Re: [PATCH V3 4/5] block: Add secure discard

[Adrian Hunter <adrian.hunter@nokia.com>]

Andrew Morton wrote:
> On Thu, 24 Jun 2010 11:44:23 +0300
> Adrian Hunter <adrian.hunter@nokia.com> wrote:
> 
>> >From b25b9a499f255ee5999c219525d82ef40382318c Mon Sep 17 00:00:00 2001
>> From: Adrian Hunter <adrian.hunter@nokia.com>
>> Date: Wed, 23 Jun 2010 15:41:38 +0300
>> Subject: [PATCH 4/5] block: Add secure discard
>>
>> Secure discard is the same as discard except that all copies
>> of the discarded sectors (perhaps created by garbage collection)
>> must also be erased.
> 
> That's not an awfully informative changelog.
> 
>>From a quick peek at the code it seems that you took your earlier
> design sketch:
> 
> On Mon, Jun 14, 2010 at 02:10:06PM +0300, Adrian Hunter wrote:
>> Needs a bio flag, a request flag, setup the request flag based on the
>> bio flag, prevent merging secure and non-secure discards, prevent drivers
>> doing non-secure discards for secure discards.
>>
>> Seems like a lot of little changes for something that no one wants.
>> Shouldn't it wait for someone to need it first?
> 
> and changed your mind and implemented it.
> 
> Is that a correct interpretation?
> 

Yes.  It does allude to that in "[PATCH V3 0/5] Add MMC erase and secure erase V3"
i.e.

Changes from V2

- move the addition of BLKSECDISCARD to a separate patch and implement it
using I/O requests
- move the MMC support of secure discard to a separate patch and support
the secure discard I/O request