutex_lock(&udev->cmdr_lock);
1311         for (i = 0; i <= udev->dbi_max; i++) {
1312                 page = radix_tree_delete(&udev->data_blocks, i);
1313                 if (page) {
1314                         __free_page(page);
1315                         atomic_dec(&global_db_count);
1316                 }
1317         }
1318         mutex_unlock(&udev->cmdr_lock);
1319 }
1320
1321 static void tcmu_dev_kref_release(struct kref *kref)
1322 {
1323         struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref);
1324         struct se_device *dev = &udev->se_dev;
1325         struct tcmu_cmd *cmd;
1326         bool all_expired = true;
1327         int i;
1328
1329         vfree(udev->mb_addr);
1330         udev->mb_addr = NULL;
1331
1332         /* Upper layer should drain all requests before calling this */
1333         spin_lock_irq(&udev->commands_lock);
1334         idr_for_each_entry(&udev->commands, cmd, i) {
1335                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1336                         all_expired = false;
1337         }
1338         idr_destroy(&udev->commands);
1339         spin_unlock_irq(&udev->commands_lock);
1340         WARN_ON(!all_expired);
1341
1342         tcmu_blocks_release(udev);
1343
1344         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1345 }
1346
1347 static int tcmu_release(struct uio_info *info, struct inode *inode)
1348 {
1349         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1350
1351         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
1352
1353         pr_debug("close\n");
1354         /* release ref from open */
1355         kref_put(&udev->kref, tcmu_dev_kref_release);
1356         return 0;
1357 }
1358
1359 static void tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
1360 {
1361         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1362
1363         if (!tcmu_kern_cmd_reply_supported)
1364                 return;
1365
1366         if (udev->nl_reply_supported <= 0)
1367                 return;
1368
1369 relock:
1370         spin_lock(&udev->nl_cmd_lock);
1371
1372         if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
1373                 spin_unlock(&udev->nl_cmd_lock);
1374                 pr_debug("sleeping for open nl cmd\n");
1375                 wait_event(udev->nl_cmd_wq, (nl_cmd->cmd == TCMU_CMD_UNSPEC));
1376                 goto relock;
1377         }
1378
1379         memset(nl_cmd, 0, sizeof(*nl_cmd));
1380         nl_cmd->cmd = cmd;
1381         init_completion(&nl_cmd->complete);
1382
1383         spin_unlock(&udev->nl_cmd_lock);
1384 }
1385
1386 static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
1387 {
1388         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1389         int ret;
1390         DEFINE_WAIT(__wait);
1391
1392         if (!tcmu_kern_cmd_reply_supported)
1393                 return 0;
1394
1395         if (udev->nl_reply_supported <= 0)
1396                 return 0;
1397
1398         pr_debug("sleeping for nl reply\n");
1399         wait_for_completion(&nl_cmd->complete);
1400
1401         spin_lock(&udev->nl_cmd_lock);
1402         nl_cmd->cmd = TCMU_CMD_UNSPEC;
1403         ret = nl_cmd->status;
1404         nl_cmd->status = 0;
1405         spin_unlock(&udev->nl_cmd_lock);
1406
1407         wake_up_all(&udev->nl_cmd_wq);
1408
1409         return ret;;
1410 }
1411
1412 static int tcmu_netlink_event(struct tcmu_dev *udev, enum tcmu_genl_cmd cmd,
1413                               int reconfig_attr, const void *reconfig_data)
1414 {
1415         struct sk_buff *skb;
1416         void *msg_header;
1417         int ret = -ENOMEM;
1418
1419         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1420         if (!skb)
1421                 return ret;
1422
1423         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
1424         if (!msg_header)
1425                 goto free_skb;
1426
1427         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, udev->uio_info.name);
1428         if (ret < 0)
1429                 goto free_skb;
1430
1431         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, udev->uio_info.uio_dev->minor);
1432         if (ret < 0)
1433                 goto free_skb;
1434
1435         ret = nla_put_u32(skb, TCMU_ATTR_DEVICE_ID, udev->se_dev.dev_index);
1436         if (ret < 0)
1437                 goto free_skb;
1438
1439         if (cmd == TCMU_CMD_RECONFIG_DEVICE) {
1440                 switch (reconfig_attr) {
1441                 case TCMU_ATTR_DEV_CFG:
1442                         ret = nla_put_string(skb, reconfig_attr, reconfig_data);
1443                         break;
1444                 case TCMU_ATTR_DEV_SIZE:
