Re: [PATCH 08/15] block, dax, pmem: reference counting infrastructure

From: Christoph Hellwig
Date: Fri Sep 25 2015 - 07:32:13 EST

On Thu, Sep 24, 2015 at 05:03:18PM -0700, Dan Williams wrote:
> That makes sense to me, especially because drivers/nvdimm/blk.c is
> broken in the same way as drivers/nvdimm/pmem.c and it would be
> awkward to have it use blk_dax_get() / blk_dax_put(). The
> percpu_refcount should be valid for all queues and it will only ever
> be > 1 in the blk_mq and libnvdimm cases (for now). Will fix.

Looking at this a bit more it might actually make sense to grab the
referene in common code before calling into ->make_request.

Jens, any opinion on that?
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