1 /* 2 * Copyright (C) 2013 Shaohua Li <shli@kernel.org> 3 * Copyright (C) 2014 Red Hat, Inc. 4 * Copyright (C) 2015 Arrikto, Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program; if not, write to the Free Software Foundation, Inc., 17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 18 */ 19 20 #include <linux/spinlock.h> 21 #include <linux/module.h> 22 #include <linux/idr.h> 23 #include <linux/kernel.h> 24 #include <linux/timer.h> 25 #include <linux/parser.h> 26 #include <linux/vmalloc.h> 27 #include <linux/uio_driver.h> 28 #include <linux/stringify.h> 29 #include <net/genetlink.h> 30 #include <scsi/scsi_common.h> 31 #include <scsi/scsi_proto.h> 32 #include <target/target_core_base.h> 33 #include <target/target_core_fabric.h> 34 #include <target/target_core_backend.h> 35 36 #include <linux/target_core_user.h> 37 38 /* 39 * Define a shared-memory interface for LIO to pass SCSI commands and 40 * data to userspace for processing. This is to allow backends that 41 * are too complex for in-kernel support to be possible. 42 * 43 * It uses the UIO framework to do a lot of the device-creation and 44 * introspection work for us. 45 * 46 * See the .h file for how the ring is laid out. Note that while the 47 * command ring is defined, the particulars of the data area are 48 * not. Offset values in the command entry point to other locations 49 * internal to the mmap()ed area. There is separate space outside the 50 * command ring for data buffers. This leaves maximum flexibility for 51 * moving buffer allocations, or even page flipping or other 52 * allocation techniques, without altering the command ring layout. 53 * 54 * SECURITY: 55 * The user process must be assumed to be malicious. There's no way to 56 * prevent it breaking the command ring protocol if it wants, but in 57 * order to prevent other issues we must only ever read *data* from 58 * the shared memory area, not offsets or sizes. This applies to 59 * command ring entries as well as the mailbox. Extra code needed for 60 * this may have a 'UAM' comment. 61 */ 62 63 64 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC) 65 66 #define CMDR_SIZE (16 * 4096) 67 #define DATA_SIZE (257 * 4096) 68 69 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE) 70 71 static struct device *tcmu_root_device; 72 73 struct tcmu_hba { 74 u32 host_id; 75 }; 76 77 #define TCMU_CONFIG_LEN 256 78 79 struct tcmu_dev { 80 struct se_device se_dev; 81 82 char *name; 83 struct se_hba *hba; 84 85 #define TCMU_DEV_BIT_OPEN 0 86 #define TCMU_DEV_BIT_BROKEN 1 87 unsigned long flags; 88 89 struct uio_info uio_info; 90 91 struct tcmu_mailbox *mb_addr; 92 size_t dev_size; 93 u32 cmdr_size; 94 u32 cmdr_last_cleaned; 95 /* Offset of data ring from start of mb */ 96 size_t data_off; 97 size_t data_size; 98 /* Ring head + tail values. */ 99 /* Must add data_off and mb_addr to get the address */ 100 size_t data_head; 101 size_t data_tail; 102 103 wait_queue_head_t wait_cmdr; 104 /* TODO should this be a mutex? */ 105 spinlock_t cmdr_lock; 106 107 struct idr commands; 108 spinlock_t commands_lock; 109 110 struct timer_list timeout; 111 112 char dev_config[TCMU_CONFIG_LEN]; 113 }; 114 115 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev) 116 117 #define CMDR_OFF sizeof(struct tcmu_mailbox) 118 119 struct tcmu_cmd { 120 struct se_cmd *se_cmd; 121 struct tcmu_dev *tcmu_dev; 122 123 uint16_t cmd_id; 124 125 /* Can't use se_cmd->data_length when cleaning up expired cmds, because if 126 cmd has been completed then accessing se_cmd is off limits */ 127 size_t data_length; 128 129 unsigned long deadline; 130 131 #define TCMU_CMD_BIT_EXPIRED 0 132 unsigned long flags; 133 }; 134 135 static struct kmem_cache *tcmu_cmd_cache; 136 137 /* multicast group */ 138 enum tcmu_multicast_groups { 139 TCMU_MCGRP_CONFIG, 140 }; 141 142 static const struct genl_multicast_group tcmu_mcgrps[] = { 143 [TCMU_MCGRP_CONFIG] = { .name = "config", }, 144 }; 145 146 /* Our generic netlink family */ 147 static struct genl_family tcmu_genl_family = { 148 .id = GENL_ID_GENERATE, 149 .hdrsize = 0, 150 .name = "TCM-USER", 151 .version = 1, 152 .maxattr = TCMU_ATTR_MAX, 153 .mcgrps = tcmu_mcgrps, 154 .