+++ /dev/null
-/*
- * ReactOS Cancel-Safe Queue library
- * Copyright (c) 2004, Vizzini (vizzini@plasmic.com)
- * Licensed under the GNU GPL for the ReactOS project
- *
- * This file implements the ReactOS CSQ library. For background and overview
- * information on these routines, read csq.h. For the authoritative reference
- * to using these routines, see the current DDK (IoCsqXXX and CsqXxx callbacks).
- *
- * There are a couple of subtle races that this library is designed to avoid.
- * Please read the code (particularly IoCsqInsertIrpEx and IoCsqRemoveIrp) for
- * some details.
- *
- * In general, we try here to avoid the race between these queue/dequeue
- * interfaces and our own cancel routine. This library supplies a cancel
- * routine that is used in all IRPs that are queued to it. The major race
- * conditions surround the proper handling of in-between cases, such as in-progress
- * queue and de-queue operations.
- *
- * When you're thinking about these operations, keep in mind that three or four
- * processors can have queue and dequeue operations in progress simultaneously,
- * and a user thread may cancel any IRP at any time. Also, these operations don't
- * all happen at DISPATCH_LEVEL all of the time, so thread switching on a single
- * processor can create races too.
- */
-
-#include <ntdef.h>
-#undef DECLSPEC_IMPORT
-#define DECLSPEC_IMPORT
-#include <ntifs.h>
-
-\f
-/*!
- * @brief Cancel routine that is installed on any IRP that this library manages
- *
- * @param DeviceObject
- * @param Irp
- *
- * @note
- * - We assume that Irp->Tail.Overlay.DriverContext[3] has either a IO_CSQ
- * or an IO_CSQ_IRP_CONTEXT in it, but we have to figure out which it is
- * - By the time this routine executes, the I/O Manager has already cleared
- * the cancel routine pointer in the IRP, so it will only be canceled once
- * - Because of this, we're guaranteed that Irp is valid the whole time
- * - Don't forget to release the cancel spinlock ASAP --> #1 hot lock in the
- * system
- * - May be called at high IRQL
- */
-_Function_class_(DRIVER_CANCEL)
-static
-VOID
-NTAPI
-IopCsqCancelRoutine(
- _Inout_ PDEVICE_OBJECT DeviceObject,
- _Inout_ _IRQL_uses_cancel_ PIRP Irp)
-{
- PIO_CSQ Csq;
- KIRQL Irql;
-
- /* First things first: */
- IoReleaseCancelSpinLock(Irp->CancelIrql);
-
- /* We could either get a context or just a csq */
- Csq = (PIO_CSQ)Irp->Tail.Overlay.DriverContext[3];
-
- if(Csq->Type == IO_TYPE_CSQ_IRP_CONTEXT)
- {
- PIO_CSQ_IRP_CONTEXT Context = (PIO_CSQ_IRP_CONTEXT)Csq;
- Csq = Context->Csq;
-
- /* clean up context while we're here */
- Context->Irp = NULL;
- }
-
- /* Now that we have our CSQ, complete the IRP */
- Csq->CsqAcquireLock(Csq, &Irql);
- Csq->CsqRemoveIrp(Csq, Irp);
- Csq->CsqReleaseLock(Csq, Irql);
-
- Csq->CsqCompleteCanceledIrp(Csq, Irp);
-}
-
-\f
-/*!
