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 <linux/target_core_user.h> 32 33/* 34 * Define a shared-memory interface for LIO to pass SCSI commands and 35 * data to userspace for processing. This is to allow backends that 36 * are too complex for in-kernel support to be possible. 37 * 38 * It uses the UIO framework to do a lot of the device-creation and 39 * introspection work for us. 40 * 41 * See the .h file for how the ring is laid out. Note that while the 42 * command ring is defined, the particulars of the data area are 43 * not. Offset values in the command entry point to other locations 44 * internal to the mmap()ed area. There is separate space outside the 45 * command ring for data buffers. This leaves maximum flexibility for 46 * moving buffer allocations, or even page flipping or other 47 * allocation techniques, without altering the command ring layout. 48 * 49 * SECURITY: 50 * The user process must be assumed to be malicious. There's no way to 51 * prevent it breaking the command ring protocol if it wants, but in 52 * order to prevent other issues we must only ever read *data* from 53 * the shared memory area, not offsets or sizes. This applies to 54 * command ring entries as well as the mailbox. Extra code needed for 55 * this may have a 'UAM' comment. 56 */ 57 58 59#define TCMU_TIME_OUT (30 * MSEC_PER_SEC) 60 61#define CMDR_SIZE (16 * 4096) 62#define DATA_SIZE (257 * 4096) 63 64#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE) 65 66static struct device *tcmu_root_device; 67 68struct tcmu_hba { 69 u32 host_id; 70}; 71 72/* User wants all cmds or just some */ 73enum passthru_level { 74 TCMU_PASS_ALL = 0, 75 TCMU_PASS_IO, 76 TCMU_PASS_INVALID, 77}; 78 79#define TCMU_CONFIG_LEN 256 80 81struct tcmu_dev { 82 struct se_device se_dev; 83 84 char *name; 85 struct se_hba *hba; 86 87#define TCMU_DEV_BIT_OPEN 0 88#define TCMU_DEV_BIT_BROKEN 1 89 unsigned long flags; 90 enum passthru_level pass_level; 91 92 struct uio_info uio_info; 93 94 struct tcmu_mailbox *mb_addr; 95 size_t dev_size; 96 u32 cmdr_size; 97 u32 cmdr_last_cleaned; 98 /* Offset of data ring from start of mb */ 99 size_t data_off; 100 size_t data_size; 101 /* Ring head + tail values. */ 102 /* Must add data_off and mb_addr to get the address */ 103 size_t data_head; 104 size_t data_tail; 105 106 wait_queue_head_t wait_cmdr; 107 /* TODO should this be a mutex? */ 108 spinlock_t cmdr_lock; 109 110 struct idr commands; 111 spinlock_t commands_lock; 112 113 struct timer_list timeout; 114 115 char dev_config[TCMU_CONFIG_LEN]; 116}; 117 118#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev) 119 120#define CMDR_OFF sizeof(struct tcmu_mailbox) 121 122struct tcmu_cmd { 123 struct se_cmd *se_cmd; 124 struct tcmu_dev *tcmu_dev; 125 126 uint16_t cmd_id; 127 128 /* Can't use se_cmd->data_length when cleaning up expired cmds, because if 129 cmd has been completed then accessing se_cmd is off limits */ 130 size_t data_length; 131 132 unsigned long deadline; 133 134#define TCMU_CMD_BIT_EXPIRED 0 135 unsigned long flags; 136}; 137 138static struct kmem_cache *tcmu_cmd_cache; 139 140/* multicast group */ 141enum tcmu_multicast_groups { 142 TCMU_MCGRP_CONFIG, 143}; 144 145static const struct genl_multicast_group tcmu_mcgrps[] = { 146 [TCMU_MCGRP_CONFIG] = { .name = "config", }, 147}; 148 149/* Our generic netlink family */ 150static struct genl_family tcmu_genl_family = { 151 .id = GENL_ID_GENERATE, 152 .hdrsize = 0, 153 .name = "TCM-USER", 154 .version = 1, 155 .maxattr = TCMU_ATTR_MAX, 156 .mcgrps = tcmu_mcgrps, 157 .