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/slab.h> 15 #include <linux/types.h> 16 #include <linux/uaccess.h> 17 #include <linux/module.h> 18 19 #include <xen/xen.h> 20 #include <xen/grant_table.h> 21 22 #include "gntdev-common.h" 23 #include "gntdev-dmabuf.h" 24 25 MODULE_IMPORT_NS(DMA_BUF); 26 27 struct gntdev_dmabuf { 28 struct gntdev_dmabuf_priv *priv; 29 struct dma_buf *dmabuf; 30 struct list_head next; 31 int fd; 32 33 union { 34 struct { 35 /* Exported buffers are reference counted. */ 36 struct kref refcount; 37 38 struct gntdev_priv *priv; 39 struct gntdev_grant_map *map; 40 } exp; 41 struct { 42 /* Granted references of the imported buffer. */ 43 grant_ref_t *refs; 44 /* Scatter-gather table of the imported buffer. */ 45 struct sg_table *sgt; 46 /* dma-buf attachment of the imported buffer. */ 47 struct dma_buf_attachment *attach; 48 } imp; 49 } u; 50 51 /* Number of pages this buffer has. */ 52 int nr_pages; 53 /* Pages of this buffer. */ 54 struct page **pages; 55 }; 56 57 struct gntdev_dmabuf_wait_obj { 58 struct list_head next; 59 struct gntdev_dmabuf *gntdev_dmabuf; 60 struct completion completion; 61 }; 62 63 struct gntdev_dmabuf_attachment { 64 struct sg_table *sgt; 65 enum dma_data_direction dir; 66 }; 67 68 struct gntdev_dmabuf_priv { 69 /* List of exported DMA buffers. */ 70 struct list_head exp_list; 71 /* List of wait objects. */ 72 struct list_head exp_wait_list; 73 /* List of imported DMA buffers. */ 74 struct list_head imp_list; 75 /* This is the lock which protects dma_buf_xxx lists. */ 76 struct mutex lock; 77 /* 78 * We reference this file while exporting dma-bufs, so 79 * the grant device context is not destroyed while there are 80 * external users alive. 81 */ 82 struct file *filp; 83 }; 84 85 /* DMA buffer export support. */ 86 87 /* Implementation of wait for exported DMA buffer to be released. */ 88 89 static void dmabuf_exp_release(struct kref *kref); 90 91 static struct gntdev_dmabuf_wait_obj * 92 dmabuf_exp_wait_obj_new(struct gntdev_dmabuf_priv *priv, 93 struct gntdev_dmabuf *gntdev_dmabuf) 94 { 95 struct gntdev_dmabuf_wait_obj *obj; 96 97 obj = kzalloc(sizeof(*obj), GFP_KERNEL); 98 if (!obj) 99 return ERR_PTR(-ENOMEM); 100 101 init_completion(&obj->completion); 102 obj->gntdev_dmabuf = gntdev_dmabuf; 103 104 mutex_lock(&priv->lock); 105 list_add(&obj->next, &priv->exp_wait_list); 106 /* Put our reference and wait for gntdev_dmabuf's release to fire. */ 107 kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release); 108 mutex_unlock(&priv->lock); 109 return obj; 110 } 111 112 static void dmabuf_exp_wait_obj_free(struct gntdev_dmabuf_priv *priv, 113 struct gntdev_dmabuf_wait_obj *obj) 114 { 115 mutex_lock(&priv->lock); 116 list_del(&obj->next); 117 mutex_unlock(&priv->lock); 118 kfree(obj); 119 } 120 121 static int dmabuf_exp_wait_obj_wait(struct gntdev_dmabuf_wait_obj *obj, 122 u32 wait_to_ms) 123 { 124 if (wait_for_completion_timeout(&obj->completion, 125 msecs_to_jiffies(wait_to_ms)) <= 0) 126 return -ETIMEDOUT; 127 128 return 0; 129 } 130 131 static void dmabuf_exp_wait_obj_signal(struct gntdev_dmabuf_priv *priv, 132 struct gntdev_dmabuf *gntdev_dmabuf) 133 { 134 struct gntdev_dmabuf_wait_obj *obj; 135 136 list_for_each_entry(obj, &priv->exp_wait_list, next) 137 if (obj->gntdev_dmabuf == gntdev_dmabuf) { 138 pr_debug("Found gntdev_dmabuf in the wait list, wake\n"); 139 complete_all(&obj->completion); 140 break; 141 } 142 } 143 144 static struct gntdev_dmabuf * 145 dmabuf_exp_wait_obj_get_dmabuf(struct gntdev_dmabuf_priv *priv, int fd) 146 { 147 struct gntdev_dmabuf *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT); 148 149 mutex_lock(&priv->lock); 150 list_for_each_entry(gntdev_dmabuf, &priv->exp_list, next) 151 if (gntdev_dmabuf->fd == fd) { 152 pr_debug("Found gntdev_dmabuf in the wait list\n"); 153 kref_get(&gntdev_dmabuf->u.exp.refcount); 154 ret = gntdev_dmabuf; 155 break; 156 } 157 mutex_unlock(&priv->lock); 158 return ret; 159 } 160 161 static int dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd, 162 int wait_to_ms) 163 { 164 struct gntdev_dmabuf *gntdev_dmabuf; 165 struct gntdev_dmabuf_wait_obj *obj; 166 int ret; 167 168 pr_debug("Will wait for dma-buf with fd %d\n", fd); 169 /* 170 * Try to find the DMA buffer: if not found means that 171 * either the buffer has already been released or file descriptor 172 * provided is wrong. 173 */ 174 gntdev_dmabuf = dmabuf_exp_wait_obj_get_dmabuf(priv, fd); 175 if (IS_ERR(gntdev_dmabuf)) 176 return PTR_ERR(gntdev_dmabuf); 177 178 /* 179 * gntdev_dmabuf still exists and is reference count locked by us now, 180 * so prepare to wait: allocate wait object and add it to the wait list, 181 * so we can find it on release. 182 */ 183 obj = dmabuf_exp_wait_obj_new(priv, gntdev_dmabuf); 184 if (IS_ERR(obj)) 185 return PTR_ERR(obj); 186 187 ret = dmabuf_exp_wait_obj_wait(obj, wait_to_ms); 188 dmabuf_exp_wait_obj_free(priv, obj); 189 return ret; 190 } 191 192 /* DMA buffer export support. */ 193 194 static struct sg_table * 195 dmabuf_pages_to_sgt(struct page **pages, unsigned int nr_pages) 196 { 197 struct sg_table *sgt; 198 int ret; 199 200 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); 201 if (!sgt) { 202 ret = -ENOMEM; 203 goto out; 204 } 205 206 ret = sg_alloc_table_from_pages(sgt, pages, nr_pages, 0, 207 nr_pages << PAGE_SHIFT, 208 GFP_KERNEL); 209 if (ret) 210 goto out; 211 212 return sgt; 213 214 out: 215 kfree(sgt); 216 return ERR_PTR(ret); 217 } 218 219 static int dmabuf_exp_ops_attach(struct dma_buf *dma_buf, 220 struct dma_buf_attachment *attach) 221 { 222 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach; 223 224 gntdev_dmabuf_attach = kzalloc(sizeof(*gntdev_dmabuf_attach), 225 GFP_KERNEL); 226 if (!gntdev_dmabuf_attach) 227 return -ENOMEM; 228 229 gntdev_dmabuf_attach->dir = DMA_NONE; 230 attach->priv = gntdev_dmabuf_attach; 231 return 0; 232 } 233 234 static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, 235 struct dma_buf_attachment *attach) 236 { 237 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv; 238 239 if (gntdev_dmabuf_attach) { 240 struct sg_table *sgt = gntdev_dmabuf_attach->sgt; 241 242 if (sgt) { 243 if (gntdev_dmabuf_attach->dir != DMA_NONE) 244 dma_unmap_sgtable(attach->dev, sgt, 245 gntdev_dmabuf_attach->dir, 246 DMA_ATTR_SKIP_CPU_SYNC); 247 sg_free_table(sgt); 248 } 249 250 kfree(sgt); 251 kfree(gntdev_dmabuf_attach); 