1445                         ret = nla_put_u64_64bit(skb, reconfig_attr,
1446                                                 *((u64 *)reconfig_data),
1447                                                 TCMU_ATTR_PAD);
1448                         break;
1449                 case TCMU_ATTR_WRITECACHE:
1450                         ret = nla_put_u8(skb, reconfig_attr,
1451                                           *((u8 *)reconfig_data));
1452                         break;
1453                 default:
1454                         BUG();
1455                 }
1456
1457                 if (ret < 0)
1458                         goto free_skb;
1459         }
1460
1461         genlmsg_end(skb, msg_header);
1462
1463         tcmu_init_genl_cmd_reply(udev, cmd);
1464
1465         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
1466                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
1467         /* We don't care if no one is listening */
1468         if (ret == -ESRCH)
1469                 ret = 0;
1470         if (!ret)
1471                 ret = tcmu_wait_genl_cmd_reply(udev);
1472
1473         return ret;
1474 free_skb:
1475         nlmsg_free(skb);
1476         return ret;
1477 }
1478
1479 static int tcmu_update_uio_info(struct tcmu_dev *udev)
1480 {
1481         struct tcmu_hba *hba = udev->hba->hba_ptr;
1482         struct uio_info *info;
1483         size_t size, used;
1484         char *str;
1485
1486         info = &udev->uio_info;
1487         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
1488                         udev->dev_config);
1489         size += 1; /* for \0 */
1490         str = kmalloc(size, GFP_KERNEL);
1491         if (!str)
1492                 return -ENOMEM;
1493
1494         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
1495         if (udev->dev_config[0])
1496                 snprintf(str + used, size - used, "/%s", udev->dev_config);
1497
1498         /* If the old string exists, free it */
1499         kfree(info->name);
1500         info->name = str;
1501
1502         return 0;
1503 }
1504
1505 static int tcmu_configure_device(struct se_device *dev)
1506 {
1507         struct tcmu_dev *udev = TCMU_DEV(dev);
1508         struct uio_info *info;
1509         struct tcmu_mailbox *mb;
1510         int ret = 0;
1511
1512         ret = tcmu_update_uio_info(udev);
1513         if (ret)
1514                 return ret;
1515
1516         info = &udev->uio_info;
1517
1518         udev->mb_addr = vzalloc(CMDR_SIZE);
1519         if (!udev->mb_addr) {
1520                 ret = -ENOMEM;
1521                 goto err_vzalloc;
1522         }
1523
1524         /* mailbox fits in first part of CMDR space */
1525         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
1526         udev->data_off = CMDR_SIZE;
1527         udev->data_size = DATA_SIZE;
1528         udev->dbi_thresh = 0; /* Default in Idle state */
1529         udev->waiting_global = false;
1530
1531         /* Initialise the mailbox of the ring buffer */
1532         mb = udev->mb_addr;
1533         mb->version = TCMU_MAILBOX_VERSION;
1534         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
1535         mb->cmdr_off = CMDR_OFF;
1536         mb->cmdr_size = udev->cmdr_size;
1537
1538         WARN_ON(!PAGE_ALIGNED(udev->data_off));
1539         WARN_ON(udev->data_size % PAGE_SIZE);
1540         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
1541
1542         info->version = __stringify(TCMU_MAILBOX_VERSION);
1543
1544         info->mem[0].name = "tcm-user command & data buffer";
1545         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
1546         info->mem[0].size = TCMU_RING_SIZE;
1547         info->mem[0].memtype = UIO_MEM_NONE;
1548
1549         info->irqcontrol = tcmu_irqcontrol;
1550         info->irq = UIO_IRQ_CUSTOM;
1551
1552         info->mmap = tcmu_mmap;
1553         info->open = tcmu_open;
1554         info->release = tcmu_release;
1555
1556         ret = uio_register_device(tcmu_root_device, info);
1557         if (ret)
1558                 goto err_register;
1559
1560         /* User can set hw_block_size before enable the device */
1561         if (dev->dev_attrib.hw_block_size == 0)
1562                 dev->dev_attrib.hw_block_size = 512;
1563         /* Other attributes can be configured in userspace */
1564         if (!dev->dev_attrib.hw_max_sectors)
1565                 dev->dev_attrib.hw_max_sectors = 128;
1566         if (!dev->dev_attrib.emulate_write_cache)
1567                 dev->dev_attrib.emulate_write_cache = 0;
1568         dev->dev_attrib.hw_queue_depth = 128;
1569
1570         /* If user didn't explicitly disable netlink reply support, use
1571          * module scope setting.
