1 /* 2 * Copyright (C) 2013 Shaohua Li <shli@kernel.org> 3 * Copyright (C) 2014 Red Hat, Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms and conditions of the GNU General Public License, 7 * version 2, as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12 * more details. 13 * 14 * You should have received a copy of the GNU General Public License along with 15 * this program; if not, write to the Free Software Foundation, Inc., 16 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 17 */ 18 19 #include <linux/spinlock.h> 20 #include <linux/module.h> 21 #include <linux/idr.h> 22 #include <linux/timer.h> 23 #include <linux/parser.h> 24 #include <scsi/scsi.h> 25 #include <scsi/scsi_host.h> 26 #include <linux/uio_driver.h> 27 #include <net/genetlink.h> 28 #include <target/target_core_base.h> 29 #include <target/target_core_fabric.h> 30 #include <target/target_core_backend.h> 31 #include <target/target_core_backend_configfs.h> 32 33 #include <linux/target_core_user.h> 34 35 /* 36 * Define a shared-memory interface for LIO to pass SCSI commands and 37 * data to userspace for processing. This is to allow backends that 38 * are too complex for in-kernel support to be possible. 39 * 40 * It uses the UIO framework to do a lot of the device-creation and 41 * introspection work for us. 42 * 43 * See the .h file for how the ring is laid out. Note that while the 44 * command ring is defined, the particulars of the data area are 45 * not. Offset values in the command entry point to other locations 46 * internal to the mmap()ed area. There is separate space outside the 47 * command ring for data buffers. This leaves maximum flexibility for 48 * moving buffer allocations, or even page flipping or other 49 * allocation techniques, without altering the command ring layout. 50 * 51 * SECURITY: 52 * The user process must be assumed to be malicious. There's no way to 53 * prevent it breaking the command ring protocol if it wants, but in 54 * order to prevent other issues we must only ever read *data* from 55 * the shared memory area, not offsets or sizes. This applies to 56 * command ring entries as well as the mailbox. Extra code needed for 57 * this may have a 'UAM' comment. 58 */ 59 60 61 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC) 62 63 #define CMDR_SIZE (16 * 4096) 64 #define DATA_SIZE (257 * 4096) 65 66 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE) 67 68 static struct device *tcmu_root_device; 69 70 struct tcmu_hba { 71 u32 host_id; 72 }; 73 74 /* User wants all cmds or just some */ 75 enum passthru_level { 76 TCMU_PASS_ALL = 0, 77 TCMU_PASS_IO, 78 TCMU_PASS_INVALID, 79 }; 80 81 #define TCMU_CONFIG_LEN 256 82 83 struct tcmu_dev { 84 struct se_device se_dev; 85 86 char *name; 87 struct se_hba *hba; 88 89 #define TCMU_DEV_BIT_OPEN 0 90 #define TCMU_DEV_BIT_BROKEN 1 91 unsigned long flags; 92 enum passthru_level pass_level; 93 94 struct uio_info uio_info; 95 96 struct tcmu_mailbox *mb_addr; 97 size_t dev_size; 98 u32 cmdr_size; 99 u32 cmdr_last_cleaned; 100 /* Offset of data ring from start of mb */ 101 size_t data_off; 102 size_t data_size; 103 /* Ring head + tail values. */ 104 /* Must add data_off and mb_addr to get the address */ 105 size_t data_head; 106 size_t data_tail; 107 108 wait_queue_head_t wait_cmdr; 109 /* TODO should this be a mutex? */ 110 spinlock_t cmdr_lock; 111 112 struct idr commands; 113 spinlock_t commands_lock; 114 115 struct timer_list timeout; 116 117 char dev_config[TCMU_CONFIG_LEN]; 118 }; 119 120 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev) 121 122 #define CMDR_OFF sizeof(struct tcmu_mailbox) 123 124 struct tcmu_cmd { 125 struct se_cmd *se_cmd; 126 struct tcmu_dev *tcmu_dev; 127 128 uint16_t cmd_id; 129 130 /* Can't use se_cmd->data_length when cleaning up expired cmds, because if 131 cmd has been completed then accessing se_cmd is off limits */ 132 size_t data_length; 133 134 unsigned long deadline; 135 136 #define TCMU_CMD_BIT_EXPIRED 0 137 unsigned long flags; 138 }; 139 140 static struct kmem_cache *tcmu_cmd_cache; 141 142 /* multicast group */ 143 enum tcmu_multicast_groups { 144 TCMU_MCGRP_CONFIG, 145 }; 146 147 static const struct genl_multicast_group tcmu_mcgrps[] = { 148 [TCMU_MCGRP_CONFIG] = { .name = "config", }, 149 }; 150 151 /* Our generic netlink family */ 152 static struct genl_family tcmu_genl_family = { 153 .id = GENL_ID_GENERATE, 154 .hdrsize = 0, 155 .name = "TCM-USER", 156 .version = 1, 157 .maxattr = TCMU_ATTR_MAX, 158 .mcgrps = tcmu_mcgrps, 159 .