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 <linux/bitops.h> 30 #include <net/genetlink.h> 31 #include <scsi/scsi_common.h> 32 #include <scsi/scsi_proto.h> 33 #include <target/target_core_base.h> 34 #include <target/target_core_fabric.h> 35 #include <target/target_core_backend.h> 36 37 #include <linux/target_core_user.h> 38 39 /* 40 * Define a shared-memory interface for LIO to pass SCSI commands and 41 * data to userspace for processing. This is to allow backends that 42 * are too complex for in-kernel support to be possible. 43 * 44 * It uses the UIO framework to do a lot of the device-creation and 45 * introspection work for us. 46 * 47 * See the .h file for how the ring is laid out. Note that while the 48 * command ring is defined, the particulars of the data area are 49 * not. Offset values in the command entry point to other locations 50 * internal to the mmap()ed area. There is separate space outside the 51 * command ring for data buffers. This leaves maximum flexibility for 52 * moving buffer allocations, or even page flipping or other 53 * allocation techniques, without altering the command ring layout. 54 * 55 * SECURITY: 56 * The user process must be assumed to be malicious. There's no way to 57 * prevent it breaking the command ring protocol if it wants, but in 58 * order to prevent other issues we must only ever read *data* from 59 * the shared memory area, not offsets or sizes. This applies to 60 * command ring entries as well as the mailbox. Extra code needed for 61 * this may have a 'UAM' comment. 62 */ 63 64 65 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC) 66 67 #define DATA_BLOCK_BITS 256 68 #define DATA_BLOCK_SIZE 4096 69 70 #define CMDR_SIZE (16 * 4096) 71 #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE) 72 73 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE) 74 75 static struct device *tcmu_root_device; 76 77 struct tcmu_hba { 78 u32 host_id; 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 93 struct uio_info uio_info; 94 95 struct tcmu_mailbox *mb_addr; 96 size_t dev_size; 97 u32 cmdr_size; 98 u32 cmdr_last_cleaned; 99 /* Offset of data area from start of mb */ 100 /* Must add data_off and mb_addr to get the address */ 101 size_t data_off; 102 size_t data_size; 103 104 DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS); 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) 121 122 struct 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 when cleaning up expired cmds, because if 129 cmd has been completed then accessing se_cmd is off limits */ 130 DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS); 131 132 unsigned long deadline; 133 134 #define TCMU_CMD_BIT_EXPIRED 0 135 unsigned long flags; 136 }; 137 138 static struct kmem_cache *tcmu_cmd_cache; 139 140 /* multicast group */ 141 enum tcmu_multicast_groups { 142 TCMU_MCGRP_CONFIG, 143 }; 144 145 static const struct genl_multicast_group tcmu_mcgrps[] = { 146 [TCMU_MCGRP_CONFIG] = { .name = "config", }, 147 }; 148 149 /* Our generic netlink family */ 150 static 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 .netnsok = true, 159 }; 160 161 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) 162 { 163 struct se_device *se_dev = se_cmd->se_dev; 164 struct tcmu_dev *udev = TCMU_DEV(se_dev); 165 struct tcmu_cmd *tcmu_cmd; 166 int cmd_id; 167 168 tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL); 169 if (!tcmu_cmd) 170 return NULL; 171 172 tcmu_cmd->se_cmd = se_cmd; 173 tcmu_cmd->tcmu_dev = udev; 174 tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT); 175 176 idr_preload(GFP_KERNEL); 177 spin_lock_irq(&udev->commands_lock); 178 cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0, 179 USHRT_MAX, GFP_NOWAIT); 180 spin_unlock_irq(&udev->commands_lock); 181 idr_preload_end(); 182 183 if (cmd_id < 0) { 184 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 185 return NULL; 186 } 187 tcmu_cmd->cmd_id = cmd_id; 188 189 return tcmu_cmd; 190 } 191 192 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size) 193 { 194 unsigned long offset = offset_in_page(vaddr); 195 