On Fri, Aug 21, 2020 at 8:14 AM Yue Hu <zbest...@gmail.com> wrote:
>
> From: Yue Hu <huy...@yulong.com>
>
> We observed warning about kzalloc() when register thermal cooling device
> in backlight_device_register(). backlight display can be a cooling device
> since reducing screen brightness will can help reduce temperature.
>
> However, ->get_max_state of backlight will assign max brightness of 1024
> to states. The memory size can be getting 1MB+ due to states * states.
> That is so large to trigger kmalloc() warning.
>
> So, let's use kvzalloc() to avoid the issue, also change kfree -> kvfree.
>
> Suggested-by: Amit Kucheria <am...@kernel.org>
> Signed-off-by: Yue Hu <huy...@yulong.com>
Reviewed-by: Amit Kucheria <am...@kernel.org>
> ---
> drivers/thermal/thermal_sysfs.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
> index aa99edb..d1703ee 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -16,6 +16,7 @@
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/slab.h>
> +#include <linux/mm.h>
> #include <linux/string.h>
> #include <linux/jiffies.h>
>
> @@ -919,7 +920,7 @@ static void cooling_device_stats_setup(struct
> thermal_cooling_device *cdev)
> var += sizeof(*stats->time_in_state) * states;
> var += sizeof(*stats->trans_table) * states * states;
>
> - stats = kzalloc(var, GFP_KERNEL);
> + stats = kvzalloc(var, GFP_KERNEL);
> if (!stats)
> return;
>
> @@ -938,7 +939,7 @@ static void cooling_device_stats_setup(struct
> thermal_cooling_device *cdev)
>
> static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev)
> {
> - kfree(cdev->stats);
> + kvfree(cdev->stats);
> cdev->stats = NULL;
> }
>
> --
> 1.9.1
>
