Use of pool buffers in IRP_MJ_READ

NTFSD
1

I feel as thought I really ought to know this after all these years.

In an IRP_MJ_READ filter (legacy or FltMgr) can I use buffers (e.g. for
decryption or decompression) which are allocated from paged pool? I think I
am being a bit wasteful in my use of non-paged pool.

Brian

2

Brian,

If it is a paging IO it must be from non-paged pool.
If the SYSTEM BUFFER flag is set, it must be from non-paged pool.

Otherwise it can be from paged pool.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no
rights.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Brian Collins
Sent: Thursday, June 17, 2004 12:20 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Use of pool buffers in IRP_MJ_READ

I feel as thought I really ought to know this after all these years.

In an IRP_MJ_READ filter (legacy or FltMgr) can I use buffers (e.g. for
decryption or decompression) which are allocated from paged pool? I
think I
am being a bit wasteful in my use of non-paged pool.

Brian

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Thanks Neal. Perfectly clear now.

Brian

“Neal Christiansen” wrote in message
news:xxxxx@ntfsd…
Brian,

If it is a paging IO it must be from non-paged pool.
If the SYSTEM BUFFER flag is set, it must be from non-paged pool.

Otherwise it can be from paged pool.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no
rights.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Brian Collins
Sent: Thursday, June 17, 2004 12:20 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Use of pool buffers in IRP_MJ_READ

I feel as thought I really ought to know this after all these years.

In an IRP_MJ_READ filter (legacy or FltMgr) can I use buffers (e.g. for
decryption or decompression) which are allocated from paged pool? I
think I
am being a bit wasteful in my use of non-paged pool.

Brian

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com