196 size = round_up(size+offset, PAGE_SIZE); 197 vaddr -= offset; 198 199 while (size) { 200 flush_dcache_page(virt_to_page(vaddr)); 201 size -= PAGE_SIZE; 202 } 203 } 204 205 /* 206 * Some ring helper functions. We don't assume size is a power of 2 so 207 * we can't use circ_buf.h. 208 */ 209 static inline size_t spc_used(size_t head, size_t tail, size_t size) 210 { 211 int diff = head - tail; 212 213 if (diff >= 0) 214 return diff; 215 else 216 return size + diff; 217 } 218 219 static inline size_t spc_free(size_t head, size_t tail, size_t size) 220 { 221 /* Keep 1 byte unused or we can't tell full from empty */ 222 return (size - spc_used(head, tail, size) - 1); 223 } 224 225 static inline size_t head_to_end(size_t head, size_t size) 226 { 227 return size - head; 228 } 229 230 static inline void new_iov(struct iovec **iov, int *iov_cnt, 231 struct tcmu_dev *udev) 232 { 233 struct iovec *iovec; 234 235 if (*iov_cnt != 0) 236 (*iov)++; 237 (*iov_cnt)++; 238 239 iovec = *iov; 240 memset(iovec, 0, sizeof(struct iovec)); 241 } 242 243 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size) 244 245 /* offset is relative to mb_addr */ 246 static inline size_t get_block_offset(struct tcmu_dev *dev, 247 int block, int remaining) 248 { 249 return dev->data_off + block * DATA_BLOCK_SIZE + 250 DATA_BLOCK_SIZE - remaining; 251 } 252 253 static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov) 254 { 255 return (size_t)iov->iov_base + iov->iov_len; 256 } 257 258 static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 259 struct scatterlist *data_sg, unsigned int data_nents, 260 struct iovec **iov, int *iov_cnt, bool copy_data) 261 { 262 int i, block; 263 int block_remaining = 0; 264 void *from, *to; 265 size_t copy_bytes, to_offset; 266 struct scatterlist *sg; 267 268 for_each_sg(data_sg, sg, data_nents, i) { 269 int sg_remaining = sg->length; 270 from = kmap_atomic(sg_page(sg)) + sg->offset; 271 while (sg_remaining > 0) { 272 if (block_remaining == 0) { 273 block = find_first_zero_bit(udev->data_bitmap, 274 DATA_BLOCK_BITS); 275 block_remaining = DATA_BLOCK_SIZE; 276 set_bit(block, udev->data_bitmap); 277 } 278 copy_bytes = min_t(size_t, sg_remaining, 279 block_remaining); 280 to_offset = get_block_offset(udev, block, 281 block_remaining); 282 to = (void *)udev->mb_addr + to_offset; 283 if (*iov_cnt != 0 && 284 to_offset == iov_tail(udev, *iov)) { 285 (*iov)->iov_len += copy_bytes; 286 } else { 287 new_iov(iov, iov_cnt, udev); 288 (*iov)->iov_base = (void __user *) to_offset; 289 (*iov)->iov_len = copy_bytes; 290 } 291 if (copy_data) { 292 memcpy(to, from + sg->length - sg_remaining, 293 copy_bytes); 294 tcmu_flush_dcache_range(to, copy_bytes); 295 } 296 sg_remaining -= copy_bytes; 297 block_remaining -= copy_bytes; 298 } 299 kunmap_atomic(from - sg->offset); 300 } 301 } 302 303 static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd) 304 { 305 bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap, 306 DATA_BLOCK_BITS); 307 } 308 309 static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap, 310 struct scatterlist *data_sg, unsigned int data_nents) 311 { 312 int i, block; 313 int block_remaining = 0; 314 void *from, *to; 315 size_t copy_bytes, from_offset; 316 struct scatterlist *sg; 317 318 for_each_sg(data_sg, sg, data_nents, i) { 319 int sg_remaining = sg->length; 320 to = kmap_atomic(sg_page(sg)) + sg->offset; 321 while (sg_remaining > 0) { 322 if (block_remaining == 0) { 323 block = find_first_bit(cmd_bitmap, 324 DATA_BLOCK_BITS); 325 block_remaining = DATA_BLOCK_SIZE; 326 clear_bit(block, cmd_bitmap); 327 } 328 copy_bytes = min_t(size_t, sg_remaining, 329 block_remaining); 330 from_offset = get_block_offset(udev, block, 331 block_remaining); 332 from = (void *) udev->mb_addr + from_offset; 333 tcmu_flush_dcache_range(from, copy_bytes); 334 memcpy(to + sg->length - sg_remaining, from, 335 copy_bytes); 336 337 sg_remaining -= copy_bytes; 338 block_remaining -= copy_bytes; 339 } 340 kunmap_atomic(to - sg->offset); 341 } 342 } 343 344 static inline size_t spc_bitmap_free(unsigned long *bitmap) 