[PATCH 01/10] block: introduce BLK_FEAT_WRITE_ZEROES_UNMAP to queue limits features

[Darrick J. Wong]

On Fri, Jun 13, 2025 at 07:56:30AM +0200, Christoph Hellwig wrote:
> On Fri, Jun 13, 2025 at 11:15:41AM +0800, Zhang Yi wrote:
> > Yeah, this solution looks good to me. However, we currently have only
> > two selections (none and unmap). What if we keep it as is and simply
> > hide this interface if BLK_FEAT_WRITE_ZEROES_UNMAP is not set, making
> > it visible only when the device supports this feature? Something like
> > below:
> 
> I really hate having all kinds of different interfaces for configurations.

I really hate the open-coded string parsing nonsense that is sysfs. ;)

> Maybe we should redo this similar to the other hardware/software interfaces
> and have a hw_ limit that is exposed by the driver and re-only in
> sysfs, and then the user configurable one without _hw.  Setting it to
> zero disables the feature.

Yeah, that fits the /sys/block/foo/queue model better.

--D