kernel_optimize_test/drivers/mtd/mtdpart.c
David Bauer c55310e30d mtd: don't lock when recursively deleting partitions
[ Upstream commit cb4543054c5c4fd33df960b41d7b483ebca8e786 ]

When recursively deleting partitions, don't acquire the masters
partition lock twice. Otherwise the process ends up in a deadlocked
state.

Fixes: 46b5889cc2 ("mtd: implement proper partition handling")
Signed-off-by: David Bauer <mail@david-bauer.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210217195320.893253-1-mail@david-bauer.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:50:09 +02:00

719 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Simple MTD partitioning layer
*
* Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
* Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
* Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kmod.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/err.h>
#include <linux/of.h>
#include "mtdcore.h"
/*
* MTD methods which simply translate the effective address and pass through
* to the _real_ device.
*/
static inline void free_partition(struct mtd_info *mtd)
{
kfree(mtd->name);
kfree(mtd);
}
static struct mtd_info *allocate_partition(struct mtd_info *parent,
const struct mtd_partition *part,
int partno, uint64_t cur_offset)
{
struct mtd_info *master = mtd_get_master(parent);
int wr_alignment = (parent->flags & MTD_NO_ERASE) ?
master->writesize : master->erasesize;
u64 parent_size = mtd_is_partition(parent) ?
parent->part.size : parent->size;
struct mtd_info *child;
u32 remainder;
char *name;
u64 tmp;
/* allocate the partition structure */
child = kzalloc(sizeof(*child), GFP_KERNEL);
name = kstrdup(part->name, GFP_KERNEL);
if (!name || !child) {
printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
parent->name);
kfree(name);
kfree(child);
return ERR_PTR(-ENOMEM);
}
/* set up the MTD object for this partition */
child->type = parent->type;
child->part.flags = parent->flags & ~part->mask_flags;
child->part.flags |= part->add_flags;
child->flags = child->part.flags;
child->part.size = part->size;
child->writesize = parent->writesize;
child->writebufsize = parent->writebufsize;
child->oobsize = parent->oobsize;
child->oobavail = parent->oobavail;
child->subpage_sft = parent->subpage_sft;
child->name = name;
child->owner = parent->owner;
/* NOTE: Historically, we didn't arrange MTDs as a tree out of
* concern for showing the same data in multiple partitions.
* However, it is very useful to have the master node present,
* so the MTD_PARTITIONED_MASTER option allows that. The master
* will have device nodes etc only if this is set, so make the
* parent conditional on that option. Note, this is a way to
* distinguish between the parent and its partitions in sysfs.
*/
child->dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd_is_partition(parent) ?
&parent->dev : parent->dev.parent;
child->dev.of_node = part->of_node;
child->parent = parent;
child->part.offset = part->offset;
INIT_LIST_HEAD(&child->partitions);
if (child->part.offset == MTDPART_OFS_APPEND)
child->part.offset = cur_offset;
if (child->part.offset == MTDPART_OFS_NXTBLK) {
tmp = cur_offset;
child->part.offset = cur_offset;
remainder = do_div(tmp, wr_alignment);
if (remainder) {
child->part.offset += wr_alignment - remainder;
printk(KERN_NOTICE "Moving partition %d: "
"0x%012llx -> 0x%012llx\n", partno,
(unsigned long long)cur_offset,
child->part.offset);
}
}
if (child->part.offset == MTDPART_OFS_RETAIN) {
child->part.offset = cur_offset;
if (parent_size - child->part.offset >= child->part.size) {
child->part.size = parent_size - child->part.offset -
child->part.size;
} else {
printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
part->name, parent_size - child->part.offset,
child->part.size);
/* register to preserve ordering */
goto out_register;
}
}
if (child->part.size == MTDPART_SIZ_FULL)
child->part.size = parent_size - child->part.offset;
printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n",
child->part.offset, child->part.offset + child->part.size,
child->name);
/* let's do some sanity checks */
if (child->part.offset >= parent_size) {
/* let's register it anyway to preserve ordering */
child->part.offset = 0;
child->part.size = 0;
/* Initialize ->erasesize to make add_mtd_device() happy. */
child->erasesize = parent->erasesize;
printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
part->name);
goto out_register;
}
if (child->part.offset + child->part.size > parent->size) {
child->part.size = parent_size - child->part.offset;
printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
part->name, parent->name, child->part.size);
}
if (parent->numeraseregions > 1) {
/* Deal with variable erase size stuff */
int i, max = parent->numeraseregions;
u64 end = child->part.offset + child->part.size;
struct mtd_erase_region_info *regions = parent->eraseregions;
/* Find the first erase regions which is part of this
* partition. */
for (i = 0; i < max && regions[i].offset <= child->part.offset;
i++)
;
/* The loop searched for the region _behind_ the first one */
if (i > 0)
i--;
/* Pick biggest erasesize */
for (; i < max && regions[i].offset < end; i++) {
if (child->erasesize < regions[i].erasesize)
child->erasesize = regions[i].erasesize;
}
BUG_ON(child->erasesize == 0);
} else {
/* Single erase size */
child->erasesize = master->erasesize;
}
/*
* Child erasesize might differ from the parent one if the parent
* exposes several regions with different erasesize. Adjust
* wr_alignment accordingly.
