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authorDan Williams <dan.j.williams@intel.com>2015-06-25 04:20:04 -0400
committerDan Williams <dan.j.williams@intel.com>2015-06-25 04:20:04 -0400
commit8c2f7e8658df1d3b7cbfa62706941d14c715823a (patch)
treeac93512841113f4d1d7a38d788ec73bb21e2d605 /drivers/nvdimm/btt_devs.c
parent0ba1c634892b3590779803a701bcb82e8c32cc7a (diff)
downloadlinux-8c2f7e8658df1d3b7cbfa62706941d14c715823a.tar.bz2
libnvdimm: infrastructure for btt devices
NVDIMM namespaces, in addition to accepting "struct bio" based requests, also have the capability to perform byte-aligned accesses. By default only the bio/block interface is used. However, if another driver can make effective use of the byte-aligned capability it can claim namespace interface and use the byte-aligned ->rw_bytes() interface. The BTT driver is the initial first consumer of this mechanism to allow adding atomic sector update semantics to a pmem or blk namespace. This patch is the sysfs infrastructure to allow configuring a BTT instance for a namespace. Enabling that BTT and performing i/o is in a subsequent patch. Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm/btt_devs.c')
-rw-r--r--drivers/nvdimm/btt_devs.c422
1 files changed, 422 insertions, 0 deletions
diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
new file mode 100644
index 000000000000..effb70a88347
--- /dev/null
+++ b/drivers/nvdimm/btt_devs.c
@@ -0,0 +1,422 @@
+/*
+ * 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/blkdev.h>
+#include <linux/device.h>
+#include <linux/genhd.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include "nd-core.h"
+#include "btt.h"
+#include "nd.h"
+
+static void __nd_btt_detach_ndns(struct nd_btt *nd_btt)
+{
+ struct nd_namespace_common *ndns = nd_btt->ndns;
+
+ dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
+ || ndns->claim != &nd_btt->dev,
+ "%s: invalid claim\n", __func__);
+ ndns->claim = NULL;
+ nd_btt->ndns = NULL;
+ put_device(&ndns->dev);
+}
+
+static void nd_btt_detach_ndns(struct nd_btt *nd_btt)
+{
+ struct nd_namespace_common *ndns = nd_btt->ndns;
+
+ if (!ndns)
+ return;
+ get_device(&ndns->dev);
+ device_lock(&ndns->dev);
+ __nd_btt_detach_ndns(nd_btt);
+ device_unlock(&ndns->dev);
+ put_device(&ndns->dev);
+}
+
+static bool __nd_btt_attach_ndns(struct nd_btt *nd_btt,
+ struct nd_namespace_common *ndns)
+{
+ if (ndns->claim)
+ return false;
+ dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
+ || nd_btt->ndns,
+ "%s: invalid claim\n", __func__);
+ ndns->claim = &nd_btt->dev;
+ nd_btt->ndns = ndns;
+ get_device(&ndns->dev);
+ return true;
+}
+
+static bool nd_btt_attach_ndns(struct nd_btt *nd_btt,
+ struct nd_namespace_common *ndns)
+{
+ bool claimed;
+
+ device_lock(&ndns->dev);
+ claimed = __nd_btt_attach_ndns(nd_btt, ndns);
+ device_unlock(&ndns->dev);
+ return claimed;
+}
+
+static void nd_btt_release(struct device *dev)
+{
+ struct nd_region *nd_region = to_nd_region(dev->parent);
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ dev_dbg(dev, "%s\n", __func__);
+ nd_btt_detach_ndns(nd_btt);
+ ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
+ kfree(nd_btt->uuid);
+ kfree(nd_btt);
+}
+
+static struct device_type nd_btt_device_type = {
+ .name = "nd_btt",
+ .release = nd_btt_release,