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps), 155 }; 156 157 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) 158 { 159 struct se_device *se_dev = se_cmd->se_dev; 160 struct tcmu_dev *udev = TCMU_DEV(se_dev); 161 struct tcmu_cmd *tcmu_cmd; 162 int cmd_id; 163 164 tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL); 165 if (!tcmu_cmd) 166 return NULL; 167 168 tcmu_cmd->se_cmd = se_cmd; 169 tcmu_cmd->tcmu_dev = udev; 170 tcmu_cmd->data_length = se_cmd->data_length; 171 172 if (se_cmd->se_cmd_flags & SCF_BIDI) { 173 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents)); 174 tcmu_cmd->data_length += se_cmd->t_bidi_data_sg->length; 175 } 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 static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 236 struct scatterlist *data_sg, unsigned int data_nents, 237 struct iovec **iov, int *iov_cnt, bool copy_data) 238 { 239 int i; 240 void *from, *to; 241 size_t copy_bytes; 242 struct scatterlist *sg; 243 244 for_each_sg(data_sg, sg, data_nents, i) { 245 copy_bytes = min_t(size_t, sg->length, 246 head_to_end(udev->data_head, udev->data_size)); 247 from = kmap_atomic(sg_page(sg)) + sg->offset; 248 to = (void *) udev->mb_addr + udev->data_off + udev->data_head; 249 250 if (copy_data) { 251 memcpy(to, from, copy_bytes); 252 tcmu_flush_dcache_range(to, copy_bytes); 253 } 254 255 /* Even iov_base is relative to mb_addr */ 256 (*iov)->iov_len = copy_bytes; 257 (*iov)->iov_base = (void __user *) udev->data_off + 258 udev->data_head; 259 (*iov_cnt)++; 260 (*iov)++; 261 262 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size); 263 264 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */ 265 if (sg->length != copy_bytes) { 266 void *from_skip = from + copy_bytes; 267 268 copy_bytes = sg->length - copy_bytes; 269 270 (*iov)->iov_len = copy_bytes; 271 (*iov)->iov_base = (void __user *) udev->data_off + 272 udev->data_head; 273 274 if (copy_data) { 275 to = (void *) udev->mb_addr + 276 udev->data_off + udev->data_head; 277 memcpy(to, from_skip, copy_bytes); 278 tcmu_flush_dcache_range(to, copy_bytes); 279 } 280 281 (*iov_cnt)++; 282 (*iov)++; 283 284 UPDATE_HEAD(udev->data_head, 285 copy_bytes, udev->data_size); 286 } 287 288 kunmap_atomic(from - sg->offset); 289 } 290 } 291 292 static void gather_and_free_data_area(struct tcmu_dev *udev, 293 struct scatterlist *data_sg, unsigned int data_nents) 294 { 295 int i; 296 void *from, *to; 297 size_t copy_bytes; 298 struct scatterlist *sg; 299 300 /* It'd be easier to look at entry's iovec again, but UAM */ 301 for_each_sg(data_sg, sg, data_nents, i) { 302 copy_bytes = min_t(size_t, sg->length, 303 head_to_end(udev->data_tail, udev->data_size)); 304 305 to = kmap_atomic(sg_page(sg)) + sg->offset; 306 WARN_ON(sg->length + sg->offset > PAGE_SIZE); 307 from = (void *) udev->mb_addr + 308 udev->data_off + udev->data_tail; 309 tcmu_flush_dcache_range(from, copy_bytes); 310 memcpy(to, from, copy_bytes); 311 312 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size); 313 314 /* Uh oh, wrapped the data buffer for this sg's data */ 315 if (sg->length != copy_bytes) { 316 void *to_skip = to + copy_bytes; 317 318 from = (void *) udev->mb_addr + 319 udev->data_off + udev->data_tail; 320 WARN_ON(udev->data_tail); 321 copy_bytes = sg->length - copy_bytes; 322 tcmu_flush_dcache_range(from, copy_bytes); 323 memcpy(to_skip, from, copy_bytes); 324 325 UPDATE_HEAD(udev->data_tail, 326 copy_bytes, udev->data_size); 327 } 328 kunmap_atomic(to - sg->offset); 329 } 330 } 331 332 /* 333 * We can't queue a command until we have space available on the cmd ring *and* 334 * space available on the data ring. 335 * 336 * Called with ring lock held. 337 */ 338 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed) 339 { 340 struct tcmu_mailbox *mb = udev->mb_addr; 341 size_t space; 342 u32 cmd_head; 343 size_t cmd_needed; 344 345 tcmu_flush_dcache_range(mb, sizeof(*mb)); 346 347 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 348 349 /* 350 * If cmd end-of-ring space is too small then we need space for a NOP plus 351 * original cmd - cmds are internally contiguous. 