- * @brief Set up a CSQ struct to initialize the queue
- *
- * @param Csq - Caller-allocated non-paged space for our IO_CSQ to be initialized
- * @param CsqInsertIrp - Insert routine
- * @param CsqRemoveIrp - Remove routine
- * @param CsqPeekNextIrp - Routine to paeek at the next IRP in queue
- * @param CsqAcquireLock - Acquire the queue's lock
- * @param CsqReleaseLock - Release the queue's lock
- * @param CsqCompleteCanceledIrp - Routine to complete IRPs when they are canceled
- *
- * @return
- * - STATUS_SUCCESS in all cases
- *
- * @note
- * - Csq must be non-paged, as the queue is manipulated with a held spinlock
- */
-NTSTATUS
-NTAPI
-IoCsqInitialize(
- _Out_ PIO_CSQ Csq,
- _In_ PIO_CSQ_INSERT_IRP CsqInsertIrp,
- _In_ PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
- _In_ PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
- _In_ PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
- _In_ PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
- _In_ PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp)
-{
- Csq->Type = IO_TYPE_CSQ;
- Csq->CsqInsertIrp = CsqInsertIrp;
- Csq->CsqRemoveIrp = CsqRemoveIrp;
- Csq->CsqPeekNextIrp = CsqPeekNextIrp;
- Csq->CsqAcquireLock = CsqAcquireLock;
- Csq->CsqReleaseLock = CsqReleaseLock;
- Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
- Csq->ReservePointer = NULL;
-
- return STATUS_SUCCESS;
-}
-
-\f
-/*!
- * @brief Set up a CSQ struct to initialize the queue (extended version)
- *
- * @param Csq - Caller-allocated non-paged space for our IO_CSQ to be initialized
- * @param CsqInsertIrpEx - Extended insert routine
- * @param CsqRemoveIrp - Remove routine
- * @param CsqPeekNextIrp - Routine to paeek at the next IRP in queue
- * @param CsqAcquireLock - Acquire the queue's lock
- * @param CsqReleaseLock - Release the queue's lock
- * @param CsqCompleteCanceledIrp - Routine to complete IRPs when they are canceled
- *
- * @return
- * - STATUS_SUCCESS in all cases
- * @note
- * - Csq must be non-paged, as the queue is manipulated with a held spinlock
- */
-NTSTATUS
-NTAPI
-IoCsqInitializeEx(
- _Out_ PIO_CSQ Csq,
- _In_ PIO_CSQ_INSERT_IRP_EX CsqInsertIrpEx,
- _In_ PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
- _In_ PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
- _In_ PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
- _In_ PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
- _In_ PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp)
-{
- Csq->Type = IO_TYPE_CSQ_EX;
- Csq->CsqInsertIrp = (PIO_CSQ_INSERT_IRP)CsqInsertIrpEx;
- Csq->CsqRemoveIrp = CsqRemoveIrp;
- Csq->CsqPeekNextIrp = CsqPeekNextIrp;
- Csq->CsqAcquireLock = CsqAcquireLock;
- Csq->CsqReleaseLock = CsqReleaseLock;
- Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
- Csq->ReservePointer = NULL;
-
- return STATUS_SUCCESS;
-}
-
-\f
-/*!
- * @brief Insert an IRP into the CSQ
- *
- * @param Csq - Pointer to the initialized CSQ
- * @param Irp - Pointer to the IRP to queue
- * @param Context - Context record to track the IRP while queued
- *
- * @return
- * - Just passes through to IoCsqInsertIrpEx, with no InsertContext
- */
-VOID
-NTAPI
-IoCsqInsertIrp(
- _Inout_ PIO_CSQ Csq,
- _Inout_ PIRP Irp,
- _Out_opt_ PIO_CSQ_IRP_CONTEXT Context)
-{
- IoCsqInsertIrpEx(Csq, Irp, Context, 0);
-}
-
-\f
-/*!
- * @brief Insert an IRP into the CSQ, with additional tracking context
- *
- * @param Csq - Pointer to the initialized CSQ
- * @param Irp - Pointer to the IRP to queue
- * @param Context - Context record to track the IRP while queued
- * @param InsertContext - additional data that is passed through to CsqInsertIrpEx
- *
- * @note
- * - Passes the additional context through to the driver-supplied callback,
- * which can be used with more sophistocated queues
- * - Marks the IRP pending in all cases
- * - Guaranteed to not queue a canceled IRP
- * - This is complicated logic, and is patterend after the Microsoft library.
- * I'm sure I have gotten the details wrong on a fine point or two, but
- * basically this works with the MS-supplied samples.