+};
+
+bool is_nd_btt(struct device *dev)
+{
+ return dev->type == &nd_btt_device_type;
+}
+EXPORT_SYMBOL(is_nd_btt);
+
+struct nd_btt *to_nd_btt(struct device *dev)
+{
+ struct nd_btt *nd_btt = container_of(dev, struct nd_btt, dev);
+
+ WARN_ON(!is_nd_btt(dev));
+ return nd_btt;
+}
+EXPORT_SYMBOL(to_nd_btt);
+
+static const unsigned long btt_lbasize_supported[] = { 512, 4096, 0 };
+
+static ssize_t sector_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
+}
+
+static ssize_t sector_size_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+ ssize_t rc;
+
+ device_lock(dev);
+ nvdimm_bus_lock(dev);
+ rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
+ btt_lbasize_supported);
+ dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
+ rc, buf, buf[len - 1] == '\n' ? "" : "\n");
+ nvdimm_bus_unlock(dev);
+ device_unlock(dev);
+
+ return rc ? rc : len;
+}
+static DEVICE_ATTR_RW(sector_size);
+
+static ssize_t uuid_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ if (nd_btt->uuid)
+ return sprintf(buf, "%pUb\n", nd_btt->uuid);
+ return sprintf(buf, "\n");
+}
+
+static ssize_t uuid_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+ ssize_t rc;
+
+ device_lock(dev);
+ rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
+ dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
+ rc, buf, buf[len - 1] == '\n' ? "" : "\n");
+ device_unlock(dev);
+
+ return rc ? rc : len;
+}
+static DEVICE_ATTR_RW(uuid);
+
+static ssize_t namespace_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+ ssize_t rc;
+
+ nvdimm_bus_lock(dev);
+ rc = sprintf(buf, "%s\n", nd_btt->ndns
+ ? dev_name(&nd_btt->ndns->dev) : "");
+ nvdimm_bus_unlock(dev);
+ return rc;
+}
+
+static int namespace_match(struct device *dev, void *data)
+{
+ char *name = data;
+
+ return strcmp(name, dev_name(dev)) == 0;
+}
+
+static bool is_nd_btt_idle(struct device *dev)
+{
+ struct nd_region *nd_region = to_nd_region(dev->parent);
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ if (nd_region->btt_seed == dev || nd_btt->ndns || dev->driver)
+ return false;
+ return true;
+}
+
+static ssize_t __namespace_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+ 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 = nd_btt->ndns;
+ if (strcmp(name, "") == 0) {
+ /* detach the namespace and destroy / reset the btt device */
+ nd_btt_detach_ndns(nd_btt);
+ if (is_nd_btt_idle(dev))
+ nd_device_unregister(dev, ND_ASYNC);
+ else {
+ nd_btt->lbasize = 0;
+ kfree(nd_btt->uuid);
+ nd_btt->uuid = NULL;
+ }
+ 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 btt\n", name);
+ len = -ENXIO;
+ goto out_attach;
+ }
+
+ WARN_ON_ONCE(!is_nvdimm_bus_locked(&nd_btt->dev));
+ if (!nd_btt_attach_ndns(nd_btt, 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;
+}
+
+static ssize_t namespace_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ ssize_t rc;
+
+ nvdimm_bus_lock(dev);
+ device_lock(dev);
+ rc = __namespace_store(dev, attr, buf, len);
+ dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
+ rc, buf, buf[len - 1] == '\n' ? "" : "\n");
+ device_unlock(dev);
+ nvdimm_bus_unlock(dev);
+
+ return rc;
+}
+static DEVICE_ATTR_RW(namespace);
+
+static struct attribute *nd_btt_attributes[] = {
+ &dev_attr_sector_size.attr,
+ &dev_attr_namespace.attr,