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps), 158}; 159 160static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) 161{ 162 struct se_device *se_dev = se_cmd->se_dev; 163 struct tcmu_dev *udev = TCMU_DEV(se_dev); 164 struct tcmu_cmd *tcmu_cmd; 165 int cmd_id; 166 167 tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL); 168 if (!tcmu_cmd) 169 return NULL; 170 171 tcmu_cmd->se_cmd = se_cmd; 172 tcmu_cmd->tcmu_dev = udev; 173 tcmu_cmd->data_length = se_cmd->data_length; 174 175 tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT); 176 177 idr_preload(GFP_KERNEL); 178 spin_lock_irq(&udev->commands_lock); 179 cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0, 180 USHRT_MAX, GFP_NOWAIT); 181 spin_unlock_irq(&udev->commands_lock); 182 idr_preload_end(); 183 184 if (cmd_id < 0) { 185 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 186 return NULL; 187 } 188 tcmu_cmd->cmd_id = cmd_id; 189 190 return tcmu_cmd; 191} 192 193static inline void tcmu_flush_dcache_range(void *vaddr, size_t size) 194{ 195 unsigned long offset = (unsigned long) vaddr & ~PAGE_MASK; 196 197 size = round_up(size+offset, PAGE_SIZE); 198 vaddr -= offset; 199 200 while (size) { 201 flush_dcache_page(virt_to_page(vaddr)); 202 size -= PAGE_SIZE; 203 } 204} 205 206/* 207 * Some ring helper functions. We don't assume size is a power of 2 so 208 * we can't use circ_buf.h. 209 */ 210static inline size_t spc_used(size_t head, size_t tail, size_t size) 211{ 212 int diff = head - tail; 213 214 if (diff >= 0) 215 return diff; 216 else 217 return size + diff; 218} 219 220static inline size_t spc_free(size_t head, size_t tail, size_t size) 221{ 222 /* Keep 1 byte unused or we can't tell full from empty */ 223 return (size - spc_used(head, tail, size) - 1); 224} 225 226static inline size_t head_to_end(size_t head, size_t size) 227{ 228 return size - head; 229} 230 231#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size) 232 233/* 234 * We can't queue a command until we have space available on the cmd ring *and* space 235 * space avail on the data ring. 236 * 237 * Called with ring lock held. 238 */ 239static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed) 240{ 241 struct tcmu_mailbox *mb = udev->mb_addr; 242 size_t space; 243 u32 cmd_head; 244 size_t cmd_needed; 245 246 tcmu_flush_dcache_range(mb, sizeof(*mb)); 247 248 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 249 250 /* 251 * If cmd end-of-ring space is too small then we need space for a NOP plus 252 * original cmd - cmds are internally contiguous. 253 */ 254 if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size) 255 cmd_needed = cmd_size; 256 else 257 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size); 258 259 space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size); 260 if (space < cmd_needed) { 261 pr_debug("no cmd space: %u %u %u\n", cmd_head, 262 udev->cmdr_last_cleaned, udev->cmdr_size); 263 return false; 264 } 265 266 space = spc_free(udev->data_head, udev->data_tail, udev->data_size); 267 if (space < data_needed) { 268 pr_debug("no data space: %zu %zu %zu\n", udev->data_head, 269 udev->data_tail, udev->data_size); 270 return false; 271 } 272 273 return true; 274} 275 276static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 277{ 278 struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; 279 struct se_cmd *se_cmd = tcmu_cmd->se_cmd; 280 size_t base_command_size, command_size; 281 struct tcmu_mailbox *mb; 282 struct tcmu_cmd_entry *entry; 283 int i; 284 struct scatterlist *sg; 285 struct iovec *iov; 286 int iov_cnt = 0; 287 uint32_t cmd_head; 288 uint64_t cdb_off; 289 290 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) 291 return -EINVAL; 292 293 /* 294 * Must be a certain minimum size for response sense info, but 295 * also may be larger if the iov array is large. 296 * 297 * iovs = sgl_nents+1, for end-of-ring case, plus another 1 298 * b/c size == offsetof one-past-element. 299 */ 300 base_command_size = max(offsetof(struct tcmu_cmd_entry, 301 req.iov[se_cmd->t_data_nents + 2]), 302 sizeof(struct tcmu_cmd_entry)); 303 command_size = base_command_size 304 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE); 305 306 WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1)); 307 308 spin_lock_irq(&udev->cmdr_lock); 309 310 mb = udev->mb_addr; 311 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 312 if ((command_size > (udev->cmdr_size / 2)) 313 || tcmu_cmd->data_length > (udev->data_size - 1)) 314 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu " 315 "cmd/data ring