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regmap: debugfs: Fix a boot time crash with early regmap init 

If called early enough, regmap_debugfs_init causes a crash, if the
fs subsystem does not have its mount cache created yet. Even if this
would work, the root node for the regmap debugfs is still missing,
thus postpone the regmap_debugfs_init in this case until the root
node is created. A special regmap_debugfs_early list is created for
this purpose which is parsed later in the boot.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Tero Kristo 2013-10-24 15:03:41 +03:00 committed by Mark Brown
parent 31d141e3a6
commit a52eaeb189
1 changed files with 52 additions and 5 deletions
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57
drivers/base/regmap/regmap-debugfs.c
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@ -15,10 +15,19 @@
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/device.h>
#include <linux/list.h>
#include "internal.h"
struct regmap_debugfs_node {
struct regmap *map;
const char *name;
struct list_head link;
};
static struct dentry *regmap_debugfs_root;
static LIST_HEAD(regmap_debugfs_early_list);
static DEFINE_MUTEX(regmap_debugfs_early_lock);
/* Calculate the length of a fixed format */
static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
@ -465,6 +474,20 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
struct rb_node *next;
struct regmap_range_node *range_node;
/* If we don't have the debugfs root yet, postpone init */
if (!regmap_debugfs_root) {
struct regmap_debugfs_node *node;
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return;
node->map = map;
node->name = name;
mutex_lock(&regmap_debugfs_early_lock);
list_add(&node->link, &regmap_debugfs_early_list);
mutex_unlock(&regmap_debugfs_early_lock);
return;
}
INIT_LIST_HEAD(&map->debugfs_off_cache);
mutex_init(&map->cache_lock);
@ -519,18 +542,42 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
void regmap_debugfs_exit(struct regmap *map)
{
debugfs_remove_recursive(map->debugfs);
mutex_lock(&map->cache_lock);
regmap_debugfs_free_dump_cache(map);
mutex_unlock(&map->cache_lock);
kfree(map->debugfs_name);
if (map->debugfs) {
debugfs_remove_recursive(map->debugfs);
mutex_lock(&map->cache_lock);
regmap_debugfs_free_dump_cache(map);
mutex_unlock(&map->cache_lock);
kfree(map->debugfs_name);
} else {
struct regmap_debugfs_node *node, *tmp;
mutex_lock(&regmap_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
link) {
if (node->map == map) {
list_del(&node->link);
kfree(node);
}
}
mutex_unlock(&regmap_debugfs_early_lock);
}
}
void regmap_debugfs_initcall(void)
{
struct regmap_debugfs_node *node, *tmp;
regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
if (!regmap_debugfs_root) {
pr_warn("regmap: Failed to create debugfs root\n");
return;
}
mutex_lock(&regmap_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
regmap_debugfs_init(node->map, node->name);
list_del(&node->link);
kfree(node);
}
mutex_unlock(&regmap_debugfs_early_lock);
}