1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * Xen dma-buf functionality for gntdev. 5 * 6 * DMA buffer implementation is based on drivers/gpu/drm/drm_prime.c. 7 * 8 * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/dma-buf.h> 14 #include <linux/dma-direct.h> 15 #include <linux/slab.h> 16 #include <linux/types.h> 17 #include <linux/uaccess.h> 18 #include <linux/module.h> 19 20 #include <xen/xen.h> 21 #include <xen/grant_table.h> 22 23 #include "gntdev-common.h" 24 #include "gntdev-dmabuf.h" 25 26 MODULE_IMPORT_NS("DMA_BUF"); 27 28 struct gntdev_dmabuf { 29 struct gntdev_dmabuf_priv *priv; 30 struct dma_buf *dmabuf; 31 struct list_head next; 32 int fd; 33 34 union { 35 struct { 36 /* Exported buffers are reference counted. */ 37 struct kref refcount; 38 39 struct gntdev_priv *priv; 40 struct gntdev_grant_map *map; 41 } exp; 42 struct { 43 /* Granted references of the imported buffer. */ 44 grant_ref_t *refs; 45 /* Scatter-gather table of the imported buffer. */ 46 struct sg_table *sgt; 47 /* dma-buf attachment of the imported buffer. */ 48 struct dma_buf_attachment *attach; 49 } imp; 50 } u; 51 52 /* Number of pages this buffer has. */ 53 int nr_pages; 54 /* Pages of this buffer (only for dma-buf export). */ 55 struct page **pages; 56 }; 57 58 struct gntdev_dmabuf_wait_obj { 59 struct list_head next; 60 struct gntdev_dmabuf *gntdev_dmabuf; 61 struct completion completion; 62 }; 63 64 struct gntdev_dmabuf_attachment { 65 struct sg_table *sgt; 66 enum dma_data_direction dir; 67 }; 68 69 struct gntdev_dmabuf_priv { 70 /* List of exported DMA buffers. */ 71 struct list_head exp_list; 72 /* List of wait objects. */ 73 struct list_head exp_wait_list; 74 /* List of imported DMA buffers. */ 75 struct list_head imp_list; 76 /* This is the lock which protects dma_buf_xxx lists. */ 77 struct mutex lock; 78 /* 79 * We reference this file while exporting dma-bufs, so 80 * the grant device context is not destroyed while there are 81 * external users alive. 82 */ 83 struct file *filp; 84 }; 85 86 /* DMA buffer export support. */ 87 88 /* Implementation of wait for exported DMA buffer to be released. */ 89 90 static void dmabuf_exp_release(struct kref *kref); 91 92 static struct gntdev_dmabuf_wait_obj * 93 dmabuf_exp_wait_obj_new(struct gntdev_dmabuf_priv *priv, 94 struct gntdev_dmabuf *gntdev_dmabuf) 95 { 96 struct gntdev_dmabuf_wait_obj *obj; 97 98 obj = kzalloc_obj(*obj); 99 if (!obj) { 100 kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release); 101 return ERR_PTR(-ENOMEM); 102 } 103 104 init_completion(&obj->completion); 105 obj->gntdev_dmabuf = gntdev_dmabuf; 106 107 mutex_lock(&priv->lock); 108 list_add(&obj->next, &priv->exp_wait_list); 109 /* Put our reference and wait for gntdev_dmabuf's release to fire. */ 110 kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release); 111 mutex_unlock(&priv->lock); 112 return obj; 113 } 114 115 static void dmabuf_exp_wait_obj_free(struct gntdev_dmabuf_priv *priv, 116 struct gntdev_dmabuf_wait_obj *obj) 117 { 118 mutex_lock(&priv->lock); 119 list_del(&obj->next); 120 mutex_unlock(&priv->lock); 121 kfree(obj); 122 } 123 124 static int dmabuf_exp_wait_obj_wait(struct gntdev_dmabuf_wait_obj *obj, 125 u32 