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps), 160 }; 161 162 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) 163 { 164 struct se_device *se_dev = se_cmd->se_dev; 165 struct tcmu_dev *udev = TCMU_DEV(se_dev); 166 struct tcmu_cmd *tcmu_cmd; 167 int cmd_id; 168 169 tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL); 170 if (!tcmu_cmd) 171 return NULL; 172 173 tcmu_cmd->se_cmd = se_cmd; 174 tcmu_cmd->tcmu_dev = udev; 175 tcmu_cmd->data_length = se_cmd->data_length; 176 177 tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT); 178 179 idr_preload(GFP_KERNEL); 180 spin_lock_irq(&udev->commands_lock); 181 cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0, 182 USHRT_MAX, GFP_NOWAIT); 183 spin_unlock_irq(&udev->commands_lock); 184 idr_preload_end(); 185 186 if (cmd_id < 0) { 187 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 188 return NULL; 189 } 190 tcmu_cmd->cmd_id = cmd_id; 191 192 return tcmu_cmd; 193 } 194 195 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size) 196 { 197 unsigned long offset = (unsigned long) vaddr & ~PAGE_MASK; 198 199 size = round_up(size+offset, PAGE_SIZE); 200 vaddr -= offset; 201 202 while (size) { 203 flush_dcache_page(virt_to_page(vaddr)); 204 size -= PAGE_SIZE; 205 } 206 } 207 208 /* 209 * Some ring helper functions. We don't assume size is a power of 2 so 210 * we can't use circ_buf.h. 211 */ 212 static inline size_t spc_used(size_t head, size_t tail, size_t size) 213 { 214 int diff = head - tail; 215 216 if (diff >= 0) 217 return diff; 218 else 219 return size + diff; 220 } 221 222 static inline size_t spc_free(size_t head, size_t tail, size_t size) 223 { 224 /* Keep 1 byte unused or we can't tell full from empty */ 225 return (size - spc_used(head, tail, size) - 1); 226 } 227 228 static inline size_t head_to_end(size_t head, size_t size) 229 { 230 return size - head; 231 } 232 233 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size) 234 235 /* 236 * We can't queue a command until we have space available on the cmd ring *and* space 237 * space avail on the data ring. 238 * 239 * Called with ring lock held. 240 */ 241 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed) 242 { 243 struct tcmu_mailbox *mb = udev->mb_addr; 244 size_t space; 245 u32 cmd_head; 246 size_t cmd_needed; 247 248 tcmu_flush_dcache_range(mb, sizeof(*mb)); 249 250 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 251 252 /* 253 * If cmd end-of-ring space is too small then we need space for a NOP plus 254 * original cmd - cmds are internally contiguous. 255 */ 256 if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size) 257 cmd_needed = cmd_size; 258 else 259 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size); 260 261 space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size); 262 if (space < cmd_needed) { 263 pr_debug("no cmd space: %u %u %u\n", cmd_head, 264 udev->cmdr_last_cleaned, udev->cmdr_size); 265 return false; 266 } 267 268 space = spc_free(udev->data_head, udev->data_tail, udev->data_size); 269 if (space < data_needed) { 270 pr_debug("no data space: %zu %zu %zu\n", udev->data_head, 271 udev->data_tail, udev->data_size); 272 return false; 273 } 274 275 return true; 276 } 277 278 static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 279 { 280 struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; 281 struct se_cmd *se_cmd = tcmu_cmd->se_cmd; 282 size_t base_command_size, command_size; 283 struct tcmu_mailbox *mb; 284 struct tcmu_cmd_entry *entry; 285 int i; 286 struct scatterlist *sg; 287 struct iovec *iov; 288 int iov_cnt = 0; 289 uint32_t cmd_head; 290 uint64_t cdb_off; 291 292 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) 293 return -EINVAL; 294 295 /* 296 * Must be a certain minimum size for response sense info, but 297 * also may be larger if the iov array is large. 