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.len_op, TCMU_OP_PAD); 348 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size); 349 entry->hdr.cmd_id = 0; /* not used for PAD */ 350 entry->hdr.kflags = 0; 351 entry->hdr.uflags = 0; 352 353 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size); 354 355 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 356 WARN_ON(cmd_head != 0); 357 } 358 359 entry = (void *) mb + CMDR_OFF + cmd_head; 360 tcmu_flush_dcache_range(entry, sizeof(*entry)); 361 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD); 362 tcmu_hdr_set_len(&entry->hdr.len_op, command_size); 363 entry->hdr.cmd_id = tcmu_cmd->cmd_id; 364 entry->hdr.kflags = 0; 365 entry->hdr.uflags = 0; 366 367 /* 368 * Fix up iovecs, and handle if allocation in data ring wrapped. 369 */ 370 iov = &entry->req.iov[0]; 371 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 372 size_t copy_bytes = min((size_t)sg->length, 373 head_to_end(udev->data_head, udev->data_size)); 374 void *from = kmap_atomic(sg_page(sg)) + sg->offset; 375 void *to = (void *) mb + udev->data_off + udev->data_head; 376 377 if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) { 378 memcpy(to, from, copy_bytes); 379 tcmu_flush_dcache_range(to, copy_bytes); 380 } 381 382 /* Even iov_base is relative to mb_addr */ 383 iov->iov_len = copy_bytes; 384 iov->iov_base = (void __user *) udev->data_off + 385 udev->data_head; 386 iov_cnt++; 387 iov++; 388 389 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 390 391 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */ 392 if (sg->length != copy_bytes) { 393 from += copy_bytes; 394 copy_bytes = sg->length - copy_bytes; 395 396 iov->iov_len = copy_bytes; 397 iov->iov_base = (void __user *) udev->data_off + 398 udev->data_head; 399 400 if (se_cmd->data_direction == DMA_TO_DEVICE) { 401 to = (void *) mb + udev->data_off + udev->data_head; 402 memcpy(to, from, copy_bytes); 403 tcmu_flush_dcache_range(to, copy_bytes); 404 } 405 406 iov_cnt++; 407 iov++; 408 409 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 410 } 411 412 kunmap_atomic(from); 413 } 414 entry->req.iov_cnt = iov_cnt; 415 entry->req.iov_bidi_cnt = 0; 416 entry->req.iov_dif_cnt = 0; 417 418 /* All offsets relative to mb_addr, not start of entry! */ 419 cdb_off = CMDR_OFF + cmd_head + base_command_size; 420 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb)); 421 entry->req.cdb_off = cdb_off; 422 tcmu_flush_dcache_range(entry, sizeof(*entry)); 423 424 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); 425 tcmu_flush_dcache_range(mb, sizeof(*mb)); 426 427 spin_unlock_irq(&udev->cmdr_lock); 428 429 /* TODO: only if FLUSH and FUA? */ 430 uio_event_notify(&udev->uio_info); 431 432 mod_timer(&udev->timeout, 433 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT))); 434 435 return 0; 436 } 437 438 static int tcmu_queue_cmd(struct se_cmd *se_cmd) 439 { 440 struct se_device *se_dev = se_cmd->se_dev; 441 struct tcmu_dev *udev = TCMU_DEV(se_dev); 442 struct tcmu_cmd *tcmu_cmd; 443 int ret; 444 445 tcmu_cmd = tcmu_alloc_cmd(se_cmd); 446 if (!tcmu_cmd) 447 return -ENOMEM; 448 449 ret = tcmu_queue_cmd_ring(tcmu_cmd); 450 if (ret < 0) { 451 pr_err("TCMU: Could not queue command\n"); 452 spin_lock_irq(&udev->commands_lock); 453 idr_remove(&udev->commands, tcmu_cmd->cmd_id); 454 spin_unlock_irq(&udev->commands_lock); 455 456 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 457 } 458 459 return