handletablectx.cpp@ 17951

Last change on this file since 17951 was 10790, checked in by vboxsync, 16 years ago
IPRT: Fixed an overlooked race found by the threaded testcase.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 10.5 KB

Line
1	/* $Id: handletablectx.cpp 10790 2008-07-21 18:43:39Z vboxsync $ */
2	/** @file
3	* IPRT - Handle Tables.
4	*/
5
6	/*
7	* Copyright (C) 2008 Sun Microsystems, Inc.
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*
26	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*******************************************************************************
32	* Header Files *
33	*******************************************************************************/
34	#include <iprt/handletable.h>
35	#include <iprt/mem.h>
36	#include <iprt/spinlock.h>
37	#include <iprt/err.h>
38	#include <iprt/assert.h>
39	#include <iprt/param.h>
40	#include <iprt/string.h>
41	#include <iprt/asm.h>
42	#include "internal/magics.h"
43	#include "handletable.h"
44
45
46	RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void pvObj, void pvCtx, uint32_t *ph)
47	{
48	/* validate the input */
49	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
50	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
51	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
52	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, VERR_INVALID_FUNCTION);
53	AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
54	AssertPtrReturn(ph, VERR_INVALID_POINTER);
55	*ph = pThis->uBase - 1;
56
57	/*
58	* Allocation loop.
59	*/
60	RTSPINLOCKTMP Tmp;
61	rtHandleTableLock(pThis, &Tmp);
62
63	int rc;
64	do
65	{
66	/*
67	* Try grab a free entry from the head of the free list.
68	*/
69	uint32_t i = pThis->iFreeHead;
70	if (i != NIL_RTHT_INDEX)
71	{
72	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, i);
73	Assert(pFree);
74	if (i == pThis->iFreeTail)
75	pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
76	else
77	pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
78	pThis->cCurAllocated++;
79	Assert(pThis->cCurAllocated <= pThis->cCur);
80
81	/*
82	* Setup the entry and return.
83	*/
84	PRTHTENTRYCTX pEntry = (PRTHTENTRYCTX)pFree;
85	pEntry->pvObj = pvObj;
86	pEntry->pvCtx = pvCtx;
87	*ph = i + pThis->uBase;
88	rc = VINF_SUCCESS;
89	}
90	/*
91	* Must expand the handle table, unless it's full.
92	*/
93	else if (pThis->cCur >= pThis->cMax)
94	{
95	rc = VERR_NO_MORE_HANDLES;
96	Assert(pThis->cCur == pThis->cCurAllocated);
97	}
98	else
99	{
100	/*
101	* Do we have to expand the 1st level table too?
102	*/
103	uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
104	uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
105	? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
106	: 0;
107	if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
108	cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
109	Assert(!cLevel1 \|\| pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
110
111	/* leave the lock (never do fancy stuff from behind a spinlock). */
112	rtHandleTableUnlock(pThis, &Tmp);
113
114	/*
115	* Do the allocation(s).
116	*/
117	rc = VERR_TRY_AGAIN;
118	void **papvLevel1 = NULL;
119	if (cLevel1)
120	{
121	papvLevel1 = (void *)RTMemAlloc(sizeof(void ) * cLevel1);
122	if (!papvLevel1)
123	return VERR_NO_MEMORY;
124	}
125
126	PRTHTENTRYCTX paTable = (PRTHTENTRYCTX)RTMemAlloc(sizeof(paTable) RTHT_LEVEL2_ENTRIES);
127	if (!paTable)
128	{
129	RTMemFree(papvLevel1);
130	return VERR_NO_MEMORY;
131	}
132
133	/* re-enter the lock. */
134	rtHandleTableLock(pThis, &Tmp);
135
136	/*
137	* Insert the new bits, but be a bit careful as someone might have
138	* raced us expanding the table.
139	*/
140	/* deal with the 1st level lookup expansion first */
141	if (cLevel1)
142	{
143	Assert(papvLevel1);
144	if (cLevel1 > pThis->cLevel1)
145	{
146	/* Replace the 1st level table. */
147	memcpy(papvLevel1, pThis->papvLevel1, sizeof(void ) pThis->cLevel1);
148	memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void ) (cLevel1 - pThis->cLevel1));
149	pThis->cLevel1 = cLevel1;
150	void **papvTmp = pThis->papvLevel1;
151	pThis->papvLevel1 = papvLevel1;
152	papvLevel1 = papvTmp;
153	}
154
155	/* free the obsolete one (outside the lock of course) */
156	rtHandleTableUnlock(pThis, &Tmp);
