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Date: Fri, 7 Feb 2020 10:31:06 -0500
From: Vivek Goyal <vgoyal@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 4/5] dax,iomap: Start using dax native zero_page_range()
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On Wed, Feb 05, 2020 at 10:33:56AM -0800, Christoph Hellwig wrote:
> On Mon, Feb 03, 2020 at 03:00:28PM -0500, Vivek Goyal wrote:
> > +	id = dax_read_lock();
> > +	rc = dax_zero_page_range(dax_dev, pgoff, offset, size);
> > +	dax_read_unlock(id);
> > +	return rc;
> 
> Is there a good reason not to move the locking into dax_zero_page_range?

Thinking more about it. If we keep locking outside, then we don't have
to take lock again when we recurse into dax_zero_page_range() in device
mapper path. IIUC, just taking lock once at top level is enough. If that's
the case then it probably is better to keep locking outside of
dax_zero_page_range().

Thanks
Vivek
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