ret; 460 } 461 462 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry) 463 { 464 struct se_cmd *se_cmd = cmd->se_cmd; 465 struct tcmu_dev *udev = cmd->tcmu_dev; 466 467 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 468 /* cmd has been completed already from timeout, just reclaim data 469 ring space */ 470 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 471 return; 472 } 473 474 if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) { 475 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 476 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n", 477 cmd->se_cmd); 478 transport_generic_request_failure(cmd->se_cmd, 479 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE); 480 cmd->se_cmd = NULL; 481 kmem_cache_free(tcmu_cmd_cache, cmd); 482 return; 483 } 484 485 if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) { 486 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, 487 se_cmd->scsi_sense_length); 488 489 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 490 } 491 else if (se_cmd->data_direction == DMA_FROM_DEVICE) { 492 struct scatterlist *sg; 493 int i; 494 495 /* It'd be easier to look at entry's iovec again, but UAM */ 496 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 497 size_t copy_bytes; 498 void *to; 499 void *from; 500 501 copy_bytes = min((size_t)sg->length, 502 head_to_end(udev->data_tail, udev->data_size)); 503 504 to = kmap_atomic(sg_page(sg)) + sg->offset; 505 WARN_ON(sg->length + sg->offset > PAGE_SIZE); 506 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 507 tcmu_flush_dcache_range(from, copy_bytes); 508 memcpy(to, from, copy_bytes); 509 510 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 511 512 /* Uh oh, wrapped the data buffer for this sg's data */ 513 if (sg->length != copy_bytes) { 514 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 515 WARN_ON(udev->data_tail); 516 to += copy_bytes; 517 copy_bytes = sg->length - copy_bytes; 518 tcmu_flush_dcache_range(from, copy_bytes); 519 memcpy(to, from, copy_bytes); 520 521 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 522 } 523 524 kunmap_atomic(to); 525 } 526 527 } else if (se_cmd->data_direction == DMA_TO_DEVICE) { 528 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 529 } else { 530 pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction); 531 } 532 533 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); 534 cmd->se_cmd = NULL; 535 536 kmem_cache_free(tcmu_cmd_cache, cmd); 537 } 538 539 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) 540 { 541 struct tcmu_mailbox *mb; 542 LIST_HEAD(cpl_cmds); 543 unsigned long flags; 544 int handled = 0; 545 546 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { 547 pr_err("ring broken, not handling completions\n"); 548 return 0; 549 } 550 551 spin_lock_irqsave(&udev->cmdr_lock, flags); 552 553 mb = udev->mb_addr; 554 tcmu_flush_dcache_range(mb, sizeof(*mb)); 555 556 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) { 557 558 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; 559 struct tcmu_cmd *cmd; 560 561 tcmu_flush_dcache_range(entry, sizeof(*entry)); 562 563 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) { 564 UPDATE_HEAD(udev->cmdr_last_cleaned, 565 tcmu_hdr_get_len(entry->hdr.len_op), 566 udev->cmdr_size); 567 continue; 568 } 569 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD); 570 571 spin_lock(&udev->commands_lock); 572 cmd = idr_find(&udev->commands, entry->hdr.cmd_id); 