Commit 6aa734a2 authored by Dan Williams's avatar Dan Williams
Browse files

libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime 



We need to hold a reference on the 'dirent' until we are sure there are
no more notifications that will be sent. As noted in the new comments we
take advantage of the fact that the references are taken and dropped
under device_lock() and that nd_device_notify() holds device_lock() over
new badblocks notifications. The notifications that happen when
badblocks are cleared only occur while the device is active.

Also take the opportunity to fix up the error messages to report the
user visible effect of a sysfs_get_dirent() failure.

Fixes: 975750a9 ("libnvdimm, pmem: Add sysfs notifications to badblocks")
Cc: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 7e5a21df

drivers/nvdimm/pmem.c

+12 −4
Original line number Diff line number Diff line
@@ -382,10 +382,8 @@ static int pmem_attach_disk(struct device *dev, 


	pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,

					  "badblocks");

	if (pmem->bb_state)

		sysfs_put(pmem->bb_state);

	else

		dev_warn(dev, "sysfs_get_dirent 'badblocks' failed\n");

	if (!pmem->bb_state)

		dev_warn(dev, "'badblocks' notification disabled\n");



	return 0;

}
@@ -418,8 +416,18 @@ static int nd_pmem_probe(struct device *dev) 


static int nd_pmem_remove(struct device *dev)

{

	struct pmem_device *pmem = dev_get_drvdata(dev);



	if (is_nd_btt(dev))

		nvdimm_namespace_detach_btt(to_nd_btt(dev));

	else {

		/*

		 * Note, this assumes device_lock() context to not race

		 * nd_pmem_notify()

		 */

		sysfs_put(pmem->bb_state);

		pmem->bb_state = NULL;

	}

	nvdimm_flush(to_nd_region(dev->parent));



	return 0;

drivers/nvdimm/region.c

+9 −4
Original line number Diff line number Diff line
@@ -60,11 +60,9 @@ static int nd_region_probe(struct device *dev) 
			return -ENODEV;

		nd_region->bb_state = sysfs_get_dirent(nd_region->dev.kobj.sd,

						       "badblocks");

		if (nd_region->bb_state)

			sysfs_put(nd_region->bb_state);

		else

		if (!nd_region->bb_state)

			dev_warn(&nd_region->dev,

				"sysfs_get_dirent 'badblocks' failed\n");

					"'badblocks' notification disabled\n");

		ndr_res.start = nd_region->ndr_start;

		ndr_res.end = nd_region->ndr_start + nd_region->ndr_size - 1;

		nvdimm_badblocks_populate(nd_region, &nd_region->bb, &ndr_res);
@@ -111,6 +109,13 @@ static int nd_region_remove(struct device *dev) 
	dev_set_drvdata(dev, NULL);

	nvdimm_bus_unlock(dev);



	/*

	 * Note, this assumes device_lock() context to not race

	 * nd_region_notify()

	 */

	sysfs_put(nd_region->bb_state);

	nd_region->bb_state = NULL;



	return 0;

}

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