On Tue, Jun 21, 2016 at 8:44 AM, Kani, Toshimitsu [off-list ref] wrote:

On Tue, 2016-06-21 at 09:41 -0400, Mike Snitzer wrote:

quoted

On Mon, Jun 20 2016 at  6:22pm -0400,
Mike Snitzer [off-list ref] wrote:

quoted

On Mon, Jun 20 2016 at  5:28pm -0400,
Kani, Toshimitsu [off-list ref] wrote:

 :

quoted

quoted

Looks good, I folded it in and tested it to work.  Pushed to my 'wip'
branch.

No longer seeing any corruption in my test that was using partitions to
span pmem devices with a dm-linear device.

Jens, any chance you'd be open to picking up the first 2 patches in this
series?  Or would you like to see them folded or something different?

I'm now wondering if we'd be better off setting a new QUEUE_FLAG_DAX
rather than establish GENHD_FL_DAX on the genhd?

It'd be quite a bit easier to allow upper layers (e.g. XFS and ext4) to
check for a queue flag.

I think GENHD_FL_DAX is more appropriate since DAX does not use a request
queue, except for protecting the underlining device being disabled while
direct_access() is called (b2e0d1625e19).

About protecting direct_access, this patch assumes that the underlining
device cannot be disabled until dtr() is called.  Is this correct?  If not,
I will need to call dax_map_atomic().

Kernel internal usages of dax should be using dax_map_atomic() to
safely resolve device removal races.