1572          */
1573         if (udev->nl_reply_supported >= 0)
1574                 udev->nl_reply_supported = tcmu_kern_cmd_reply_supported;
1575
1576         /*
1577          * Get a ref incase userspace does a close on the uio device before
1578          * LIO has initiated tcmu_free_device.
1579          */
1580         kref_get(&udev->kref);
1581
1582         ret = tcmu_netlink_event(udev, TCMU_CMD_ADDED_DEVICE, 0, NULL);
1583         if (ret)
1584                 goto err_netlink;
1585
1586         mutex_lock(&root_udev_mutex);
1587         list_add(&udev->node, &root_udev);
1588         mutex_unlock(&root_udev_mutex);
1589
1590         return 0;
1591
1592 err_netlink:
1593         kref_put(&udev->kref, tcmu_dev_kref_release);
1594         uio_unregister_device(&udev->uio_info);
1595 err_register:
1596         vfree(udev->mb_addr);
1597         udev->mb_addr = NULL;
1598 err_vzalloc:
1599         kfree(info->name);
1600         info->name = NULL;
1601
1602         return ret;
1603 }
1604
1605 static bool tcmu_dev_configured(struct tcmu_dev *udev)
1606 {
1607         return udev->uio_info.uio_dev ? true : false;
1608 }
1609
1610 static void tcmu_free_device(struct se_device *dev)
1611 {
1612         struct tcmu_dev *udev = TCMU_DEV(dev);
1613
1614         /* release ref from init */
1615         kref_put(&udev->kref, tcmu_dev_kref_release);
1616 }
1617
1618 static void tcmu_destroy_device(struct se_device *dev)
1619 {
1620         struct tcmu_dev *udev = TCMU_DEV(dev);
1621
1622         del_timer_sync(&udev->timeout);
1623
1624         mutex_lock(&root_udev_mutex);
1625         list_del(&udev->node);
1626         mutex_unlock(&root_udev_mutex);
1627
1628         tcmu_netlink_event(udev, TCMU_CMD_REMOVED_DEVICE, 0, NULL);
1629
1630         uio_unregister_device(&udev->uio_info);
1631
1632         /* release ref from configure */
1633         kref_put(&udev->kref, tcmu_dev_kref_release);
1634 }
1635
1636 enum {
1637         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
1638         Opt_nl_reply_supported, Opt_err,
1639 };
1640
1641 static match_table_t tokens = {
1642         {Opt_dev_config, "dev_config=%s"},
1643         {Opt_dev_size, "dev_size=%u"},
1644         {Opt_hw_block_size, "hw_block_size=%u"},
1645         {Opt_hw_max_sectors, "hw_max_sectors=%u"},
1646         {Opt_nl_reply_supported, "nl_reply_supported=%d"},
1647         {Opt_err, NULL}
1648 };
1649
1650 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
1651 {
1652         unsigned long tmp_ul;
1653         char *arg_p;
1654         int ret;
1655
1656         arg_p = match_strdup(arg);
1657         if (!arg_p)
1658                 return -ENOMEM;
1659
1660         ret = kstrtoul(arg_p, 0, &tmp_ul);
1661         kfree(arg_p);
1662         if (ret < 0) {
1663                 pr_err("kstrtoul() failed for dev attrib\n");
1664                 return ret;
1665         }
1666         if (!tmp_ul) {
1667                 pr_err("dev attrib must be nonzero\n");
1668                 return -EINVAL;
1669         }
1670         *dev_attrib = tmp_ul;
1671         return 0;
1672 }
1673
1674 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1675                 const char *page, ssize_t count)
1676 {
1677         struct tcmu_dev *udev = TCMU_DEV(dev);
1678         char *orig, *ptr, *opts, *arg_p;
1679         substring_t args[MAX_OPT_ARGS];
1680         int ret = 0, token;
1681
1682         opts = kstrdup(page, GFP_KERNEL);
1683         if (!opts)
1684                 return -ENOMEM;
1685
1686         orig = opts;
1687
1688         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1689                 if (!*ptr)
1690                         continue;
1691
1692                 token = match_token(ptr, tokens, args);
1693                 switch (token) {
1694                 case Opt_dev_config:
1695                         if (match_strlcpy(udev->dev_config, &args[0],
1696                                           TCMU_CONFIG_LEN) == 0) {
1697                                 ret = -EINVAL;
1698                                 break;
1699                         }
1700                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1701                         break;
1702                 case Opt_dev_size:
1703                         arg_p = match_strdup(&args[0]);
1704                         if (!arg_p) {
1705                                 ret = -ENOMEM;
1706                                 break;
1707                         }
1708                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1709                         kfree(arg_p);