352 */ 353 if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size) 354 cmd_needed = cmd_size; 355 else 356 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size); 357 358 space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size); 359 if (space < cmd_needed) { 360 pr_debug("no cmd space: %u %u %u\n", cmd_head, 361 udev->cmdr_last_cleaned, udev->cmdr_size); 362 return false; 363 } 364 365 space = spc_free(udev->data_head, udev->data_tail, udev->data_size); 366 if (space < data_needed) { 367 pr_debug("no data space: %zu %zu %zu\n", udev->data_head, 368 udev->data_tail, udev->data_size); 369 return false; 370 } 371 372 return true; 373 } 374 375 static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 376 { 377 struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; 378 struct se_cmd *se_cmd = tcmu_cmd->se_cmd; 379 size_t base_command_size, command_size; 380 struct tcmu_mailbox *mb; 381 struct tcmu_cmd_entry *entry; 382 struct iovec *iov; 383 int iov_cnt; 384 uint32_t cmd_head; 385 uint64_t cdb_off; 386 bool copy_to_data_area; 387 388 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) 389 return -EINVAL; 390 391 /* 392 * Must be a certain minimum size for response sense info, but 393 * also may be larger if the iov array is large. 394 * 395 * iovs = sgl_nents+1, for end-of-ring case, plus another 1 396 * b/c size == offsetof one-past-element. 397 */ 398 base_command_size = max(offsetof(struct tcmu_cmd_entry, 399 req.iov[se_cmd->t_bidi_data_nents + 400 se_cmd->t_data_nents + 2]), 401 sizeof(struct tcmu_cmd_entry)); 402 command_size = base_command_size 403 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE); 404 405 WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1)); 406 407 spin_lock_irq(&udev->cmdr_lock); 408 409 mb = udev->mb_addr; 410 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 411 if ((command_size > (udev->cmdr_size / 2)) 412 || tcmu_cmd->data_length > (udev->data_size - 1)) 413 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu " 414 "cmd/data ring buffers\n", command_size, tcmu_cmd->data_length, 415 udev->cmdr_size, udev->data_size); 416 417 while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) { 418 int ret; 419 DEFINE_WAIT(__wait); 420 421 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); 422 423 pr_debug("sleeping for ring space\n"); 424 spin_unlock_irq(&udev->cmdr_lock); 425 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT)); 426 finish_wait(&udev->wait_cmdr, &__wait); 427 if (!ret) { 428 pr_warn("tcmu: command timed out\n"); 429 return -ETIMEDOUT; 430 } 431 432 spin_lock_irq(&udev->cmdr_lock); 433 434 /* We dropped cmdr_lock, cmd_head is stale */ 435 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 436 } 437 438 /* Insert a PAD if end-of-ring space is too small */ 439 if (head_to_end(cmd_head, udev->cmdr_size) < command_size) { 440 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size); 441 442 entry = (void *) mb + CMDR_OFF + cmd_head; 443 tcmu_flush_dcache_range(entry, sizeof(*entry)); 444 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD); 445 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size); 446 entry->hdr.cmd_id = 0; /* not used for PAD */ 447 entry->hdr.kflags = 0; 448 entry->hdr.uflags = 0; 449 450 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size); 451 452 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 453 WARN_ON(cmd_head != 0); 454 } 455 456 entry = (void *) mb + CMDR_OFF + cmd_head; 457 tcmu_flush_dcache_range(entry, sizeof(*entry)); 458 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD); 459 tcmu_hdr_set_len(&entry->hdr.len_op, command_size); 460 entry->hdr.cmd_id = tcmu_cmd->cmd_id; 461 entry->hdr.kflags = 0; 462 entry->hdr.uflags = 0; 463 464 /* 465 * Fix up iovecs, and handle if allocation in data ring wrapped. 