buffers\n", command_size, tcmu_cmd->data_length, 316 udev->cmdr_size, udev->data_size); 317 318 while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) { 319 int ret; 320 DEFINE_WAIT(__wait); 321 322 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); 323 324 pr_debug("sleeping for ring space\n"); 325 spin_unlock_irq(&udev->cmdr_lock); 326 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT)); 327 finish_wait(&udev->wait_cmdr, &__wait); 328 if (!ret) { 329 pr_warn("tcmu: command timed out\n"); 330 return -ETIMEDOUT; 331 } 332 333 spin_lock_irq(&udev->cmdr_lock); 334 335 /* We dropped cmdr_lock, cmd_head is stale */ 336 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 337 } 338 339 /* Insert a PAD if end-of-ring space is too small */ 340 if (head_to_end(cmd_head, udev->cmdr_size) < command_size) { 341 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size); 342 343 entry = (void *) mb + CMDR_OFF + cmd_head; 344 tcmu_flush_dcache_range(entry, sizeof(*entry)); 345 tcmu_hdr_set_op(&entry->hdr, TCMU_OP_PAD); 346 tcmu_hdr_set_len(&entry->hdr, pad_size); 347 348 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size); 349 350 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 351 WARN_ON(cmd_head != 0); 352 } 353 354 entry = (void *) mb + CMDR_OFF + cmd_head; 355 tcmu_flush_dcache_range(entry, sizeof(*entry)); 356 tcmu_hdr_set_op(&entry->hdr, TCMU_OP_CMD); 357 tcmu_hdr_set_len(&entry->hdr, command_size); 358 entry->cmd_id = tcmu_cmd->cmd_id; 359 360 /* 361 * Fix up iovecs, and handle if allocation in data ring wrapped. 362 */ 363 iov = &entry->req.iov[0]; 364 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 365 size_t copy_bytes = min((size_t)sg->length, 366 head_to_end(udev->data_head, udev->data_size)); 367 void *from = kmap_atomic(sg_page(sg)) + sg->offset; 368 void *to = (void *) mb + udev->data_off + udev->data_head; 369 370 if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) { 371 memcpy(to, from, copy_bytes); 372 tcmu_flush_dcache_range(to, copy_bytes); 373 } 374 375 /* Even iov_base is relative to mb_addr */ 376 iov->iov_len = copy_bytes; 377 iov->iov_base = (void *) udev->data_off + udev->data_head; 378 iov_cnt++; 379 iov++; 380 381 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 382 383 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */ 384 if (sg->length != copy_bytes) { 385 from += copy_bytes; 386 copy_bytes = sg->length - copy_bytes; 387 388 iov->iov_len = copy_bytes; 389 iov->iov_base = (void *) udev->data_off + udev->data_head; 390 391 if (se_cmd->data_direction == DMA_TO_DEVICE) { 392 to = (void *) mb + udev->data_off + udev->data_head; 393 memcpy(to, from, copy_bytes); 394 tcmu_flush_dcache_range(to, copy_bytes); 395 } 396 397 iov_cnt++; 398 iov++; 399 400 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 401 } 402 403 kunmap_atomic(from); 404 } 405 entry->req.iov_cnt = iov_cnt; 406 407 /* All offsets relative to mb_addr, not start of entry! */ 408 cdb_off = CMDR_OFF + cmd_head + base_command_size; 409 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb)); 410 entry->req.cdb_off = cdb_off; 411 tcmu_flush_dcache_range(entry, sizeof(*entry)); 412 413 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); 414 tcmu_flush_dcache_range(mb, sizeof(*mb)); 415 416 spin_unlock_irq(&udev->cmdr_lock); 417 418 /* TODO: only if FLUSH and FUA? */ 419 uio_event_notify(&udev->uio_info); 420 421 mod_timer(&udev->timeout, 422 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT))); 423 424 return 0; 425} 426 427static int tcmu_queue_cmd(struct se_cmd *se_cmd) 428{ 429 struct se_device *se_dev = se_cmd->se_dev; 430 struct tcmu_dev *udev = TCMU_DEV(se_dev); 431 struct tcmu_cmd *tcmu_cmd; 432 int ret; 433 434 tcmu_cmd = tcmu_alloc_cmd(se_cmd); 435 if (!tcmu_cmd) 436 return -ENOMEM; 437 438 ret = tcmu_queue_cmd_ring(tcmu_cmd); 439 if (ret < 0) { 440 pr_err("TCMU: Could not queue command\n"); 441 spin_lock_irq(&udev->commands_lock); 442 idr_remove(&udev->commands, tcmu_cmd->cmd_id); 443 spin_unlock_irq(&udev->commands_lock); 444 445 