252 attach->priv = NULL; 253 } 254 } 255 256 static struct sg_table * 257 dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach, 258 enum dma_data_direction dir) 259 { 260 struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv; 261 struct gntdev_dmabuf *gntdev_dmabuf = attach->dmabuf->priv; 262 struct sg_table *sgt; 263 264 pr_debug("Mapping %d pages for dev %p\n", gntdev_dmabuf->nr_pages, 265 attach->dev); 266 267 if (dir == DMA_NONE || !gntdev_dmabuf_attach) 268 return ERR_PTR(-EINVAL); 269 270 /* Return the cached mapping when possible. */ 271 if (gntdev_dmabuf_attach->dir == dir) 272 return gntdev_dmabuf_attach->sgt; 273 274 /* 275 * Two mappings with different directions for the same attachment are 276 * not allowed. 277 */ 278 if (gntdev_dmabuf_attach->dir != DMA_NONE) 279 return ERR_PTR(-EBUSY); 280 281 sgt = dmabuf_pages_to_sgt(gntdev_dmabuf->pages, 282 gntdev_dmabuf->nr_pages); 283 if (!IS_ERR(sgt)) { 284 if (dma_map_sgtable(attach->dev, sgt, dir, 285 DMA_ATTR_SKIP_CPU_SYNC)) { 286 sg_free_table(sgt); 287 kfree(sgt); 288 sgt = ERR_PTR(-ENOMEM); 289 } else { 290 gntdev_dmabuf_attach->sgt = sgt; 291 gntdev_dmabuf_attach->dir = dir; 292 } 293 } 294 if (IS_ERR(sgt)) 295 pr_debug("Failed to map sg table for dev %p\n", attach->dev); 296 return sgt; 297 } 298 299 static void dmabuf_exp_ops_unmap_dma_buf(struct dma_buf_attachment *attach, 300 struct sg_table *sgt, 301 enum dma_data_direction dir) 302 { 303 /* Not implemented. The unmap is done at dmabuf_exp_ops_detach(). */ 304 } 305 306 static void dmabuf_exp_release(struct kref *kref) 307 { 308 struct gntdev_dmabuf *gntdev_dmabuf = 309 container_of(kref, struct gntdev_dmabuf, u.exp.refcount); 310 311 dmabuf_exp_wait_obj_signal(gntdev_dmabuf->priv, gntdev_dmabuf); 312 list_del(&gntdev_dmabuf->next); 313 fput(gntdev_dmabuf->priv->filp); 314 kfree(gntdev_dmabuf); 315 } 316 317 static void dmabuf_exp_remove_map(struct gntdev_priv *priv, 318 struct gntdev_grant_map *map) 319 { 320 mutex_lock(&priv->lock); 321 list_del(&map->next); 322 gntdev_put_map(NULL /* already removed */, map); 323 mutex_unlock(&priv->lock); 324 } 325 326 static void dmabuf_exp_ops_release(struct dma_buf *dma_buf) 327 { 328 struct gntdev_dmabuf *gntdev_dmabuf = dma_buf->priv; 329 struct gntdev_dmabuf_priv *priv = gntdev_dmabuf->priv; 330 331 dmabuf_exp_remove_map(gntdev_dmabuf->u.exp.priv, 332 gntdev_dmabuf->u.exp.map); 333 mutex_lock(&priv->lock); 334 kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release); 335 mutex_unlock(&priv->lock); 336 } 337 338 static const struct dma_buf_ops dmabuf_exp_ops = { 339 .attach = dmabuf_exp_ops_attach, 340 .detach = dmabuf_exp_ops_detach, 341 .map_dma_buf = dmabuf_exp_ops_map_dma_buf, 342 .unmap_dma_buf = dmabuf_exp_ops_unmap_dma_buf, 343 .release = dmabuf_exp_ops_release, 344 }; 345 346 struct gntdev_dmabuf_export_args { 347 struct gntdev_priv *priv; 348 struct gntdev_grant_map *map; 349 struct gntdev_dmabuf_priv *dmabuf_priv; 350 struct device *dev; 351 int count; 352 struct page **pages; 353 u32 fd; 354 }; 355 356 static int dmabuf_exp_from_pages(struct gntdev_dmabuf_export_args *args) 357 { 358 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 359 