298 * 299 * iovs = sgl_nents+1, for end-of-ring case, plus another 1 300 * b/c size == offsetof one-past-element. 301 */ 302 base_command_size = max(offsetof(struct tcmu_cmd_entry, 303 req.iov[se_cmd->t_data_nents + 2]), 304 sizeof(struct tcmu_cmd_entry)); 305 command_size = base_command_size 306 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE); 307 308 WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1)); 309 310 spin_lock_irq(&udev->cmdr_lock); 311 312 mb = udev->mb_addr; 313 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 314 if ((command_size > (udev->cmdr_size / 2)) 315 || tcmu_cmd->data_length > (udev->data_size - 1)) 316 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu " 317 "cmd/data ring buffers\n", command_size, tcmu_cmd->data_length, 318 udev->cmdr_size, udev->data_size); 319 320 while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) { 321 int ret; 322 DEFINE_WAIT(__wait); 323 324 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); 325 326 pr_debug("sleeping for ring space\n"); 327 spin_unlock_irq(&udev->cmdr_lock); 328 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT)); 329 finish_wait(&udev->wait_cmdr, &__wait); 330 if (!ret) { 331 pr_warn("tcmu: command timed out\n"); 332 return -ETIMEDOUT; 333 } 334 335 spin_lock_irq(&udev->cmdr_lock); 336 337 /* We dropped cmdr_lock, cmd_head is stale */ 338 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 339 } 340 341 /* Insert a PAD if end-of-ring space is too small */ 342 if (head_to_end(cmd_head, udev->cmdr_size) < command_size) { 343 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size); 344 345 entry = (void *) mb + CMDR_OFF + cmd_head; 346 tcmu_flush_dcache_range(entry, sizeof(*entry)); 347 tcmu_hdr_set_op(&entry->hdr, TCMU_OP_PAD); 348 tcmu_hdr_set_len(&entry->hdr, pad_size); 349 350 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size); 351 352 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 353 WARN_ON(cmd_head != 0); 354 } 355 356 entry = (void *) mb + CMDR_OFF + cmd_head; 357 tcmu_flush_dcache_range(entry, sizeof(*entry)); 358 tcmu_hdr_set_op(&entry->hdr, TCMU_OP_CMD); 359 tcmu_hdr_set_len(&entry->hdr, command_size); 360 entry->cmd_id = tcmu_cmd->cmd_id; 361 362 /* 363 * Fix up iovecs, and handle if allocation in data ring wrapped. 364 */ 365 iov = &entry->req.iov[0]; 366 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 367 size_t copy_bytes = min((size_t)sg->length, 368 head_to_end(udev->data_head, udev->data_size)); 369 void *from = kmap_atomic(sg_page(sg)) + sg->offset; 370 void *to = (void *) mb + udev->data_off + udev->data_head; 371 372 if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) { 373 memcpy(to, from, copy_bytes); 374 tcmu_flush_dcache_range(to, copy_bytes); 375 } 376 377 /* Even iov_base is relative to mb_addr */ 378 iov->iov_len = copy_bytes; 379 iov->iov_base = (void *) udev->data_off + udev->data_head; 380 iov_cnt++; 381 iov++; 382 383 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 384 385 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */ 386 if (sg->length != copy_bytes) { 387 from += copy_bytes; 388 copy_bytes = sg->length - copy_bytes; 389 390 iov->iov_len = copy_bytes; 391 iov->iov_base = (void *) udev->data_off + udev->data_head; 392 393 if (se_cmd->data_direction == DMA_TO_DEVICE) { 394 to = (void *) mb + udev->data_off + udev->data_head; 395 memcpy(to, from, copy_bytes); 396 tcmu_flush_dcache_range(to, copy_bytes); 397 } 398 399 iov_cnt++; 400 iov++; 401 402 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 403 } 404 405 kunmap_atomic(from); 406 } 407 entry->req.iov_cnt = iov_cnt; 408 409 /* All offsets relative to mb_addr, not start of entry! */ 410 cdb_off = CMDR_OFF + cmd_head + base_command_size; 411 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb)); 412 entry->req.cdb_off = cdb_off; 413 tcmu_flush_dcache_range(entry, sizeof(*entry)); 414 415 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); 416 tcmu_flush_dcache_range(mb, sizeof(*mb)); 417 418 spin_unlock_irq(&udev->cmdr_lock); 419 420 /* TODO: only if FLUSH and FUA? */ 421 uio_event_notify(&udev->uio_info); 422 423 mod_timer(&udev->timeout, 424 