Re: [PATCH 1/5] [BLOCK] Add 'discard' request handling

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2008-08-08 at 08:22 -0600, Matthew Wilcox wrote:
> If the current T10 and T13 proposals stand unmodified, it'll be a bit of a
> pain to implement fully.  PUNCH currently requires creating a data buffer
> and attaching it to the command.  When we get down into libata, we then
> want to throw that data buffer away again because TRIM doesn't need a
> data buffer (indeed to translate PUNCH to TRIM, we need to send a series
> of commands because PUNCH allows you to specify a set of ranges whereas
> TRIM only lets you send one range at a time).
> 
> Let's hope T10 agrees that only one range is necessary at a time.

Weird. Does it really make sense for us to be 'translating' from generic
requests to SCSI and then from those to ATA? I hadn't realised our code
was that baroque...

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation