semrw-lockless-generic.cpp revision 2805b95732a8d26015a397626b96049a6e6573e7
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * IPRT Testcase - RTSemXRoads, generic implementation.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Copyright (C) 2009 Sun Microsystems, Inc.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * This file is part of VirtualBox Open Source Edition (OSE), as
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * available from http://www.virtualbox.org. This file is free software;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * you can redistribute it and/or modify it under the terms of the GNU
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * General Public License (GPL) as published by the Free Software
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Foundation, in version 2 as it comes in the "COPYING" file of the
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * The contents of this file may alternatively be used under the terms
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * of the Common Development and Distribution License Version 1.0
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * VirtualBox OSE distribution, in which case the provisions of the
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * CDDL are applicable instead of those of the GPL.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * You may elect to license modified versions of this file under the
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * terms and conditions of either the GPL or the CDDL or both.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Clara, CA 95054 USA or visit http://www.sun.com if you need
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * additional information or have any questions.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync/*******************************************************************************
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync* Header Files *
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync*******************************************************************************/
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync/*******************************************************************************
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync* Structures and Typedefs *
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync*******************************************************************************/
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** Magic value (RTSEMRW_MAGIC). */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* The state variable.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * All accesses are atomic and it bits are defined like this:
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bits 0..14 - cReads.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bit 15 - Unused.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bits 16..31 - cWrites. - doesn't make sense here
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bit 31 - fDirection; 0=Read, 1=Write.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bits 32..46 - cWaitingReads
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bit 47 - Unused.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bits 48..62 - cWaitingWrites
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Bit 63 - Unused.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** The write owner. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** The number of reads made by the current writer. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** The number of reads made by the current writer. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** What the writer threads are blocking on. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** What the read threads are blocking on when waiting for the writer to
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * finish. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** Indicates whether hEvtRead needs resetting. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync bool volatile fNeedReset;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** The validator record for the writer. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** The validator record for the readers. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync/*******************************************************************************
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync* Defined Constants And Macros *
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync*******************************************************************************/
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync#define RTSEMRW_CNT_RD_MASK (RTSEMRW_CNT_MASK << RTSEMRW_CNT_RD_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync#define RTSEMRW_CNT_WR_MASK (RTSEMRW_CNT_MASK << RTSEMRW_CNT_WR_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync#define RTSEMRW_DIR_MASK RT_BIT_64(RTSEMRW_DIR_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync#define RTSEMRW_WAIT_CNT_RD_MASK (RTSEMRW_CNT_MASK << RTSEMRW_WAIT_CNT_RD_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync//#define RTSEMRW_WAIT_CNT_WR_SHIFT 48
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync//#define RTSEMRW_WAIT_CNT_WR_MASK (RTSEMRW_CNT_MASK << RTSEMRW_WAIT_CNT_WR_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTSEMRWINTERNAL *pThis = (RTSEMRWINTERNAL *)RTMemAlloc(sizeof(*pThis));
2805b95732a8d26015a397626b96049a6e6573e7vboxsync RTLockValidatorRecExclInit(&pThis->ValidatorWrite, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW", pThis, true);
2805b95732a8d26015a397626b96049a6e6573e7vboxsync RTLockValidatorRecSharedInit(&pThis->ValidatorRead, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW", pThis, false /*fSignaller*/, true);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecMakeSiblings(&pThis->ValidatorWrite.Core, &pThis->ValidatorRead.Core);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate input.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync Assert(!(ASMAtomicReadU64(&pThis->u64State) & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)));
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Invalidate the object and free up the resources.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMRW_MAGIC, RTSEMRW_MAGIC), VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ASMAtomicXchgHandle(&pThis->hEvtRead, NIL_RTSEMEVENTMULTI, &hEvtRead);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ASMAtomicXchgHandle(&pThis->hEvtWrite, NIL_RTSEMEVENT, &hEvtWrite);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncstatic int rtSemRWRequestRead(RTSEMRW hRWSem, unsigned cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate input.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
2805b95732a8d26015a397626b96049a6e6573e7vboxsync int rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Get cracking...