466 */ 467 iov = &entry->req.iov[0]; 468 iov_cnt = 0; 469 copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE 470 || se_cmd->se_cmd_flags & SCF_BIDI); 471 alloc_and_scatter_data_area(udev, se_cmd->t_data_sg, 472 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area); 473 entry->req.iov_cnt = iov_cnt; 474 entry->req.iov_dif_cnt = 0; 475 476 /* Handle BIDI commands */ 477 iov_cnt = 0; 478 alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg, 479 se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false); 480 entry->req.iov_bidi_cnt = iov_cnt; 481 482 /* All offsets relative to mb_addr, not start of entry! */ 483 cdb_off = CMDR_OFF + cmd_head + base_command_size; 484 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb)); 485 entry->req.cdb_off = cdb_off; 486 tcmu_flush_dcache_range(entry, sizeof(*entry)); 487 488 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); 489 tcmu_flush_dcache_range(mb, sizeof(*mb)); 490 491 spin_unlock_irq(&udev->cmdr_lock); 492 493 /* TODO: only if FLUSH and FUA? */ 494 uio_event_notify(&udev->uio_info); 495 496 mod_timer(&udev->timeout, 497 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT))); 498 499 return 0; 500 } 501 502 static int tcmu_queue_cmd(struct se_cmd *se_cmd) 503 { 504 struct se_device *se_dev = se_cmd->se_dev; 505 struct tcmu_dev *udev = TCMU_DEV(se_dev); 506 struct tcmu_cmd *tcmu_cmd; 507 int ret; 508 509 tcmu_cmd = tcmu_alloc_cmd(se_cmd); 510 if (!tcmu_cmd) 511 return -ENOMEM; 512 513 ret = tcmu_queue_cmd_ring(tcmu_cmd); 514 if (ret < 0) { 515 pr_err("TCMU: Could not queue command\n"); 516 spin_lock_irq(&udev->commands_lock); 517 idr_remove(&udev->commands, tcmu_cmd->cmd_id); 518 spin_unlock_irq(&udev->commands_lock); 519 520 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 521 } 522 523 return ret; 524 } 525 526 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry) 527 { 528 struct se_cmd *se_cmd = cmd->se_cmd; 529 struct tcmu_dev *udev = cmd->tcmu_dev; 530 531 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 532 /* cmd has been completed already from timeout, just reclaim data 533 ring space */ 534 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 535 return; 536 } 537 538 if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) { 539 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 540 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n", 541 cmd->se_cmd); 542 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION; 543 } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) { 544 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, 545 se_cmd->scsi_sense_length); 546 547 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 548 } else if (se_cmd->se_cmd_flags & SCF_BIDI) { 549 /* Discard data_out buffer */ 550 UPDATE_HEAD(udev->data_tail, 551 (size_t)se_cmd->t_data_sg->length, udev->data_size); 552 553 /* Get Data-In buffer */ 554 gather_and_free_data_area(udev, 555 se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents); 556 } else if (se_cmd->data_direction == DMA_FROM_DEVICE) { 557 gather_and_free_data_area(udev, 558 se_cmd->t_data_sg, se_cmd->t_data_nents); 559 } else if (se_cmd->data_direction == DMA_TO_DEVICE) { 560 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size); 561 } else if (se_cmd->data_direction != DMA_NONE) { 562 pr_warn("TCMU: data direction was %d!