wait_to_ms) 126 { 127 if (wait_for_completion_timeout(&obj->completion, 128 msecs_to_jiffies(wait_to_ms)) <= 0) 129 return -ETIMEDOUT; 130 131 return 0; 132 } 133 134 static void dmabuf_exp_wait_obj_signal(struct gntdev_dmabuf_priv *priv, 135 struct gntdev_dmabuf *gntdev_dmabuf) 136 { 137 struct gntdev_dmabuf_wait_obj *obj; 138 139 list_for_each_entry(obj, &priv->exp_wait_list, next) 140 if (obj->gntdev_dmabuf == gntdev_dmabuf) { 141 pr_debug("Found gntdev_dmabuf in the wait list, wake\n"); 142 complete_all(&obj->completion); 143 break; 144 } 145 } 146 147 static struct gntdev_dmabuf * 148 dmabuf_exp_wait_obj_get_dmabuf(struct gntdev_dmabuf_priv *priv, int fd) 149 { 150 struct gntdev_dmabuf *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT); 151 152 mutex_lock(&priv->lock); 153 list_for_each_entry(gntdev_dmabuf, &priv->exp_list, next) 154 if (gntdev_dmabuf->fd == fd) { 155 pr_debug("Found gntdev_dmabuf in the wait list\n"); 156 kref_get(&gntdev_dmabuf->u.exp.refcount); 157 ret = gntdev_dmabuf; 158 break; 159 } 160 mutex_unlock(&priv->lock); 161 return ret; 162 } 163 164 static int dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd, 165 int wait_to_ms) 166 { 167 struct gntdev_dmabuf *gntdev_dmabuf; 168 struct gntdev_dmabuf_wait_obj *obj; 169 int ret; 170 171 pr_debug("Will wait for dma-buf with fd %d\n", fd); 172 /* 173 * Try to find the DMA buffer: if not found means that 174 * either the buffer has already been released or file descriptor 175 * provided is wrong. 176 */ 177 gntdev_dmabuf = dmabuf_exp_wait_obj_get_dmabuf(priv, fd); 178 if (IS_ERR(gntdev_dmabuf)) 179 return PTR_ERR(gntdev_dmabuf); 180 181 /* 182 * gntdev_dmabuf still exists and is reference count locked by us now, 183 * so prepare to wait: allocate wait object and add it to the wait list, 184 * so we can find it on release. 185 */ 186 obj = dmabuf_exp_wait_obj_new(priv, gntdev_dmabuf); 187 if (IS_ERR(obj)) 188 return PTR_ERR(obj); 189 190 ret = dmabuf_exp_wait_obj_wait(obj, wait_to_ms); 191 dmabuf_exp_wait_obj_free(priv, obj); 192 return ret; 193 } 194 195 /* DMA buffer export support. */ 196 197 static struct sg_table * 198 dmabuf_pages_to_sgt(struct page **pages, unsigned int nr_pages) 199 { 200 struct sg_table *sgt; 201 int ret; 202 203 sgt = kmalloc_obj(*sgt); 204 if (!sgt) { 205 ret = -ENOMEM; 206 goto out; 207 } 208 209 ret = sg_alloc_table_from_pages(sgt, pages, nr_pages, 0, 210 nr_pages << PAGE_SHIFT, 211 GFP_KERNEL); 212 if (ret) 213 goto out; 214 215 return sgt; 216 217 out: 218 kfree(sgt); 219 return ERR_PTR(ret); 220 } 221 222 static int dmabuf_exp_ops_attach(struct dma_buf *dma_buf, 223 struct dma_buf_attachment *attach) 224 { 225 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach; 226 227 gntdev_dmabuf_attach = kzalloc_obj(*gntdev_dmabuf_attach); 228 if (!gntdev_dmabuf_attach) 229 return -ENOMEM; 230 231 gntdev_dmabuf_attach->dir = DMA_NONE; 232 attach->priv = gntdev_dmabuf_attach; 233 return 0; 234 } 235 236 static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, 237 struct dma_buf_attachment *attach) 238 { 239 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv; 240 241 if (gntdev_dmabuf_attach) { 242 struct sg_table *sgt = gntdev_dmabuf_attach->sgt; 243 244 