1710                         if (ret < 0)
1711                                 pr_err("kstrtoul() failed for dev_size=\n");
1712                         break;
1713                 case Opt_hw_block_size:
1714                         ret = tcmu_set_dev_attrib(&args[0],
1715                                         &(dev->dev_attrib.hw_block_size));
1716                         break;
1717                 case Opt_hw_max_sectors:
1718                         ret = tcmu_set_dev_attrib(&args[0],
1719                                         &(dev->dev_attrib.hw_max_sectors));
1720                         break;
1721                 case Opt_nl_reply_supported:
1722                         arg_p = match_strdup(&args[0]);
1723                         if (!arg_p) {
1724                                 ret = -ENOMEM;
1725                                 break;
1726                         }
1727                         ret = kstrtoint(arg_p, 0, &udev->nl_reply_supported);
1728                         kfree(arg_p);
1729                         if (ret < 0)
1730                                 pr_err("kstrtoint() failed for nl_reply_supported=\n");
1731                         break;
1732                 default:
1733                         break;
1734                 }
1735
1736                 if (ret)
1737                         break;
1738         }
1739
1740         kfree(orig);
1741         return (!ret) ? count : ret;
1742 }
1743
1744 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1745 {
1746         struct tcmu_dev *udev = TCMU_DEV(dev);
1747         ssize_t bl = 0;
1748
1749         bl = sprintf(b + bl, "Config: %s ",
1750                      udev->dev_config[0] ? udev->dev_config : "NULL");
1751         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1752
1753         return bl;
1754 }
1755
1756 static sector_t tcmu_get_blocks(struct se_device *dev)
1757 {
1758         struct tcmu_dev *udev = TCMU_DEV(dev);
1759
1760         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1761                        dev->dev_attrib.block_size);
1762 }
1763
1764 static sense_reason_t
1765 tcmu_parse_cdb(struct se_cmd *cmd)
1766 {
1767         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1768 }
1769
1770 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
1771 {
1772         struct se_dev_attrib *da = container_of(to_config_group(item),
1773                                         struct se_dev_attrib, da_group);
1774         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1775
1776         return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
1777 }
1778
1779 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
1780                                        size_t count)
1781 {
1782         struct se_dev_attrib *da = container_of(to_config_group(item),
1783                                         struct se_dev_attrib, da_group);
1784         struct tcmu_dev *udev = container_of(da->da_dev,
1785                                         struct tcmu_dev, se_dev);
1786         u32 val;
1787         int ret;
1788
1789         if (da->da_dev->export_count) {
1790                 pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
1791                 return -EINVAL;
1792         }
1793
1794         ret = kstrtou32(page, 0, &val);
1795         if (ret < 0)
1796                 return ret;
1797
1798         udev->cmd_time_out = val * MSEC_PER_SEC;
1799         return count;
1800 }
1801 CONFIGFS_ATTR(tcmu_, cmd_time_out);
1802
1803 static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
1804 {
1805         struct se_dev_attrib *da = container_of(to_config_group(item),
1806                                                 struct se_dev_attrib, da_group);
1807         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1808
1809         return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
1810 }
1811
1812 static ssize_t tcmu_dev_config_store(struct config_item *item, const char *page,
1813                                      size_t count)
1814 {
1815         struct se_dev_attrib *da = container_of(to_config_group(item),
1816                                                 struct se_dev_attrib, da_group);
1817         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1818         int ret, len;
1819
1820         len = strlen(page);
1821         if (!len || len > TCMU_CONFIG_LEN - 1)
1822                 return -EINVAL;
1823
1824         /* Check if device has been configured before */
1825         if (tcmu_dev_configured(udev)) {