157	RTMemFree(papvLevel1);
158	rtHandleTableLock(pThis, &Tmp);
159	}
160
161	/* insert the table we allocated. */
162	uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
163	if ( iLevel1New < pThis->cLevel1
164	&& pThis->cCur < pThis->cMax)
165	{
166	pThis->papvLevel1[iLevel1New] = paTable;
167
168	/* link all entries into a free list. */
169	Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
170	for (uint32_t i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
171	{
172	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
173	paTable[i].pvCtx = (void *)~(uintptr_t)7;
174	}
175	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
176	paTable[RTHT_LEVEL2_ENTRIES - 1].pvCtx = (void *)~(uintptr_t)7;
177
178	/* join the free list with the other. */
179	if (pThis->iFreeTail == NIL_RTHT_INDEX)
180	pThis->iFreeHead = pThis->cCur;
181	else
182	{
183	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, pThis->iFreeTail);
184	Assert(pPrev);
185	RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
186	}
187	pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
188
189	pThis->cCur += RTHT_LEVEL2_ENTRIES;
190	}
191	else
192	{
193	/* free the table (raced someone, and we lost). */
194	rtHandleTableUnlock(pThis, &Tmp);
195	RTMemFree(paTable);
196	rtHandleTableLock(pThis, &Tmp);
197	}
198
199	rc = VERR_TRY_AGAIN;
200	}
201	} while (rc == VERR_TRY_AGAIN);
202
203	rtHandleTableUnlock(pThis, &Tmp);
204
205	return rc;
206	}
207
208
209	RTDECL(void ) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void pvCtx)
210	{
211	/* validate the input */
212	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
213	AssertPtrReturn(pThis, NULL);
214	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
215	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, NULL);
216
217	void *pvObj = NULL;
218
219	/* acquire the lock */
220	RTSPINLOCKTMP Tmp;
221	rtHandleTableLock(pThis, &Tmp);
222
223	/*
224	* Perform the lookup and retaining.
225	*/
226	PRTHTENTRYCTX pEntry = rtHandleTableLookupWithCtx(pThis, h);
227	if (pEntry && pEntry->pvCtx == pvCtx)
228	{
229	pvObj = pEntry->pvObj;
230	if (!RTHT_IS_FREE(pvObj))
231	{
232	if (pThis->pfnRetain)
233	{
234	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, pvCtx, pThis->pvRetainUser);
235	if (RT_FAILURE(rc))
236	pvObj = NULL;
237	}
238	}
239	else
240	pvObj = NULL;
241	}
242
243	/* release the lock */
244	rtHandleTableUnlock(pThis, &Tmp);
245	return pvObj;
246	}
247
248
249	RTDECL(void ) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void pvCtx)
250	{
251	/* validate the input */
252	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
253	AssertPtrReturn(pThis, NULL);
254	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
255	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, NULL);
256
257	void *pvObj = NULL;
258
259	/* acquire the lock */
260	RTSPINLOCKTMP Tmp;
261	rtHandleTableLock(pThis, &Tmp);
262
263	/*
264	* Perform the lookup and retaining.
265	*/
266	PRTHTENTRYCTX pEntry = rtHandleTableLookupWithCtx(pThis, h);
267	if (pEntry && pEntry->pvCtx == pvCtx)
268	{
269	pvObj = pEntry->pvObj;
270	if (!RTHT_IS_FREE(pvObj))
271	{
272	if (pThis->pfnRetain)
273	{
274	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, pvCtx, pThis->pvRetainUser);
275	if (RT_FAILURE(rc))
276	pvObj = NULL;
277	}
278
279	/*
280	* Link it into the free list.
281	*/
282	if (pvObj)
283	{
284	pEntry->pvCtx = (void *)~(uintptr_t)7;
285
286	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
287	RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
288
289	uint32_t const i = h - pThis->uBase;
290	if (pThis->iFreeTail == NIL_RTHT_INDEX)
291	pThis->iFreeHead = pThis->iFreeTail = i;
292	else
293	{
294	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, pThis->iFreeTail);
295	Assert(pPrev);
296	RTHT_SET_FREE_IDX(pPrev, i);
297	pThis->iFreeTail = i;
298	}
299
300	Assert(pThis->cCurAllocated > 0);
301	pThis->cCurAllocated--;
302	}
303	}
304	else
305	pvObj = NULL;
306	}
307
308	/* release the lock */
309	rtHandleTableUnlock(pThis, &Tmp);
310	return pvObj;
311	}
312

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source: vbox/trunk/src/VBox/Runtime/common/misc/handletablectx.cpp@ 17951

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