When reading token data from sysfs on my Inspiron 3505, the token
locations and values are wrong. This happens because match_attribute()
blindly assumes that all entries in da_tokens have an associated
entry in token_attrs.
This however is not true as soon as da_tokens[] contains zeroed
token entries. Those entries are being skipped when initialising
token_attrs, breaking the core assumption of match_attribute().
Fix this by defining an extra struct for each pair of token attributes
and use container_of() to retrieve token information.
Tested on a Dell Inspiron 3050.
Fixes: 33b9ca1e53b4 ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens")
Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
---
Changes since v1:
- remove style changes
- improve sizeof() usage with pointer targets
---
drivers/platform/x86/dell/dell-smbios-base.c | 92 ++++++++------------
1 file changed, 36 insertions(+), 56 deletions(-)
diff --git a/drivers/platform/x86/dell/dell-smbios-base.c b/drivers/platform/x86/dell/dell-smbios-base.c
index e61bfaf8b5c4..86b95206cb1b 100644
--- a/drivers/platform/x86/dell/dell-smbios-base.c
+++ b/drivers/platform/x86/dell/dell-smbios-base.c
@@ -11,6 +11,7 @@
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/container_of.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/capability.h>
@@ -25,11 +26,16 @@ static u32 da_supported_commands;
static int da_num_tokens;
static struct platform_device *platform_device;
static struct calling_interface_token *da_tokens;
-static struct device_attribute *token_location_attrs;
-static struct device_attribute *token_value_attrs;
+static struct token_sysfs_data *token_entries;
static struct attribute **token_attrs;
static DEFINE_MUTEX(smbios_mutex);
+struct token_sysfs_data {
+ struct device_attribute location_attr;
+ struct device_attribute value_attr;
+ struct calling_interface_token *token;
+};
+
struct smbios_device {
struct list_head list;
struct device *device;
@@ -416,47 +422,26 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
}
}
-static int match_attribute(struct device *dev,
- struct device_attribute *attr)
-{
- int i;
-
- for (i = 0; i < da_num_tokens * 2; i++) {
- if (!token_attrs[i])
- continue;
- if (strcmp(token_attrs[i]->name, attr->attr.name) == 0)
- return i/2;
- }
- dev_dbg(dev, "couldn't match: %s\n", attr->attr.name);
- return -EINVAL;
-}
-
static ssize_t location_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- int i;
+ struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, location_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- i = match_attribute(dev, attr);
- if (i > 0)
- return sysfs_emit(buf, "%08x", da_tokens[i].location);
- return 0;
+ return sysfs_emit(buf, "%08x", data->token->location);
}
static ssize_t value_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- int i;
+ struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, value_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- i = match_attribute(dev, attr);
- if (i > 0)
- return sysfs_emit(buf, "%08x", da_tokens[i].value);
- return 0;
+ return sysfs_emit(buf, "%08x", data->token->value);
}
static struct attribute_group smbios_attribute_group = {
@@ -473,22 +458,15 @@ static int build_tokens_sysfs(struct platform_device *dev)
{
char *location_name;
char *value_name;
- size_t size;
int ret;
int i, j;
- /* (number of tokens + 1 for null terminated */
- size = sizeof(struct device_attribute) * (da_num_tokens + 1);
- token_location_attrs = kzalloc(size, GFP_KERNEL);
- if (!token_location_attrs)
+ token_entries = kcalloc(da_num_tokens, sizeof(*token_entries), GFP_KERNEL);
+ if (!token_entries)
return -ENOMEM;
- token_value_attrs = kzalloc(size, GFP_KERNEL);
- if (!token_value_attrs)
- goto out_allocate_value;
/* need to store both location and value + terminator*/
- size = sizeof(struct attribute *) * ((2 * da_num_tokens) + 1);
- token_attrs = kzalloc(size, GFP_KERNEL);
+ token_attrs = kcalloc((2 * da_num_tokens) + 1, sizeof(*token_attrs), GFP_KERNEL);
if (!token_attrs)
goto out_allocate_attrs;
@@ -496,27 +474,32 @@ static int build_tokens_sysfs(struct platform_device *dev)
/* skip empty */
if (da_tokens[i].tokenID == 0)
continue;
+
+ token_entries[i].token = &da_tokens[i];
+
/* add location */
location_name = kasprintf(GFP_KERNEL, "%04x_location",
da_tokens[i].tokenID);
if (location_name == NULL)
goto out_unwind_strings;
- sysfs_attr_init(&token_location_attrs[i].attr);
- token_location_attrs[i].attr.name = location_name;
- token_location_attrs[i].attr.mode = 0444;
- token_location_attrs[i].show = location_show;
- token_attrs[j++] = &token_location_attrs[i].attr;
+
+ sysfs_attr_init(&token_entries[i].location_attr.attr);
+ token_entries[i].location_attr.attr.name = location_name;
+ token_entries[i].location_attr.attr.mode = 0444;
+ token_entries[i].location_attr.show = location_show;
+ token_attrs[j++] = &token_entries[i].location_attr.attr;
/* add value */
value_name = kasprintf(GFP_KERNEL, "%04x_value",
da_tokens[i].tokenID);
if (value_name == NULL)
goto loop_fail_create_value;
- sysfs_attr_init(&token_value_attrs[i].attr);
- token_value_attrs[i].attr.name = value_name;
- token_value_attrs[i].attr.mode = 0444;
- token_value_attrs[i].show = value_show;
- token_attrs[j++] = &token_value_attrs[i].attr;
+
+ sysfs_attr_init(&token_entries[i].value_attr.attr);
+ token_entries[i].value_attr.attr.name = value_name;
+ token_entries[i].value_attr.attr.mode = 0444;
+ token_entries[i].value_attr.show = value_show;
+ token_attrs[j++] = &token_entries[i].value_attr.attr;
continue;
loop_fail_create_value:
@@ -532,14 +515,12 @@ static int build_tokens_sysfs(struct platform_device *dev)
out_unwind_strings:
while (i--) {
- kfree(token_location_attrs[i].attr.name);
- kfree(token_value_attrs[i].attr.name);
+ kfree(token_entries[i].location_attr.attr.name);
+ kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
out_allocate_attrs:
- kfree(token_value_attrs);
-out_allocate_value:
- kfree(token_location_attrs);
+ kfree(token_entries);
return -ENOMEM;
}
@@ -551,12 +532,11 @@ static void free_group(struct platform_device *pdev)
sysfs_remove_group(&pdev->dev.kobj,
&smbios_attribute_group);
for (i = 0; i < da_num_tokens; i++) {
- kfree(token_location_attrs[i].attr.name);
- kfree(token_value_attrs[i].attr.name);
+ kfree(token_entries[i].location_attr.attr.name);
+ kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
- kfree(token_value_attrs);
- kfree(token_location_attrs);
+ kfree(token_entries);
}
static int __init dell_smbios_init(void)
--
2.39.2