\n", 563 se_cmd->data_direction); 564 } 565 566 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); 567 cmd->se_cmd = NULL; 568 569 kmem_cache_free(tcmu_cmd_cache, cmd); 570 } 571 572 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) 573 { 574 struct tcmu_mailbox *mb; 575 unsigned long flags; 576 int handled = 0; 577 578 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { 579 pr_err("ring broken, not handling completions\n"); 580 return 0; 581 } 582 583 spin_lock_irqsave(&udev->cmdr_lock, flags); 584 585 mb = udev->mb_addr; 586 tcmu_flush_dcache_range(mb, sizeof(*mb)); 587 588 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) { 589 590 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; 591 struct tcmu_cmd *cmd; 592 593 tcmu_flush_dcache_range(entry, sizeof(*entry)); 594 595 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) { 596 UPDATE_HEAD(udev->cmdr_last_cleaned, 597 tcmu_hdr_get_len(entry->hdr.len_op), 598 udev->cmdr_size); 599 continue; 600 } 601 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD); 602 603 spin_lock(&udev->commands_lock); 604 cmd = idr_find(&udev->commands, entry->hdr.cmd_id); 605 if (cmd) 606 idr_remove(&udev->commands, cmd->cmd_id); 607 spin_unlock(&udev->commands_lock); 608 609 if (!cmd) { 610 pr_err("cmd_id not found, ring is broken\n"); 611 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); 612 break; 613 } 614 615 tcmu_handle_completion(cmd, entry); 616 617 UPDATE_HEAD(udev->cmdr_last_cleaned, 618 tcmu_hdr_get_len(entry->hdr.len_op), 619 udev->cmdr_size); 620 621 handled++; 622 } 623 624 if (mb->cmd_tail == mb->cmd_head) 625 del_timer(&udev->timeout); /* no more pending cmds */ 626 627 spin_unlock_irqrestore(&udev->cmdr_lock, flags); 628 629 wake_up(&udev->wait_cmdr); 630 631 return handled; 632 } 633 634 static int tcmu_check_expired_cmd(int id, void *p, void *data) 635 { 636 struct tcmu_cmd *cmd = p; 637 638 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 639 return 0; 640 641 if (!time_after(cmd->deadline, jiffies)) 642 return 0; 643 644 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags); 645 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); 646 cmd->se_cmd = NULL; 647 648 kmem_cache_free(tcmu_cmd_cache, cmd); 649 650 return 0; 651 } 652 653 static void tcmu_device_timedout(unsigned long data) 654 { 655 struct tcmu_dev *udev = (struct tcmu_dev *)data; 656 unsigned long flags; 657 int handled; 658 659 handled = tcmu_handle_completions(udev); 660 661 pr_warn("%d completions handled from timeout\n", handled); 662 663 spin_lock_irqsave(&udev->commands_lock, flags); 664 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); 665 spin_unlock_irqrestore(&udev->commands_lock, flags); 666 667 /* 668 * We don't need to wakeup threads on wait_cmdr since they have their 669 * own timeout. 670 */ 671 } 672 673 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) 674 { 675 struct tcmu_hba *tcmu_hba; 676 677 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL); 678 if (!tcmu_hba) 679 return -ENOMEM; 680 681 tcmu_hba->host_id = host_id; 682 hba->hba_ptr = tcmu_hba; 683 684 return 0; 685 } 686 687 static void tcmu_detach_hba(struct se_hba *hba) 688 { 689 kfree(hba->hba_ptr); 690 hba->hba_ptr = NULL; 691 } 692 693 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 694 { 695 struct tcmu_dev *udev; 696 697 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL); 698 if (!udev) 699 return NULL; 700 701 udev->name = kstrdup(name, GFP_KERNEL); 702 if (!udev->name) { 703 kfree(udev); 704 return NULL; 705 } 706 707 udev->hba = hba; 708 709 init_waitqueue_head(&udev->wait_cmdr); 710 spin_lock_init(&udev->cmdr_lock); 711 712 idr_init(&udev->commands); 713 spin_lock_init(&udev->commands_lock); 714 715 setup_timer(&udev->timeout, tcmu_device_timedout, 716 (unsigned long)udev); 717 718 return &udev->se_dev; 719 } 720 721 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) 722 { 723 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info); 724 725 tcmu_handle_completions(tcmu_dev); 726 727 return 0; 728 } 729 730 /* 731 * mmap code from uio.c. Copied here because we want to hook mmap() 732 * and this stuff must come along. 