libnvdimm, pfn: 'struct page' provider infrastructure
Implement the base infrastructure for libnvdimm PFN devices. Similar to
BTT devices they take a namespace as a backing device and layer
functionality on top. In this case the functionality is reserving space
for an array of 'struct page' entries to be handed out through
pfn_to_page(). For now this is just the basic libnvdimm-device-model for
configuring the base PFN device.
As the namespace claiming mechanism for PFN devices is mostly identical
to BTT devices drivers/nvdimm/claim.c is created to house the common
bits.
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
new file mode 100644
index 0000000..e8f03b0
--- /dev/null
+++ b/drivers/nvdimm/claim.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/device.h>
+#include <linux/sizes.h>
+#include "nd-core.h"
+#include "pfn.h"
+#include "btt.h"
+#include "nd.h"
+
+void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns)
+{
+ struct nd_namespace_common *ndns = *_ndns;
+
+ dev_WARN_ONCE(dev, !mutex_is_locked(&ndns->dev.mutex)
+ || ndns->claim != dev,
+ "%s: invalid claim\n", __func__);
+ ndns->claim = NULL;
+ *_ndns = NULL;
+ put_device(&ndns->dev);
+}
+
+void nd_detach_ndns(struct device *dev,
+ struct nd_namespace_common **_ndns)
+{
+ struct nd_namespace_common *ndns = *_ndns;
+
+ if (!ndns)
+ return;
+ get_device(&ndns->dev);
+ device_lock(&ndns->dev);
+ __nd_detach_ndns(dev, _ndns);
+ device_unlock(&ndns->dev);
+ put_device(&ndns->dev);
+}
+
+bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
+ struct nd_namespace_common **_ndns)
+{
+ if (attach->claim)
+ return false;
+ dev_WARN_ONCE(dev, !mutex_is_locked(&attach->dev.mutex)
+ || *_ndns,
+ "%s: invalid claim\n", __func__);
+ attach->claim = dev;
+ *_ndns = attach;
+ get_device(&attach->dev);
+ return true;
+}
+
+bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
+ struct nd_namespace_common **_ndns)
+{
+ bool claimed;
+
+ device_lock(&attach->dev);
+ claimed = __nd_attach_ndns(dev, attach, _ndns);
+ device_unlock(&attach->dev);
+ return claimed;
+}
+
+static int namespace_match(struct device *dev, void *data)
+{
+ char *name = data;
+
+ return strcmp(name, dev_name(dev)) == 0;
+}
+
+static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
+{
+ struct nd_region *nd_region = to_nd_region(dev->parent);
+ struct device *seed = NULL;
+
+ if (is_nd_btt(dev))
+ seed = nd_region->btt_seed;
+ else if (is_nd_pfn(dev))
+ seed = nd_region->pfn_seed;
+
+ if (seed == dev || ndns || dev->driver)
+ return false;
+ return true;
+}
+
+static void nd_detach_and_reset(struct device *dev,
+ struct nd_namespace_common **_ndns)
+{
+ /* detach the namespace and destroy / reset the device */
+ nd_detach_ndns(dev, _ndns);
+ if (is_idle(dev, *_ndns)) {
+ nd_device_unregister(dev, ND_ASYNC);
+ } else if (is_nd_btt(dev)) {
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ nd_btt->lbasize = 0;
+ kfree(nd_btt->uuid);
+ nd_btt->uuid = NULL;
+ } else if (is_nd_pfn(dev)) {
+ struct nd_pfn *nd_pfn = to_nd_pfn(dev);
+
+ kfree(nd_pfn->uuid);
+ nd_pfn->uuid = NULL;
+ nd_pfn->mode = PFN_MODE_NONE;
+ }
+}
+
+ssize_t nd_namespace_store(struct device *dev,
+ struct nd_namespace_common **_ndns, const char *buf,
+ size_t len)
+{
+ struct nd_namespace_common *ndns;
+ struct device *found;
+ char *name;
+
+ if (dev->driver) {
+ dev_dbg(dev, "%s: -EBUSY\n", __func__);
+ return -EBUSY;
+ }
+
+ name = kstrndup(buf, len, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ strim(name);
+
+ if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
+ /* pass */;
+ else {
+ len = -EINVAL;
+ goto out;
+ }
+
+ ndns = *_ndns;
+ if (strcmp(name, "") == 0) {
+ nd_detach_and_reset(dev, _ndns);
+ goto out;
+ } else if (ndns) {
+ dev_dbg(dev, "namespace already set to: %s\n",
+ dev_name(&ndns->dev));
+ len = -EBUSY;
+ goto out;
+ }
+
+ found = device_find_child(dev->parent, name, namespace_match);
+ if (!found) {
+ dev_dbg(dev, "'%s' not found under %s\n", name,
+ dev_name(dev->parent));
+ len = -ENODEV;
+ goto out;
+ }
+
+ ndns = to_ndns(found);
+ if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
+ dev_dbg(dev, "%s too small to host\n", name);
+ len = -ENXIO;
+ goto out_attach;
+ }
+
+ WARN_ON_ONCE(!is_nvdimm_bus_locked(dev));
+ if (!nd_attach_ndns(dev, ndns, _ndns)) {
+ dev_dbg(dev, "%s already claimed\n",
+ dev_name(&ndns->dev));
+ len = -EBUSY;
+ }
+
+ out_attach:
+ put_device(&ndns->dev); /* from device_find_child */
+ out:
+ kfree(name);
+ return len;
+}
+
+/*
+ * nd_sb_checksum: compute checksum for a generic info block
+ *
+ * Returns a fletcher64 checksum of everything in the given info block
+ * except the last field (since that's where the checksum lives).
+ */
+u64 nd_sb_checksum(struct nd_gen_sb *nd_gen_sb)
+{
+ u64 sum;
+ __le64 sum_save;
+
+ BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);
+ BUILD_BUG_ON(sizeof(struct nd_pfn_sb) != SZ_4K);
+ BUILD_BUG_ON(sizeof(struct nd_gen_sb) != SZ_4K);
+
+ sum_save = nd_gen_sb->checksum;
+ nd_gen_sb->checksum = 0;
+ sum = nd_fletcher64(nd_gen_sb, sizeof(*nd_gen_sb), 1);
+ nd_gen_sb->checksum = sum_save;
+ return sum;
+}
+EXPORT_SYMBOL(nd_sb_checksum);