[dm-devel] [PATCH v2 4/4] brd: implement secure erase and write zeroes

[Christoph Hellwig]

On Tue, Sep 20, 2022 at 01:59:46PM -0400, Mikulas Patocka wrote:
> This patch implements REQ_OP_SECURE_ERASE and REQ_OP_WRITE_ZEROES on brd.
> Write zeroes will free the pages just like discard, but the difference is
> that it writes zeroes to the preceding and following page if the range is
> not aligned on page boundary. Secure erase is just like write zeroes,
> except that it clears the page content before freeing the page.

So while I can see the use case for the simple discard you mentioned,
and maybe even the WRITE_ZEROES, I'd rather have a really good
justification for REQ_OP_SECURE_ERASE.  It is a bad interface,
and there are alsmost no good reasons for ever using it.  So sprinkling
it in random drivers just we can is not helpful.