Messages in this thread | | | Date | Tue, 9 Jun 2015 08:42:00 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v5 17/21] libnvdimm: infrastructure for btt devices |
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On Mon, Jun 01, 2015 at 08:15:41PM -0400, Dan Williams wrote: > Block devices from an nd bus, in addition to accepting "struct bio" > based requests, also have the capability to perform byte-aligned > accesses. By default only the bio/block interface is used. However, if > another driver can make effective use of the byte-aligned capability it > can claim/disable the block interface and use the byte-aligned "nd_io" > interface. > > The BTT driver is the initial first consumer of this mechanism to allow > layering atomic sector update guarantees on top of nd_io capable > libnvdimm-block-devices, or their partitions.
As mentioned during the last time of the review the layering here is complete broken. If you expose additional capabilities from a block device do it at the block device level. That is enhance the rw_page callback to allo byte sized access, add a capability flag on the queue, etc.
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