- */
-NTSTATUS
-NTAPI
-IoCsqInsertIrpEx(
- _Inout_ PIO_CSQ Csq,
- _Inout_ PIRP Irp,
- _Out_opt_ PIO_CSQ_IRP_CONTEXT Context,
- _In_opt_ PVOID InsertContext)
-{
- NTSTATUS Retval = STATUS_SUCCESS;
- KIRQL Irql;
-
- Csq->CsqAcquireLock(Csq, &Irql);
-
- do
- {
- /* mark all irps pending -- says so in the cancel sample */
- IoMarkIrpPending(Irp);
-
- /* set up the context if we have one */
- if(Context)
- {
- Context->Type = IO_TYPE_CSQ_IRP_CONTEXT;
- Context->Irp = Irp;
- Context->Csq = Csq;
- Irp->Tail.Overlay.DriverContext[3] = Context;
- }
- else
- Irp->Tail.Overlay.DriverContext[3] = Csq;
-
- /*
- * NOTE! This is very sensitive to order. If you set the cancel routine
- * *before* you queue the IRP, our cancel routine will get called back for
- * an IRP that isn't in its queue.
- *
- * There are three possibilities:
- * 1) We get an IRP, we queue it, and it is valid the whole way
- * 2) We get an IRP, and the IO manager cancels it before we're done here
- * 3) We get an IRP, queue it, and the IO manager cancels it.
- *
- * #2 is is a booger.
- *
- * When the IO manger receives a request to cancel an IRP, it sets the cancel
- * bit in the IRP's control byte to TRUE. Then, it looks to see if a cancel
- * routine is set. If it isn't, the IO manager just returns to the caller.
- * If there *is* a routine, it gets called.
- *
- * If we test for cancel first and then set the cancel routine, there is a spot
- * between test and set that the IO manager can cancel us without our knowledge,
- * so we miss a cancel request. That is bad.
- *
- * If we set a routine first and then test for cancel, we race with our completion
- * routine: We set the routine, the IO Manager sets cancel, we test cancel and find
- * it is TRUE. Meanwhile the IO manager has called our cancel routine already, so
- * we can't complete the IRP because it'll rip it out from under the cancel routine.
- *
- * The IO manager does us a favor though: it nulls out the cancel routine in the IRP
- * before calling it. Therefore, if we test to see if the cancel routine is NULL
- * (after we have just set it), that means our own cancel routine is already working
- * on the IRP, and we can just return quietly. Otherwise, we have to de-queue the
- * IRP and cancel it ourselves.
- *
- * We have to go through all of this mess because this API guarantees that we will
- * never return having left a canceled IRP in the queue.
- */
-
- /* Step 1: Queue the IRP */
- if(Csq->Type == IO_TYPE_CSQ)
- Csq->CsqInsertIrp(Csq, Irp);
- else
- {
- PIO_CSQ_INSERT_IRP_EX pCsqInsertIrpEx = (PIO_CSQ_INSERT_IRP_EX)Csq->CsqInsertIrp;
- Retval = pCsqInsertIrpEx(Csq, Irp, InsertContext);
- if(Retval != STATUS_SUCCESS)
- break;
- }
-
- /* Step 2: Set our cancel routine */
- (void)IoSetCancelRoutine(Irp, IopCsqCancelRoutine);
-
- /* Step 3: Deal with an IRP that is already canceled */
- if(!Irp->Cancel)
- break;
-
- /*
- * Since we're canceled, see if our cancel routine is already running
- * If this is NULL, the IO Manager has already called our cancel routine
- */
- if(!IoSetCancelRoutine(Irp, NULL))
- break;
-
-
- Irp->Tail.Overlay.DriverContext[3] = 0;
-
- /* OK, looks like we have to de-queue and complete this ourselves */
- Csq->CsqRemoveIrp(Csq, Irp);
- Csq->CsqCompleteCanceledIrp(Csq, Irp);
-
- if(Context)
- Context->Irp = NULL;
- }
- while(0);
-
- Csq->CsqReleaseLock(Csq, Irql);
-
- return Retval;
-}
-
-\f
-/*!
