Re: [PATCH V2 0/4] Add MMC erase and secure erase

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

Christoph Hellwig wrote:
> On Sun, Jun 13, 2010 at 01:01:34PM +0300, Adrian Hunter wrote:
>> Hi
>>
>> Add ability to do MMC erase and secure erase operations from userspace,
>> using the BLKDISCARD ioctl and a newly created BLKSECDISCARD ioctl.
> 
> Have you done any measurement if the use of the block layer changes
> performance of the discard requests for you?

No.  For my purposes there will be only 1 discard request for the entire
device which will take several minutes to process, so block layer
performance is not a factor.

> I'd really prefer to
> send down the secure erase that way, too.  This could easily be done
> by having a DISCARD_SECURE rw flag, which just ORs another flag into
> the request type field.

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?