if (sgt) { 245 if (gntdev_dmabuf_attach->dir != DMA_NONE) 246 dma_unmap_sgtable(attach->dev, sgt, 247 gntdev_dmabuf_attach->dir, 248 DMA_ATTR_SKIP_CPU_SYNC); 249 sg_free_table(sgt); 250 } 251 252 kfree(sgt); 253 kfree(gntdev_dmabuf_attach); 254 attach->priv = NULL; 255 } 256 } 257 258 static struct sg_table * 259 dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach, 260 enum dma_data_direction dir) 261 { 262 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv; 263 struct gntdev_dmabuf *gntdev_dmabuf = attach->dmabuf->priv; 264 struct sg_table *sgt; 265 266 pr_debug("Mapping %d pages for dev %p\n", gntdev_dmabuf->nr_pages, 267 attach->dev); 268 269 if (dir == DMA_NONE || !gntdev_dmabuf_attach) 270 return ERR_PTR(-EINVAL); 271 272 /* Return the cached mapping when possible. */ 273 if (gntdev_dmabuf_attach->dir == dir) 274 return gntdev_dmabuf_attach->sgt; 275 276 /* 277 * Two mappings with different directions for the same attachment are 278 * not allowed. 279 */ 280 if (gntdev_dmabuf_attach->dir != DMA_NONE) 281 return ERR_PTR(-EBUSY); 282 283 sgt = dmabuf_pages_to_sgt(gntdev_dmabuf->pages, 284 gntdev_dmabuf->nr_pages); 285 if (!IS_ERR(sgt)) { 286 if (dma_map_sgtable(attach->dev, sgt, dir, 287 DMA_ATTR_SKIP_CPU_SYNC)) { 288 sg_free_table(sgt); 289 kfree(sgt); 290 sgt = ERR_PTR(-ENOMEM); 291 } else { 292 gntdev_dmabuf_attach->sgt = sgt; 293 gntdev_dmabuf_attach->dir = dir; 294 } 295 } 296 if (IS_ERR(sgt)) 297 pr_debug("Failed to map sg table for dev %p\n", attach->dev); 298 return sgt; 299 } 300 301 static void dmabuf_exp_ops_unmap_dma_buf(struct dma_buf_attachment *attach, 302 struct sg_table *sgt, 303 enum dma_data_direction dir) 304 { 305 /* Not implemented. The unmap is done at dmabuf_exp_ops_detach(). */ 306 } 307 308 static void dmabuf_exp_release(struct kref *kref) 309 { 310 struct gntdev_dmabuf *gntdev_dmabuf = 311 container_of(kref, struct gntdev_dmabuf, u.exp.refcount); 312 313 dmabuf_exp_wait_obj_signal(gntdev_dmabuf->priv, gntdev_dmabuf); 314 list_del(&gntdev_dmabuf->next); 315 fput(gntdev_dmabuf->priv->filp); 316 kfree(gntdev_dmabuf); 317 } 318 319 static void dmabuf_exp_remove_map(struct gntdev_priv *priv, 320 struct gntdev_grant_map *map) 321 { 322 mutex_lock(&priv->lock); 323 list_del(&map->next); 324 gntdev_put_map(NULL /* already removed */, map); 325 mutex_unlock(&priv->lock); 326 } 327 328 static void dmabuf_exp_ops_release(struct dma_buf *dma_buf) 329 { 330 struct gntdev_dmabuf *gntdev_dmabuf = dma_buf->priv; 331 struct gntdev_dmabuf_priv *priv = gntdev_dmabuf->priv; 332 333 dmabuf_exp_remove_map(gntdev_dmabuf->u.exp.priv, 334 gntdev_dmabuf->u.exp.map); 335 mutex_lock(&priv->lock); 336 kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release); 337 mutex_unlock(&priv->lock); 338 } 339 340 static const struct dma_buf_ops dmabuf_exp_ops = { 341 .attach = dmabuf_exp_ops_attach, 342 .detach = dmabuf_exp_ops_detach, 343 .map_dma_buf = dmabuf_exp_ops_map_dma_buf, 344 .unmap_dma_buf = dmabuf_exp_ops_unmap_dma_buf, 345 .release = dmabuf_exp_ops_release, 346 }; 347 348 struct gntdev_dmabuf_export_args { 349 struct gntdev_priv *priv; 350 struct gntdev_grant_map *map; 351 struct gntdev_dmabuf_priv *dmabuf_priv; 352 struct device *dev; 353 