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From: yushang on 29 Sep 2009 10:55
On Sep 28, 2:40 am, "Alexander Grigoriev" <al...(a)earthlink.net> wrote:
> Also with paging IO.
>
> "Maxim S. Shatskih" <ma...(a)storagecraft.com.no.spam> wrote in messagenews:O6MzP65PKHA.4428(a)TK2MSFTNGP02.phx.gbl...
>
> > But even from Irp->MdlAddress with MmGetMdlVirtualAddress, I also get
> > NULL
>
> Valid case if the MDL was built using MmAllocatePagesForMdl
>
> --
> Maxim S. Shatskih
> Windows DDK MVP
> ma...(a)storagecraft.comhttp://www.storagecraft.com

I know there are some SCSI commands which require neither read nor
write (for example SCSIOP_VERIFY), srb for these commands will have
NULL databuffer . How about paging IO ? In my understanding , paging
IO is the reading or writing of page file . These operations will be
mapped to SCSIOP_READ / WRITE , right ? Thanks
From: Maxim S. Shatskih on 1 Oct 2009 16:11
> NULL databuffer . How about paging IO ? In my understanding , paging
> IO is the reading or writing of page file .

Memory-mapped files too.

>These operations will be
> mapped to SCSIOP_READ / WRITE , right ? Thanks

Yes, but MDLs for this IO are built in a special way.

--
Maxim S. Shatskih
Windows DDK MVP
maxim(a)storagecraft.com
http://www.storagecraft.com

From: yushang on 7 Oct 2009 08:17
On Oct 2, 4:11 am, "Maxim S. Shatskih"
<ma...(a)storagecraft.com.no.spam> wrote:
> > NULL databuffer . How about paging IO ? In my understanding , paging
> > IO is the reading or writing of page file .
>
> Memory-mapped files too.
>
> >These operations will be
> > mapped to SCSIOP_READ / WRITE , right ? Thanks
>
> Yes, but MDLs for this IO are built in a special way.
>
> --
> Maxim S. Shatskih
> Windows DDK MVP
> ma...(a)storagecraft.comhttp://www.storagecraft.com

Then how to explain address like 0x001769E0 ? It seems a user space
address .
From: Alexander Grigoriev on 7 Oct 2009 09:59
That means the request came from user mode.

"yushang" <yusunn(a)gmail.com> wrote in message
news:757405fe-0de3-4795-9cd6-ab86f0623fa2(a)d15g2000prc.googlegroups.com...
> On Oct 2, 4:11 am, "Maxim S. Shatskih"
> <ma...(a)storagecraft.com.no.spam> wrote:
>> > NULL databuffer . How about paging IO ? In my understanding , paging
>> > IO is the reading or writing of page file .
>>
>> Memory-mapped files too.
>>
>> >These operations will be
>> > mapped to SCSIOP_READ / WRITE , right ? Thanks
>>
>> Yes, but MDLs for this IO are built in a special way.
>>
>> --
>> Maxim S. Shatskih
>> Windows DDK MVP
>> ma...(a)storagecraft.comhttp://www.storagecraft.com
>
> Then how to explain address like 0x001769E0 ? It seems a user space
> address .


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