From 8c2f7e8658df1d3b7cbfa62706941d14c715823a Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 25 Jun 2015 04:20:04 -0400 Subject: 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 Cc: Neil Brown Signed-off-by: Dan Williams --- drivers/nvdimm/btt_devs.c | 422 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 422 insertions(+) create mode 100644 drivers/nvdimm/btt_devs.c (limited to 'drivers/nvdimm/btt_devs.c') 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 +#include +#include +#include +#include +#include +#include +#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) : ""); + if (rc < 0) { + __nd_btt_detach_ndns(to_nd_btt(dev)); + put_device(dev); + } + + return rc; +} +EXPORT_SYMBOL(nd_btt_probe); -- cgit