Re: [PATCH 1/2] block: fix leaks associated with discard requestpayload

From: Boaz Harrosh
Date: Wed Jun 30 2010 - 06:25:13 EST


On 06/30/2010 11:42 AM, Christoph Hellwig wrote:
> On Wed, Jun 30, 2010 at 11:32:43AM +0300, Boaz Harrosh wrote:
>> May I ask a silly question? Why the dynamic allocation?
>>
>> Why not have a const-static single global page at the block-layer somewhere
>> that will be used for all discard-type operations and be done with it once and
>> for all. A single page can be used for any size bio , any number of concurrent
>> discards, any ZERO needed operation. It can also be used by other operations
>> like padding and others. In fact isn't there one for the libsata padding?
>
> for UNMAP we need to write into the payload. And for ATA TRIM we need
> to write into the WRITE SAME payload.

OK, Thanks, I see. Is it one of these operations, (like we have in OSD) where
the CDB information spills into the payload? like the scatter-gather and extent
lists and such. Do we actually use a WRITE_SAME which is not zero? for what use?

> That's another layering violation
> for those looking for them, btw..
>

Agreed
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