345 { 346 return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS - 347 bitmap_weight(bitmap, DATA_BLOCK_BITS)); 348 } 349 350 /* 351 * We can't queue a command until we have space available on the cmd ring *and* 352 * space available on the data area. 353 * 354 * Called with ring lock held. 355 */ 356 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed) 357 { 358 struct tcmu_mailbox *mb = udev->mb_addr; 359 size_t space, cmd_needed; 360 u32 cmd_head; 361 362 tcmu_flush_dcache_range(mb, sizeof(*mb)); 363 364 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 365 366 /* 367 * If cmd end-of-ring space is too small then we need space for a NOP plus 368 * original cmd - cmds are internally contiguous. 369 */ 370 if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size) 371 cmd_needed = cmd_size; 372 else 373 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size); 374 375 space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size); 376 if (space < cmd_needed) { 377 pr_debug("no cmd space: %u %u %u\n", cmd_head, 378 udev->cmdr_last_cleaned, udev->cmdr_size); 379 return false; 380 } 381 382 space = spc_bitmap_free(udev->data_bitmap); 383 if (space < data_needed) { 384 pr_debug("no data space: only %zu available, but ask for %zu\n", 385 space, data_needed); 386 return false; 387 } 388 389 return true; 390 } 391 392 static sense_reason_t 393 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 394 { 395 struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; 396 struct se_cmd *se_cmd = tcmu_cmd->se_cmd; 397 size_t base_command_size, command_size; 398 struct tcmu_mailbox *mb; 399 struct tcmu_cmd_entry *entry; 400 struct iovec *iov; 401 int iov_cnt; 402 uint32_t cmd_head; 403 uint64_t cdb_off; 404 bool copy_to_data_area; 405 size_t data_length; 406 DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS); 407 408 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) 409 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 410 411 /* 412 * Must be a certain minimum size for response sense info, but 413 * also may be larger if the iov array is large. 414 * 415 * We prepare way too many iovs for potential uses here, because it's 416 * expensive to tell how many regions are freed in the bitmap 417 */ 418 base_command_size = max(offsetof(struct tcmu_cmd_entry, 419 req.iov[se_cmd->t_bidi_data_nents + 420 se_cmd->t_data_nents]), 421 sizeof(struct tcmu_cmd_entry)); 422 command_size = base_command_size 423 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE); 424 425 WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1)); 426 427 spin_lock_irq(&udev->cmdr_lock); 428 429 mb = udev->mb_addr; 430 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 431 data_length = se_cmd->data_length; 432 if (se_cmd->se_cmd_flags & SCF_BIDI) { 433 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents)); 434 data_length += se_cmd->t_bidi_data_sg->length; 435 } 436 if ((command_size > (udev->cmdr_size / 2)) || 437 data_length > udev->data_size) { 438 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu " 439 "cmd ring/data area\n", command_size, data_length, 440 udev->cmdr_size, udev->data_size); 441 spin_unlock_irq(&udev->cmdr_lock); 442 return TCM_INVALID_CDB_FIELD; 443 } 444 445 while (!is_ring_space_avail(udev, command_size, data_length)) { 446 int ret; 447 DEFINE_WAIT(__wait); 448 449 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); 450 451 pr_debug("sleeping for ring space\n"); 452 spin_unlock_irq(&udev->cmdr_lock); 453 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT)); 454 finish_wait(&udev->wait_cmdr, &__wait); 455 if (!ret) { 456 pr_warn("tcmu: command timed out\n"); 457 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 458 } 459 460 spin_lock_irq(&udev->cmdr_lock); 461 462 /* We dropped cmdr_lock, cmd_head is stale */ 463 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 464 } 465 466 /* Insert a PAD if end-of-ring space is too small */ 467 if (head_to_end(cmd_head, udev->cmdr_size) < command_size) { 468 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size); 469 470 entry = (void *) mb + CMDR_OFF + cmd_head; 471 tcmu_flush_dcache_range(entry, sizeof(*entry)); 472 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD); 473 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size); 474 entry->hdr.cmd_id = 0; /* not used for PAD */ 475 entry->hdr.kflags = 0; 476 entry->hdr.uflags = 0; 477 478 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size); 479 480 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ 481 WARN_ON(cmd_head != 0); 482 } 483 484 entry = (void *) mb + CMDR_OFF + cmd_head; 485 tcmu_flush_dcache_range(entry, sizeof(*entry)); 486 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD); 487 tcmu_hdr_set_len(&entry->hdr.len_op, command_size); 488 entry->hdr.cmd_id = tcmu_cmd->cmd_id; 489 entry->hdr.kflags = 0; 490 entry->hdr.uflags = 0; 491 492 bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS); 493 494 /* Handle allocating space from the data area */ 495 iov = &entry->req.iov[0]; 496 iov_cnt = 0; 497 copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE 498 || se_cmd->se_cmd_flags & SCF_BIDI); 499 alloc_and_scatter_data_area(udev, se_cmd->t_data_sg, 500 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area); 501 entry->req.iov_cnt = iov_cnt; 502 entry->req.iov_dif_cnt = 0; 503 504 /* Handle BIDI commands */ 505 iov_cnt = 0; 506 alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg, 507 se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false); 508 entry->req.iov_bidi_cnt = iov_cnt; 509 510 /* cmd's data_bitmap is what changed in process */ 511 bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap, 512 DATA_BLOCK_BITS); 513 514 /* All offsets relative to mb_addr, not start of entry! */ 515 cdb_off = CMDR_OFF + cmd_head + base_command_size; 516 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb)); 517 entry->req.cdb_off = cdb_off; 518 tcmu_flush_dcache_range(entry, sizeof(*entry)); 519 520 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); 521 tcmu_flush_dcache_range(mb, sizeof(*mb)); 522 523 spin_unlock_irq(&udev->cmdr_lock); 524 525 /* TODO: only if FLUSH and FUA? */ 526 uio_event_notify(&udev->uio_info); 527 528 mod_timer(&udev->timeout, 529 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT))); 530 531 return TCM_NO_SENSE; 532 } 533 534 static sense_reason_t 535 tcmu_queue_cmd(struct se_cmd *se_cmd) 536 { 537 struct se_device *se_dev = se_cmd->se_dev; 538 struct tcmu_dev *udev = TCMU_DEV(se_dev); 539 struct tcmu_cmd *tcmu_cmd; 540 int ret; 541 542 tcmu_cmd = tcmu_alloc_cmd(se_cmd); 543 if (!tcmu_cmd) 544 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 545 546 ret = tcmu_queue_cmd_ring(tcmu_cmd); 547 if (ret != TCM_NO_SENSE) { 548 pr_err("TCMU: Could not queue command\n"); 549 spin_lock_irq(&udev->commands_lock); 550 idr_remove(&udev->commands, tcmu_cmd->cmd_id); 551 spin_unlock_irq(&udev->commands_lock); 552 553 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); 554 } 555 556 return ret; 557 } 558 559 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry) 560 { 561 struct se_cmd *se_cmd = cmd->se_cmd; 562 struct tcmu_dev *udev = cmd->tcmu_dev; 563 564 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 565 /* 566 * cmd has been completed already from timeout, just reclaim 567 * data area space and free cmd 568 */ 569 free_data_area(udev, cmd); 570 571 kmem_cache_free(tcmu_cmd_cache, cmd); 572 return; 573 } 574 575 if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) { 576 free_data_area(udev, cmd); 577 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n", 578 cmd->se_cmd); 579 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION; 580 } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) { 581 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, 582 se_cmd->scsi_sense_length); 583 free_data_area(udev, cmd); 584 } else if (se_cmd->se_cmd_flags & SCF_BIDI) { 585 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS); 586 587 /* Get Data-In buffer before clean up */ 588 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS); 589 gather_data_area(udev, bitmap, 590 se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents); 591 free_data_area(udev, cmd); 592 } else if (se_cmd->data_direction == DMA_FROM_DEVICE) { 593 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS); 594 595 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS); 596 gather_data_area(udev, bitmap, 597 se_cmd->t_data_sg, se_cmd->t_data_nents); 598 free_data_area(udev, cmd); 599 } else if (se_cmd->data_direction == DMA_TO_DEVICE) { 600 free_data_area(udev, cmd); 601 } else if (se_cmd->data_direction != DMA_NONE) { 602 pr_warn("TCMU: data direction was %d!