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 446 } 447 448 return ret; 449} 450 451static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry) 452{ 453 struct se_cmd *se_cmd = cmd->se_cmd; 454 struct tcmu_dev *udev = cmd->tcmu_dev; 455 456 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 457 /* cmd has been completed already from timeout, just reclaim data 458 ring space */ 459 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 460 return; 461 } 462 463 if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) { 464 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, 465 se_cmd->scsi_sense_length); 466 467 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 468 } 469 else if (se_cmd->data_direction == DMA_FROM_DEVICE) { 470 struct scatterlist *sg; 471 int i; 472 473 /* It'd be easier to look at entry's iovec again, but UAM */ 474 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) { 475 size_t copy_bytes; 476 void *to; 477 void *from; 478 479 copy_bytes = min((size_t)sg->length, 480 head_to_end(udev->data_tail, udev->data_size)); 481 482 to = kmap_atomic(sg_page(sg)) + sg->offset; 483 WARN_ON(sg->length + sg->offset > PAGE_SIZE); 484 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 485 tcmu_flush_dcache_range(from, copy_bytes); 486 memcpy(to, from, copy_bytes); 487 488 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 489 490 /* Uh oh, wrapped the data buffer for this sg's data */ 491 if (sg->length != copy_bytes) { 492 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail; 493 WARN_ON(udev->data_tail); 494 to += copy_bytes; 495 copy_bytes = sg->length - copy_bytes; 496 tcmu_flush_dcache_range(from, copy_bytes); 497 memcpy(to, from, copy_bytes); 498 499 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 500 } 501 502 kunmap_atomic(to); 503 } 504 505 } else if (se_cmd->data_direction == DMA_TO_DEVICE) { 506 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 507 } else { 508 pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction); 509 } 510 511 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); 512 cmd->se_cmd = NULL; 513 514 kmem_cache_free(tcmu_cmd_cache, cmd); 515} 516 517static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) 518{ 519 struct tcmu_mailbox *mb; 520 LIST_HEAD(cpl_cmds); 521 unsigned long flags; 522 int handled = 0; 523 524 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { 525 pr_err("ring broken, not handling completions\n"); 526 return 0; 527 } 528 529 spin_lock_irqsave(&udev->cmdr_lock, flags); 530 531 mb = udev->mb_addr; 532 tcmu_flush_dcache_range(mb, sizeof(*mb)); 533 534 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) { 535 536 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; 537 struct tcmu_cmd *cmd; 538 539 tcmu_flush_dcache_range(entry, sizeof(*entry)); 540 541 if (tcmu_hdr_get_op(&entry->hdr) == TCMU_OP_PAD) { 542 UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); 543 continue; 544 } 545 WARN_ON(tcmu_hdr_get_op(&entry->hdr) != TCMU_OP_CMD); 546 547 spin_lock(&udev->commands_lock); 548 cmd = idr_find(&udev->commands, entry->cmd_id); 549 if (cmd) 550 idr_remove(&udev->commands, cmd->cmd_id); 551 spin_unlock(&udev->commands_lock); 552 553 if (!cmd) { 554 pr_err("cmd_id not found, ring is broken\n"); 555 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); 556 break; 557 } 558 559 tcmu_handle_completion(cmd, entry); 560 561 UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); 562 563 handled++; 564 } 565 566 if (mb->cmd_tail == mb->cmd_head) 567 del_timer(&udev->timeout); /* no more pending cmds */ 568 569 spin_unlock_irqrestore(&udev->cmdr_lock, flags); 570 571 wake_up(&udev->wait_cmdr); 572 573 return handled; 574} 575 576static int tcmu_check_expired_cmd(int id, void *p, void *data) 577{ 578 struct tcmu_cmd *cmd = p; 579 580 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 581 return 0; 582 583 if (!time_after(cmd->deadline, jiffies)) 584 return 0; 585 586 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags); 587 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); 588 