1826                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1827                                          TCMU_ATTR_DEV_CFG, page);
1828                 if (ret) {
1829                         pr_err("Unable to reconfigure device\n");
1830                         return ret;
1831                 }
1832                 strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
1833
1834                 ret = tcmu_update_uio_info(udev);
1835                 if (ret)
1836                         return ret;
1837                 return count;
1838         }
1839         strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
1840
1841         return count;
1842 }
1843 CONFIGFS_ATTR(tcmu_, dev_config);
1844
1845 static ssize_t tcmu_dev_size_show(struct config_item *item, char *page)
1846 {
1847         struct se_dev_attrib *da = container_of(to_config_group(item),
1848                                                 struct se_dev_attrib, da_group);
1849         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1850
1851         return snprintf(page, PAGE_SIZE, "%zu\n", udev->dev_size);
1852 }
1853
1854 static ssize_t tcmu_dev_size_store(struct config_item *item, const char *page,
1855                                    size_t count)
1856 {
1857         struct se_dev_attrib *da = container_of(to_config_group(item),
1858                                                 struct se_dev_attrib, da_group);
1859         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1860         u64 val;
1861         int ret;
1862
1863         ret = kstrtou64(page, 0, &val);
1864         if (ret < 0)
1865                 return ret;
1866
1867         /* Check if device has been configured before */
1868         if (tcmu_dev_configured(udev)) {
1869                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1870                                          TCMU_ATTR_DEV_SIZE, &val);
1871                 if (ret) {
1872                         pr_err("Unable to reconfigure device\n");
1873                         return ret;
1874                 }
1875         }
1876         udev->dev_size = val;
1877         return count;
1878 }
1879 CONFIGFS_ATTR(tcmu_, dev_size);
1880
1881 static ssize_t tcmu_nl_reply_supported_show(struct config_item *item,
1882                 char *page)
1883 {
1884         struct se_dev_attrib *da = container_of(to_config_group(item),
1885                                                 struct se_dev_attrib, da_group);
1886         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1887
1888         return snprintf(page, PAGE_SIZE, "%d\n", udev->nl_reply_supported);
1889 }
1890
1891 static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
1892                 const char *page, size_t count)
1893 {
1894         struct se_dev_attrib *da = container_of(to_config_group(item),
1895                                                 struct se_dev_attrib, da_group);
1896         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1897         s8 val;
1898         int ret;
1899
1900         ret = kstrtos8(page, 0, &val);
1901         if (ret < 0)
1902                 return ret;
1903
1904         udev->nl_reply_supported = val;
1905         return count;
1906 }
1907 CONFIGFS_ATTR(tcmu_, nl_reply_supported);
1908
1909 static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
1910                                              char *page)
1911 {
1912         struct se_dev_attrib *da = container_of(to_config_group(item),
1913                                         struct se_dev_attrib, da_group);
1914
1915         return snprintf(page, PAGE_SIZE, "%i\n", da->emulate_write_cache);
1916 }
1917
1918 static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
1919                                               const char *page, size_t count)
1920 {
1921         struct se_dev_attrib *da = container_of(to_config_group(item),
1922                                         struct se_dev_attrib, da_group);
1923         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
1924         u8 val;
1925         int ret;
1926
1927         ret = kstrtou8(page, 0, &val);
1928         if (ret < 0)
1929                 return ret;
1930
1931         /* Check if device has been configured before */
1932         if (tcmu_dev_configured(udev)) {
1933                 ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
1934                                          TCMU_ATTR_WRITECACHE, &val);
1935                 if (ret) {
1936                         pr_err("Unable to reconfigure device\n");
1937                         return ret;