\n", 603 se_cmd->data_direction); 604 } 605 606 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); 607 cmd->se_cmd = NULL; 608 609 kmem_cache_free(tcmu_cmd_cache, cmd); 610 } 611 612 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) 613 { 614 struct tcmu_mailbox *mb; 615 unsigned long flags; 616 int handled = 0; 617 618 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { 619 pr_err("ring broken, not handling completions\n"); 620 return 0; 621 } 622 623 spin_lock_irqsave(&udev->cmdr_lock, flags); 624 625 mb = udev->mb_addr; 626 tcmu_flush_dcache_range(mb, sizeof(*mb)); 627 628 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) { 629 630 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; 631 struct tcmu_cmd *cmd; 632 633 tcmu_flush_dcache_range(entry, sizeof(*entry)); 634 635 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) { 636 UPDATE_HEAD(udev->cmdr_last_cleaned, 637 tcmu_hdr_get_len(entry->hdr.len_op), 638 udev->cmdr_size); 639 continue; 640 } 641 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD); 642 643 spin_lock(&udev->commands_lock); 644 cmd = idr_find(&udev->commands, entry->hdr.cmd_id); 645 if (cmd) 646 idr_remove(&udev->commands, cmd->cmd_id); 647 spin_unlock(&udev->commands_lock); 648 649 if (!cmd) { 650 pr_err("cmd_id not found, ring is broken\n"); 651 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); 652 break; 653 } 654 655 tcmu_handle_completion(cmd, entry); 656 657 UPDATE_HEAD(udev->cmdr_last_cleaned, 658 tcmu_hdr_get_len(entry->hdr.len_op), 659 udev->cmdr_size); 660 661 handled++; 662 } 663 664 if (mb->cmd_tail == mb->cmd_head) 665 del_timer(&udev->timeout); /* no more pending cmds */ 666 667 spin_unlock_irqrestore(&udev->cmdr_lock, flags); 668 669 wake_up(&udev->wait_cmdr); 670 671 return handled; 672 } 673 674 static int tcmu_check_expired_cmd(int id, void *p, void *data) 675 { 676 struct tcmu_cmd *cmd = p; 677 678 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) 679 return 0; 680 681 if (!time_after(jiffies, cmd->deadline)) 682 return 0; 683 684 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags); 685 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); 686 cmd->se_cmd = NULL; 687 688 kmem_cache_free(tcmu_cmd_cache, cmd); 689 690 return 0; 691 } 692 693 static void tcmu_device_timedout(unsigned long data) 694 { 695 struct tcmu_dev *udev = (struct tcmu_dev *)data; 696 unsigned long flags; 697 int handled; 698 699 handled = tcmu_handle_completions(udev); 700 701 pr_warn("%d completions handled from timeout\n", handled); 702 703 spin_lock_irqsave(&udev->commands_lock, flags); 704 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); 705 spin_unlock_irqrestore(&udev->commands_lock, flags); 706 707 /* 708 * We don't need to wakeup threads on wait_cmdr since they have their 709 * own timeout. 710 */ 711 } 712 713 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) 714 { 715 struct tcmu_hba *tcmu_hba; 716 717 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL); 718 if (!tcmu_hba) 719 return -ENOMEM; 720 721 tcmu_hba->host_id = host_id; 722 hba->hba_ptr = tcmu_hba; 723 724 return 0; 725 } 726 727 static void tcmu_detach_hba(struct se_hba *hba) 728 { 729 kfree(hba->hba_ptr); 730 hba->hba_ptr = NULL; 731 } 732 733 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 734 { 735 struct tcmu_dev *udev; 736 737 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL); 738 if (!udev) 739 return NULL; 740 741 udev->name = kstrdup(name, GFP_KERNEL); 742 if (!udev->name) { 743 kfree(udev); 744 return NULL; 745 } 