*/
if (!(child->flags & MTD_NO_ERASE))
wr_alignment = child->erasesize;
tmp = mtd_get_master_ofs(child, 0);
remainder = do_div(tmp, wr_alignment);
if ((child->flags & MTD_WRITEABLE) && remainder) {
/* Doesn't start on a boundary of major erase size */
/* FIXME: Let it be writable if it is on a boundary of
* _minor_ erase size though */
child->flags &= ~MTD_WRITEABLE;
printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
part->name);
}
tmp = mtd_get_master_ofs(child, 0) + child->part.size;
remainder = do_div(tmp, wr_alignment);
if ((child->flags & MTD_WRITEABLE) && remainder) {
child->flags &= ~MTD_WRITEABLE;
printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
part->name);
}
child->size = child->part.size;
child->ecc_step_size = parent->ecc_step_size;
child->ecc_strength = parent->ecc_strength;
child->bitflip_threshold = parent->bitflip_threshold;
if (master->_block_isbad) {
uint64_t offs = 0;
while (offs < child->part.size) {
if (mtd_block_isreserved(child, offs))
child->ecc_stats.bbtblocks++;
else if (mtd_block_isbad(child, offs))
child->ecc_stats.badblocks++;
offs += child->erasesize;
}
}
out_register:
return child;
}
static ssize_t mtd_partition_offset_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%lld\n", mtd->part.offset);
}
static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);
static const struct attribute *mtd_partition_attrs[] = {
&dev_attr_offset.attr,
NULL
};
static int mtd_add_partition_attrs(struct mtd_info *new)
{
int ret = sysfs_create_files(&new->dev.kobj, mtd_partition_attrs);
if (ret)
printk(KERN_WARNING
"mtd: failed to create partition attrs, err=%d\n", ret);
return ret;
}
int mtd_add_partition(struct mtd_info *parent, const char *name,
long long offset, long long length)
{
struct mtd_info *master = mtd_get_master(parent);
u64 parent_size = mtd_is_partition(parent) ?
parent->part.size : parent->size;
struct mtd_partition part;
struct mtd_info *child;
int ret = 0;
/* the direct offset is expected */
if (offset == MTDPART_OFS_APPEND ||
offset == MTDPART_OFS_NXTBLK)
return -EINVAL;
if (length == MTDPART_SIZ_FULL)
length = parent_size - offset;
if (length <= 0)
return -EINVAL;
memset(&part, 0, sizeof(part));
part.name = name;
part.size = length;
part.offset = offset;
child = allocate_partition(parent, &part, -1, offset);
if (IS_ERR(child))
return PTR_ERR(child);
mutex_lock(&master->master.partitions_lock);
list_add_tail(&child->part.node, &parent->partitions);
mutex_unlock(&master->master.partitions_lock);
ret = add_mtd_device(child);
if (ret)
goto err_remove_part;
mtd_add_partition_attrs(child);
return 0;
err_remove_part:
mutex_lock(&master->master.partitions_lock);
list_del(&child->part.node);
mutex_unlock(&master->master.partitions_lock);
free_partition(child);
return ret;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);
/**
* __mtd_del_partition - delete MTD partition
*
* @priv: MTD structure to be deleted
*
* This function must be called with the partitions mutex locked.
*/
static int __mtd_del_partition(struct mtd_info *mtd)
{
struct mtd_info *child, *next;
int err;
list_for_each_entry_safe(child, next, &mtd->partitions, part.node) {
err = __mtd_del_partition(child);
if (err)
return err;
}
sysfs_remove_files(&mtd->dev.kobj, mtd_partition_attrs);
err = del_mtd_device(mtd);
if (err)
return err;
list_del(&child->part.node);
free_partition(mtd);
return 0;
}
/*
* This function unregisters and destroy all slave MTD objects which are
* attached to the given MTD object, recursively.