1938                 }
1939         }
1940
1941         da->emulate_write_cache = val;
1942         return count;
1943 }
1944 CONFIGFS_ATTR(tcmu_, emulate_write_cache);
1945
1946 static struct configfs_attribute *tcmu_attrib_attrs[] = {
1947         &tcmu_attr_cmd_time_out,
1948         &tcmu_attr_dev_config,
1949         &tcmu_attr_dev_size,
1950         &tcmu_attr_emulate_write_cache,
1951         &tcmu_attr_nl_reply_supported,
1952         NULL,
1953 };
1954
1955 static struct configfs_attribute **tcmu_attrs;
1956
1957 static struct target_backend_ops tcmu_ops = {
1958         .name                   = "user",
1959         .owner                  = THIS_MODULE,
1960         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1961         .attach_hba             = tcmu_attach_hba,
1962         .detach_hba             = tcmu_detach_hba,
1963         .alloc_device           = tcmu_alloc_device,
1964         .configure_device       = tcmu_configure_device,
1965         .destroy_device         = tcmu_destroy_device,
1966         .free_device            = tcmu_free_device,
1967         .parse_cdb              = tcmu_parse_cdb,
1968         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1969         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1970         .get_device_type        = sbc_get_device_type,
1971         .get_blocks             = tcmu_get_blocks,
1972         .tb_dev_attrib_attrs    = NULL,
1973 };
1974
1975 static int unmap_thread_fn(void *data)
1976 {
1977         struct tcmu_dev *udev;
1978         loff_t off;
1979         uint32_t start, end, block;
1980         struct page *page;
1981         int i;
1982
1983         while (!kthread_should_stop()) {
1984                 DEFINE_WAIT(__wait);
1985
1986                 prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
1987                 schedule();
1988                 finish_wait(&unmap_wait, &__wait);
1989
1990                 if (kthread_should_stop())
1991                         break;
1992
1993                 mutex_lock(&root_udev_mutex);
1994                 list_for_each_entry(udev, &root_udev, node) {
1995                         mutex_lock(&udev->cmdr_lock);
1996
1997                         /* Try to complete the finished commands first */
1998                         tcmu_handle_completions(udev);
1999
2000                         /* Skip the udevs waiting the global pool or in idle */
2001                         if (udev->waiting_global || !udev->dbi_thresh) {
2002                                 mutex_unlock(&udev->cmdr_lock);
2003                                 continue;
2004                         }
2005
2006                         end = udev->dbi_max + 1;
2007                         block = find_last_bit(udev->data_bitmap, end);
2008                         if (block == udev->dbi_max) {
2009                                 /*
2010                                  * The last bit is dbi_max, so there is
2011                                  * no need to shrink any blocks.
2012                                  */
2013                                 mutex_unlock(&udev->cmdr_lock);
2014                                 continue;
2015                         } else if (block == end) {
2016                                 /* The current udev will goto idle state */
2017                                 udev->dbi_thresh = start = 0;
2018                                 udev->dbi_max = 0;
2019                         } else {
2020                                 udev->dbi_thresh = start = block + 1;
2021                                 udev->dbi_max = block;
2022                         }
2023
2024                         /* Here will truncate the data area from off */
2025                         off = udev->data_off + start * DATA_BLOCK_SIZE;
2026                         unmap_mapping_range(udev->inode->i_mapping, off, 0, 1);
2027
2028                         /* Release the block pages */
2029                         for (i = start; i < end; i++) {
2030                                 page = radix_tree_delete(&udev->data_blocks, i);
2031                                 if (page) {
2032                                         __free_page(page);
2033                                         atomic_dec(&global_db_count);
2034                                 }
2035                         }
2036                         mutex_unlock(&udev->cmdr_lock);
2037                 }
2038
2039                 /*
2040                  * Try to wake up the udevs who are waiting
2041                  * for the global data pool.