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT))); 425 426 return 0; 427 } 428 429 static int tcmu_queue_cmd(struct se_cmd *se_cmd) 430 { 431 struct se_device *se_dev = se_cmd->se_dev; 432 struct tcmu_dev *udev = TCMU_DEV(se_dev); 433 struct tcmu_cmd *tcmu_cmd; 434 int ret; 435 436 tcmu_cmd = tcmu_alloc_cmd(se_cmd); 437 if (!tcmu_cmd) 438 return -ENOMEM; 439 440 ret = tcmu_queue_cmd_ring(tcmu_cmd); 441 if (ret < 0) { 442 pr_err("TCMU: Could not queue command\n"); 443 spin_lock_irq(&udev->commands_lock); 444 idr_remove(&udev->commands, tcmu_cmd->cmd_id); 445 spin_unlock_irq(&udev->commands_lock); 446 447 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 448 } 449 450 return ret; 451 } 452 453 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry) 454 { 455 struct se_cmd *se_cmd = cmd->se_cmd; 456 struct tcmu_dev *udev = cmd->tcmu_dev; 457 458 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 459 /* cmd has been completed already from timeout, just reclaim data 460 ring space */ 461 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 462 return; 463 } 464 465 if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) { 466 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, 467 se_cmd->scsi_sense_length); 468 469 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 470 } 471 else if (se_cmd->data_direction == DMA_FROM_DEVICE) { 472 struct scatterlist *sg; 473 int i; 474 475 /* It'd be easier to look at entry's iovec again, but UAM */ 476 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 477 size_t copy_bytes; 478 void *to; 479 void *from; 480 481 copy_bytes = min((size_t)sg->length, 482 head_to_end(udev->data_tail, udev->data_size)); 483 484 to = kmap_atomic(sg_page(sg)) + sg->offset; 485 WARN_ON(sg->length + sg->offset > PAGE_SIZE); 486 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 487 tcmu_flush_dcache_range(from, copy_bytes); 488 memcpy(to, from, copy_bytes); 489 490 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 491 492 /* Uh oh, wrapped the data buffer for this sg's data */ 493 if (sg->length != copy_bytes) { 494 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 495 WARN_ON(udev->data_tail); 496 to += copy_bytes; 497 copy_bytes = sg->length - copy_bytes; 498 tcmu_flush_dcache_range(from, copy_bytes); 499 memcpy(to, from, copy_bytes); 500 501 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 502 } 503 504 kunmap_atomic(to); 505 } 506 507 } else if (se_cmd->data_direction == DMA_TO_DEVICE) { 508 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 509 } else { 510 pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction); 511 } 512 513 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); 514 cmd->se_cmd = NULL; 515 516 kmem_cache_free(tcmu_cmd_cache, cmd); 517 } 518 519 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) 520 { 521 struct tcmu_mailbox *mb; 522 LIST_HEAD(cpl_cmds); 523 unsigned long flags; 524 int handled = 0; 525 526 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { 527 pr_err("ring broken, not handling completions\n"); 528 return 0; 529 } 530 531 spin_lock_irqsave(&udev->cmdr_lock, flags); 532 533 mb = udev->mb_addr; 534 tcmu_flush_dcache_range(mb, sizeof(*mb)); 535 536 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) { 537 538 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; 539 struct tcmu_cmd *cmd; 540 541 tcmu_flush_dcache_range(entry, sizeof(*entry)); 542 543 if (tcmu_hdr_get_op(&entry->hdr) == TCMU_OP_PAD) { 544 UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); 545 continue; 546 } 547 WARN_ON(tcmu_hdr_get_op(&entry->hdr) != TCMU_OP_CMD); 548 549 spin_lock(&udev->commands_lock); 550 cmd = idr_find(&udev->commands, entry->cmd_id); 551 if (cmd) 552 idr_remove(&udev->commands, cmd->cmd_id); 553 spin_unlock(&udev->commands_lock); 554 555 if (!cmd) { 556 pr_err("cmd_id not found, ring is broken\n"); 557 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); 558 break; 559 } 560 561 tcmu_handle_completion(cmd, entry); 562 563 UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); 564 565 handled++; 566 } 567 568 if (mb->cmd_tail == mb->cmd_head) 569 del_timer(&udev->timeout); /* no more pending cmds */ 570 571 spin_unlock_irqrestore(&udev->cmdr_lock, flags); 572 573 wake_up(&udev->wait_cmdr); 574 575 return handled; 576 } 577 578 static int tcmu_check_expired_cmd(int id, void *p, void *data) 579 { 580 struct tcmu_cmd *cmd = p; 581 582 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 583 return 0; 584 585 if (!time_after(cmd->deadline, jiffies)) 586 return 0; 587 588 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags); 589 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); 590 cmd->se_cmd = NULL; 591 592 kmem_cache_free(tcmu_cmd_cache, cmd); 593 594 return 0; 595 } 596 597 static void tcmu_device_timedout(unsigned long data) 598 { 599 struct tcmu_dev *udev = (struct tcmu_dev *)data; 600 unsigned long flags; 601 int handled; 602 603 handled = tcmu_handle_completions(udev); 604 605 pr_warn("%d completions handled from timeout\n", handled); 606 607 spin_lock_irqsave(&udev->commands_lock, flags); 608 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); 609 spin_unlock_irqrestore(&udev->commands_lock, flags); 610 611 /* 612 * We don't need to wakeup threads on wait_cmdr since they have their 613 * own timeout. 614 */ 615 } 616 617 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) 618 { 619 struct tcmu_hba *tcmu_hba; 620 621 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL); 622 if (!tcmu_hba) 623 return -ENOMEM; 624 625 tcmu_hba->host_id = host_id; 626 hba->hba_ptr = tcmu_hba; 627 628 return 0; 629 } 630 631 static void tcmu_detach_hba(struct se_hba *hba) 632 { 633 kfree(hba->hba_ptr); 634 hba->hba_ptr = NULL; 635 } 636 637 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 638 { 639 struct tcmu_dev *udev; 640 641 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL); 642 if (!udev) 643 return NULL; 644 645 udev->name = kstrdup(name, GFP_KERNEL); 646 if (!udev->name) { 647 kfree(udev); 648 return NULL; 649 } 650 651 udev->hba = hba; 652 653 init_waitqueue_head(&udev->wait_cmdr); 654 spin_lock_init(&udev->cmdr_lock); 655 656 idr_init(&udev->commands); 657 spin_lock_init(&udev->commands_lock); 658 659 setup_timer(&udev->timeout, tcmu_device_timedout, 660 (unsigned long)udev); 661 662 udev->pass_level = TCMU_PASS_ALL; 663 664 return &udev->se_dev; 665 } 666 667 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) 668 { 669 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info); 670 671 tcmu_handle_completions(tcmu_dev); 672 673 return 0; 674 } 675 676 /* 677 * mmap code from uio.c. Copied here because we want to hook mmap() 678 * and this stuff must come along. 679 */ 680 static int tcmu_find_mem_index(struct vm_area_struct *vma) 681 { 682 struct tcmu_dev *udev = vma->vm_private_data; 683 struct uio_info *info = &udev->uio_info; 684 685 if (vma->vm_pgoff < MAX_UIO_MAPS) { 686 if (info->mem[vma->vm_pgoff].size == 0) 687 return -1; 688 return (int)vma->vm_pgoff; 689 } 690 return -1; 691 } 692 693 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 694 { 695 struct tcmu_dev *udev = vma->vm_private_data; 696 struct uio_info *info = &udev->uio_info; 697 struct page *page; 698 unsigned long offset; 699 void *addr; 700 701 int mi = tcmu_find_mem_index(vma); 702 if (mi < 0) 703 return VM_FAULT_SIGBUS; 704 705 /* 706 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 707 * to use mem[N]. 708 */ 709 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 710 711 addr = (void *)(unsigned long)info->mem[mi].addr + offset; 712 if (info->mem[mi].memtype == UIO_MEM_LOGICAL) 713 page = virt_to_page(addr); 714 else 715 page = vmalloc_to_page(addr); 716 get_page(page); 717 vmf->page = page; 718 return 0; 719 } 720 721 static const struct vm_operations_struct tcmu_vm_ops = { 722 .fault = tcmu_vma_fault, 723 }; 724 725 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma) 726 { 727 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 728 729 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 730 vma->vm_ops = &tcmu_vm_ops; 731 732 vma->vm_private_data = udev; 733 734 /* Ensure the mmap is exactly the right size */ 735 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT)) 736 return -EINVAL; 737 738 return 0; 739 } 740 741 static int tcmu_open(struct uio_info *info, struct