[PATCHv2] NVMe: Create discard zero quirk white list

[Johannes Thumshirn]

On Fri, Mar 04, 2016 at 01:15:17PM -0700, Keith Busch wrote:
> The NVMe specification does not require discarded blocks return zeroes on
> read, but provides that behavior as a possibility. Some applications more
> efficiently use an SSD if reads on discarded blocks were deterministically
> zero, based on the "discard_zeroes_data" queue attribute.
> 
> There is no specification defined way to determine device behavior on
> discarded blocks, so the driver always left the queue setting disabled. We
> can only know behavior based on individual device models, so this patch
> adds a flag to the NVMe "quirk" list that vendors may set if they know
> their controller works that way. The patch also sets the new flag for one
> such known device.
> 
> Signed-off-by: Keith Busch <keith.busch at intel.com>

Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>

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Johannes Thumshirn                                          Storage
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