struct gntdev_dmabuf *gntdev_dmabuf; 360 int ret; 361 362 gntdev_dmabuf = kzalloc(sizeof(*gntdev_dmabuf), GFP_KERNEL); 363 if (!gntdev_dmabuf) 364 return -ENOMEM; 365 366 kref_init(&gntdev_dmabuf->u.exp.refcount); 367 368 gntdev_dmabuf->priv = args->dmabuf_priv; 369 gntdev_dmabuf->nr_pages = args->count; 370 gntdev_dmabuf->pages = args->pages; 371 gntdev_dmabuf->u.exp.priv = args->priv; 372 gntdev_dmabuf->u.exp.map = args->map; 373 374 exp_info.exp_name = KBUILD_MODNAME; 375 if (args->dev->driver && args->dev->driver->owner) 376 exp_info.owner = args->dev->driver->owner; 377 else 378 exp_info.owner = THIS_MODULE; 379 exp_info.ops = &dmabuf_exp_ops; 380 exp_info.size = args->count << PAGE_SHIFT; 381 exp_info.flags = O_RDWR; 382 exp_info.priv = gntdev_dmabuf; 383 384 gntdev_dmabuf->dmabuf = dma_buf_export(&exp_info); 385 if (IS_ERR(gntdev_dmabuf->dmabuf)) { 386 ret = PTR_ERR(gntdev_dmabuf->dmabuf); 387 gntdev_dmabuf->dmabuf = NULL; 388 goto fail; 389 } 390 391 ret = dma_buf_fd(gntdev_dmabuf->dmabuf, O_CLOEXEC); 392 if (ret < 0) 393 goto fail; 394 395 gntdev_dmabuf->fd = ret; 396 args->fd = ret; 397 398 pr_debug("Exporting DMA buffer with fd %d\n", ret); 399 400 mutex_lock(&args->dmabuf_priv->lock); 401 list_add(&gntdev_dmabuf->next, &args->dmabuf_priv->exp_list); 402 mutex_unlock(&args->dmabuf_priv->lock); 403 get_file(gntdev_dmabuf->priv->filp); 404 return 0; 405 406 fail: 407 if (gntdev_dmabuf->dmabuf) 408 dma_buf_put(gntdev_dmabuf->dmabuf); 409 kfree(gntdev_dmabuf); 410 return ret; 411 } 412 413 static struct gntdev_grant_map * 414 dmabuf_exp_alloc_backing_storage(struct gntdev_priv *priv, int dmabuf_flags, 415 int count) 416 { 417 struct gntdev_grant_map *map; 418 419 if (unlikely(gntdev_test_page_count(count))) 420 return ERR_PTR(-EINVAL); 421 422 if ((dmabuf_flags & GNTDEV_DMA_FLAG_WC) && 423 (dmabuf_flags & GNTDEV_DMA_FLAG_COHERENT)) { 424 pr_debug("Wrong dma-buf flags: 0x%x\n", dmabuf_flags); 425 return ERR_PTR(-EINVAL); 426 } 427 428 map = gntdev_alloc_map(priv, count, dmabuf_flags); 429 if (!map) 430 return ERR_PTR(-ENOMEM); 431 432 return map; 433 } 434 435 static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags, 436 int count, u32 domid, u32 *refs, u32 *fd) 437 { 438 struct gntdev_grant_map *map; 439 struct gntdev_dmabuf_export_args args; 440 int i, ret; 441 442 map = dmabuf_exp_alloc_backing_storage(priv, flags, count); 443 if (IS_ERR(map)) 444 return PTR_ERR(map); 445 446 for (i = 0; i < count; i++) { 447 map->grants[i].domid = domid; 448 map->grants[i].ref = refs[i]; 449 } 450 451 mutex_lock(&priv->lock); 452 gntdev_add_map(priv, map); 453 mutex_unlock(&priv->lock); 454 455 map->flags |= GNTMAP_host_map; 456 #if defined(CONFIG_X86) 457 map->flags |= GNTMAP_device_map; 458 #endif 459 460 ret = gntdev_map_grant_pages(map); 461 if (ret < 0) 462 goto out; 463 464 args.priv = priv; 465 args.map = map; 466 args.dev = priv->dma_dev; 467 args.dmabuf_priv = priv->dmabuf_priv; 468 args.count = map->count; 469 args.pages = map->pages; 470 args.fd = -1; /* Shut up unnecessary gcc warning for i386 */ 471 472 ret = dmabuf_exp_from_pages(&args); 473 if (ret < 0) 474 goto out; 475 476 *fd = args.fd; 477 return 0; 478 479 out: 480 