733 */ 734 static int tcmu_find_mem_index(struct vm_area_struct *vma) 735 { 736 struct tcmu_dev *udev = vma->vm_private_data; 737 struct uio_info *info = &udev->uio_info; 738 739 if (vma->vm_pgoff < MAX_UIO_MAPS) { 740 if (info->mem[vma->vm_pgoff].size == 0) 741 return -1; 742 return (int)vma->vm_pgoff; 743 } 744 return -1; 745 } 746 747 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 748 { 749 struct tcmu_dev *udev = vma->vm_private_data; 750 struct uio_info *info = &udev->uio_info; 751 struct page *page; 752 unsigned long offset; 753 void *addr; 754 755 int mi = tcmu_find_mem_index(vma); 756 if (mi < 0) 757 return VM_FAULT_SIGBUS; 758 759 /* 760 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 761 * to use mem[N]. 762 */ 763 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 764 765 addr = (void *)(unsigned long)info->mem[mi].addr + offset; 766 if (info->mem[mi].memtype == UIO_MEM_LOGICAL) 767 page = virt_to_page(addr); 768 else 769 page = vmalloc_to_page(addr); 770 get_page(page); 771 vmf->page = page; 772 return 0; 773 } 774 775 static const struct vm_operations_struct tcmu_vm_ops = { 776 .fault = tcmu_vma_fault, 777 }; 778 779 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma) 780 { 781 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 782 783 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 784 vma->vm_ops = &tcmu_vm_ops; 785 786 vma->vm_private_data = udev; 787 788 /* Ensure the mmap is exactly the right size */ 789 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT)) 790 return -EINVAL; 791 792 return 0; 793 } 794 795 static int tcmu_open(struct uio_info *info, struct inode *inode) 796 { 797 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 798 799 /* O_EXCL not supported for char devs, so fake it? */ 800 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags)) 801 return -EBUSY; 802 803 pr_debug("open\n"); 804 805 return 0; 806 } 807 808 static int tcmu_release(struct uio_info *info, struct inode *inode) 809 { 810 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 811 812 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags); 813 814 pr_debug("close\n"); 815 816 return 0; 817 } 818 819 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) 820 { 821 struct sk_buff *skb; 822 void *msg_header; 823 int ret = -ENOMEM; 824 825 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); 826 if (!skb) 827 return ret; 828 829 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); 830 if (!msg_header) 831 goto free_skb; 832 833 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); 834 if (ret < 0) 835 goto free_skb; 836 837 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); 838 if (ret < 0) 839 goto free_skb; 840 841 genlmsg_end(skb, msg_header); 842 843 ret = genlmsg_multicast(&tcmu_genl_family, skb, 0, 844 TCMU_MCGRP_CONFIG, GFP_KERNEL); 845 846 /* We don't care if no one is listening */ 847 if (ret == -ESRCH) 848 ret = 0; 849 850 return ret; 851 free_skb: 852 nlmsg_free(skb); 853 return ret; 854 } 855 856 static int tcmu_configure_device(struct se_device *dev) 857 { 858 struct tcmu_dev *udev = TCMU_DEV(dev); 859 struct tcmu_hba *hba = udev->hba->hba_ptr; 860 struct uio_info *info; 861 struct tcmu_mailbox *mb; 862 size_t size; 863 size_t used; 864 int ret = 0; 865 char *str; 866 867 info = &udev->uio_info; 868 869 size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name, 870 udev->dev_config); 871 size += 1; /* for \0 */ 872 str = kmalloc(size, GFP_KERNEL); 873 if (!str) 874 return -ENOMEM; 875 876 used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name); 877 878 if (udev->dev_config[0]) 879 snprintf(str + used, size - used, "/%s", udev->dev_config); 880 881 info->name = str; 882 883 udev->mb_addr = vzalloc(TCMU_RING_SIZE); 884 if (!udev->mb_addr) { 885 ret = -ENOMEM; 886 goto err_vzalloc; 887 } 888 889 /* mailbox fits in first part of CMDR space */ 890 udev->cmdr_size = CMDR_SIZE - CMDR_OFF; 891 udev->data_off = CMDR_SIZE; 892 udev->data_size = TCMU_RING_SIZE - CMDR_SIZE; 893 894 mb = udev->mb_addr; 895 mb->version = TCMU_MAILBOX_VERSION; 896 mb->cmdr_off = CMDR_OFF; 897 mb->cmdr_size = udev->cmdr_size; 898 899 WARN_ON(!PAGE_ALIGNED(udev->data_off)); 900 WARN_ON(udev->data_size % PAGE_SIZE); 901 902 info->version = __stringify(TCMU_MAILBOX_VERSION); 903 904 info->mem[0].name = "tcm-user command & data buffer"; 905 info->mem[0].addr = (phys_addr_t) udev->mb_addr; 906 info->mem[0].size = TCMU_RING_SIZE; 907 info->mem[0].memtype = UIO_MEM_VIRTUAL; 908 909 info->irqcontrol = tcmu_irqcontrol; 910 info->irq = UIO_IRQ_CUSTOM; 911 912 info->mmap = tcmu_mmap; 913 info->open = tcmu_open; 914 info->release = tcmu_release; 915 916 ret = uio_register_device(tcmu_root_device, info); 917 if (ret) 918 goto err_register; 919 920 /* Other attributes can be configured in userspace */ 921 dev->dev_attrib.hw_block_size = 512; 922 dev->dev_attrib.hw_max_sectors = 128; 923 dev->dev_attrib.hw_queue_depth = 128; 924 925 ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name, 926 udev->uio_info.uio_dev->minor); 927 if (ret) 928 goto err_netlink; 929 930 return 0; 931 932 err_netlink: 933 uio_unregister_device(&udev->uio_info); 934 err_register: 935 vfree(udev->mb_addr); 936 err_vzalloc: 937 kfree(info->name); 938 939 return ret; 940 } 941 942 static int tcmu_check_pending_cmd(int id, void *p, void *data) 943 { 944 struct tcmu_cmd *cmd = p; 945 946 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 947 return 0; 948 return -EINVAL; 949 } 950 951 static void tcmu_dev_call_rcu(struct rcu_head *p) 952 { 953 struct se_device *dev = container_of(p, struct se_device, rcu_head); 954 struct tcmu_dev *udev = TCMU_DEV(dev); 955 956 kfree(udev); 957 } 958 959 static void tcmu_free_device(struct se_device *dev) 960 { 961 struct tcmu_dev *udev = TCMU_DEV(dev); 962 int i; 963 964 del_timer_sync(&udev->timeout); 965 966 vfree(udev->mb_addr); 967 968 /* Upper layer should drain all requests before calling this */ 969 spin_lock_irq(&udev->commands_lock); 970 i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL); 971 idr_destroy(&udev->commands); 972 spin_unlock_irq(&udev->commands_lock); 973 WARN_ON(i); 974 975 /* Device was configured */ 976 if (udev->uio_info.uio_dev) { 977 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name, 978 udev->uio_info.uio_dev->minor); 979 980 uio_unregister_device(&udev->uio_info); 981 kfree(udev->uio_info.name); 982 kfree(udev->name); 983 } 984 call_rcu(&dev->rcu_head, tcmu_dev_call_rcu); 985 } 986 987 enum { 988 Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err, 989 }; 990 991 static match_table_t tokens = { 992 {Opt_dev_config, "dev_config=%s"}, 993 {Opt_dev_size, "dev_size=%u"}, 994 {Opt_hw_block_size, "hw_block_size=%u"}, 995 {Opt_err, NULL} 996 }; 997 998 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 999 const char *page, ssize_t count) 1000 { 1001 struct tcmu_dev *udev = TCMU_DEV(dev); 1002 char *orig, *ptr, *opts, *arg_p; 1003 substring_t args[MAX_OPT_ARGS]; 1004 int ret = 0, token; 1005 unsigned long tmp_ul; 1006 1007 opts = kstrdup(page, GFP_KERNEL); 1008 if (!opts) 1009 return -ENOMEM; 1010 1011 orig = opts; 1012 1013 while ((ptr = strsep(&opts, ",\n")) != NULL) { 1014 if (!