Re: ZwWriteFile and buffer reuse

Hi mate

Is it your ISR code????????

You cannot call *ANY* of Zw... functions from ISR, and you cannot wait
on synchronization objects either - at IRQL>=DISPATCH_LEVEL your
choice is severely constrained. You have to re-design your problem -
you cannot run the above code either as ISR or as DPC

Anton Bassov

RJ wrote:
Here is my file create routine and file write routines. I make sure in the
interrupt routine that ZwWrite routine is completed. But seems it doesn't
mean than write operation is actually completed. I tried to use event object
to signal write complete as shown below. But this event object never set
into signaled state.
RJ

status = ZwCreateFile(&(pDevExt->hFileHandle),
GENERIC_WRITE | SYNCHRONIZE,
&objAttrs,
&ioStatus,
0,
FILE_ATTRIBUTE_NORMAL,
0,
FILE_SUPERSEDE, FILE_SYNCHRONOUS_IO_ALERT,
NULL,
0);


KeClearEvent(gpDevExt->pfileEvent);
status = ZwWriteFile( pDevExt->hFileHandle,
pDevExt->pfileEvent,
NULL,
NULL,
&ioStatus,
pucStartAddress,
ulNumBytes,
NULL,
NULL);

KeWaitForSingleObject(pDevExt->pfileEvent,
Executive,
KernelMode,
FALSE,
NULL);



"Skywing [MVP]" wrote:

Wait until either NtWriteFile returns or signals asynchronous completion.
You cannot touch a buffer passed to NtReadFile/NtWriteFile while it is
working on the operation.

--
Ken Johnson (Skywing)
Windows SDK MVP
http://www.nynaeve.net

"RJ" <RJ@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:1E31915E-06C5-4721-8784-5ED892157540@xxxxxxxxxxxxxxxx
I use ZwWriteFile function to write data from a buffer to a file in a
worker
thread. I would like to know when can I resue the input buffer again to
fill
new data. Buffer is filled in the interrupt/DPC and once the buffer is
filled, a worker thread is scheduled to write the data to file. My
interrupt
routine is trying to write new date to the buffer while NtWriteFile
routine
is still running. This creates a bugcheck.
Any help appreciated.
Thanks,
RJ




.

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