int count; 354 struct page **pages; 355 u32 fd; 356 }; 357 358 static int dmabuf_exp_from_pages(struct gntdev_dmabuf_export_args *args) 359 { 360 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 361 struct gntdev_dmabuf *gntdev_dmabuf __free(kfree) = NULL; 362 CLASS(get_unused_fd, ret)(O_CLOEXEC); 363 364 if (ret < 0) 365 return ret; 366 367 gntdev_dmabuf = kzalloc_obj(*gntdev_dmabuf); 368 if (!gntdev_dmabuf) 369 return -ENOMEM; 370 371 kref_init(&gntdev_dmabuf->u.exp.refcount); 372 373 gntdev_dmabuf->priv = args->dmabuf_priv; 374 gntdev_dmabuf->nr_pages = args->count; 375 gntdev_dmabuf->pages = args->pages; 376 gntdev_dmabuf->u.exp.priv = args->priv; 377 gntdev_dmabuf->u.exp.map = args->map; 378 379 exp_info.exp_name = KBUILD_MODNAME; 380 if (args->dev->driver && args->dev->driver->owner) 381 exp_info.owner = args->dev->driver->owner; 382 else 383 exp_info.owner = THIS_MODULE; 384 exp_info.ops = &dmabuf_exp_ops; 385 exp_info.size = args->count << PAGE_SHIFT; 386 exp_info.flags = O_RDWR; 387 exp_info.priv = gntdev_dmabuf; 388 389 gntdev_dmabuf->dmabuf = dma_buf_export(&exp_info); 390 if (IS_ERR(gntdev_dmabuf->dmabuf)) 391 return PTR_ERR(gntdev_dmabuf->dmabuf); 392 393 gntdev_dmabuf->fd = ret; 394 args->fd = ret; 395 396 pr_debug("Exporting DMA buffer with fd %d\n", ret); 397 398 get_file(gntdev_dmabuf->priv->filp); 399 mutex_lock(&args->dmabuf_priv->lock); 400 list_add(&gntdev_dmabuf->next, &args->dmabuf_priv->exp_list); 401 mutex_unlock(&args->dmabuf_priv->lock); 402 403 fd_install(take_fd(ret), no_free_ptr(gntdev_dmabuf)->dmabuf->file); 404 return 0; 405 } 406 407 static struct gntdev_grant_map * 408 dmabuf_exp_alloc_backing_storage(struct gntdev_priv *priv, int dmabuf_flags, 409 int count) 410 { 411 struct gntdev_grant_map *map; 412 413 if (unlikely(gntdev_test_page_count(count))) 414 return ERR_PTR(-EINVAL); 415 416 if ((dmabuf_flags & GNTDEV_DMA_FLAG_WC) && 417 (dmabuf_flags & GNTDEV_DMA_FLAG_COHERENT)) { 418 pr_debug("Wrong dma-buf flags: 0x%x\n", dmabuf_flags); 419 return ERR_PTR(-EINVAL); 420 } 421 422 map = gntdev_alloc_map(priv, count, dmabuf_flags); 423 if (!map) 424 return ERR_PTR(-ENOMEM); 425 426 return map; 427 } 428 429 static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags, 430 int count, u32 domid, u32 *refs, u32 *fd) 431 { 432 struct gntdev_grant_map *map; 433 struct gntdev_dmabuf_export_args args; 434 int i, ret; 435 436 map = dmabuf_exp_alloc_backing_storage(priv, flags, count); 437 if (IS_ERR(map)) 438 return PTR_ERR(map); 439 440 for (i = 0; i < count; i++) { 441 map->grants[i].domid = domid; 442 map->grants[i].ref = refs[i]; 443 } 444 445 mutex_lock(&priv->lock); 446 gntdev_add_map(priv, map); 447 mutex_unlock(&priv->lock); 448 449 map->flags |= GNTMAP_host_map; 450 #if defined(CONFIG_X86) 451 map->flags |= GNTMAP_device_map; 452 #endif 453 454 ret = gntdev_map_grant_pages(map); 455 if (ret < 0) 456 goto out; 457 458 args.priv = priv; 459 args.map = map; 460 args.dev = priv->dma_dev; 461 args.dmabuf_priv = priv->dmabuf_priv; 462 args.count = map->count; 463 args.pages = map->pages; 464 args.fd = -1; /* Shut up unnecessary gcc warning for i386 */ 465 466 ret = dmabuf_exp_from_pages(&args); 467 if (ret < 0) 468 goto out; 469 