573 if (cmd) 574 idr_remove(&udev->commands, cmd->cmd_id); 575 spin_unlock(&udev->commands_lock); 576 577 if (!cmd) { 578 pr_err("cmd_id not found, ring is broken\n"); 579 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); 580 break; 581 } 582 583 tcmu_handle_completion(cmd, entry); 584 585 UPDATE_HEAD(udev->cmdr_last_cleaned, 586 tcmu_hdr_get_len(entry->hdr.len_op), 587 udev->cmdr_size); 588 589 handled++; 590 } 591 592 if (mb->cmd_tail == mb->cmd_head) 593 del_timer(&udev->timeout); /* no more pending cmds */ 594 595 spin_unlock_irqrestore(&udev->cmdr_lock, flags); 596 597 wake_up(&udev->wait_cmdr); 598 599 return handled; 600 } 601 602 static int tcmu_check_expired_cmd(int id, void *p, void *data) 603 { 604 struct tcmu_cmd *cmd = p; 605 606 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 607 return 0; 608 609 if (!time_after(cmd->deadline, jiffies)) 610 return 0; 611 612 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags); 613 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); 614 cmd->se_cmd = NULL; 615 616 kmem_cache_free(tcmu_cmd_cache, cmd); 617 618 return 0; 619 } 620 621 static void tcmu_device_timedout(unsigned long data) 622 { 623 struct tcmu_dev *udev = (struct tcmu_dev *)data; 624 unsigned long flags; 625 int handled; 626 627 handled = tcmu_handle_completions(udev); 628 629 pr_warn("%d completions handled from timeout\n", handled); 630 631 spin_lock_irqsave(&udev->commands_lock, flags); 632 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); 633 spin_unlock_irqrestore(&udev->commands_lock, flags); 634 635 /* 636 * We don't need to wakeup threads on wait_cmdr since they have their 637 * own timeout. 638 */ 639 } 640 641 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) 642 { 643 struct tcmu_hba *tcmu_hba; 644 645 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL); 646 if (!tcmu_hba) 647 return -ENOMEM; 648 649 tcmu_hba->host_id = host_id; 650 hba->hba_ptr = tcmu_hba; 651 652 return 0; 653 } 654 655 static void tcmu_detach_hba(struct se_hba *hba) 656 { 657 kfree(hba->hba_ptr); 658 hba->hba_ptr = NULL; 659 } 660 661 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 662 { 663 struct tcmu_dev *udev; 664 665 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL); 666 if (!udev) 667 return NULL; 668 669 udev->name = kstrdup(name, GFP_KERNEL); 670 if (!udev->name) { 671 kfree(udev); 672 return NULL; 673 } 674 675 udev->hba = hba; 676 677 init_waitqueue_head(&udev->wait_cmdr); 678 spin_lock_init(&udev->cmdr_lock); 679 680 idr_init(&udev->commands); 681 spin_lock_init(&udev->commands_lock); 682 683 setup_timer(&udev->timeout, tcmu_device_timedout, 684 (unsigned long)udev); 685 686 udev->pass_level = TCMU_PASS_ALL; 687 688 return &udev->se_dev; 689 } 690 691 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) 692 { 693 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info); 694 695 tcmu_handle_completions(tcmu_dev); 696 697 return 0; 698 } 699 700 /* 701 * mmap code from uio.c. Copied here because we want to hook mmap() 702 * and this stuff must come along. 703 */ 704 static int tcmu_find_mem_index(struct vm_area_struct *vma) 705 { 706 struct tcmu_dev *udev = vma->vm_private_data; 707 struct uio_info *info = &udev->uio_info; 708 709 if (vma->vm_pgoff < MAX_UIO_MAPS) { 710 if (info->mem[vma->vm_pgoff].size == 0) 711 return -1; 712 return (int)vma->vm_pgoff; 713 } 714 return -1; 715 } 716 717 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 718 { 719 struct tcmu_dev *udev = vma->vm_private_data; 720 struct uio_info *info = &udev->uio_info; 721 struct page *page; 722 unsigned long offset; 723 void *addr; 724 725 int mi = tcmu_find_mem_index(vma); 726 if (mi < 0) 727 return VM_FAULT_SIGBUS; 728 729 /* 730 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 731 * to use mem[N]. 