inode *inode) 742 { 743 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 744 745 /* O_EXCL not supported for char devs, so fake it? */ 746 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags)) 747 return -EBUSY; 748 749 pr_debug("open\n"); 750 751 return 0; 752 } 753 754 static int tcmu_release(struct uio_info *info, struct inode *inode) 755 { 756 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 757 758 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags); 759 760 pr_debug("close\n"); 761 762 return 0; 763 } 764 765 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) 766 { 767 struct sk_buff *skb; 768 void *msg_header; 769 int ret = -ENOMEM; 770 771 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); 772 if (!skb) 773 return ret; 774 775 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); 776 if (!msg_header) 777 goto free_skb; 778 779 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); 780 if (ret < 0) 781 goto free_skb; 782 783 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); 784 if (ret < 0) 785 goto free_skb; 786 787 genlmsg_end(skb, msg_header); 788 789 ret = genlmsg_multicast(&tcmu_genl_family, skb, 0, 790 TCMU_MCGRP_CONFIG, GFP_KERNEL); 791 792 /* We don't care if no one is listening */ 793 if (ret == -ESRCH) 794 ret = 0; 795 796 return ret; 797 free_skb: 798 nlmsg_free(skb); 799 return ret; 800 } 801 802 static int tcmu_configure_device(struct se_device *dev) 803 { 804 struct tcmu_dev *udev = TCMU_DEV(dev); 805 struct tcmu_hba *hba = udev->hba->hba_ptr; 806 struct uio_info *info; 807 struct tcmu_mailbox *mb; 808 size_t size; 809 size_t used; 810 int ret = 0; 811 char *str; 812 813 info = &udev->uio_info; 814 815 size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name, 816 udev->dev_config); 817 size += 1; /* for \0 */ 818 str = kmalloc(size, GFP_KERNEL); 819 if (!str) 820 return -ENOMEM; 821 822 used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name); 823 824 if (udev->dev_config[0]) 825 snprintf(str + used, size - used, "/%s", udev->dev_config); 826 827 info->name = str; 828 829 udev->mb_addr = vzalloc(TCMU_RING_SIZE); 830 if (!udev->mb_addr) { 831 ret = -ENOMEM; 832 goto err_vzalloc; 833 } 834 835 /* mailbox fits in first part of CMDR space */ 836 udev->cmdr_size = CMDR_SIZE - CMDR_OFF; 837 udev->data_off = CMDR_SIZE; 838 udev->data_size = TCMU_RING_SIZE - CMDR_SIZE; 839 840 mb = udev->mb_addr; 841 mb->version = 1; 842 mb->cmdr_off = CMDR_OFF; 843 mb->cmdr_size = udev->cmdr_size; 844 845 WARN_ON(!PAGE_ALIGNED(udev->data_off)); 846 WARN_ON(udev->data_size % PAGE_SIZE); 847 848 info->version = "1"; 849 850 info->mem[0].name = "tcm-user command & data buffer"; 851 info->mem[0].addr = (phys_addr_t) udev->mb_addr; 852 info->mem[0].size = TCMU_RING_SIZE; 853 info->mem[0].memtype = UIO_MEM_VIRTUAL; 854 855 info->irqcontrol = tcmu_irqcontrol; 856 info->irq = UIO_IRQ_CUSTOM; 857 858 info->mmap = tcmu_mmap; 859 info->open = tcmu_open; 860 info->release = tcmu_release; 861 862 ret = uio_register_device(tcmu_root_device, info); 863 if (ret) 864 goto err_register; 865 866 /* Other attributes can be configured in userspace */ 867 dev->dev_attrib.hw_block_size = 512; 868 dev->dev_attrib.hw_max_sectors = 128; 869 dev->dev_attrib.hw_queue_depth = 128; 870 871 ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name, 872 udev->uio_info.uio_dev->minor); 873 if (ret) 874 goto err_netlink; 875 876 return 0; 877 878 err_netlink: 879 uio_unregister_device(&udev->uio_info); 880 err_register: 881 vfree(udev->mb_addr); 882 err_vzalloc: 883 kfree(info->name); 884 885 return ret; 886 } 887 888 static int tcmu_check_pending_cmd(int id, void *p, void *data) 889 { 890 struct tcmu_cmd *cmd = p; 891 892 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 893 return 0; 894 return -EINVAL; 895 } 896 897 static void tcmu_free_device(struct se_device *dev) 898 { 899 struct tcmu_dev *udev = TCMU_DEV(dev); 900 int i; 901 902 del_timer_sync(&udev->timeout); 903 904 vfree(udev->mb_addr); 905 906 /* Upper layer should drain all requests before calling this */ 907 spin_lock_irq(&udev->commands_lock); 908 i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL); 909 