470 *fd = args.fd; 471 return 0; 472 473 out: 474 dmabuf_exp_remove_map(priv, map); 475 return ret; 476 } 477 478 /* DMA buffer import support. */ 479 480 static int 481 dmabuf_imp_grant_foreign_access(unsigned long *gfns, u32 *refs, 482 int count, int domid) 483 { 484 grant_ref_t priv_gref_head; 485 int i, ret; 486 487 ret = gnttab_alloc_grant_references(count, &priv_gref_head); 488 if (ret < 0) { 489 pr_debug("Cannot allocate grant references, ret %d\n", ret); 490 return ret; 491 } 492 493 for (i = 0; i < count; i++) { 494 int cur_ref; 495 496 cur_ref = gnttab_claim_grant_reference(&priv_gref_head); 497 if (cur_ref < 0) { 498 ret = cur_ref; 499 pr_debug("Cannot claim grant reference, ret %d\n", ret); 500 goto out; 501 } 502 503 gnttab_grant_foreign_access_ref(cur_ref, domid, 504 gfns[i], 0); 505 refs[i] = cur_ref; 506 } 507 508 return 0; 509 510 out: 511 gnttab_free_grant_references(priv_gref_head); 512 return ret; 513 } 514 515 static void dmabuf_imp_end_foreign_access(u32 *refs, int count) 516 { 517 int i; 518 519 for (i = 0; i < count; i++) 520 if (refs[i] != INVALID_GRANT_REF) 521 gnttab_end_foreign_access(refs[i], NULL); 522 } 523 524 static void dmabuf_imp_free_storage(struct gntdev_dmabuf *gntdev_dmabuf) 525 { 526 kfree(gntdev_dmabuf->u.imp.refs); 527 kfree(gntdev_dmabuf); 528 } 529 530 static struct gntdev_dmabuf *dmabuf_imp_alloc_storage(int count) 531 { 532 struct gntdev_dmabuf *gntdev_dmabuf; 533 int i; 534 535 gntdev_dmabuf = kzalloc_obj(*gntdev_dmabuf); 536 if (!gntdev_dmabuf) 537 goto fail_no_free; 538 539 gntdev_dmabuf->u.imp.refs = kzalloc_objs(gntdev_dmabuf->u.imp.refs[0], 540 count); 541 if (!gntdev_dmabuf->u.imp.refs) 542 goto fail; 543 544 gntdev_dmabuf->nr_pages = count; 545 546 for (i = 0; i < count; i++) 547 gntdev_dmabuf->u.imp.refs[i] = INVALID_GRANT_REF; 548 549 return gntdev_dmabuf; 550 551 fail: 552 dmabuf_imp_free_storage(gntdev_dmabuf); 553 fail_no_free: 554 return ERR_PTR(-ENOMEM); 555 } 556 557 static struct gntdev_dmabuf * 558 dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev, 559 int fd, int count, int domid) 560 { 561 struct gntdev_dmabuf *gntdev_dmabuf, *ret; 562 struct dma_buf *dma_buf; 563 struct dma_buf_attachment *attach; 564 struct sg_table *sgt; 565 struct sg_dma_page_iter sg_iter; 566 unsigned long *gfns; 567 int i; 568 569 dma_buf = dma_buf_get(fd); 570 if (IS_ERR(dma_buf)) 571 return ERR_CAST(dma_buf); 572 573 gntdev_dmabuf = dmabuf_imp_alloc_storage(count); 574 if (IS_ERR(gntdev_dmabuf)) { 575 ret = gntdev_dmabuf; 576 goto fail_put; 577 } 578 579 gntdev_dmabuf->priv = priv; 580 gntdev_dmabuf->fd = fd; 581 582 attach = dma_buf_attach(dma_buf, dev); 583 if (IS_ERR(attach)) { 584 ret = ERR_CAST(attach); 585 goto fail_free_obj; 586 } 587 588 gntdev_dmabuf->u.imp.attach = attach; 589 590 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL); 591 if (IS_ERR(sgt)) { 592 ret = ERR_CAST(sgt); 593 goto fail_detach; 594 } 595 596 /* Check that we have zero offset. */ 597 if (sgt->sgl->offset) { 598 ret = ERR_PTR(-EINVAL); 599 pr_debug("DMA buffer has %d bytes offset, user-space expects 0\n", 600 sgt->sgl->offset); 601 goto fail_unmap; 602 } 603 604 /* Check number of pages that imported buffer has. */ 605 if (attach->dmabuf->size != gntdev_dmabuf->nr_pages << PAGE_SHIFT) { 606 ret = ERR_PTR(-EINVAL); 607 pr_debug("DMA buffer has %zu pages, user-space expects %d\n", 608 attach->dmabuf->size, gntdev_dmabuf->nr_pages); 609 goto fail_unmap; 610 } 611 612 gntdev_dmabuf->u.imp.sgt = sgt; 613 614 gfns = kcalloc(count, sizeof(*gfns), GFP_KERNEL); 615 if (!gfns) { 616 ret = ERR_PTR(-ENOMEM); 617 goto fail_unmap; 618 } 619 620 /* 621 * Now convert sgt to array of gfns without accessing underlying pages. 622 * It is not allowed to access the underlying struct page of an sg table 623 * exported by DMA-buf, but since we deal with special Xen dma device here 624 * (not a normal physical one) look at the dma addresses in the sg table 625 * and then calculate gfns directly from them. 626 */ 627 i = 0; 628 for_each_sgtable_dma_page(sgt, &sg_iter, 0) { 629 dma_addr_t addr = sg_page_iter_dma_address(&sg_iter); 630 unsigned long pfn = bfn_to_pfn(XEN_PFN_DOWN(dma_to_phys(dev, addr))); 631 632 gfns[i++] = pfn_to_gfn(pfn); 633 } 634 635 ret = ERR_PTR(dmabuf_imp_grant_foreign_access(gfns, 636 gntdev_dmabuf->u.imp.refs, 637 count, domid)); 638 kfree(gfns); 639 if (IS_ERR(ret)) 640 goto fail_end_access; 641 642 pr_debug("Imported DMA buffer with fd %d\n", fd); 643 644 mutex_lock(&priv->lock); 645 list_add(&gntdev_dmabuf->next, &priv->imp_list); 646 mutex_unlock(&priv->lock); 647 648 return gntdev_dmabuf; 649 650 fail_end_access: 651 dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs, count); 652 fail_unmap: 653 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL); 654 fail_detach: 655 dma_buf_detach(dma_buf, attach); 656 fail_free_obj: 657 dmabuf_imp_free_storage(gntdev_dmabuf); 658 fail_put: 659 dma_buf_put(dma_buf); 660 return ret; 661 } 662 663 /* 664 * Find the hyper dma-buf by its file descriptor and remove 665 * it from the buffer's list. 666 */ 667 static struct gntdev_dmabuf * 668 dmabuf_imp_find_unlink(struct gntdev_dmabuf_priv *priv, int fd) 669 { 670 struct gntdev_dmabuf *q, *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT); 671 672 mutex_lock(&priv->lock); 673 list_for_each_entry_safe(gntdev_dmabuf, q, &priv->imp_list, next) { 674 if (gntdev_dmabuf->fd == fd) { 675 pr_debug("Found gntdev_dmabuf in the import list\n"); 676 ret = gntdev_dmabuf; 677 list_del(&gntdev_dmabuf->next); 678 break; 679 } 680 } 681 mutex_unlock(&priv->lock); 682 return ret; 683 } 684 685 static int dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd) 686 { 687 struct gntdev_dmabuf *gntdev_dmabuf; 688 struct dma_buf_attachment *attach; 689 struct dma_buf *dma_buf; 690 691 gntdev_dmabuf = dmabuf_imp_find_unlink(priv, fd); 692 if (IS_ERR(gntdev_dmabuf)) 693 return PTR_ERR(gntdev_dmabuf); 694 695 pr_debug("Releasing DMA buffer with fd %d\n", fd); 696 697 dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs, 698 gntdev_dmabuf->nr_pages); 699 700 attach = gntdev_dmabuf->u.imp.attach; 701 702 if (gntdev_dmabuf->u.imp.sgt) 703 dma_buf_unmap_attachment_unlocked(attach, gntdev_dmabuf->u.imp.sgt, 704 DMA_BIDIRECTIONAL); 705 dma_buf = attach->dmabuf; 706 dma_buf_detach(attach->dmabuf, attach); 707 dma_buf_put(dma_buf); 708 709 dmabuf_imp_free_storage(gntdev_dmabuf); 710 return 0; 711 } 712 713 static