1 /* 2 * Written by Julian Elischer (julian@tfs.com) 3 * for TRW Financial Systems for use under the MACH(2.5) operating system. 4 * 5 * TRW Financial Systems, in accordance with their agreement with Carnegie 6 * Mellon University, makes this software available to CMU to distribute 7 * or use in any manner that they see fit as long as this message is kept with 8 * the software. For this reason TFS also grants any other persons or 9 * organisations permission to use or modify this software. 10 * 11 * TFS supplies this software to be publicly redistributed 12 * on the understanding that TFS is not responsible for the correct 13 * functioning of this software in any circumstances. 14 * 15 * $FreeBSD: src/sys/cam/cam_extend.c,v 1.3 1999/08/28 00:40:39 peter Exp $ 16 * $DragonFly: src/sys/bus/cam/cam_extend.c,v 1.8 2006/12/22 23:12:16 swildner Exp $ 17 */ 18 /* 19 * XXX XXX XXX XXX We should get DEVFS working so that we 20 * don't have to do this, possibly sparse, array based junk. 21 * XXX: We can do this now with cdev_t, that's even better. 22 */ 23 /* 24 * Extensible arrays: Use a realloc like implementation to permit 25 * the arrays to be extend. 26 */ 27 #include <sys/param.h> 28 #include <sys/systm.h> 29 #include <sys/kernel.h> 30 #include <sys/malloc.h> 31 32 #include "cam_extend.h" 33 34 struct extend_array 35 { 36 int nelem; 37 void **ps; 38 }; 39 40 /* EXTEND_CHUNK: Number of extend slots to allocate whenever we need a new 41 * one. 42 */ 43 #ifndef EXTEND_CHUNK 44 #define EXTEND_CHUNK 8 45 #endif 46 47 struct extend_array * 48 cam_extend_new(void) 49 { 50 return(kmalloc(sizeof(struct extend_array), M_DEVBUF, 51 M_INTWAIT | M_ZERO)); 52 } 53 54 void * 55 cam_extend_set(struct extend_array *ea, int index, void *value) 56 { 57 if (index >= ea->nelem) { 58 void **space; 59 space = kmalloc(sizeof(void *) * (index + EXTEND_CHUNK), 60 M_DEVBUF, M_INTWAIT | M_ZERO); 61 62 /* Make sure we have something to copy before we copy it */ 63 if (ea->nelem) { 64 bcopy(ea->ps, space, sizeof(void *) * ea->nelem); 65 kfree(ea->ps, M_DEVBUF); 66 } 67 68 ea->ps = space; 69 ea->nelem = index + EXTEND_CHUNK; 70 } 71 if (ea->ps[index]) { 72 kprintf("extend_set: entry %d already has storage.\n", index); 73 return 0; 74 } 75 else 76 ea->ps[index] = value; 77 78 return value; 79 } 80 81 void * 82 cam_extend_get(struct extend_array *ea, 83 int index) 84 { 85 if (ea == NULL || index >= ea->nelem || index < 0) 86 return NULL; 87 return ea->ps[index]; 88 } 89 90 void 91 cam_extend_release(struct extend_array *ea, int index) 92 { 93 void *p = cam_extend_get(ea, index); 94 if (p) { 95 ea->ps[index] = 0; 96 } 97 } 98