idr_destroy(&udev->commands); 910 spin_unlock_irq(&udev->commands_lock); 911 WARN_ON(i); 912 913 /* Device was configured */ 914 if (udev->uio_info.uio_dev) { 915 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name, 916 udev->uio_info.uio_dev->minor); 917 918 uio_unregister_device(&udev->uio_info); 919 kfree(udev->uio_info.name); 920 kfree(udev->name); 921 } 922 923 kfree(udev); 924 } 925 926 enum { 927 Opt_dev_config, Opt_dev_size, Opt_err, Opt_pass_level, 928 }; 929 930 static match_table_t tokens = { 931 {Opt_dev_config, "dev_config=%s"}, 932 {Opt_dev_size, "dev_size=%u"}, 933 {Opt_pass_level, "pass_level=%u"}, 934 {Opt_err, NULL} 935 }; 936 937 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 938 const char *page, ssize_t count) 939 { 940 struct tcmu_dev *udev = TCMU_DEV(dev); 941 char *orig, *ptr, *opts, *arg_p; 942 substring_t args[MAX_OPT_ARGS]; 943 int ret = 0, token; 944 int arg; 945 946 opts = kstrdup(page, GFP_KERNEL); 947 if (!opts) 948 return -ENOMEM; 949 950 orig = opts; 951 952 while ((ptr = strsep(&opts, ",\n")) != NULL) { 953 if (!*ptr) 954 continue; 955 956 token = match_token(ptr, tokens, args); 957 switch (token) { 958 case Opt_dev_config: 959 if (match_strlcpy(udev->dev_config, &args[0], 960 TCMU_CONFIG_LEN) == 0) { 961 ret = -EINVAL; 962 break; 963 } 964 pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config); 965 break; 966 case Opt_dev_size: 967 arg_p = match_strdup(&args[0]); 968 if (!arg_p) { 969 ret = -ENOMEM; 970 break; 971 } 972 ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size); 973 kfree(arg_p); 974 if (ret < 0) 975 pr_err("kstrtoul() failed for dev_size=\n"); 976 break; 977 case Opt_pass_level: 978 match_int(args, &arg); 979 if (arg >= TCMU_PASS_INVALID) { 980 pr_warn("TCMU: Invalid pass_level: %d\n", arg); 981 break; 982 } 983 984 pr_debug("TCMU: Setting pass_level to %d\n", arg); 985 udev->pass_level = arg; 986 break; 987 default: 988 break; 989 } 990 } 991 992 kfree(orig); 993 return (!ret) ? count : ret; 994 } 995 996 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b) 997 { 998 struct tcmu_dev *udev = TCMU_DEV(dev); 999 ssize_t bl = 0; 1000 1001 bl = sprintf(b + bl, "Config: %s ", 1002 udev->dev_config[0] ? udev->dev_config : "NULL"); 1003 bl += sprintf(b + bl, "Size: %zu PassLevel: %u\n", 1004 udev->dev_size, udev->pass_level); 1005 1006 return bl; 1007 } 1008 1009 static sector_t tcmu_get_blocks(struct se_device *dev) 1010 { 1011 struct tcmu_dev *udev = TCMU_DEV(dev); 1012 1013 return div_u64(udev->dev_size - dev->dev_attrib.block_size, 1014 dev->dev_attrib.block_size); 1015 } 1016 1017 static sense_reason_t 1018 tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents, 1019 enum dma_data_direction data_direction) 1020 { 1021 int ret; 1022 1023 ret = tcmu_queue_cmd(se_cmd); 1024 1025 if (ret != 0) 1026 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 1027 else 1028 return TCM_NO_SENSE; 1029 } 1030 1031 static sense_reason_t 1032 tcmu_pass_op(struct se_cmd *se_cmd) 1033 { 1034 int ret = tcmu_queue_cmd(se_cmd); 1035 1036 if (ret != 0) 1037 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 1038 else 1039 return TCM_NO_SENSE; 1040 } 1041 1042 static struct sbc_ops tcmu_sbc_ops = { 1043 .execute_rw = tcmu_execute_rw, 1044 .execute_sync_cache = tcmu_pass_op, 1045 .execute_write_same = tcmu_pass_op, 1046 .execute_write_same_unmap = tcmu_pass_op, 1047 .execute_unmap = tcmu_pass_op, 1048 }; 1049 1050 static sense_reason_t 1051 tcmu_parse_cdb(struct se_cmd *cmd) 1052 { 1053 unsigned char *cdb = cmd->t_task_cdb; 1054 struct tcmu_dev *udev = TCMU_DEV(cmd->se_dev); 1055 sense_reason_t ret; 1056 1057 switch (udev->pass_level) { 1058 case TCMU_PASS_ALL: 1059 /* We're just like pscsi, then */ 1060 /* 1061 * For REPORT LUNS we always need to emulate the response, for everything 1062 * else, pass it up. 1063 */ 1064 switch (cdb[0]) { 1065 case REPORT_LUNS: 1066 cmd->execute_cmd = spc_emulate_report_luns; 1067 break; 1068 case READ_6: 1069 case READ_10: 1070 case READ_12: 1071 case READ_16: 1072 case WRITE_6: 1073 case WRITE_10: 1074 case WRITE_12: 1075 case WRITE_16: 1076 case WRITE_VERIFY: 1077 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB; 