linux-kernel - Re: [PATCH 09/16 v2] Input: atmel_mxt_ts - optimize writing of object table entries

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 13 Apr 2012 11:13:30 +0200
From:	"Henrik Rydberg" <rydberg@...omail.se>
To:	Daniel Kurtz <djkurtz@...omium.org>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Nick Dyer <nick.dyer@...ev.co.uk>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, Benson Leung <bleung@...omium.org>,
	Yufeng Shen <miletus@...omium.org>
Subject: Re: [PATCH 09/16 v2] Input: atmel_mxt_ts - optimize writing of
 object table entries

Hi Daniel,

> Write each object using a single bulk i2c write transfer.
> 
> Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
> Reviewed-by: Joonyoung Shim <jy0922.shim@...sung.com>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c |   28 ++++++++++++++--------------
>  1 files changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index a865967..3abc5b0 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -628,33 +628,33 @@ end:
>  static int mxt_check_reg_init(struct mxt_data *data)
>  {
>  	const struct mxt_platform_data *pdata = data->pdata;
> -	struct mxt_object *object;
>  	struct device *dev = &data->client->dev;
> -	int index = 0;
> -	int i, j, config_offset, config_size;
> +	int i, offset;
> +	int ret;
>  
>  	if (!pdata->config) {
>  		dev_dbg(dev, "No cfg data defined, skipping reg init\n");
>  		return 0;
>  	}
>  
> -	for (i = 0; i < data->info.object_num; i++) {
> -		object = data->object_table + i;
> +	for (offset = 0, i = 0; i < data->info.object_num; i++) {
> +		struct mxt_object *object = &data->object_table[i];
> +		size_t config_size;
>  
>  		if (!mxt_object_writable(object->type))
>  			continue;
>  
>  		config_size = object->size * object->instances;
> -		for (j = 0; j < config_size; j++) {
> -			config_offset = index + j;
> -			if (config_offset > pdata->config_length) {
> -				dev_err(dev, "Not enough config data!\n");
> -				return -EINVAL;
> -			}
> -			mxt_write_object(data, object->type, j,
> -					 pdata->config[config_offset]);
> +		if (offset + config_size > pdata->config_length) {
> +			dev_err(dev, "Not enough config data!\n");
> +			return -EINVAL;
>  		}
> -		index += config_size;
> +
> +		ret = mxt_write_reg(data->client, object->start_address,
> +				    config_size, &pdata->config[offset]);

How big is config_size? Removing the need for a stack copy here would
be better, see patch 11.

> +		if (ret)
> +			return ret;
> +		offset += config_size;
>  	}
>  
>  	return 0;
> -- 
> 1.7.7.3
> 

Thanks,
Henrik
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/