*ptr) 1015 continue; 1016 1017 token = match_token(ptr, tokens, args); 1018 switch (token) { 1019 case Opt_dev_config: 1020 if (match_strlcpy(udev->dev_config, &args[0], 1021 TCMU_CONFIG_LEN) == 0) { 1022 ret = -EINVAL; 1023 break; 1024 } 1025 pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config); 1026 break; 1027 case Opt_dev_size: 1028 arg_p = match_strdup(&args[0]); 1029 if (!arg_p) { 1030 ret = -ENOMEM; 1031 break; 1032 } 1033 ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size); 1034 kfree(arg_p); 1035 if (ret < 0) 1036 pr_err("kstrtoul() failed for dev_size=\n"); 1037 break; 1038 case Opt_hw_block_size: 1039 arg_p = match_strdup(&args[0]); 1040 if (!arg_p) { 1041 ret = -ENOMEM; 1042 break; 1043 } 1044 ret = kstrtoul(arg_p, 0, &tmp_ul); 1045 kfree(arg_p); 1046 if (ret < 0) { 1047 pr_err("kstrtoul() failed for hw_block_size=\n"); 1048 break; 1049 } 1050 if (!tmp_ul) { 1051 pr_err("hw_block_size must be nonzero\n"); 1052 break; 1053 } 1054 dev->dev_attrib.hw_block_size = tmp_ul; 1055 break; 1056 default: 1057 break; 1058 } 1059 } 1060 1061 kfree(orig); 1062 return (!ret) ? count : ret; 1063 } 1064 1065 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b) 1066 { 1067 struct tcmu_dev *udev = TCMU_DEV(dev); 1068 ssize_t bl = 0; 1069 1070 bl = sprintf(b + bl, "Config: %s ", 1071 udev->dev_config[0] ? udev->dev_config : "NULL"); 1072 bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size); 1073 1074 return bl; 1075 } 1076 1077 static sector_t tcmu_get_blocks(struct se_device *dev) 1078 { 1079 struct tcmu_dev *udev = TCMU_DEV(dev); 1080 1081 return div_u64(udev->dev_size - dev->dev_attrib.block_size, 1082 dev->dev_attrib.block_size); 1083 } 1084 1085 static sense_reason_t 1086 tcmu_pass_op(struct se_cmd *se_cmd) 1087 { 1088 int ret = tcmu_queue_cmd(se_cmd); 1089 1090 if (ret != 0) 1091 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 1092 else 1093 return TCM_NO_SENSE; 1094 } 1095 1096 static sense_reason_t 1097 tcmu_parse_cdb(struct se_cmd *cmd) 1098 { 1099 return passthrough_parse_cdb(cmd, tcmu_pass_op); 1100 } 1101 1102 static const struct target_backend_ops tcmu_ops = { 1103 .name = "user", 1104 .inquiry_prod = "USER", 1105 .inquiry_rev = TCMU_VERSION, 1106 .owner = THIS_MODULE, 1107 .transport_flags = TRANSPORT_FLAG_PASSTHROUGH, 1108 .attach_hba = tcmu_attach_hba, 1109 .detach_hba = tcmu_detach_hba, 1110 .alloc_device = tcmu_alloc_device, 1111 .configure_device = tcmu_configure_device, 1112 .free_device = tcmu_free_device, 1113 .parse_cdb = tcmu_parse_cdb, 1114 .set_configfs_dev_params = tcmu_set_configfs_dev_params, 1115 .show_configfs_dev_params = tcmu_show_configfs_dev_params, 1116 .get_device_type = sbc_get_device_type, 1117 .get_blocks = tcmu_get_blocks, 1118 .tb_dev_attrib_attrs = passthrough_attrib_attrs, 1119 }; 1120 1121 static int __init tcmu_module_init(void) 1122 { 1123 int ret; 1124 1125 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0); 1126 1127 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache", 1128 sizeof(struct tcmu_cmd), 1129 __alignof__(struct tcmu_cmd), 1130 0, NULL); 1131 if (!tcmu_cmd_cache) 1132 return -ENOMEM; 1133 1134 tcmu_root_device = root_device_register("tcm_user"); 1135 if (IS_ERR(tcmu_root_device)) { 1136 ret = PTR_ERR(tcmu_root_device); 1137 goto out_free_cache; 1138 } 1139 1140 ret = genl_register_family(&tcmu_genl_family); 1141 if (ret < 0) { 1142 goto out_unreg_device; 1143 } 1144 1145 ret = transport_backend_register(&tcmu_ops); 1146 if (ret) 1147 goto out_unreg_genl; 1148 1149 return 0; 1150 1151 out_unreg_genl: 1152 genl_unregister_family(&tcmu_genl_family); 1153 out_unreg_device: 1154 root_device_unregister(tcmu_root_device); 1155 out_free_cache: 1156 kmem_cache_destroy(tcmu_cmd_cache); 1157 1158 return ret; 1159 } 1160 1161 static void __exit tcmu_module_exit(void) 1162 { 1163 target_backend_unregister(&tcmu_ops); 1164 genl_unregister_family(&tcmu_genl_family); 1165 root_device_unregister(tcmu_root_device); 1166 kmem_cache_destroy(tcmu_cmd_cache); 1167 } 1168 1169 MODULE_DESCRIPTION("TCM USER subsystem plugin"); 1170 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>"); 1171 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>"); 1172 MODULE_LICENSE("GPL"); 1173 1174 module_init(tcmu_module_init); 1175 module_exit(tcmu_module_exit); 1176