Merge tag 'libnvdimm-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm and device-dax updates from Dan Williams:

 - Fix the error code polarity for the device-dax/mapping attribute

 - For the device-dax and libnvdimm bus implementations stop
   implementing a useless return code for the remove() callback.

 - Miscellaneous cleanups

* tag 'libnvdimm-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax-device: Make remove callback return void
  device-dax: Drop an empty .remove callback
  device-dax: Fix error path in dax_driver_register
  device-dax: Properly handle drivers without remove callback
  device-dax: Prevent registering drivers without probe callback
  libnvdimm: Make remove callback return void
  libnvdimm/dimm: Simplify nvdimm_remove()
  device-dax: Fix default return code of range_parse()

10 files changed, 35 insertions, 40 deletions

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 737b207c9e30..452e85ae87a8 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -179,7 +179,10 @@ static int dax_bus_remove(struct device *dev)
 	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
 	struct dev_dax *dev_dax = to_dev_dax(dev);
 
-	return dax_drv->remove(dev_dax);
+	if (dax_drv->remove)
+		dax_drv->remove(dev_dax);
+
+	return 0;
 }
 
 static struct bus_type dax_bus_type = {
@@ -1038,7 +1041,7 @@ static ssize_t range_parse(const char *opt, size_t len, struct range *range)
 {
 	unsigned long long addr = 0;
 	char *start, *end, *str;
-	ssize_t rc = EINVAL;
+	ssize_t rc = -EINVAL;
 
 	str = kstrdup(opt, GFP_KERNEL);
 	if (!str)
@@ -1392,6 +1395,13 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
 	struct device_driver *drv = &dax_drv->drv;
 	int rc = 0;
 
+	/*
+	 * dax_bus_probe() calls dax_drv->probe() unconditionally.
+	 * So better be safe than sorry and ensure it is provided.
+	 */
+	if (!dax_drv->probe)
+		return -EINVAL;
+
 	INIT_LIST_HEAD(&dax_drv->ids);
 	drv->owner = module;
 	drv->name = mod_name;
@@ -1409,7 +1419,15 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
 	mutex_unlock(&dax_bus_lock);
 	if (rc)
 		return rc;
-	return driver_register(drv);
+
+	rc = driver_register(drv);
+	if (rc && dax_drv->match_always) {
+		mutex_lock(&dax_bus_lock);
+		match_always_count -= dax_drv->match_always;
+		mutex_unlock(&dax_bus_lock);
+	}
+
+	return rc;
 }
 EXPORT_SYMBOL_GPL(__dax_driver_register);
 
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 72b92f95509f..1e946ad7780a 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -39,7 +39,7 @@ struct dax_device_driver {
 	struct list_head ids;
 	int match_always;
 	int (*probe)(struct dev_dax *dev);
-	int (*remove)(struct dev_dax *dev);
+	void (*remove)(struct dev_dax *dev);
 };
 
 int __dax_driver_register(struct dax_device_driver *dax_drv,
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 5da2980bb16b..db92573c94e8 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -452,15 +452,9 @@ int dev_dax_probe(struct dev_dax *dev_dax)
 }
 EXPORT_SYMBOL_GPL(dev_dax_probe);
 
-static int dev_dax_remove(struct dev_dax *dev_dax)
-{
-	/* all probe actions are unwound by devm */
-	return 0;
-}
-
 static struct dax_device_driver device_dax_driver = {
 	.probe = dev_dax_probe,
-	.remove = dev_dax_remove,
+	/* all probe actions are unwound by devm, so .remove isn't necessary */
 	.match_always = 1,
 };
 
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 403ec42472d1..ac231cc36359 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -136,7 +136,7 @@ err_res_name:
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
+static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	int i, success = 0;
 	struct device *dev = &dev_dax->dev;
@@ -176,11 +176,9 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 		kfree(data);
 		dev_set_drvdata(dev, NULL);
 	}
-
-	return 0;
 }
 #else
-static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
+static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	/*
 	 * Without hotremove purposely leak the request_mem_region() for the
@@ -190,7 +188,6 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 	 * request_mem_region().
 	 */
 	any_hotremove_failed = true;
-	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
diff --git a/drivers/dax/pmem/compat.c b/drivers/dax/pmem/compat.c
index 863c114fd88c..d81dc35fd65d 100644
--- a/drivers/dax/pmem/compat.c
+++ b/drivers/dax/pmem/compat.c
@@ -41,10 +41,9 @@ static int dax_pmem_compat_release(struct device *dev, void *data)
 	return 0;
 }
 