cmd->se_cmd = NULL; 589 590 kmem_cache_free(tcmu_cmd_cache, cmd); 591 592 return 0; 593} 594 595static void tcmu_device_timedout(unsigned long data) 596{ 597 struct tcmu_dev *udev = (struct tcmu_dev *)data; 598 unsigned long flags; 599 int handled; 600 601 handled = tcmu_handle_completions(udev); 602 603 pr_warn("%d completions handled from timeout\n", handled); 604 605 spin_lock_irqsave(&udev->commands_lock, flags); 606 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); 607 spin_unlock_irqrestore(&udev->commands_lock, flags); 608 609 /* 610 * We don't need to wakeup threads on wait_cmdr since they have their 611 * own timeout. 612 */ 613} 614 615static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) 616{ 617 struct tcmu_hba *tcmu_hba; 618 619 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL); 620 if (!tcmu_hba) 621 return -ENOMEM; 622 623 tcmu_hba->host_id = host_id; 624 hba->hba_ptr = tcmu_hba; 625 626 return 0; 627} 628 629static void tcmu_detach_hba(struct se_hba *hba) 630{ 631 kfree(hba->hba_ptr); 632 hba->hba_ptr = NULL; 633} 634 635static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 636{ 637 struct tcmu_dev *udev; 638 639 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL); 640 if (!udev) 641 return NULL; 642 643 udev->name = kstrdup(name, GFP_KERNEL); 644 if (!udev->name) { 645 kfree(udev); 646 return NULL; 647 } 648 649 udev->hba = hba; 650 651 init_waitqueue_head(&udev->wait_cmdr); 652 spin_lock_init(&udev->cmdr_lock); 653 654 idr_init(&udev->commands); 655 spin_lock_init(&udev->commands_lock); 656 657 setup_timer(&udev->timeout, tcmu_device_timedout, 658 (unsigned long)udev); 659 660 udev->pass_level = TCMU_PASS_ALL; 661 662 return &udev->se_dev; 663} 664 665static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) 666{ 667 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info); 668 669 tcmu_handle_completions(tcmu_dev); 670 671 return 0; 672} 673 674/* 675 * mmap code from uio.c. Copied here because we want to hook mmap() 676 * and this stuff must come along. 677 */ 678static int tcmu_find_mem_index(struct vm_area_struct *vma) 679{ 680 struct tcmu_dev *udev = vma->vm_private_data; 681 struct uio_info *info = &udev->uio_info; 682 683 if (vma->vm_pgoff < MAX_UIO_MAPS) { 684 if (info->mem[vma->vm_pgoff].size == 0) 685 return -1; 686 return (int)vma->vm_pgoff; 687 } 688 return -1; 689} 690 691static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 692{ 693 struct tcmu_dev *udev = vma->vm_private_data; 694 struct uio_info *info = &udev->uio_info; 695 struct page *page; 696 unsigned long offset; 697 void *addr; 698 699 int mi = tcmu_find_mem_index(vma); 700 if (mi < 0) 701 return VM_FAULT_SIGBUS; 702 703 /* 704 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 705 * to use mem[N]. 706 */ 707 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 708 709 addr = (void *)(unsigned long)info->mem[mi].addr + offset; 710 if (info->mem[mi].memtype == UIO_MEM_LOGICAL) 711 page = virt_to_page(addr); 712 else 713 page = vmalloc_to_page(addr); 714 get_page(page); 715 vmf->page = page; 716 return 0; 717} 718 719static const struct vm_operations_struct tcmu_vm_ops = { 720 .fault = tcmu_vma_fault, 721}; 722 723static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma) 724{ 725 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 726 727 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 728 vma->vm_ops = &tcmu_vm_ops; 729 730 vma->vm_private_data = udev; 731 732 /* Ensure the mmap is exactly the right size */ 733 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT)) 734 return -EINVAL; 735 736 return 0; 737} 738 739static int tcmu_open(struct uio_info *info, struct inode *inode) 740{ 741 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 742 743 /* O_EXCL not supported for char devs, so fake it? */ 744 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags)) 745 return -EBUSY; 746 747 pr_debug("open\n"); 748 749 return 0; 750} 751 752static int tcmu_release(struct uio_info *info, struct inode *inode) 753{ 754 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 