1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24*0Sstevel@tonic-gate * Use is subject to license terms. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 28*0Sstevel@tonic-gate 29*0Sstevel@tonic-gate #include <sys/types.h> 30*0Sstevel@tonic-gate #include <sys/id_space.h> 31*0Sstevel@tonic-gate #include <sys/debug.h> 32*0Sstevel@tonic-gate 33*0Sstevel@tonic-gate /* 34*0Sstevel@tonic-gate * ID Spaces 35*0Sstevel@tonic-gate * 36*0Sstevel@tonic-gate * The id_space_t provides a simple implementation of a managed range of 37*0Sstevel@tonic-gate * integer identifiers using a vmem arena. An ID space guarantees that the 38*0Sstevel@tonic-gate * next identifer returned by an allocation is larger than the previous one, 39*0Sstevel@tonic-gate * unless there are no larger slots remaining in the range. In this case, 40*0Sstevel@tonic-gate * the ID space will return the first available slot in the lower part of the 41*0Sstevel@tonic-gate * range (viewing the previous identifier as a partitioning element). If no 42*0Sstevel@tonic-gate * slots are available, id_alloc() will sleep until an identifier becomes 43*0Sstevel@tonic-gate * available. Accordingly, id_space allocations must be initiated from 44*0Sstevel@tonic-gate * contexts where sleeping is acceptable. id_alloc_nosleep() will return 45*0Sstevel@tonic-gate * -1 if no slots are available or if the system is low on memory. If 46*0Sstevel@tonic-gate * id_alloc_nosleep() fails, callers should not try to extend the ID 47*0Sstevel@tonic-gate * space. This is to avoid making a possible low-memory situation 48*0Sstevel@tonic-gate * worse. 49*0Sstevel@tonic-gate * 50*0Sstevel@tonic-gate * As an ID space is designed for representing a range of id_t's, there 51*0Sstevel@tonic-gate * is a preexisting maximal range: [0, MAXUID]. ID space requests 52*0Sstevel@tonic-gate * outside that range will fail on a DEBUG kernel. 53*0Sstevel@tonic-gate * 54*0Sstevel@tonic-gate * (Presently, the id_space_t abstraction supports only direct allocations; ID 55*0Sstevel@tonic-gate * reservation, in which an ID is allocated but placed in a internal 56*0Sstevel@tonic-gate * dictionary for later use, should be added when a consuming subsystem 57*0Sstevel@tonic-gate * arrives.) 58*0Sstevel@tonic-gate */ 59*0Sstevel@tonic-gate 60*0Sstevel@tonic-gate /* 61*0Sstevel@tonic-gate * Create an arena to represent the range [low, high). 62*0Sstevel@tonic-gate * Caller must be in a context in which VM_SLEEP is legal. 63*0Sstevel@tonic-gate */ 64*0Sstevel@tonic-gate id_space_t * 65*0Sstevel@tonic-gate id_space_create(const char *name, id_t low, id_t high) 66*0Sstevel@tonic-gate { 67*0Sstevel@tonic-gate ASSERT(low >= 0); 68*0Sstevel@tonic-gate ASSERT(low < high); 69*0Sstevel@tonic-gate 70*0Sstevel@tonic-gate return (vmem_create(name, (void *)(uintptr_t)(low + 1), high - low, 1, 71*0Sstevel@tonic-gate NULL, NULL, NULL, 0, VM_SLEEP | VMC_IDENTIFIER)); 72*0Sstevel@tonic-gate } 73*0Sstevel@tonic-gate 74*0Sstevel@tonic-gate /* 75*0Sstevel@tonic-gate * Destroy a previously created ID space. 76*0Sstevel@tonic-gate * No restrictions on caller's context. 77*0Sstevel@tonic-gate */ 78*0Sstevel@tonic-gate void 79*0Sstevel@tonic-gate id_space_destroy(id_space_t *isp) 80*0Sstevel@tonic-gate { 81*0Sstevel@tonic-gate vmem_destroy(isp); 82*0Sstevel@tonic-gate } 83*0Sstevel@tonic-gate 84*0Sstevel@tonic-gate void 85*0Sstevel@tonic-gate id_space_extend(id_space_t *isp, id_t low, id_t high) 86*0Sstevel@tonic-gate { 87*0Sstevel@tonic-gate (void) vmem_add(isp, 88*0Sstevel@tonic-gate (void *)(uintptr_t)(low + 1), high - low, VM_SLEEP); 89*0Sstevel@tonic-gate } 90*0Sstevel@tonic-gate 91*0Sstevel@tonic-gate /* 92*0Sstevel@tonic-gate * Allocate an id_t from specified ID space. 93*0Sstevel@tonic-gate * Caller must be in a context in which VM_SLEEP is legal. 94*0Sstevel@tonic-gate */ 95*0Sstevel@tonic-gate id_t 96*0Sstevel@tonic-gate id_alloc(id_space_t *isp) 97*0Sstevel@tonic-gate { 98*0Sstevel@tonic-gate return ((id_t)(uintptr_t) 99*0Sstevel@tonic-gate vmem_alloc(isp, 1, VM_SLEEP | VM_NEXTFIT) - 1); 100*0Sstevel@tonic-gate } 101*0Sstevel@tonic-gate 102*0Sstevel@tonic-gate /* 103*0Sstevel@tonic-gate * Allocate an id_t from specified ID space. 104*0Sstevel@tonic-gate * Returns -1 on failure (see module block comments for more information on 105*0Sstevel@tonic-gate * failure modes). 106*0Sstevel@tonic-gate */ 107*0Sstevel@tonic-gate id_t 108*0Sstevel@tonic-gate id_alloc_nosleep(id_space_t *isp) 109*0Sstevel@tonic-gate { 110*0Sstevel@tonic-gate return ((id_t)(uintptr_t) 111*0Sstevel@tonic-gate vmem_alloc(isp, 1, VM_NOSLEEP | VM_NEXTFIT) - 1); 112*0Sstevel@tonic-gate } 113*0Sstevel@tonic-gate 114*0Sstevel@tonic-gate /* 115*0Sstevel@tonic-gate * Free a previously allocated ID. 116*0Sstevel@tonic-gate * No restrictions on caller's context. 117*0Sstevel@tonic-gate */ 118*0Sstevel@tonic-gate void 119*0Sstevel@tonic-gate id_free(id_space_t *isp, id_t id) 120*0Sstevel@tonic-gate { 121*0Sstevel@tonic-gate vmem_free(isp, (void *)(uintptr_t)(id + 1), 1); 122*0Sstevel@tonic-gate } 123