[PATCH v2 1/2] platform/x86: dell-smbios: Fix wrong token data in sysfs

[PATCH v2 1/2] platform/x86: dell-smbios: Fix wrong token data in sysfs

[Armin Wolf]

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@gmx.de>
---
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

[PATCH v2 2/2] platform/x86: dell-smbios: Simplify error handling

[Armin Wolf]

When the allocation of value_name fails, the error handling code
uses two gotos for error handling, which is not necessary.

Simplify the error handling in this case by only using a single goto.

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
Changes since v1:
- add patch
---
 drivers/platform/x86/dell/dell-smbios-base.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-smbios-base.c b/drivers/platform/x86/dell/dell-smbios-base.c
index 86b95206cb1b..b562ed99ec4e 100644
--- a/drivers/platform/x86/dell/dell-smbios-base.c
+++ b/drivers/platform/x86/dell/dell-smbios-base.c
@@ -492,19 +492,16 @@ static int build_tokens_sysfs(struct platform_device *dev)
 		/* add value */
 		value_name = kasprintf(GFP_KERNEL, "%04x_value",
 				       da_tokens[i].tokenID);
-		if (value_name == NULL)
-			goto loop_fail_create_value;
+		if (!value_name) {
+			kfree(location_name);
+			goto out_unwind_strings;
+		}

 		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:
-		kfree(location_name);
-		goto out_unwind_strings;
 	}
 	smbios_attribute_group.attrs = token_attrs;

--
2.39.2

Re: [PATCH v2 1/2] platform/x86: dell-smbios: Fix wrong token data in sysfs

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 7756 bytes --]

On Tue, 28 May 2024, Armin Wolf wrote:

> 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@gmx.de>
> ---
> 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);

This isn't actually required for the fix since it's in practice just a
syntatic cleanup but then it is harmful either.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.

>  	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
> 

Re: [PATCH v2 2/2] platform/x86: dell-smbios: Simplify error handling

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 1742 bytes --]

On Tue, 28 May 2024, Armin Wolf wrote:

> When the allocation of value_name fails, the error handling code
> uses two gotos for error handling, which is not necessary.
> 
> Simplify the error handling in this case by only using a single goto.
> 
> Tested on a Dell Inspiron 3505.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
> Changes since v1:
> - add patch
> ---
>  drivers/platform/x86/dell/dell-smbios-base.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-smbios-base.c b/drivers/platform/x86/dell/dell-smbios-base.c
> index 86b95206cb1b..b562ed99ec4e 100644
> --- a/drivers/platform/x86/dell/dell-smbios-base.c
> +++ b/drivers/platform/x86/dell/dell-smbios-base.c
> @@ -492,19 +492,16 @@ static int build_tokens_sysfs(struct platform_device *dev)
>  		/* add value */
>  		value_name = kasprintf(GFP_KERNEL, "%04x_value",
>  				       da_tokens[i].tokenID);
> -		if (value_name == NULL)
> -			goto loop_fail_create_value;
> +		if (!value_name) {
> +			kfree(location_name);
> +			goto out_unwind_strings;
> +		}
> 
>  		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:
> -		kfree(location_name);
> -		goto out_unwind_strings;
>  	}
>  	smbios_attribute_group.attrs = token_attrs;

Good cleanup. Using continue on the main level of a loop is almost never a 
good idea.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.

Re: [PATCH v2 1/2] platform/x86: dell-smbios: Fix wrong token data in sysfs

[Hans de Goede]

Hi,

On 5/28/24 10:49 PM, Armin Wolf wrote:
> 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@gmx.de>
> ---
> Changes since v1:
> - remove style changes
> - improve sizeof() usage with pointer targets

Thank you for your patch-series, I've applied this series to my
review-hans branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

I will include this patch in my next fixes pull-req to Linus
for the current kernel development cycle.

Regards,

Hans




> ---
>  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
>