函数源码 |
Source File:mm\slab_common.c |
Create Date:2022-07-27 15:54:06 |
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424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 | /** * kmem_cache_create_usercopy - Create a cache with a region suitable * for copying to userspace * @name: A string which is used in /proc/slabinfo to identify this cache. * @size: The size of objects to be created in this cache. * @align: The required alignment for the objects. * @flags: SLAB flags * @useroffset: Usercopy region offset * @usersize: Usercopy region size * @ctor: A constructor for the objects. * * Cannot be called within a interrupt, but can be interrupted. * The @ctor is run when new pages are allocated by the cache. * * The flags are * * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) * to catch references to uninitialised memory. * * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check * for buffer overruns. * * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware * cacheline. This can be beneficial if you're counting cycles as closely * as davem. * * Return: a pointer to the cache on success, NULL on failure. */ struct kmem_cache * kmem_cache_create_usercopy( const char *name, unsigned int size, unsigned int align, slab_flags_t flags, unsigned int useroffset, unsigned int usersize, void (*ctor)( void *)) { struct kmem_cache *s = NULL; const char *cache_name; int err; get_online_cpus(); get_online_mems(); memcg_get_cache_ids(); mutex_lock(&slab_mutex); err = kmem_cache_sanity_check(name, size); if (err) { goto out_unlock; } /* Refuse requests with allocator specific flags */ if (flags & ~SLAB_FLAGS_PERMITTED) { err = -EINVAL; goto out_unlock; } /* * Some allocators will constraint the set of valid flags to a subset * of all flags. We expect them to define CACHE_CREATE_MASK in this * case, and we'll just provide them with a sanitized version of the * passed flags. */ flags &= CACHE_CREATE_MASK; /* Fail closed on bad usersize of useroffset values. */ if (WARN_ON(!usersize && useroffset) || WARN_ON(size < usersize || size - usersize < useroffset)) usersize = useroffset = 0; if (!usersize) s = __kmem_cache_alias(name, size, align, flags, ctor); if (s) goto out_unlock; cache_name = kstrdup_const(name, GFP_KERNEL); if (!cache_name) { err = -ENOMEM; goto out_unlock; } s = create_cache(cache_name, size, calculate_alignment(flags, align, size), flags, useroffset, usersize, ctor, NULL, NULL); if (IS_ERR(s)) { err = PTR_ERR(s); kfree_const(cache_name); } out_unlock: mutex_unlock(&slab_mutex); memcg_put_cache_ids(); put_online_mems(); put_online_cpus(); if (err) { if (flags & SLAB_PANIC) panic( "kmem_cache_create: Failed to create slab '%s'. Error %d\n" , name, err); else { pr_warn( "kmem_cache_create(%s) failed with error %d\n" , name, err); dump_stack(); } return NULL; } return s; } |