732 */ 733 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 734 735 addr = (void *)(unsigned long)info->mem[mi].addr + offset; 736 if (info->mem[mi].memtype == UIO_MEM_LOGICAL) 737 page = virt_to_page(addr); 738 else 739 page = vmalloc_to_page(addr); 740 get_page(page); 741 vmf->page = page; 742 return 0; 743 } 744 745 static const struct vm_operations_struct tcmu_vm_ops = { 746 .fault = tcmu_vma_fault, 747 }; 748 749 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma) 750 { 751 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 752 753 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 754 vma->vm_ops = &tcmu_vm_ops; 755 756 vma->vm_private_data = udev; 757 758 /* Ensure the mmap is exactly the right size */ 759 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT)) 760 return -EINVAL; 761 762 return 0; 763 } 764 765 static int tcmu_open(struct uio_info *info, struct inode *inode) 766 { 767 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 768 769 /* O_EXCL not supported for char devs, so fake it? */ 770 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags)) 771 return -EBUSY; 772 773 pr_debug("open\n"); 774 775 return 0; 776 } 777 778 static int tcmu_release(struct uio_info *info, struct inode *inode) 779 { 780 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 781 782 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags); 783 784 pr_debug("close\n"); 785 786 return 0; 787 } 788 789 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) 790 { 791 struct sk_buff *skb; 792 void *msg_header; 793 int ret = -ENOMEM; 794 795 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); 796 if (!skb) 797 return ret; 798 799 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); 800 if (!msg_header) 801 goto free_skb; 802 803 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); 804 if (ret < 0) 805 goto free_skb; 806 807 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); 808 if (ret < 0) 809 goto free_skb; 810 811 genlmsg_end(skb, msg_header); 812 813 ret = genlmsg_multicast(&tcmu_genl_family, skb, 0, 814 TCMU_MCGRP_CONFIG, GFP_KERNEL); 815 816 /* We don't care if no one is listening */ 817 if (ret == -ESRCH) 818 ret = 0; 819 820 return ret; 821 free_skb: 822 nlmsg_free(skb); 823 return ret; 824 } 825 826 static int tcmu_configure_device(struct se_device *dev) 827 { 828 struct tcmu_dev *udev = TCMU_DEV(dev); 829 struct tcmu_hba *hba = udev->hba->hba_ptr; 830 struct uio_info *info; 831 struct tcmu_mailbox *mb; 832 size_t size; 833 size_t used; 834 int ret = 0; 835 char *str; 836 837 info = &udev->uio_info; 838 839 size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name, 840 udev->dev_config); 841 size += 1; /* for \0 */ 842 str = kmalloc(size, GFP_KERNEL); 843 if (!str) 844 return -ENOMEM; 845 846 used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name); 847 848 if (udev->dev_config[0]) 849 snprintf(str + used, size - used, "/%s", udev->dev_config); 850 851 info->name = str; 852 853 udev->mb_addr = vzalloc(TCMU_RING_SIZE); 854 if (!udev->mb_addr) { 855 ret = -ENOMEM; 856 goto err_vzalloc; 857 } 858 859 /* mailbox