-static int dax_pmem_compat_remove(struct device *dev)
+static void dax_pmem_compat_remove(struct device *dev)
 {
 	device_for_each_child(dev, NULL, dax_pmem_compat_release);
-	return 0;
 }
 
 static struct nd_device_driver dax_pmem_compat_driver = {
diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c
index e03a1f38d750..7b9556291eb1 100644
--- a/drivers/nvdimm/blk.c
+++ b/drivers/nvdimm/blk.c
@@ -310,11 +310,10 @@ static int nd_blk_probe(struct device *dev)
 		return nsblk_attach_disk(nsblk);
 }
 
-static int nd_blk_remove(struct device *dev)
+static void nd_blk_remove(struct device *dev)
 {
 	if (is_nd_btt(dev))
 		nvdimm_namespace_detach_btt(to_nd_btt(dev));
-	return 0;
 }
 
 static struct nd_device_driver nd_blk_driver = {
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 2304c6183822..48f0985ca8a0 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -113,18 +113,17 @@ static int nvdimm_bus_remove(struct device *dev)
 	struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
 	struct module *provider = to_bus_provider(dev);
 	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
-	int rc = 0;
 
 	if (nd_drv->remove) {
 		debug_nvdimm_lock(dev);
-		rc = nd_drv->remove(dev);
+		nd_drv->remove(dev);
 		debug_nvdimm_unlock(dev);
 	}
 
-	dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
-			dev_name(dev), rc);
+	dev_dbg(&nvdimm_bus->dev, "%s.remove(%s)\n", dev->driver->name,
+			dev_name(dev));
 	module_put(provider);
-	return rc;
+	return 0;
 }
 
 static void nvdimm_bus_shutdown(struct device *dev)
@@ -427,7 +426,7 @@ static void free_badrange_list(struct list_head *badrange_list)
 	list_del_init(badrange_list);
 }
 
-static int nd_bus_remove(struct device *dev)
+static void nd_bus_remove(struct device *dev)
 {
 	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
 
@@ -446,8 +445,6 @@ static int nd_bus_remove(struct device *dev)
 	spin_unlock(&nvdimm_bus->badrange.lock);
 
 	nvdimm_bus_destroy_ndctl(nvdimm_bus);
-
-	return 0;
 }
 
 static int nd_bus_probe(struct device *dev)
diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 7d4ddc4d9322..91d9163ee303 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -113,19 +113,14 @@ static int nvdimm_probe(struct device *dev)
 	return rc;
 }
 
-static int nvdimm_remove(struct device *dev)
+static void nvdimm_remove(struct device *dev)
 {
 	struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
 
-	if (!ndd)
-		return 0;
-
 	nvdimm_bus_lock(dev);
 	dev_set_drvdata(dev, NULL);
 	nvdimm_bus_unlock(dev);
 	put_ndd(ndd);
-
-	return 0;
 }
 
 static struct nd_device_driver nvdimm_driver = {
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 281fedb4dc4d..b8a85bfb2e95 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -563,7 +563,7 @@ static int nd_pmem_probe(struct device *dev)
 	return pmem_attach_disk(dev, ndns);
 }
 
-static int nd_pmem_remove(struct device *dev)
+static void nd_pmem_remove(struct device *dev)
 {
 	struct pmem_device *pmem = dev_get_drvdata(dev);
 
@@ -578,8 +578,6 @@ static int nd_pmem_remove(struct device *dev)
 		pmem->bb_state = NULL;
 	}
 	nvdimm_flush(to_nd_region(dev->parent), NULL);
-
-	return 0;
 }
 
 static void nd_pmem_shutdown(struct device *dev)
diff --git a/drivers/nvdimm/region.c b/drivers/nvdimm/region.c
index bfce87ed72ab..e0c34120df37 100644
--- a/drivers/nvdimm/region.c
+++ b/drivers/nvdimm/region.c
@@ -87,7 +87,7 @@ static int child_unregister(struct device *dev, void *data)
 	return 0;
 }
 
-static int nd_region_remove(struct device *dev)
+static void nd_region_remove(struct device *dev)
 {
 	struct nd_region *nd_region = to_nd_region(dev);
 
@@ -108,8 +108,6 @@ static int nd_region_remove(struct device *dev)
 	 */
 	sysfs_put(nd_region->bb_state);
 	nd_region->bb_state = NULL;
-
-	return 0;
 }
 
 static int child_notify(struct device *dev, void *data)