1078 /* FALLTHROUGH */ 1079 default: 1080 cmd->execute_cmd = tcmu_pass_op; 1081 } 1082 ret = TCM_NO_SENSE; 1083 break; 1084 case TCMU_PASS_IO: 1085 ret = sbc_parse_cdb(cmd, &tcmu_sbc_ops); 1086 break; 1087 default: 1088 pr_err("Unknown tcm-user pass level %d\n", udev->pass_level); 1089 ret = TCM_CHECK_CONDITION_ABORT_CMD; 1090 } 1091 1092 return ret; 1093 } 1094 1095 DEF_TB_DEFAULT_ATTRIBS(tcmu); 1096 1097 static struct configfs_attribute *tcmu_backend_dev_attrs[] = { 1098 &tcmu_dev_attrib_emulate_model_alias.attr, 1099 &tcmu_dev_attrib_emulate_dpo.attr, 1100 &tcmu_dev_attrib_emulate_fua_write.attr, 1101 &tcmu_dev_attrib_emulate_fua_read.attr, 1102 &tcmu_dev_attrib_emulate_write_cache.attr, 1103 &tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr, 1104 &tcmu_dev_attrib_emulate_tas.attr, 1105 &tcmu_dev_attrib_emulate_tpu.attr, 1106 &tcmu_dev_attrib_emulate_tpws.attr, 1107 &tcmu_dev_attrib_emulate_caw.attr, 1108 &tcmu_dev_attrib_emulate_3pc.attr, 1109 &tcmu_dev_attrib_pi_prot_type.attr, 1110 &tcmu_dev_attrib_hw_pi_prot_type.attr, 1111 &tcmu_dev_attrib_pi_prot_format.attr, 1112 &tcmu_dev_attrib_enforce_pr_isids.attr, 1113 &tcmu_dev_attrib_is_nonrot.attr, 1114 &tcmu_dev_attrib_emulate_rest_reord.attr, 1115 &tcmu_dev_attrib_force_pr_aptpl.attr, 1116 &tcmu_dev_attrib_hw_block_size.attr, 1117 &tcmu_dev_attrib_block_size.attr, 1118 &tcmu_dev_attrib_hw_max_sectors.attr, 1119 &tcmu_dev_attrib_optimal_sectors.attr, 1120 &tcmu_dev_attrib_hw_queue_depth.attr, 1121 &tcmu_dev_attrib_queue_depth.attr, 1122 &tcmu_dev_attrib_max_unmap_lba_count.attr, 1123 &tcmu_dev_attrib_max_unmap_block_desc_count.attr, 1124 &tcmu_dev_attrib_unmap_granularity.attr, 1125 &tcmu_dev_attrib_unmap_granularity_alignment.attr, 1126 &tcmu_dev_attrib_max_write_same_len.attr, 1127 NULL, 1128 }; 1129 1130 static struct se_subsystem_api tcmu_template = { 1131 .name = "user", 1132 .inquiry_prod = "USER", 1133 .inquiry_rev = TCMU_VERSION, 1134 .owner = THIS_MODULE, 1135 .transport_type = TRANSPORT_PLUGIN_VHBA_PDEV, 1136 .attach_hba = tcmu_attach_hba, 1137 .detach_hba = tcmu_detach_hba, 1138 .alloc_device = tcmu_alloc_device, 1139 .configure_device = tcmu_configure_device, 1140 .free_device = tcmu_free_device, 1141 .parse_cdb = tcmu_parse_cdb, 1142 .set_configfs_dev_params = tcmu_set_configfs_dev_params, 1143 .show_configfs_dev_params = tcmu_show_configfs_dev_params, 1144 .get_device_type = sbc_get_device_type, 1145 .get_blocks = tcmu_get_blocks, 1146 }; 1147 1148 static int __init tcmu_module_init(void) 1149 { 1150 struct target_backend_cits *tbc = &tcmu_template.tb_cits; 1151 int ret; 1152 1153 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0); 1154 1155 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache", 1156 sizeof(struct tcmu_cmd), 1157 __alignof__(struct tcmu_cmd), 1158 0, NULL); 1159 if (!tcmu_cmd_cache) 1160 return -ENOMEM; 1161 1162 tcmu_root_device = root_device_register("tcm_user"); 1163 if (IS_ERR(tcmu_root_device)) { 1164 ret = PTR_ERR(tcmu_root_device); 1165 goto out_free_cache; 1166 } 1167 1168 ret = genl_register_family(&tcmu_genl_family); 1169 if (ret < 0) { 1170 goto out_unreg_device; 1171 } 1172 1173 target_core_setup_sub_cits(&tcmu_template); 1174 tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs; 1175 1176 ret = transport_subsystem_register(&tcmu_template); 1177 if (ret) 1178 goto out_unreg_genl; 1179 1180 return 0; 1181 1182 out_unreg_genl: 1183 genl_unregister_family(&tcmu_genl_family); 1184 out_unreg_device: 1185 root_device_unregister(tcmu_root_device); 1186 out_free_cache: 1187 kmem_cache_destroy(tcmu_cmd_cache); 1188 1189 return ret; 1190 } 1191 1192 static void __exit tcmu_module_exit(void) 1193 { 1194 transport_subsystem_release(&tcmu_template); 1195 genl_unregister_family(&tcmu_genl_family); 1196 root_device_unregister(tcmu_root_device); 1197 kmem_cache_destroy(tcmu_cmd_cache); 1198 } 1199 1200 MODULE_DESCRIPTION("TCM USER subsystem plugin"); 1201 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>"); 1202 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>"); 1203 MODULE_LICENSE("GPL"); 1204 1205 module_init(tcmu_module_init); 1206 module_exit(tcmu_module_exit); 1207