Replace use of sprintf in *_show attributes with sysfs_emit for writing
to sysfs. While the current implementation works, sysfs_emit helps prevent
potential buffer overflows and aligns with kernel documentation
Documentation/filesystems/sysfs.rst.

Tested on an x86_64 system with acpi_tad built as a module:
- Inserted patched acpi_tad.ko successfully
- Verified /sys/devices/platform/ACPI000E:00/time and /caps are accessible
- Confirmed correct output from 'cat' with no dmesg errors

Signed-off-by: Sukrut Heroorkar <hsukrut3@gmail.com>
---
 drivers/acpi/acpi_tad.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpi_tad.c b/drivers/acpi/acpi_tad.c
index 825c2a8acea4..91d7d90c47da 100644
--- a/drivers/acpi/acpi_tad.c
+++ b/drivers/acpi/acpi_tad.c
@@ -233,7 +233,7 @@ static ssize_t time_show(struct device *dev, struct device_attribute *attr,
 	if (ret)
 		return ret;
 
-	return sprintf(buf, "%u:%u:%u:%u:%u:%u:%d:%u\n",
+	return sysfs_emit(buf, "%u:%u:%u:%u:%u:%u:%d:%u\n",
 		       rt.year, rt.month, rt.day, rt.hour, rt.minute, rt.second,
 		       rt.tz, rt.daylight);
 }
@@ -428,7 +428,7 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
 {
 	struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "0x%02X\n", dd->capabilities);
+	return sysfs_emit(buf, "0x%02X\n", dd->capabilities);
 }
 
 static DEVICE_ATTR_RO(caps);
-- 
2.43.0

On Wed, Jul 16, 2025 at 2:36 PM Sukrut Heroorkar <hsukrut3@gmail.com> wrote:
>
> Replace use of sprintf in *_show attributes with sysfs_emit for writing
> to sysfs. While the current implementation works, sysfs_emit helps prevent
> potential buffer overflows and aligns with kernel documentation
> Documentation/filesystems/sysfs.rst.
>
> Tested on an x86_64 system with acpi_tad built as a module:
> - Inserted patched acpi_tad.ko successfully
> - Verified /sys/devices/platform/ACPI000E:00/time and /caps are accessible
> - Confirmed correct output from 'cat' with no dmesg errors
>
> Signed-off-by: Sukrut Heroorkar <hsukrut3@gmail.com>
> ---
>  drivers/acpi/acpi_tad.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/acpi_tad.c b/drivers/acpi/acpi_tad.c
> index 825c2a8acea4..91d7d90c47da 100644
> --- a/drivers/acpi/acpi_tad.c
> +++ b/drivers/acpi/acpi_tad.c
> @@ -233,7 +233,7 @@ static ssize_t time_show(struct device *dev, struct device_attribute *attr,
>         if (ret)
>                 return ret;
>
> -       return sprintf(buf, "%u:%u:%u:%u:%u:%u:%d:%u\n",
> +       return sysfs_emit(buf, "%u:%u:%u:%u:%u:%u:%d:%u\n",
>                        rt.year, rt.month, rt.day, rt.hour, rt.minute, rt.second,
>                        rt.tz, rt.daylight);
>  }
> @@ -428,7 +428,7 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
>  {
>         struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
>
> -       return sprintf(buf, "0x%02X\n", dd->capabilities);
> +       return sysfs_emit(buf, "0x%02X\n", dd->capabilities);
>  }
>
>  static DEVICE_ATTR_RO(caps);
> --

Applied as 6.17 material, thanks!