fits in first part of CMDR space */ 860 udev->cmdr_size = CMDR_SIZE - CMDR_OFF; 861 udev->data_off = CMDR_SIZE; 862 udev->data_size = TCMU_RING_SIZE - CMDR_SIZE; 863 864 mb = udev->mb_addr; 865 mb->version = TCMU_MAILBOX_VERSION; 866 mb->cmdr_off = CMDR_OFF; 867 mb->cmdr_size = udev->cmdr_size; 868 869 WARN_ON(!PAGE_ALIGNED(udev->data_off)); 870 WARN_ON(udev->data_size % PAGE_SIZE); 871 872 info->version = xstr(TCMU_MAILBOX_VERSION); 873 874 info->mem[0].name = "tcm-user command & data buffer"; 875 info->mem[0].addr = (phys_addr_t) udev->mb_addr; 876 info->mem[0].size = TCMU_RING_SIZE; 877 info->mem[0].memtype = UIO_MEM_VIRTUAL; 878 879 info->irqcontrol = tcmu_irqcontrol; 880 info->irq = UIO_IRQ_CUSTOM; 881 882 info->mmap = tcmu_mmap; 883 info->open = tcmu_open; 884 info->release = tcmu_release; 885 886 ret = uio_register_device(tcmu_root_device, info); 887 if (ret) 888 goto err_register; 889 890 /* Other attributes can be configured in userspace */ 891 dev->dev_attrib.hw_block_size = 512; 892 dev->dev_attrib.hw_max_sectors = 128; 893 dev->dev_attrib.hw_queue_depth = 128; 894 895 ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name, 896 udev->uio_info.uio_dev->minor); 897 if (ret) 898 goto err_netlink; 899 900 return 0; 901 902 err_netlink: 903 uio_unregister_device(&udev->uio_info); 904 err_register: 905 vfree(udev->mb_addr); 906 err_vzalloc: 907 kfree(info->name); 908 909 return ret; 910 } 911 912 static int tcmu_check_pending_cmd(int id, void *p, void *data) 913 { 914 struct tcmu_cmd *cmd = p; 915 916 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 917 return 0; 918 return -EINVAL; 919 } 920 921 static void tcmu_free_device(struct se_device *dev) 922 { 923 struct tcmu_dev *udev = TCMU_DEV(dev); 924 int i; 925 926 del_timer_sync(&udev->timeout); 927 928 vfree(udev->mb_addr); 929 930 /* Upper layer should drain all requests before calling this */ 931 spin_lock_irq(&udev->commands_lock); 932 i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL); 933 idr_destroy(&udev->commands); 934 spin_unlock_irq(&udev->commands_lock); 935 WARN_ON(i); 936 937 /* Device was configured */ 938 if (udev->uio_info.uio_dev) { 939 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name, 940 udev->uio_info.uio_dev->minor); 941 942 uio_unregister_device(&udev->uio_info); 943 kfree(udev->uio_info.name); 944 kfree(udev->name); 945 } 946 947 kfree(udev); 948 } 949 950 enum { 951 Opt_dev_config, Opt_dev_size, Opt_err, Opt_pass_level, 952 }; 953 954 static match_table_t tokens = { 955 {Opt_dev_config, "dev_config=%s"}, 956 {Opt_dev_size, "dev_size=%u"}, 957 {Opt_pass_level, "pass_level=%u"}, 958 {Opt_err, NULL} 959 }; 960 961 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 962 const char *page, ssize_t count) 963 { 964 struct tcmu_dev *udev = TCMU_DEV(dev); 965 char *orig, *ptr, *opts, *arg_p; 966 substring_t args[MAX_OPT_ARGS]; 967 int ret = 0, token; 968 int arg; 969 970 opts = kstrdup(page, GFP_KERNEL); 971 if (!opts) 972 return -ENOMEM; 973 974 orig = opts; 975 976 while ((ptr = strsep(&opts, ",\n")) != NULL) { 977 if (!