746 747 udev->hba = hba; 748 749 init_waitqueue_head(&udev->wait_cmdr); 750 spin_lock_init(&udev->cmdr_lock); 751 752 idr_init(&udev->commands); 753 spin_lock_init(&udev->commands_lock); 754 755 setup_timer(&udev->timeout, tcmu_device_timedout, 756 (unsigned long)udev); 757 758 return &udev->se_dev; 759 } 760 761 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) 762 { 763 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info); 764 765 tcmu_handle_completions(tcmu_dev); 766 767 return 0; 768 } 769 770 /* 771 * mmap code from uio.c. Copied here because we want to hook mmap() 772 * and this stuff must come along. 773 */ 774 static int tcmu_find_mem_index(struct vm_area_struct *vma) 775 { 776 struct tcmu_dev *udev = vma->vm_private_data; 777 struct uio_info *info = &udev->uio_info; 778 779 if (vma->vm_pgoff < MAX_UIO_MAPS) { 780 if (info->mem[vma->vm_pgoff].size == 0) 781 return -1; 782 return (int)vma->vm_pgoff; 783 } 784 return -1; 785 } 786 787 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 788 { 789 struct tcmu_dev *udev = vma->vm_private_data; 790 struct uio_info *info = &udev->uio_info; 791 struct page *page; 792 unsigned long offset; 793 void *addr; 794 795 int mi = tcmu_find_mem_index(vma); 796 if (mi < 0) 797 return VM_FAULT_SIGBUS; 798 799 /* 800 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 801 * to use mem[N]. 802 */ 803 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 804 805 addr = (void *)(unsigned long)info->mem[mi].addr + offset; 806 if (info->mem[mi].memtype == UIO_MEM_LOGICAL) 807 page = virt_to_page(addr); 808 else 809 page = vmalloc_to_page(addr); 810 get_page(page); 811 vmf->page = page; 812 return 0; 813 } 814 815 static const struct vm_operations_struct tcmu_vm_ops = { 816 .fault = tcmu_vma_fault, 817 }; 818 819 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma) 820 { 821 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 822 823 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 824 vma->vm_ops = &tcmu_vm_ops; 825 826 vma->vm_private_data = udev; 827 828 /* Ensure the mmap is exactly the right size */ 829 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT)) 830 return -EINVAL; 831 832 return 0; 833 } 834 835 static int tcmu_open(struct uio_info *info, struct inode *inode) 836 { 837 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 838 839 /* O_EXCL not supported for char devs, so fake it? */ 840 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags)) 841 return -EBUSY; 842 843 pr_debug("open\n"); 844 845 return 0; 846 } 847 848 static int tcmu_release(struct uio_info *info, struct inode *inode) 849 { 850 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info); 851 852 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags); 853 854 pr_debug("close\n"); 855 856 return 0; 857 } 858 859 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) 860 { 861 struct sk_buff *skb; 862 void *msg_header; 863 int ret = -ENOMEM; 864 865 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); 866 if (!skb) 867 return ret; 868 869 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); 870 if (!msg_header) 871 goto free_skb; 872 873 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); 874 if (ret < 0) 875 goto free_skb; 876 877 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); 878 if (ret < 0) 879 goto free_skb; 880 881 genlmsg_end(skb, msg_header); 882 883 ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0, 884 TCMU_MCGRP_CONFIG, GFP_KERNEL); 885 886 /* We don't care if no one is listening */ 887 if (ret == -ESRCH) 888 ret = 0; 889 890 return ret; 891 free_skb: 892 nlmsg_free(skb); 893 return ret; 894 } 895 896 static int tcmu_configure_device(struct se_device *dev) 897 { 898 struct tcmu_dev *udev = TCMU_DEV(dev); 899 struct tcmu_hba *hba = udev->hba->hba_ptr; 900 struct uio_info *info; 901 struct tcmu_mailbox *mb; 902 size_t size; 903 size_t used; 904 int ret = 0; 905 char *str; 906 907 info = &udev->uio_info; 908 909 size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name, 910 udev->dev_config); 911 size += 1; /* for \0 */ 912 str = kmalloc(size, GFP_KERNEL); 913 if (!str) 914 return -ENOMEM; 915 916 used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name); 917 918 if (udev->dev_config[0]) 919 snprintf(str + used, size - used, "/%s", udev->dev_config); 920 921 info->name = str; 922 923 udev->mb_addr = vzalloc(TCMU_RING_SIZE); 924 if (!udev->mb_addr) { 925 ret = -ENOMEM; 926 goto err_vzalloc; 927 } 928 929 /* mailbox fits in first part of CMDR space */ 930 udev->cmdr_size = CMDR_SIZE - CMDR_OFF; 931 udev->data_off = CMDR_SIZE; 932 udev->data_size = TCMU_RING_SIZE - CMDR_SIZE; 933 934 mb = udev->mb_addr; 935 mb->version = TCMU_MAILBOX_VERSION; 936 mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC; 937 mb->cmdr_off = CMDR_OFF; 938 mb->cmdr_size = udev->cmdr_size; 939 940 WARN_ON(!PAGE_ALIGNED(udev->data_off)); 941 WARN_ON(udev->data_size % PAGE_SIZE); 942 WARN_ON(udev->data_size % DATA_BLOCK_SIZE); 943 944 info->version = __stringify(TCMU_MAILBOX_VERSION); 945 946 info->mem[0].name = "tcm-user command & data buffer"; 947 info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr; 948 info->mem[0].size = TCMU_RING_SIZE; 949 info->mem[0].memtype = UIO_MEM_VIRTUAL; 950 951 info->irqcontrol = tcmu_irqcontrol; 952 info->irq = UIO_IRQ_CUSTOM; 953 954 info->mmap = tcmu_mmap; 955 info->open = tcmu_open; 956 info->release = tcmu_release; 957 958 ret = uio_register_device(tcmu_root_device, info); 959 if (ret) 960 goto err_register; 961 962 /* User can set hw_block_size before enable the device */ 963 if (dev->dev_attrib.hw_block_size == 0) 964 dev->dev_attrib.hw_block_size = 512; 965 /* Other attributes can be configured in userspace */ 966 dev->dev_attrib.hw_max_sectors = 128; 967 dev->dev_attrib.hw_queue_depth = 128; 968 969 ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name, 970 udev->uio_info.uio_dev->minor); 971 if (ret) 972 goto err_netlink; 973 974 return 0; 975 976 err_netlink: 977 uio_unregister_device(&udev->uio_info); 978 err_register: 979 vfree(udev->mb_addr); 980 err_vzalloc: 981 kfree(info->name); 982 983 return ret; 984 } 985 986 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd) 987 { 988 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { 989 kmem_cache_free(tcmu_cmd_cache, cmd); 990 return 0; 991 } 992 return -EINVAL; 993 } 994 995 static void tcmu_dev_call_rcu(struct rcu_head *p) 996 { 997 struct se_device *dev = container_of(p, struct se_device, rcu_head); 998 struct tcmu_dev *udev = TCMU_DEV(dev); 999 1000 kfree(udev); 1001 } 1002 1003 static void tcmu_free_device(struct se_device *dev) 1004 { 1005 struct tcmu_dev *udev = TCMU_DEV(dev); 1006 struct tcmu_cmd *cmd; 1007 bool all_expired = true; 1008 int i; 1009 1010 del_timer_sync(&udev->timeout); 1011 1012 vfree(udev->mb_addr); 1013 1014 /* Upper layer should drain all requests before calling this */ 1015 spin_lock_irq(&udev->commands_lock); 1016 idr_for_each_entry(&udev->commands, cmd, i) { 1017 if (tcmu_check_and_free_pending_cmd(cmd) != 0) 1018 all_expired = false; 1019 } 1020 idr_destroy(&udev->commands); 1021 spin_unlock_irq(&udev->commands_lock); 1022 WARN_ON(!all_expired); 1023 1024 /* Device was configured */ 1025 if (udev->uio_info.uio_dev) { 1026 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name, 1027 udev->uio_info.uio_dev->minor); 1028 1029 uio_unregister_device(&udev->uio_info); 1030 kfree(udev->uio_info.name); 1031 kfree(udev->name); 1032 } 1033 call_rcu(&dev->rcu_head, tcmu_dev_call_rcu); 1034 } 1035 1036 enum { 1037 Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err, 1038 }; 1039 1040 static match_table_t tokens = { 1041 {Opt_dev_config, "dev_config=%s"}, 1042 {Opt_dev_size, "dev_size=%u"}, 1043 {Opt_hw_block_size, "hw_block_size=%u"}, 1044 {Opt_err, NULL} 1045 }; 1046 1047 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 1048 const char *page, ssize_t count) 1049 { 1050 struct tcmu_dev *udev = TCMU_DEV(dev); 1051 char *orig, *ptr, *opts, *arg_p; 1052 substring_t args[MAX_OPT_ARGS]; 1053 int ret = 0, token; 1054 unsigned long tmp_ul; 1055 1056 opts = kstrdup(page, GFP_KERNEL); 1057 if (!opts) 1058 return -ENOMEM; 1059 1060 orig = opts; 1061 1062 while ((ptr = strsep(&opts, ",\n")) != NULL) { 1063 if (!