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* It flows in the right direction, try follow it before it changes. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync else if ((u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) == 0)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Wrong direction, but we're alone here and can simply try switch the direction. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State |= (UINT64_C(1) << RTSEMRW_CNT_RD_SHIFT) | (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Is the writer perhaps doing a read recursion? */
f4859dbc9e6e61d81adba530beddf0c374ac9011vboxsync ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* If the timeout is 0, return already. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Add ourselves to the queue and wait for the direction to change. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_WAIT_CNT_RD_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State |= (c << RTSEMRW_CNT_RD_SHIFT) | (cWait << RTSEMRW_WAIT_CNT_RD_SHIFT);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync rc = RTLockValidatorRecSharedCheckBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, false);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync rc = RTSemEventMultiWaitNoResume(pThis->hEvtRead, cMillies);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync rc = RTSemEventMultiWait(pThis->hEvtRead, cMillies);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Decrement the counts and return the error. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64OldState = u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT; Assert(c > 0);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT; Assert(cWait > 0);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_WAIT_CNT_RD_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State |= (c << RTSEMRW_CNT_RD_SHIFT) | (cWait << RTSEMRW_WAIT_CNT_RD_SHIFT);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Decrement the wait count and maybe reset the semaphore (if we're last). */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* got it! */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT));
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestRead(RTSEMRW RWSem, unsigned cMillies)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, false, NULL);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, false, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestReadDebug(RTSEMRW RWSem, unsigned cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, false, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW RWSem, unsigned cMillies)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, true, NULL);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, true, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW RWSem, unsigned cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestRead(RWSem, cMillies, true, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate handle.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Check the direction and take action accordingly.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc9 = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, NIL_RTTHREAD);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Don't change the direction. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Reverse the direction and signal the reader threads. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_DIR_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State |= RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
f4859dbc9e6e61d81adba530beddf0c374ac9011vboxsync ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(hNativeSelf == hNativeWriter, VERR_NOT_OWNER);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->cWriterReads > 0, VERR_NOT_OWNER);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncDECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, unsigned cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate input.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
2805b95732a8d26015a397626b96049a6e6573e7vboxsync int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Check if we're already the owner and just recursing.
f4859dbc9e6e61d81adba530beddf0c374ac9011vboxsync ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT));
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorWrite, pSrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Get cracking.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ( (u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync || (u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) != 0)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* It flows in the right direction, try follow it before it changes. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync else if ((u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) == 0)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Wrong direction, but we're alone here and can simply try switch the direction. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State |= (UINT64_C(1) << RTSEMRW_CNT_WR_SHIFT) | (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Wrong direction and we're not supposed to wait, just return. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Add ourselves to the write count and break out to do the wait. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * If we're in write mode now try grab the ownership. Play fair if there
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * are threads already waiting.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync bool fDone = (u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync && ( ((u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT) == 1
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ASMAtomicCmpXchgHandle(&pThis->hNativeWriter, hNativeSelf, NIL_RTNATIVETHREAD, fDone);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Wait for our turn.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync rc = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, false);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync rc = RTSemEventWaitNoResume(pThis->hEvtWrite, cMillies);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Decrement the counts and return the error. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64OldState = u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT; Assert(c > 0);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ASMAtomicCmpXchgHandle(&pThis->hNativeWriter, hNativeSelf, NIL_RTNATIVETHREAD, fDone);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertMsg(iLoop < 1000, ("%u\n", iLoop)); /* may loop a few times here... */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT));
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestWrite(RTSEMRW RWSem, unsigned cMillies)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, false, NULL);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, false, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW RWSem, unsigned cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, false, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW RWSem, unsigned cMillies)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, true, NULL);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, true, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW RWSem, unsigned cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync return rtSemRWRequestWrite(RWSem, cMillies, true, &SrcPos);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate handle.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
f4859dbc9e6e61d81adba530beddf0c374ac9011vboxsync ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(hNativeSelf == hNativeWriter, VERR_NOT_OWNER);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Unwind a recursion.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->cWriterReads == 0, VERR_WRONG_ORDER); /* (must release all read recursions before the final write.) */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, true);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Update the state.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /** @todo validate order. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ASMAtomicWriteHandle(&pThis->hNativeWriter, NIL_RTNATIVETHREAD);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Don't change the direction, wait up the next writer if any. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync /* Reverse the direction and signal the reader threads. */
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync u64State &= ~(RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync int rc9 = RTLockValidatorRecExclUnwind(&pThis->ValidatorWrite);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate handle.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Check ownership.
f4859dbc9e6e61d81adba530beddf0c374ac9011vboxsync ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW RWSem)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate handle.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Return the requested data.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsyncRTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW RWSem)
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate handle.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Return the requested data.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Validate input.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync * Return the requested data.
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
e1fd337d575f2a4c053c6fe7a811e2fd1a31e874vboxsync if ((u64State & RTSEMRW_DIR_MASK) != (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))