*ptr) 978 continue; 979 980 token = match_token(ptr, tokens, args); 981 switch (token) { 982 case Opt_dev_config: 983 if (match_strlcpy(udev->dev_config, &args[0], 984 TCMU_CONFIG_LEN) == 0) { 985 ret = -EINVAL; 986 break; 987 } 988 pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config); 989 break; 990 case Opt_dev_size: 991 arg_p = match_strdup(&args[0]); 992 if (!arg_p) { 993 ret = -ENOMEM; 994 break; 995 } 996 ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size); 997 kfree(arg_p); 998 if (ret < 0) 999 pr_err("kstrtoul() failed for dev_size=\n"); 1000 break; 1001 case Opt_pass_level: 1002 match_int(args, &arg); 1003 if (arg >= TCMU_PASS_INVALID) { 1004 pr_warn("TCMU: Invalid pass_level: %d\n", arg); 1005 break; 1006 } 1007 1008 pr_debug("TCMU: Setting pass_level to %d\n", arg); 1009 udev->pass_level = arg; 1010 break; 1011 default: 1012 break; 1013 } 1014 } 1015 1016 kfree(orig); 1017 return (!ret) ? count : ret; 1018 } 1019 1020 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b) 1021 { 1022 struct tcmu_dev *udev = TCMU_DEV(dev); 1023 ssize_t bl = 0; 1024 1025 bl = sprintf(b + bl, "Config: %s ", 1026 udev->dev_config[0] ? udev->dev_config : "NULL"); 1027 bl += sprintf(b + bl, "Size: %zu PassLevel: %u\n", 1028 udev->dev_size, udev->pass_level); 1029 1030 return bl; 1031 } 1032 1033 static sector_t tcmu_get_blocks(struct se_device *dev) 1034 { 1035 struct tcmu_dev *udev = TCMU_DEV(dev); 1036 1037 return div_u64(udev->dev_size - dev->dev_attrib.block_size, 1038 dev->dev_attrib.block_size); 1039 } 1040 1041 static sense_reason_t 1042 tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents, 1043 enum dma_data_direction data_direction) 1044 { 1045 int ret; 1046 1047 ret = tcmu_queue_cmd(se_cmd); 1048 1049 if (ret != 0) 1050 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 1051 else 1052 return TCM_NO_SENSE; 1053 } 1054 1055 static sense_reason_t 1056 tcmu_pass_op(struct se_cmd *se_cmd) 1057 { 1058 int ret = tcmu_queue_cmd(se_cmd); 1059 1060 if (ret != 0) 1061 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 1062 else 1063 return TCM_NO_SENSE; 1064 } 1065 1066 static struct sbc_ops tcmu_sbc_ops = { 1067 .execute_rw = tcmu_execute_rw, 1068 .execute_sync_cache = tcmu_pass_op, 1069 .execute_write_same = tcmu_pass_op, 1070 .execute_write_same_unmap = tcmu_pass_op, 1071 .execute_unmap = tcmu_pass_op, 1072 }; 1073 1074 static sense_reason_t 1075 tcmu_parse_cdb(struct se_cmd *cmd) 1076 { 1077 unsigned char *cdb = cmd->t_task_cdb; 1078 struct tcmu_dev *udev = TCMU_DEV(cmd->se_dev); 1079 sense_reason_t ret; 1080 1081 switch (udev->pass_level) { 1082 case TCMU_PASS_ALL: 1083 /* We're just like pscsi, then */ 1084 /* 1085 * For REPORT LUNS we always need to emulate the response, for everything 1086 * else, pass it up. 1087 */ 1088 switch (cdb[0]) { 1089 case REPORT_LUNS: 1090 cmd->execute_cmd = spc_emulate_report_luns; 1091 break; 1092 case READ_6: 1093 case READ_10: 1094 case READ_12: 1095 case READ_16: 1096 case WRITE_6: 1097 case WRITE_10: 1098 case WRITE_12: 1099 case WRITE_16: 1100 case WRITE_VERIFY: 1101 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB; 1102 /* FALLTHROUGH */ 1103 default: 1104 cmd->execute_cmd = tcmu_pass_op; 1105 } 1106 ret = TCM_NO_SENSE; 1107 break; 1108 case TCMU_PASS_IO: 1109 ret = sbc_parse_cdb(cmd, &tcmu_sbc_ops); 1110 break; 1111 default: 1112 pr_err("Unknown tcm-user pass level %d\n", udev->pass_level); 1113 ret = TCM_CHECK_CONDITION_ABORT_CMD; 1114 } 1115 1116 return ret; 1117 } 1118 1119 DEF_TB_DEFAULT_ATTRIBS(tcmu); 1120 1121 static struct configfs_attribute *tcmu_backend_dev_attrs[] = { 1122 &tcmu_dev_attrib_emulate_model_alias.attr, 1123 &tcmu_dev_attrib_emulate_dpo.attr, 1124 &tcmu_dev_attrib_emulate_fua_write.attr, 1125 &tcmu_dev_attrib_emulate_fua_read.attr, 1126 &tcmu_dev_attrib_emulate_write_cache.attr, 