755 756 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags); 757 758 pr_debug("close\n"); 759 760 return 0; 761} 762 763static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) 764{ 765 struct sk_buff *skb; 766 void *msg_header; 767 int ret = -ENOMEM; 768 769 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); 770 if (!skb) 771 return ret; 772 773 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); 774 if (!msg_header) 775 goto free_skb; 776 777 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); 778 if (ret < 0) 779 goto free_skb; 780 781 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); 782 if (ret < 0) 783 goto free_skb; 784 785 ret = genlmsg_end(skb, msg_header); 786 if (ret < 0) 787 goto free_skb; 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; 797free_skb: 798 nlmsg_free(skb); 799 return ret; 800} 801 802static 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 878err_netlink: 879 uio_unregister_device(&udev->uio_info); 880err_register: 881 vfree(udev->mb_addr); 882err_vzalloc: 883 kfree(info->name); 884 885 return ret; 886} 887 888static 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 897static 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 926enum { 927 Opt_dev_config, Opt_dev_size, Opt_err, Opt_pass_level, 928}; 929 930static 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 937static 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 996static 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 1009static 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 1017static sense_reason_t 1018tcmu_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 1031static sense_reason_t 1032tcmu_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 1042static 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 1050static sense_reason_t 1051tcmu_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 1095static struct se_subsystem_api tcmu_template = { 1096 .name = "user", 1097 .inquiry_prod = "USER", 1098 .inquiry_rev = TCMU_VERSION, 1099 .owner = THIS_MODULE, 1100 .transport_type = TRANSPORT_PLUGIN_VHBA_PDEV, 1101 .attach_hba = tcmu_attach_hba, 1102 .detach_hba = tcmu_detach_hba, 1103 .alloc_device = tcmu_alloc_device, 1104 .configure_device = tcmu_configure_device, 1105 .free_device = tcmu_free_device, 1106 .parse_cdb = tcmu_parse_cdb, 1107 .set_configfs_dev_params = tcmu_set_configfs_dev_params, 1108 .show_configfs_dev_params = tcmu_show_configfs_dev_params, 1109 .get_device_type = sbc_get_device_type, 1110 .get_blocks = tcmu_get_blocks, 1111}; 1112 1113static int __init tcmu_module_init(void) 1114{ 1115 int ret; 1116 1117 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0); 1118 1119 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache", 1120 sizeof(struct tcmu_cmd), 1121 __alignof__(struct tcmu_cmd), 1122 0, NULL); 1123 if (!tcmu_cmd_cache) 1124 return -ENOMEM; 1125 1126 tcmu_root_device = root_device_register("tcm_user"); 1127 if (IS_ERR(tcmu_root_device)) { 1128 ret = PTR_ERR(tcmu_root_device); 1129 goto out_free_cache; 1130 } 1131 1132 ret = genl_register_family(&tcmu_genl_family); 1133 if (ret < 0) { 1134 goto out_unreg_device; 1135 } 1136 1137 ret = transport_subsystem_register(&tcmu_template); 1138 if (ret) 1139 goto out_unreg_genl; 1140 1141 return 0; 1142 1143out_unreg_genl: 1144 genl_unregister_family(&tcmu_genl_family); 1145out_unreg_device: 1146 root_device_unregister(tcmu_root_device); 1147out_free_cache: 1148 kmem_cache_destroy(tcmu_cmd_cache); 1149 1150 return ret; 1151} 1152 1153static void __exit tcmu_module_exit(void) 1154{ 1155 transport_subsystem_release(&tcmu_template); 1156 genl_unregister_family(&tcmu_genl_family); 1157 root_device_unregister(tcmu_root_device); 1158 kmem_cache_destroy(tcmu_cmd_cache); 1159} 1160 1161MODULE_DESCRIPTION("TCM USER subsystem plugin"); 1162MODULE_AUTHOR("Shaohua Li <shli@kernel.org>"); 1163MODULE_AUTHOR("Andy Grover <agrover@redhat.com>"); 1164MODULE_LICENSE("GPL"); 1165 1166module_init(tcmu_module_init); 1167module_exit(tcmu_module_exit); 1168