*/
static int __del_mtd_partitions(struct mtd_info *mtd)
{
struct mtd_info *child, *next;
LIST_HEAD(tmp_list);
int ret, err = 0;
list_for_each_entry_safe(child, next, &mtd->partitions, part.node) {
if (mtd_has_partitions(child))
__del_mtd_partitions(child);
pr_info("Deleting %s MTD partition\n", child->name);
ret = del_mtd_device(child);
if (ret < 0) {
pr_err("Error when deleting partition \"%s\" (%d)\n",
child->name, ret);
err = ret;
continue;
}
list_del(&child->part.node);
free_partition(child);
}
return err;
}
int del_mtd_partitions(struct mtd_info *mtd)
{
struct mtd_info *master = mtd_get_master(mtd);
int ret;
pr_info("Deleting MTD partitions on \"%s\":\n", mtd->name);
mutex_lock(&master->master.partitions_lock);
ret = __del_mtd_partitions(mtd);
mutex_unlock(&master->master.partitions_lock);
return ret;
}
int mtd_del_partition(struct mtd_info *mtd, int partno)
{
struct mtd_info *child, *master = mtd_get_master(mtd);
int ret = -EINVAL;
mutex_lock(&master->master.partitions_lock);
list_for_each_entry(child, &mtd->partitions, part.node) {
if (child->index == partno) {
ret = __mtd_del_partition(child);
break;
}
}
mutex_unlock(&master->master.partitions_lock);
return ret;
}
EXPORT_SYMBOL_GPL(mtd_del_partition);
/*
* This function, given a parent MTD object and a partition table, creates
* and registers the child MTD objects which are bound to the parent according
* to the partition definitions.
*
* For historical reasons, this function's caller only registers the parent
* if the MTD_PARTITIONED_MASTER config option is set.
*/
int add_mtd_partitions(struct mtd_info *parent,
const struct mtd_partition *parts,
int nbparts)
{
struct mtd_info *child, *master = mtd_get_master(parent);
uint64_t cur_offset = 0;
int i, ret;
printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n",
nbparts, parent->name);
for (i = 0; i < nbparts; i++) {
child = allocate_partition(parent, parts + i, i, cur_offset);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto err_del_partitions;
}
mutex_lock(&master->master.partitions_lock);
list_add_tail(&child->part.node, &parent->partitions);
mutex_unlock(&master->master.partitions_lock);
ret = add_mtd_device(child);
if (ret) {
mutex_lock(&master->master.partitions_lock);
list_del(&child->part.node);
mutex_unlock(&master->master.partitions_lock);
free_partition(child);
goto err_del_partitions;
}
mtd_add_partition_attrs(child);
/* Look for subpartitions */
parse_mtd_partitions(child, parts[i].types, NULL);
cur_offset = child->part.offset + child->part.size;
}
return 0;
err_del_partitions:
del_mtd_partitions(master);
return ret;
}
static DEFINE_SPINLOCK(part_parser_lock);
static LIST_HEAD(part_parsers);
static struct mtd_part_parser *mtd_part_parser_get(const char *name)
{
struct mtd_part_parser *p, *ret = NULL;
spin_lock(&part_parser_lock);
list_for_each_entry(p, &part_parsers, list)
if (!strcmp(p->name, name) && try_module_get(p->owner)) {
ret = p;
break;
}
spin_unlock(&part_parser_lock);
return ret;
}
static inline void mtd_part_parser_put(const struct mtd_part_parser *p)
{
module_put(p->owner);
}
/*
* Many partition parsers just expected the core to kfree() all their data in
* one chunk. Do that by default.
*/
static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts,
int nr_parts)
{
kfree(pparts);
}
int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner)
{
p->owner = owner;
if (!p->cleanup)
p->cleanup = &mtd_part_parser_cleanup_default;
spin_lock(&part_parser_lock);
list_add(&p->list, &part_parsers);
spin_unlock(&part_parser_lock);
return 0;
}
EXPORT_SYMBOL_GPL(__register_mtd_parser);
void deregister_mtd_parser(struct mtd_part_parser *p)
{
spin_lock(&part_parser_lock);
list_del(&p->list);
spin_unlock(&part_parser_lock);
}
EXPORT_SYMBOL_GPL(deregister_mtd_parser);
/*
* Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
* are changing this array!
*/
static const char * const default_mtd_part_types[] = {
"cmdlinepart",
"ofpart",
NULL
};
/* Check DT only when looking for subpartitions. */
static const char * const default_subpartition_types[] = {
"ofpart",
NULL
};
static int mtd_part_do_parse(struct mtd_part_parser *parser,
struct mtd_info *master,
struct mtd_partitions *pparts,
struct mtd_part_parser_data *data)
{
int ret;
ret = (*parser->parse_fn)(master, &pparts->parts, data);
pr_debug("%s: parser %s: %i\n", master->name, parser->name, ret);
if (ret <= 0)
return ret;
pr_notice("%d %s partitions found on MTD device %s\n", ret,
parser->name, master->name);
pparts->nr_parts = ret;
pparts->parser = parser;
return ret;
}
/**
* mtd_part_get_compatible_parser - find MTD parser by a compatible string
*
* @compat: compatible string describing partitions in a device tree
*
* MTD parsers can specify supported partitions by providing a table of
* compatibility strings. This function finds a parser that advertises support
* for a passed value of "compatible".