dmabuf_exp_remove_map(priv, map); 481 return ret; 482 } 483 484 /* DMA buffer import support. */ 485 486 static int 487 dmabuf_imp_grant_foreign_access(struct page **pages, u32 *refs, 488 int count, int domid) 489 { 490 grant_ref_t priv_gref_head; 491 int i, ret; 492 493 ret = gnttab_alloc_grant_references(count, &priv_gref_head); 494 if (ret < 0) { 495 pr_debug("Cannot allocate grant references, ret %d\n", ret); 496 return ret; 497 } 498 499 for (i = 0; i < count; i++) { 500 int cur_ref; 501 502 cur_ref = gnttab_claim_grant_reference(&priv_gref_head); 503 if (cur_ref < 0) { 504 ret = cur_ref; 505 pr_debug("Cannot claim grant reference, ret %d\n", ret); 506 goto out; 507 } 508 509 gnttab_grant_foreign_access_ref(cur_ref, domid, 510 xen_page_to_gfn(pages[i]), 0); 511 refs[i] = cur_ref; 512 } 513 514 return 0; 515 516 out: 517 gnttab_free_grant_references(priv_gref_head); 518 return ret; 519 } 520 521 static void dmabuf_imp_end_foreign_access(u32 *refs, int count) 522 { 523 int i; 524 525 for (i = 0; i < count; i++) 526 if (refs[i] != INVALID_GRANT_REF) 527 gnttab_end_foreign_access(refs[i], NULL); 528 } 529 530 static void dmabuf_imp_free_storage(struct gntdev_dmabuf *gntdev_dmabuf) 531 { 532 kfree(gntdev_dmabuf->pages); 533 kfree(gntdev_dmabuf->u.imp.refs); 534 kfree(gntdev_dmabuf); 535 } 536 537 static struct gntdev_dmabuf *dmabuf_imp_alloc_storage(int count) 538 { 539 struct gntdev_dmabuf *gntdev_dmabuf; 540 int i; 541 542 gntdev_dmabuf = kzalloc(sizeof(*gntdev_dmabuf), GFP_KERNEL); 543 if (!gntdev_dmabuf) 544 goto fail_no_free; 545 546 gntdev_dmabuf->u.imp.refs = kcalloc(count, 547 sizeof(gntdev_dmabuf->u.imp.refs[0]), 548 GFP_KERNEL); 549 if (!gntdev_dmabuf->u.imp.refs) 550 goto fail; 551 552 gntdev_dmabuf->pages = kcalloc(count, 553 sizeof(gntdev_dmabuf->pages[0]), 554 GFP_KERNEL); 555 if (!gntdev_dmabuf->pages) 556 goto fail; 557 558 gntdev_dmabuf->nr_pages = count; 559 560 for (i = 0; i < count; i++) 561 gntdev_dmabuf->u.imp.refs[i] = INVALID_GRANT_REF; 562 563 return gntdev_dmabuf; 564 565 fail: 566 dmabuf_imp_free_storage(gntdev_dmabuf); 567 fail_no_free: 568 return ERR_PTR(-ENOMEM); 569 } 570 571 static struct gntdev_dmabuf * 572 dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev, 573 int fd, int count, int domid) 574 { 575 struct gntdev_dmabuf *gntdev_dmabuf, *ret; 576 struct dma_buf *dma_buf; 577 struct dma_buf_attachment *attach; 578 struct sg_table *sgt; 579 struct sg_page_iter sg_iter; 580 int i; 581 582 dma_buf = dma_buf_get(fd); 583 if (IS_ERR(dma_buf)) 584 return ERR_CAST(dma_buf); 585 586 gntdev_dmabuf = dmabuf_imp_alloc_storage(count); 587 if (IS_ERR(gntdev_dmabuf)) { 588 ret = gntdev_dmabuf; 589 goto fail_put; 590 } 591 592 gntdev_dmabuf->priv = priv; 593 gntdev_dmabuf->fd = fd; 594 595 attach = dma_buf_attach(dma_buf, dev); 596 if (IS_ERR(attach)) { 597 ret = ERR_CAST(attach); 598 goto fail_free_obj; 599 } 600 601 gntdev_dmabuf->u.imp.attach = attach; 602 603 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL); 604 if (IS_ERR(sgt)) { 605 ret = ERR_CAST(sgt); 606 goto fail_detach; 607 } 608 609 /* Check that we have zero offset. */ 610 if (sgt->sgl->offset) { 611 ret = ERR_PTR(-EINVAL); 612 pr_debug("DMA buffer