1127 &tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr, 1128 &tcmu_dev_attrib_emulate_tas.attr, 1129 &tcmu_dev_attrib_emulate_tpu.attr, 1130 &tcmu_dev_attrib_emulate_tpws.attr, 1131 &tcmu_dev_attrib_emulate_caw.attr, 1132 &tcmu_dev_attrib_emulate_3pc.attr, 1133 &tcmu_dev_attrib_pi_prot_type.attr, 1134 &tcmu_dev_attrib_hw_pi_prot_type.attr, 1135 &tcmu_dev_attrib_pi_prot_format.attr, 1136 &tcmu_dev_attrib_enforce_pr_isids.attr, 1137 &tcmu_dev_attrib_is_nonrot.attr, 1138 &tcmu_dev_attrib_emulate_rest_reord.attr, 1139 &tcmu_dev_attrib_force_pr_aptpl.attr, 1140 &tcmu_dev_attrib_hw_block_size.attr, 1141 &tcmu_dev_attrib_block_size.attr, 1142 &tcmu_dev_attrib_hw_max_sectors.attr, 1143 &tcmu_dev_attrib_optimal_sectors.attr, 1144 &tcmu_dev_attrib_hw_queue_depth.attr, 1145 &tcmu_dev_attrib_queue_depth.attr, 1146 &tcmu_dev_attrib_max_unmap_lba_count.attr, 1147 &tcmu_dev_attrib_max_unmap_block_desc_count.attr, 1148 &tcmu_dev_attrib_unmap_granularity.attr, 1149 &tcmu_dev_attrib_unmap_granularity_alignment.attr, 1150 &tcmu_dev_attrib_max_write_same_len.attr, 1151 NULL, 1152 }; 1153 1154 static struct se_subsystem_api tcmu_template = { 1155 .name = "user", 1156 .inquiry_prod = "USER", 1157 .inquiry_rev = TCMU_VERSION, 1158 .owner = THIS_MODULE, 1159 .transport_type = TRANSPORT_PLUGIN_VHBA_PDEV, 1160 .attach_hba = tcmu_attach_hba, 1161 .detach_hba = tcmu_detach_hba, 1162 .alloc_device = tcmu_alloc_device, 1163 .configure_device = tcmu_configure_device, 1164 .free_device = tcmu_free_device, 1165 .parse_cdb = tcmu_parse_cdb, 1166 .set_configfs_dev_params = tcmu_set_configfs_dev_params, 1167 .show_configfs_dev_params = tcmu_show_configfs_dev_params, 1168 .get_device_type = sbc_get_device_type, 1169 .get_blocks = tcmu_get_blocks, 1170 }; 1171 1172 static int __init tcmu_module_init(void) 1173 { 1174 struct target_backend_cits *tbc = &tcmu_template.tb_cits; 1175 int ret; 1176 1177 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0); 1178 1179 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache", 1180 sizeof(struct tcmu_cmd), 1181 __alignof__(struct tcmu_cmd), 1182 0, NULL); 1183 if (!tcmu_cmd_cache) 1184 return -ENOMEM; 1185 1186 tcmu_root_device = root_device_register("tcm_user"); 1187 if (IS_ERR(tcmu_root_device)) { 1188 ret = PTR_ERR(tcmu_root_device); 1189 goto out_free_cache; 1190 } 1191 1192 ret = genl_register_family(&tcmu_genl_family); 1193 if (ret < 0) { 1194 goto out_unreg_device; 1195 } 1196 1197 target_core_setup_sub_cits(&tcmu_template); 1198 tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs; 1199 1200 ret = transport_subsystem_register(&tcmu_template); 1201 if (ret) 1202 goto out_unreg_genl; 1203 1204 return 0; 1205 1206 out_unreg_genl: 1207 genl_unregister_family(&tcmu_genl_family); 1208 out_unreg_device: 1209 root_device_unregister(tcmu_root_device); 1210 out_free_cache: 1211 kmem_cache_destroy(tcmu_cmd_cache); 1212 1213 return ret; 1214 } 1215 1216 static void __exit tcmu_module_exit(void) 1217 { 1218 transport_subsystem_release(&tcmu_template); 1219 genl_unregister_family(&tcmu_genl_family); 1220 root_device_unregister(tcmu_root_device); 1221 kmem_cache_destroy(tcmu_cmd_cache); 1222 } 1223 1224 MODULE_DESCRIPTION("TCM USER subsystem plugin"); 1225 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>"); 1226 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>"); 1227 MODULE_LICENSE("GPL"); 1228 1229 module_init(tcmu_module_init); 1230 module_exit(tcmu_module_exit); 1231