*/
static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
{
struct mtd_part_parser *p, *ret = NULL;
spin_lock(&part_parser_lock);
list_for_each_entry(p, &part_parsers, list) {
const struct of_device_id *matches;
matches = p->of_match_table;
if (!matches)
continue;
for (; matches->compatible[0]; matches++) {
if (!strcmp(matches->compatible, compat) &&
try_module_get(p->owner)) {
ret = p;
break;
}
}
if (ret)
break;
}
spin_unlock(&part_parser_lock);
return ret;
}
static int mtd_part_of_parse(struct mtd_info *master,
struct mtd_partitions *pparts)
{
struct mtd_part_parser *parser;
struct device_node *np;
struct property *prop;
const char *compat;
const char *fixed = "fixed-partitions";
int ret, err = 0;
np = mtd_get_of_node(master);
if (mtd_is_partition(master))
of_node_get(np);
else
np = of_get_child_by_name(np, "partitions");
of_property_for_each_string(np, "compatible", prop, compat) {
parser = mtd_part_get_compatible_parser(compat);
if (!parser)
continue;
ret = mtd_part_do_parse(parser, master, pparts, NULL);
if (ret > 0) {
of_node_put(np);
return ret;
}
mtd_part_parser_put(parser);
if (ret < 0 && !err)
err = ret;
}
of_node_put(np);
/*
* For backward compatibility we have to try the "fixed-partitions"
* parser. It supports old DT format with partitions specified as a
* direct subnodes of a flash device DT node without any compatibility
* specified we could match.
*/
parser = mtd_part_parser_get(fixed);
if (!parser && !request_module("%s", fixed))
parser = mtd_part_parser_get(fixed);
if (parser) {
ret = mtd_part_do_parse(parser, master, pparts, NULL);
if (ret > 0)
return ret;
mtd_part_parser_put(parser);
if (ret < 0 && !err)
err = ret;
}
return err;
}
/**
* parse_mtd_partitions - parse and register MTD partitions
*
* @master: the master partition (describes whole MTD device)
* @types: names of partition parsers to try or %NULL
* @data: MTD partition parser-specific data
*
* This function tries to find & register partitions on MTD device @master. It
* uses MTD partition parsers, specified in @types. However, if @types is %NULL,
* then the default list of parsers is used. The default list contains only the
* "cmdlinepart" and "ofpart" parsers ATM.
* Note: If there are more then one parser in @types, the kernel only takes the
* partitions parsed out by the first parser.
*
* This function may return:
* o a negative error code in case of failure
* o number of found partitions otherwise
*/
int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
struct mtd_part_parser_data *data)
{
struct mtd_partitions pparts = { };
struct mtd_part_parser *parser;
int ret, err = 0;
if (!types)
types = mtd_is_partition(master) ? default_subpartition_types :
default_mtd_part_types;
for ( ; *types; types++) {
/*
* ofpart is a special type that means OF partitioning info
* should be used. It requires a bit different logic so it is
* handled in a separated function.
*/
if (!strcmp(*types, "ofpart")) {
ret = mtd_part_of_parse(master, &pparts);
} else {
pr_debug("%s: parsing partitions %s\n", master->name,
*types);
parser = mtd_part_parser_get(*types);
if (!parser && !request_module("%s", *types))
parser = mtd_part_parser_get(*types);
pr_debug("%s: got parser %s\n", master->name,
parser ? parser->name : NULL);
if (!parser)
continue;
ret = mtd_part_do_parse(parser, master, &pparts, data);
if (ret <= 0)
mtd_part_parser_put(parser);
}
/* Found partitions! */
if (ret > 0) {
err = add_mtd_partitions(master, pparts.parts,
pparts.nr_parts);
mtd_part_parser_cleanup(&pparts);
return err ? err : pparts.nr_parts;
}
/*
* Stash the first error we see; only report it if no parser
* succeeds
*/
if (ret < 0 && !err)
err = ret;
}
return err;
}
void mtd_part_parser_cleanup(struct mtd_partitions *parts)
{
const struct mtd_part_parser *parser;
if (!parts)
return;
parser = parts->parser;
if (parser) {
if (parser->cleanup)
parser->cleanup(parts->parts, parts->nr_parts);
mtd_part_parser_put(parser);
}
}
/* Returns the size of the entire flash chip */
uint64_t mtd_get_device_size(const struct mtd_info *mtd)
{
struct mtd_info *master = mtd_get_master((struct mtd_info *)mtd);
return master->size;
}
EXPORT_SYMBOL_GPL(mtd_get_device_size);