[PATCH 4.9 02/21] acpi, nfit: fix health event notification

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Williams <dan.j.williams@intel.com>

commit adf6895754e2503d994a765535fd1813f8834674 upstream.

Integration testing with a BIOS that generates injected health event
notifications fails to communicate those events to userspace. The nfit
driver neglects to link the ACPI DIMM device with the necessary driver
data so acpi_nvdimm_notify() fails this lookup:

        nfit_mem = dev_get_drvdata(dev);
        if (nfit_mem && nfit_mem->flags_attr)
                sysfs_notify_dirent(nfit_mem->flags_attr);

Add the necessary linkage when installing the notification handler and
clean it up when the nfit driver instance is torn down.

Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Fixes: ba9c8dd3c222 ("acpi, nfit: add dimm device notification support")
Reported-by: Daniel Osawa <daniel.k.osawa@intel.com>
Tested-by: Daniel Osawa <daniel.k.osawa@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/nfit/core.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1390,6 +1390,11 @@ static int acpi_nfit_add_dimm(struct acp
 				dev_name(&adev_dimm->dev));
 		return -ENXIO;
 	}
+	/*
+	 * Record nfit_mem for the notification path to track back to
+	 * the nfit sysfs attributes for this dimm device object.
+	 */
+	dev_set_drvdata(&adev_dimm->dev, nfit_mem);
 
 	/*
 	 * Until standardization materializes we need to consider 4
@@ -1446,9 +1451,11 @@ static void shutdown_dimm_notify(void *d
 			sysfs_put(nfit_mem->flags_attr);
 			nfit_mem->flags_attr = NULL;
 		}
-		if (adev_dimm)
+		if (adev_dimm) {
 			acpi_remove_notify_handler(adev_dimm->handle,
 					ACPI_DEVICE_NOTIFY, acpi_nvdimm_notify);
+			dev_set_drvdata(&adev_dimm->dev, NULL);
+		}
 	}
 	mutex_unlock(&acpi_desc->init_mutex);
 }