- * @brief Remove anb IRP from the queue
- *
- * @param Csq - Queue to remove the IRP from
- * @param Context - Context record containing the IRP to be dequeued
- *
- * @return
- * - Pointer to an IRP if we found it
- *
- * @note
- * - Don't forget that we can be canceled any time up to the point
- * where we unset our cancel routine
- */
-PIRP
-NTAPI
-IoCsqRemoveIrp(
- _Inout_ PIO_CSQ Csq,
- _Inout_ PIO_CSQ_IRP_CONTEXT Context)
-{
- KIRQL Irql;
- PIRP Irp = NULL;
-
- Csq->CsqAcquireLock(Csq, &Irql);
-
- do
- {
- /* It's possible that this IRP could have been canceled */
- Irp = Context->Irp;
-
- if(!Irp)
- break;
-
- ASSERT(Context->Csq == Csq);
-
- /* Unset the cancel routine and see if it has already been canceled */
- if(!IoSetCancelRoutine(Irp, NULL))
- {
- /*
- * already gone, return NULL --> NOTE that we cannot touch this IRP *or* the context,
- * since the context is being simultaneously twiddled by the cancel routine
- */
- Irp = NULL;
- break;
- }
-
- ASSERT(Context == Irp->Tail.Overlay.DriverContext[3]);
-
- /* This IRP is valid and is ours. Dequeue it, fix it up, and return */
- Csq->CsqRemoveIrp(Csq, Irp);
-
- Context = (PIO_CSQ_IRP_CONTEXT)InterlockedExchangePointer(&Irp->Tail.Overlay.DriverContext[3], NULL);
-
- if (Context && Context->Type == IO_TYPE_CSQ_IRP_CONTEXT)
- {
- Context->Irp = NULL;
-
- ASSERT(Context->Csq == Csq);
- }
-
- Irp->Tail.Overlay.DriverContext[3] = 0;
- }
- while(0);
-
- Csq->CsqReleaseLock(Csq, Irql);
-
- return Irp;
-}
-
-/*!
- * @brief IoCsqRemoveNextIrp - Removes the next IRP from the queue
- *
- * @param Csq - Queue to remove the IRP from
- * @param PeekContext - Identifier of the IRP to be removed
- *
- * @return
- * Pointer to the IRP that was removed, or NULL if one
- * could not be found
- *
- * @note
- * - This function is sensitive to yet another race condition.
- * The basic idea is that we have to return the first IRP that
- * we get that matches the PeekContext >that is not already canceled<.
- * Therefore, we have to do a trick similar to the one done in Insert
- * above.
- */
-PIRP
-NTAPI
-IoCsqRemoveNextIrp(
- _Inout_ PIO_CSQ Csq,
- _In_opt_ PVOID PeekContext)
-{
- KIRQL Irql;
- PIRP Irp = NULL;
- PIO_CSQ_IRP_CONTEXT Context;
-
- Csq->CsqAcquireLock(Csq, &Irql);
-
- while((Irp = Csq->CsqPeekNextIrp(Csq, Irp, PeekContext)))
- {
- /*
- * If the cancel routine is gone, we're already canceled,
- * and are spinning on the queue lock in our own cancel
- * routine. Move on to the next candidate. It'll get
- * removed by the cance routine.
- */
- if(!IoSetCancelRoutine(Irp, NULL))
- continue;
-
- Csq->CsqRemoveIrp(Csq, Irp);
-
- /* Unset the context stuff and return */
- Context = (PIO_CSQ_IRP_CONTEXT)InterlockedExchangePointer(&Irp->Tail.Overlay.DriverContext[3], NULL);
-
- if (Context && Context->Type == IO_TYPE_CSQ_IRP_CONTEXT)
- {
- Context->Irp = NULL;
-
- ASSERT(Context->Csq == Csq);
- }
-
- Irp->Tail.Overlay.DriverContext[3] = 0;
-
- break;
- }
-
- Csq->CsqReleaseLock(Csq, Irql);
-
- return Irp;
-}
-
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