drivers/nvdimm/claim.c - linux-imx - Git at Google

 /*
  * 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 <linux/pmem.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;
 	else if (is_nd_dax(dev))
 		seed = nd_region->dax_seed;

 	if (seed == dev || ndns || dev->driver)
 		return false;
 	return true;
 }

 struct nd_pfn *to_nd_pfn_safe(struct device *dev)
 {
 	/*
 	 * pfn device attributes are re-used by dax device instances, so we
 	 * need to be careful to correct device-to-nd_pfn conversion.
 	 */
 	if (is_nd_pfn(dev))
 		return to_nd_pfn(dev);

 	if (is_nd_dax(dev)) {
 		struct nd_dax *nd_dax = to_nd_dax(dev);

 		return &nd_dax->nd_pfn;
 	}

 	WARN_ON(1);
 	return NULL;
 }

 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) || is_nd_dax(dev)) {
 		struct nd_pfn *nd_pfn = to_nd_pfn_safe(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);

 static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 		resource_size_t offset, void *buf, size_t size, int rw)
 {
 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);

 	if (unlikely(offset + size > nsio->size)) {
 		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 		return -EFAULT;
 	}

 	if (rw == READ) {
 		unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);

 		if (unlikely(is_bad_pmem(&nsio->bb, offset / 512, sz_align)))
 			return -EIO;
 		return memcpy_from_pmem(buf, nsio->addr + offset, size);
 	} else {
 		memcpy_to_pmem(nsio->addr + offset, buf, size);
 		nvdimm_flush(to_nd_region(ndns->dev.parent));
 	}

 	return 0;
 }

 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
 {
 	struct resource *res = &nsio->res;
 	struct nd_namespace_common *ndns = &nsio->common;

 	nsio->size = resource_size(res);
 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
 				dev_name(dev))) {
 		dev_warn(dev, "could not reserve region %pR\n", res);
 		return -EBUSY;
 	}

 	ndns->rw_bytes = nsio_rw_bytes;
 	if (devm_init_badblocks(dev, &nsio->bb))
 		return -ENOMEM;
 	nvdimm_badblocks_populate(to_nd_region(ndns->dev.parent), &nsio->bb,
 			&nsio->res);

 	nsio->addr = devm_memremap(dev, res->start, resource_size(res),
 			ARCH_MEMREMAP_PMEM);

 	return PTR_ERR_OR_ZERO(nsio->addr);
 }
 EXPORT_SYMBOL_GPL(devm_nsio_enable);

 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio)
 {
 	struct resource *res = &nsio->res;

 	devm_memunmap(dev, nsio->addr);
 	devm_exit_badblocks(dev, &nsio->bb);
 	devm_release_mem_region(dev, res->start, resource_size(res));
 }
 EXPORT_SYMBOL_GPL(devm_nsio_disable);
	/*
	* 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 <linux/pmem.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;
	else if (is_nd_dax(dev))
	seed = nd_region->dax_seed;

	if (seed == dev \|\| ndns \|\| dev->driver)
	return false;
	return true;
	}

	struct nd_pfn to_nd_pfn_safe(struct device dev)
	{
	/*
	* pfn device attributes are re-used by dax device instances, so we
	* need to be careful to correct device-to-nd_pfn conversion.
	*/
	if (is_nd_pfn(dev))
	return to_nd_pfn(dev);

	if (is_nd_dax(dev)) {
	struct nd_dax *nd_dax = to_nd_dax(dev);

	return &nd_dax->nd_pfn;
	}

	WARN_ON(1);
	return NULL;
	}

	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) \|\| is_nd_dax(dev)) {
	struct nd_pfn *nd_pfn = to_nd_pfn_safe(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);

	static int nsio_rw_bytes(struct nd_namespace_common *ndns,
	resource_size_t offset, void *buf, size_t size, int rw)
	{
	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);

	if (unlikely(offset + size > nsio->size)) {
	dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
	return -EFAULT;
	}

	if (rw == READ) {
	unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);

	if (unlikely(is_bad_pmem(&nsio->bb, offset / 512, sz_align)))
	return -EIO;
	return memcpy_from_pmem(buf, nsio->addr + offset, size);
	} else {
	memcpy_to_pmem(nsio->addr + offset, buf, size);
	nvdimm_flush(to_nd_region(ndns->dev.parent));
	}

	return 0;
	}

	int devm_nsio_enable(struct device dev, struct nd_namespace_io nsio)
	{
	struct resource *res = &nsio->res;
	struct nd_namespace_common *ndns = &nsio->common;

	nsio->size = resource_size(res);
	if (!devm_request_mem_region(dev, res->start, resource_size(res),
	dev_name(dev))) {
	dev_warn(dev, "could not reserve region %pR\n", res);
	return -EBUSY;
	}

	ndns->rw_bytes = nsio_rw_bytes;
	if (devm_init_badblocks(dev, &nsio->bb))
	return -ENOMEM;
	nvdimm_badblocks_populate(to_nd_region(ndns->dev.parent), &nsio->bb,
	&nsio->res);

	nsio->addr = devm_memremap(dev, res->start, resource_size(res),
	ARCH_MEMREMAP_PMEM);

	return PTR_ERR_OR_ZERO(nsio->addr);
	}
	EXPORT_SYMBOL_GPL(devm_nsio_enable);

	void devm_nsio_disable(struct device dev, struct nd_namespace_io nsio)
	{
	struct resource *res = &nsio->res;

	devm_memunmap(dev, nsio->addr);
	devm_exit_badblocks(dev, &nsio->bb);
	devm_release_mem_region(dev, res->start, resource_size(res));
	}
	EXPORT_SYMBOL_GPL(devm_nsio_disable);