static int rtCritSectRwEnterShared(PRTCRITSECTRW pThis, PCRTLOCKVALSRCPOS pSrcPos, bool fTryOnly)
{
/*
* Validate input.
*/
AssertPtr(pThis);
AssertReturn(pThis->u32Magic == RTCRITSECTRW_MAGIC, VERR_SEM_DESTROYED);
#ifdef IN_RING0
Assert(pThis->fFlags & RTCRITSECT_FLAGS_RING0);
#else
Assert(!(pThis->fFlags & RTCRITSECT_FLAGS_RING0));
#endif
#ifdef RTCRITSECTRW_STRICT
RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
if (!fTryOnly)
{
int rc9;
RTNATIVETHREAD hNativeWriter;
ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
if (hNativeWriter != NIL_RTTHREAD && hNativeWriter == RTThreadNativeSelf())
rc9 = RTLockValidatorRecExclCheckOrder(pThis->pValidatorWrite, hThreadSelf, pSrcPos, RT_INDEFINITE_WAIT);
else
rc9 = RTLockValidatorRecSharedCheckOrder(pThis->pValidatorRead, hThreadSelf, pSrcPos, RT_INDEFINITE_WAIT);
if (RT_FAILURE(rc9))
return rc9;
}
#endif
/*
* Get cracking...
*/
uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
uint64_t u64OldState = u64State;
for (;;)
{
if ((u64State & RTCSRW_DIR_MASK) == (RTCSRW_DIR_READ << RTCSRW_DIR_SHIFT))
{
/* It flows in the right direction, try follow it before it changes. */
uint64_t c = (u64State & RTCSRW_CNT_RD_MASK) >> RTCSRW_CNT_RD_SHIFT;
c++;
Assert(c < RTCSRW_CNT_MASK / 2);
u64State &= ~RTCSRW_CNT_RD_MASK;
u64State |= c << RTCSRW_CNT_RD_SHIFT;
if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
{
#ifdef RTCRITSECTRW_STRICT
RTLockValidatorRecSharedAddOwner(pThis->pValidatorRead, hThreadSelf, pSrcPos);
#endif
break;
}
}
else if ((u64State & (RTCSRW_CNT_RD_MASK | RTCSRW_CNT_WR_MASK)) == 0)
static int rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
{
/*
* Validate input.
*/
RTSEMRWINTERNAL *pThis = hRWSem;
if (pThis == NIL_RTSEMRW)
return VINF_SUCCESS;
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
#ifdef RTSEMRW_STRICT
RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
if (cMillies > 0)
{
int rc9;
RTNATIVETHREAD hNativeWriter;
ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
if (hNativeWriter != NIL_RTTHREAD && hNativeWriter == RTThreadNativeSelf())
rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
else
rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies);
if (RT_FAILURE(rc9))
return rc9;
}
#endif
/*
* Get cracking...
*/
uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
uint64_t u64OldState = u64State;
for (;;)
{
if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
{
/* It flows in the right direction, try follow it before it changes. */
uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
c++;
Assert(c < RTSEMRW_CNT_MASK / 2);
u64State &= ~RTSEMRW_CNT_RD_MASK;
u64State |= c << RTSEMRW_CNT_RD_SHIFT;
if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
{
#ifdef RTSEMRW_STRICT
RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
#endif
break;
}
}
else if ((u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) == 0)
RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
{
/*
* Validate handle.
*/
struct RTSEMRWINTERNAL *pThis = hRWSem;
AssertPtrReturn(pThis, false);
AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
/*
* Check ownership.
*/
RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
RTNATIVETHREAD hWriter;
ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
return hWriter == hNativeSelf;
}
RTDECL(bool) RTSemRWIsReadOwner(RTSEMRW hRWSem, bool fWannaHear)
{
/*
* Validate handle.
*/
struct RTSEMRWINTERNAL *pThis = hRWSem;
AssertPtrReturn(pThis, false);
AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
/*
* Check write ownership. The writer is also a valid reader.
*/
RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
RTNATIVETHREAD hWriter;
ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
if (hWriter == hNativeSelf)
return true;
if (hWriter != NIL_RTNATIVETHREAD)
return false;
#ifdef RTSEMRW_STRICT
/*
* Ask the lock validator.
*/
NOREF(fWannaHear);
return RTLockValidatorRecSharedIsOwner(&pThis->ValidatorRead, NIL_RTTHREAD);
#else
/*
* If there are no reads we cannot be one of them... But if there are we
* cannot know and can only return what the caller want to hear.
*/
if (pThis->cReads == 0)
return false;
return fWannaHear;
#endif
}
