[GIT PULL] libnvdimm fix for 4.2-rc4

[Williams, Dan J]

Hi Linus, please pull from...

  git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm libnvdimm-fixes

...to receive a minor fix for the libnvdimm subsystem.

This is not critical.  The problem can be worked around in userspace by
putting the namespace temporarily into raw mode
(ndctl_namespace_set_raw_mode() from libndctl), but that is awkward for
management utilities.  I would consider it a candidate for 4.2-stable if
it does not make 4.2.

The following changes since commit 52721d9d3334c1cb1f76219a161084094ec634dc:

  Linux 4.2-rc3 (2015-07-19 14:45:02 -0700)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm libnvdimm-fixes

for you to fetch changes up to 8ca243536d21ae2d08f61b1c5af4ac3d4bb697e4:

  libnvdimm: fix namespace seed creation (2015-07-25 09:57:56 -0700)

----------------------------------------------------------------
Dan Williams (1):
      libnvdimm: fix namespace seed creation

 drivers/nvdimm/region_devs.c | 5 +++++
 1 file changed, 5 insertions(+)

commit 8ca243536d21ae2d08f61b1c5af4ac3d4bb697e4
Author: Dan Williams <dan.j.williams@xxxxxxxxx>
Date:   Fri Jul 24 23:42:34 2015 -0400

    libnvdimm: fix namespace seed creation
    
    A new BLK namespace "seed" device is created whenever the current seed
    is successfully probed.  However, if that namespace is assigned to a BTT
    it may never directly experience a successful probe as it is a
    subordinate device to a BTT configuration.
    
    The effect of the current code is that no new namespaces can be
    instantiated, after the seed namespace, to consume available BLK DPA
    capacity.  Fix this by treating a successful BTT probe event as a
    successful probe event for the backing namespace.
    
    Reported-by: Nicholas Moulin <nicholas.w.moulin@xxxxxxxxxxxxxxx>
    Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index a5233422f9dc..7384455792bf 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -458,10 +458,15 @@ static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
 		nvdimm_bus_unlock(dev);
 	}
 	if (is_nd_btt(dev) && probe) {
+		struct nd_btt *nd_btt = to_nd_btt(dev);
+
 		nd_region = to_nd_region(dev->parent);
 		nvdimm_bus_lock(dev);
 		if (nd_region->btt_seed == dev)
 			nd_region_create_btt_seed(nd_region);
+		if (nd_region->ns_seed == &nd_btt->ndns->dev &&
+				is_nd_blk(dev->parent))
+			nd_region_create_blk_seed(nd_region);
 		nvdimm_bus_unlock(dev);
 	}
 }