2042                  */
2043                 list_for_each_entry(udev, &root_udev, node) {
2044                         if (udev->waiting_global)
2045                                 wake_up(&udev->wait_cmdr);
2046                 }
2047                 mutex_unlock(&root_udev_mutex);
2048         }
2049
2050         return 0;
2051 }
2052
2053 static int __init tcmu_module_init(void)
2054 {
2055         int ret, i, k, len = 0;
2056
2057         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
2058
2059         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
2060                                 sizeof(struct tcmu_cmd),
2061                                 __alignof__(struct tcmu_cmd),
2062                                 0, NULL);
2063         if (!tcmu_cmd_cache)
2064                 return -ENOMEM;
2065
2066         tcmu_root_device = root_device_register("tcm_user");
2067         if (IS_ERR(tcmu_root_device)) {
2068                 ret = PTR_ERR(tcmu_root_device);
2069                 goto out_free_cache;
2070         }
2071
2072         ret = genl_register_family(&tcmu_genl_family);
2073         if (ret < 0) {
2074                 goto out_unreg_device;
2075         }
2076
2077         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2078                 len += sizeof(struct configfs_attribute *);
2079         }
2080         for (i = 0; tcmu_attrib_attrs[i] != NULL; i++) {
2081                 len += sizeof(struct configfs_attribute *);
2082         }
2083         len += sizeof(struct configfs_attribute *);
2084
2085         tcmu_attrs = kzalloc(len, GFP_KERNEL);
2086         if (!tcmu_attrs) {
2087                 ret = -ENOMEM;
2088                 goto out_unreg_genl;
2089         }
2090
2091         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2092                 tcmu_attrs[i] = passthrough_attrib_attrs[i];
2093         }
2094         for (k = 0; tcmu_attrib_attrs[k] != NULL; k++) {
2095                 tcmu_attrs[i] = tcmu_attrib_attrs[k];
2096                 i++;
2097         }
2098         tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
2099
2100         ret = transport_backend_register(&tcmu_ops);
2101         if (ret)
2102                 goto out_attrs;
2103
2104         init_waitqueue_head(&unmap_wait);
2105         unmap_thread = kthread_run(unmap_thread_fn, NULL, "tcmu_unmap");
2106         if (IS_ERR(unmap_thread)) {
2107                 ret = PTR_ERR(unmap_thread);
2108                 goto out_unreg_transport;
2109         }
2110
2111         return 0;
2112
2113 out_unreg_transport:
2114         target_backend_unregister(&tcmu_ops);
2115 out_attrs:
2116         kfree(tcmu_attrs);
2117 out_unreg_genl:
2118         genl_unregister_family(&tcmu_genl_family);
2119 out_unreg_device:
2120         root_device_unregister(tcmu_root_device);
2121 out_free_cache:
2122         kmem_cache_destroy(tcmu_cmd_cache);
2123
2124         return ret;
2125 }
2126
2127 static void __exit tcmu_module_exit(void)
2128 {
2129         kthread_stop(unmap_thread);
2130         target_backend_unregister(&tcmu_ops);
2131         kfree(tcmu_attrs);
2132         genl_unregister_family(&tcmu_genl_family);
2133         root_device_unregister(tcmu_root_device);
2134         kmem_cache_destroy(tcmu_cmd_cache);
2135 }
2136
2137 MODULE_DESCRIPTION("TCM USER subsystem plugin");
2138 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
2139 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
2140 MODULE_LICENSE("GPL");
2141
2142 module_init(tcmu_module_init);
2143 module_exit(tcmu_module_exit);