*ptr) 1064 continue; 1065 1066 token = match_token(ptr, tokens, args); 1067 switch (token) { 1068 case Opt_dev_config: 1069 if (match_strlcpy(udev->dev_config, &args[0], 1070 TCMU_CONFIG_LEN) == 0) { 1071 ret = -EINVAL; 1072 break; 1073 } 1074 pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config); 1075 break; 1076 case Opt_dev_size: 1077 arg_p = match_strdup(&args[0]); 1078 if (!arg_p) { 1079 ret = -ENOMEM; 1080 break; 1081 } 1082 ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size); 1083 kfree(arg_p); 1084 if (ret < 0) 1085 pr_err("kstrtoul() failed for dev_size=\n"); 1086 break; 1087 case Opt_hw_block_size: 1088 arg_p = match_strdup(&args[0]); 1089 if (!arg_p) { 1090 ret = -ENOMEM; 1091 break; 1092 } 1093 ret = kstrtoul(arg_p, 0, &tmp_ul); 1094 kfree(arg_p); 1095 if (ret < 0) { 1096 pr_err("kstrtoul() failed for hw_block_size=\n"); 1097 break; 1098 } 1099 if (!tmp_ul) { 1100 pr_err("hw_block_size must be nonzero\n"); 1101 break; 1102 } 1103 dev->dev_attrib.hw_block_size = tmp_ul; 1104 break; 1105 default: 1106 break; 1107 } 1108 } 1109 1110 kfree(orig); 1111 return (!ret) ? count : ret; 1112 } 1113 1114 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b) 1115 { 1116 struct tcmu_dev *udev = TCMU_DEV(dev); 1117 ssize_t bl = 0; 1118 1119 bl = sprintf(b + bl, "Config: %s ", 1120 udev->dev_config[0] ? udev->dev_config : "NULL"); 1121 bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size); 1122 1123 return bl; 1124 } 1125 1126 static sector_t tcmu_get_blocks(struct se_device *dev) 1127 { 1128 struct tcmu_dev *udev = TCMU_DEV(dev); 1129 1130 return div_u64(udev->dev_size - dev->dev_attrib.block_size, 1131 dev->dev_attrib.block_size); 1132 } 1133 1134 static sense_reason_t 1135 tcmu_parse_cdb(struct se_cmd *cmd) 1136 { 1137 return passthrough_parse_cdb(cmd, tcmu_queue_cmd); 1138 } 1139 1140 static const struct target_backend_ops tcmu_ops = { 1141 .name = "user", 1142 .owner = THIS_MODULE, 1143 .transport_flags = TRANSPORT_FLAG_PASSTHROUGH, 1144 .attach_hba = tcmu_attach_hba, 1145 .detach_hba = tcmu_detach_hba, 1146 .alloc_device = tcmu_alloc_device, 1147 .configure_device = tcmu_configure_device, 1148 .free_device = tcmu_free_device, 1149 .parse_cdb = tcmu_parse_cdb, 1150 .set_configfs_dev_params = tcmu_set_configfs_dev_params, 1151 .show_configfs_dev_params = tcmu_show_configfs_dev_params, 1152 .get_device_type = sbc_get_device_type, 1153 .get_blocks = tcmu_get_blocks, 1154 .tb_dev_attrib_attrs = passthrough_attrib_attrs, 1155 }; 1156 1157 static int __init tcmu_module_init(void) 1158 { 1159 int ret; 1160 1161 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0); 1162 1163 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache", 1164 sizeof(struct tcmu_cmd), 1165 __alignof__(struct tcmu_cmd), 1166 0, NULL); 1167 if (!tcmu_cmd_cache) 1168 return -ENOMEM; 1169 1170 tcmu_root_device = root_device_register("tcm_user"); 1171 if (IS_ERR(tcmu_root_device)) { 1172 ret = PTR_ERR(tcmu_root_device); 1173 goto out_free_cache; 1174 } 1175 1176 ret = genl_register_family(&tcmu_genl_family); 1177 if (ret < 0) { 1178 goto out_unreg_device; 1179 } 1180 1181 ret = transport_backend_register(&tcmu_ops); 1182 if (ret) 1183 goto out_unreg_genl; 1184 1185 return 0; 1186 1187 out_unreg_genl: 1188 genl_unregister_family(&tcmu_genl_family); 1189 out_unreg_device: 1190 root_device_unregister(tcmu_root_device); 1191 out_free_cache: 1192 kmem_cache_destroy(tcmu_cmd_cache); 1193 1194 return ret; 1195 } 1196 1197 static void __exit tcmu_module_exit(void) 1198 { 1199 target_backend_unregister(&tcmu_ops); 1200 genl_unregister_family(&tcmu_genl_family); 1201 root_device_unregister(tcmu_root_device); 1202 kmem_cache_destroy(tcmu_cmd_cache); 1203 } 1204 1205 MODULE_DESCRIPTION("TCM USER subsystem plugin"); 1206 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>"); 1207 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>"); 1208 MODULE_LICENSE("GPL"); 1209 1210 module_init(tcmu_module_init); 1211 module_exit(tcmu_module_exit); 1212