has %d bytes offset, user-space expects 0\n", 613 sgt->sgl->offset); 614 goto fail_unmap; 615 } 616 617 /* Check number of pages that imported buffer has. */ 618 if (attach->dmabuf->size != gntdev_dmabuf->nr_pages << PAGE_SHIFT) { 619 ret = ERR_PTR(-EINVAL); 620 pr_debug("DMA buffer has %zu pages, user-space expects %d\n", 621 attach->dmabuf->size, gntdev_dmabuf->nr_pages); 622 goto fail_unmap; 623 } 624 625 gntdev_dmabuf->u.imp.sgt = sgt; 626 627 /* Now convert sgt to array of pages and check for page validity. */ 628 i = 0; 629 for_each_sgtable_page(sgt, &sg_iter, 0) { 630 struct page *page = sg_page_iter_page(&sg_iter); 631 /* 632 * Check if page is valid: this can happen if we are given 633 * a page from VRAM or other resources which are not backed 634 * by a struct page. 635 */ 636 if (!pfn_valid(page_to_pfn(page))) { 637 ret = ERR_PTR(-EINVAL); 638 goto fail_unmap; 639 } 640 641 gntdev_dmabuf->pages[i++] = page; 642 } 643 644 ret = ERR_PTR(dmabuf_imp_grant_foreign_access(gntdev_dmabuf->pages, 645 gntdev_dmabuf->u.imp.refs, 646 count, domid)); 647 if (IS_ERR(ret)) 648 goto fail_end_access; 649 650 pr_debug("Imported DMA buffer with fd %d\n", fd); 651 652 mutex_lock(&priv->lock); 653 list_add(&gntdev_dmabuf->next, &priv->imp_list); 654 mutex_unlock(&priv->lock); 655 656 return gntdev_dmabuf; 657 658 fail_end_access: 659 dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs, count); 660 fail_unmap: 661 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL); 662 fail_detach: 663 dma_buf_detach(dma_buf, attach); 664 fail_free_obj: 665 dmabuf_imp_free_storage(gntdev_dmabuf); 666 fail_put: 667 dma_buf_put(dma_buf); 668 return ret; 669 } 670 671 /* 672 * Find the hyper dma-buf by its file descriptor and remove 673 * it from the buffer's list. 674 */ 675 static struct gntdev_dmabuf * 676 dmabuf_imp_find_unlink(struct gntdev_dmabuf_priv *priv, int fd) 677 { 678 struct gntdev_dmabuf *q, *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT); 679 680 mutex_lock(&priv->lock); 681 list_for_each_entry_safe(gntdev_dmabuf, q, &priv->imp_list, next) { 682 if (gntdev_dmabuf->fd == fd) { 683 pr_debug("Found gntdev_dmabuf in the import list\n"); 684 ret = gntdev_dmabuf; 685 list_del(&gntdev_dmabuf->next); 686 break; 687 } 688 } 689 mutex_unlock(&priv->lock); 690 return ret; 691 } 692 693 static int dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd) 694 { 695 struct gntdev_dmabuf *gntdev_dmabuf; 696 struct dma_buf_attachment *attach; 697 struct dma_buf *dma_buf; 698 699 gntdev_dmabuf = dmabuf_imp_find_unlink(priv, fd); 700 if (IS_ERR(gntdev_dmabuf)) 701 return PTR_ERR(gntdev_dmabuf); 702 703 pr_debug("Releasing DMA buffer with fd %d\n", fd); 704 705 dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs, 706 gntdev_dmabuf->nr_pages); 707 708 attach = gntdev_dmabuf->u.imp.attach; 709 710 if (gntdev_dmabuf->u.imp.sgt) 711 dma_buf_unmap_attachment(attach, gntdev_dmabuf->u.imp.sgt, 712 DMA_BIDIRECTIONAL); 713 dma_buf = attach->dmabuf; 714 dma_buf_detach(attach->dmabuf, attach); 715 dma_buf_put(dma_buf); 716 717 dmabuf_imp_free_storage(gntdev_dmabuf); 718 return 0; 719 } 720 721 static void dmabuf_imp_release_all(struct gntdev_dmabuf_priv *priv) 