void dmabuf_imp_release_all(struct gntdev_dmabuf_priv *priv) 714 { 715 struct gntdev_dmabuf *q, *gntdev_dmabuf; 716 717 list_for_each_entry_safe(gntdev_dmabuf, q, &priv->imp_list, next) 718 dmabuf_imp_release(priv, gntdev_dmabuf->fd); 719 } 720 721 /* DMA buffer IOCTL support. */ 722 723 long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, 724 struct ioctl_gntdev_dmabuf_exp_from_refs __user *u) 725 { 726 struct ioctl_gntdev_dmabuf_exp_from_refs op; 727 u32 *refs; 728 long ret; 729 730 if (xen_pv_domain()) { 731 pr_debug("Cannot provide dma-buf in a PV domain\n"); 732 return -EINVAL; 733 } 734 735 if (copy_from_user(&op, u, sizeof(op)) != 0) 736 return -EFAULT; 737 738 if (unlikely(gntdev_test_page_count(op.count))) 739 return -EINVAL; 740 741 refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL); 742 if (!refs) 743 return -ENOMEM; 744 745 if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) { 746 ret = -EFAULT; 747 goto out; 748 } 749 750 ret = dmabuf_exp_from_refs(priv, op.flags, op.count, 751 op.domid, refs, &op.fd); 752 if (ret) 753 goto out; 754 755 if (copy_to_user(u, &op, sizeof(op)) != 0) 756 ret = -EFAULT; 757 758 out: 759 kfree(refs); 760 return ret; 761 } 762 763 long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv, 764 struct ioctl_gntdev_dmabuf_exp_wait_released __user *u) 765 { 766 struct ioctl_gntdev_dmabuf_exp_wait_released op; 767 768 if (copy_from_user(&op, u, sizeof(op)) != 0) 769 return -EFAULT; 770 771 return dmabuf_exp_wait_released(priv->dmabuf_priv, op.fd, 772 op.wait_to_ms); 773 } 774 775 long gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv, 776 struct ioctl_gntdev_dmabuf_imp_to_refs __user *u) 777 { 778 struct ioctl_gntdev_dmabuf_imp_to_refs op; 779 struct gntdev_dmabuf *gntdev_dmabuf; 780 long ret; 781 782 if (copy_from_user(&op, u, sizeof(op)) != 0) 783 return -EFAULT; 784 785 if (unlikely(gntdev_test_page_count(op.count))) 786 return -EINVAL; 787 788 gntdev_dmabuf = dmabuf_imp_to_refs(priv->dmabuf_priv, 789 priv->dma_dev, op.fd, 790 op.count, op.domid); 791 if (IS_ERR(gntdev_dmabuf)) 792 return PTR_ERR(gntdev_dmabuf); 793 794 if (copy_to_user(u->refs, gntdev_dmabuf->u.imp.refs, 795 sizeof(*u->refs) * op.count) != 0) { 796 ret = -EFAULT; 797 goto out_release; 798 } 799 return 0; 800 801 out_release: 802 dmabuf_imp_release(priv->dmabuf_priv, op.fd); 803 return ret; 804 } 805 806 long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv, 807 struct ioctl_gntdev_dmabuf_imp_release __user *u) 808 { 809 struct ioctl_gntdev_dmabuf_imp_release op; 810 811 if (copy_from_user(&op, u, sizeof(op)) != 0) 812 return -EFAULT; 813 814 return dmabuf_imp_release(priv->dmabuf_priv, op.fd); 815 } 816 817 struct gntdev_dmabuf_priv *gntdev_dmabuf_init(struct file *filp) 818 { 819 struct gntdev_dmabuf_priv *priv; 820 821 priv = kzalloc_obj(*priv); 822 if (!priv) 823 return ERR_PTR(-ENOMEM); 824 825 mutex_init(&priv->lock); 826 INIT_LIST_HEAD(&priv->exp_list); 827 INIT_LIST_HEAD(&priv->exp_wait_list); 828 INIT_LIST_HEAD(&priv->imp_list); 829 830 priv->filp = filp; 831 832 return priv; 833 } 834 835 void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv) 836 { 837 dmabuf_imp_release_all(priv); 838 kfree(priv); 839 } 840