+ &dev_attr_uuid.attr,
+ NULL,
+};
+
+static struct attribute_group nd_btt_attribute_group = {
+ .attrs = nd_btt_attributes,
+};
+
+static const struct attribute_group *nd_btt_attribute_groups[] = {
+ &nd_btt_attribute_group,
+ &nd_device_attribute_group,
+ NULL,
+};
+
+static struct device *__nd_btt_create(struct nd_region *nd_region,
+ unsigned long lbasize, u8 *uuid,
+ struct nd_namespace_common *ndns)
+{
+ struct nd_btt *nd_btt;
+ struct device *dev;
+
+ nd_btt = kzalloc(sizeof(*nd_btt), GFP_KERNEL);
+ if (!nd_btt)
+ return NULL;
+
+ nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
+ if (nd_btt->id < 0) {
+ kfree(nd_btt);
+ return NULL;
+ }
+
+ nd_btt->lbasize = lbasize;
+ if (uuid)
+ uuid = kmemdup(uuid, 16, GFP_KERNEL);
+ nd_btt->uuid = uuid;
+ dev = &nd_btt->dev;
+ dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
+ dev->parent = &nd_region->dev;
+ dev->type = &nd_btt_device_type;
+ dev->groups = nd_btt_attribute_groups;
+ device_initialize(&nd_btt->dev);
+ if (ndns && !__nd_btt_attach_ndns(nd_btt, ndns)) {
+ dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
+ __func__, dev_name(ndns->claim));
+ put_device(dev);
+ return NULL;
+ }
+ return dev;
+}
+
+struct device *nd_btt_create(struct nd_region *nd_region)
+{
+ struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
+
+ if (dev)
+ __nd_device_register(dev);
+ return dev;
+}
+
+/*
+ * nd_btt_sb_checksum: compute checksum for btt 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_btt_sb_checksum(struct btt_sb *btt_sb)
+{
+ u64 sum, sum_save;
+
+ sum_save = btt_sb->checksum;
+ btt_sb->checksum = 0;
+ sum = nd_fletcher64(btt_sb, sizeof(*btt_sb), 1);
+ btt_sb->checksum = sum_save;
+ return sum;
+}
+EXPORT_SYMBOL(nd_btt_sb_checksum);
+
+static int __nd_btt_probe(struct nd_btt *nd_btt,
+ struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
+{
+ u64 checksum;
+
+ if (!btt_sb || !ndns || !nd_btt)
+ return -ENODEV;
+
+ if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
+ return -ENXIO;
+
+ if (nvdimm_namespace_capacity(ndns) < SZ_16M)
+ return -ENXIO;
+
+ if (memcmp(btt_sb->signature, BTT_SIG, BTT_SIG_LEN) != 0)
+ return -ENODEV;
+
+ checksum = le64_to_cpu(btt_sb->checksum);
+ btt_sb->checksum = 0;
+ if (checksum != nd_btt_sb_checksum(btt_sb))
+ return -ENODEV;
+ btt_sb->checksum = cpu_to_le64(checksum);
+
+ nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
+ nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
+ if (!nd_btt->uuid)
+ return -ENOMEM;
+
+ __nd_device_register(&nd_btt->dev);
+
+ return 0;
+}
+
+int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
+{
+ int rc;
+ struct device *dev;
+ struct btt_sb *btt_sb;
+ struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
+
+ if (ndns->force_raw)
+ return -ENODEV;
+
+ nvdimm_bus_lock(&ndns->dev);
+ dev = __nd_btt_create(nd_region, 0, NULL, ndns);
+ nvdimm_bus_unlock(&ndns->dev);
+ if (!dev)
+ return -ENOMEM;
+ dev_set_drvdata(dev, drvdata);
+ btt_sb = kzalloc(sizeof(*btt_sb), GFP_KERNEL);
+ rc = __nd_btt_probe(to_nd_btt(dev), ndns, btt_sb);
+ kfree(btt_sb);
+ dev_dbg(&ndns->dev, "%s: btt: %s\n", __func__,
+ rc == 0 ? dev_name(dev) : "<none>");
+ if (rc < 0) {
+ __nd_btt_detach_ndns(to_nd_btt(dev));
+ put_device(dev);
+ }
+
+ return rc;
+}
+EXPORT_SYMBOL(nd_btt_probe);