722 { 723 struct gntdev_dmabuf *q, *gntdev_dmabuf; 724 725 list_for_each_entry_safe(gntdev_dmabuf, q, &priv->imp_list, next) 726 dmabuf_imp_release(priv, gntdev_dmabuf->fd); 727 } 728 729 /* DMA buffer IOCTL support. */ 730 731 long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod, 732 struct ioctl_gntdev_dmabuf_exp_from_refs __user *u) 733 { 734 struct ioctl_gntdev_dmabuf_exp_from_refs op; 735 u32 *refs; 736 long ret; 737 738 if (use_ptemod) { 739 pr_debug("Cannot provide dma-buf: use_ptemode %d\n", 740 use_ptemod); 741 return -EINVAL; 742 } 743 744 if (copy_from_user(&op, u, sizeof(op)) != 0) 745 return -EFAULT; 746 747 if (unlikely(gntdev_test_page_count(op.count))) 748 return -EINVAL; 749 750 refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL); 751 if (!refs) 752 return -ENOMEM; 753 754 if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) { 755 ret = -EFAULT; 756 goto out; 757 } 758 759 ret = dmabuf_exp_from_refs(priv, op.flags, op.count, 760 op.domid, refs, &op.fd); 761 if (ret) 762 goto out; 763 764 if (copy_to_user(u, &op, sizeof(op)) != 0) 765 ret = -EFAULT; 766 767 out: 768 kfree(refs); 769 return ret; 770 } 771 772 long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv, 773 struct ioctl_gntdev_dmabuf_exp_wait_released __user *u) 774 { 775 struct ioctl_gntdev_dmabuf_exp_wait_released op; 776 777 if (copy_from_user(&op, u, sizeof(op)) != 0) 778 return -EFAULT; 779 780 return dmabuf_exp_wait_released(priv->dmabuf_priv, op.fd, 781 op.wait_to_ms); 782 } 783 784 long gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv, 785 struct ioctl_gntdev_dmabuf_imp_to_refs __user *u) 786 { 787 struct ioctl_gntdev_dmabuf_imp_to_refs op; 788 struct gntdev_dmabuf *gntdev_dmabuf; 789 long ret; 790 791 if (copy_from_user(&op, u, sizeof(op)) != 0) 792 return -EFAULT; 793 794 if (unlikely(gntdev_test_page_count(op.count))) 795 return -EINVAL; 796 797 gntdev_dmabuf = dmabuf_imp_to_refs(priv->dmabuf_priv, 798 priv->dma_dev, op.fd, 799 op.count, op.domid); 800 if (IS_ERR(gntdev_dmabuf)) 801 return PTR_ERR(gntdev_dmabuf); 802 803 if (copy_to_user(u->refs, gntdev_dmabuf->u.imp.refs, 804 sizeof(*u->refs) * op.count) != 0) { 805 ret = -EFAULT; 806 goto out_release; 807 } 808 return 0; 809 810 out_release: 811 dmabuf_imp_release(priv->dmabuf_priv, op.fd); 812 return ret; 813 } 814 815 long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv, 816 struct ioctl_gntdev_dmabuf_imp_release __user *u) 817 { 818 struct ioctl_gntdev_dmabuf_imp_release op; 819 820 if (copy_from_user(&op, u, sizeof(op)) != 0) 821 return -EFAULT; 822 823 return dmabuf_imp_release(priv->dmabuf_priv, op.fd); 824 } 825 826 struct gntdev_dmabuf_priv *gntdev_dmabuf_init(struct file *filp) 827 { 828 struct gntdev_dmabuf_priv *priv; 829 830 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 831 if (!priv) 832 return ERR_PTR(-ENOMEM); 833 834 mutex_init(&priv->lock); 835 INIT_LIST_HEAD(&priv->exp_list); 836 INIT_LIST_HEAD(&priv->exp_wait_list); 837 INIT_LIST_HEAD(&priv->imp_list); 838 839 priv->filp = filp; 840 841 return priv; 842 } 843 844 void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv) 845 { 846 dmabuf_imp_release_all(priv); 847 kfree(priv); 848 } 849