Re: [igt-dev] [PATCH i-g-t 3/8] lib/params: overhaul param saving

[Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>]

On 28.4.2020 15.26, Petri Latvala wrote:
> On Tue, Apr 21, 2020 at 07:17:20PM +0300, Juha-Pekka Heikkila wrote:
>> From: Jani Nikula <jani.nikula@intel.com>
>>
>> More generic, use existing functions.
>>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
>> ---
>>   lib/igt_params.c | 101 +++++++++++++++++++----------------------------
>>   1 file changed, 41 insertions(+), 60 deletions(-)
>>
>> diff --git a/lib/igt_params.c b/lib/igt_params.c
>> index f220e73b..b5ac1266 100644
>> --- a/lib/igt_params.c
>> +++ b/lib/igt_params.c
>> @@ -34,92 +34,74 @@
>>   #include "igt_params.h"
>>   #include "igt_sysfs.h"
>>   
>> -#define MODULE_PARAM_DIR "/sys/module/i915/parameters/"
>> -#define PARAM_NAME_MAX_SZ 32
>> -#define PARAM_VALUE_MAX_SZ 16
>> -#define PARAM_FILE_PATH_MAX_SZ (strlen(MODULE_PARAM_DIR) + PARAM_NAME_MAX_SZ)
>> -
>>   struct module_param_data {
>> -	char name[PARAM_NAME_MAX_SZ];
>> -	char original_value[PARAM_VALUE_MAX_SZ];
>> +	char *path;
>> +	char *name;
>> +	char *original_value;
>>   
>>   	struct module_param_data *next;
>>   };
>>   struct module_param_data *module_params = NULL;
>>   
>> -static void igt_module_param_exit_handler(int sig)
>> +static void igt_params_exit_handler(int sig)
>>   {
>> -	const size_t dir_len = strlen(MODULE_PARAM_DIR);
>> -	char file_path[PARAM_FILE_PATH_MAX_SZ];
>>   	struct module_param_data *data;
>> -	int fd;
>> -
>> -	/* We don't need to assert string sizes on this function since they were
>> -	 * already checked before being stored on the lists. Besides,
>> -	 * igt_assert() is not AS-Safe. */
>> -	strcpy(file_path, MODULE_PARAM_DIR);
>> +	int dir;
>>   
>>   	for (data = module_params; data != NULL; data = data->next) {
>> -		strcpy(file_path + dir_len, data->name);
>> -
>> -		fd = open(file_path, O_RDWR);
>> -		if (fd >= 0) {
>> -			int size = strlen (data->original_value);
>> -
>> -			if (size != write(fd, data->original_value, size)) {
>> -				const char msg[] = "WARNING: Module parameters "
>> -					"may not have been reset to their "
>> -					"original values\n";
>> -				assert(write(STDERR_FILENO, msg, sizeof(msg))
>> -				       == sizeof(msg));
>> -			}
>> -
>> -			close(fd);
>> +		dir = open(data->path, O_RDONLY);
>> +
>> +		if (!igt_sysfs_set(dir, data->name, data->original_value)) {
>> +			const char msg[] = "WARNING: Module parameters "
>> +				"may not have been reset to their "
>> +				"original values\n";
>> +			assert(write(STDERR_FILENO, msg, sizeof(msg))
>> +			       == sizeof(msg));
>>   		}
>> +
>> +		close(dir);
>>   	}
>>   	/* free() is not AS-Safe, so we can't call it here. */
>>   }
>>   
>>   /**
>> - * igt_save_module_param:
>> - * @name: name of the i915.ko module parameter
>> - * @file_path: full sysfs file path for the parameter
>> + * igt_params_save:
>> + * @dir: file handle for path
>> + * @path: full path to the sysfs directory
>> + * @name: name of the sysfs attribute
>>    *
>> - * Reads the current value of an i915.ko module parameter, saves it on an array,
>> - * then installs an exit handler to restore it when the program exits.
>> + * Reads the current value of a sysfs attribute, saves it on an array, then
>> + * installs an exit handler to restore it when the program exits.
>>    *
>>    * It is safe to call this function multiple times for the same parameter.
>>    *
>>    * Notice that this function is called by igt_set_module_param(), so that one -
>>    * or one of its wrappers - is the only function the test programs need to call.
>>    */
>> -static void igt_save_module_param(const char *name, const char *file_path)
>> +static void igt_params_save(int dir, const char *path, const char *name)
>>   {
>>   	struct module_param_data *data;
>> -	size_t n;
>> -	int fd;
>>   
>>   	/* Check if this parameter is already saved. */
>>   	for (data = module_params; data != NULL; data = data->next)
>> -		if (strncmp(data->name, name, PARAM_NAME_MAX_SZ) == 0)
>> +		if (strcmp(data->path, path) == 0 &&
>> +		    strcmp(data->name, name) == 0)
>>   			return;
>>   
>>   	if (!module_params)
>> -		igt_install_exit_handler(igt_module_param_exit_handler);
>> +		igt_install_exit_handler(igt_params_exit_handler);
>>   
>>   	data = calloc(1, sizeof (*data));
>>   	igt_assert(data);
>>   
>> -	strncpy(data->name, name, PARAM_NAME_MAX_SZ - 1);
>> -
>> -	fd = open(file_path, O_RDONLY);
>> -	igt_assert(fd >= 0);
>> +	data->path = strdup(path);
>> +	igt_assert(data->path);
>>   
>> -	n = read(fd, data->original_value, PARAM_VALUE_MAX_SZ);
>> -	igt_assert_f(n > 0 && n < PARAM_VALUE_MAX_SZ,
>> -		     "Need to increase PARAM_VALUE_MAX_SZ\n");
>> +	data->name = strdup(name);
>> +	igt_assert(data->name);
>>   
>> -	igt_assert(close(fd) == 0);
>> +	data->original_value = igt_sysfs_get(dir, name);
>> +	igt_assert(data->original_value);
>>   
>>   	data->next = module_params;
>>   	module_params = data;
>> @@ -205,22 +187,21 @@ bool igt_params_set(int device, const char *parameter, const char *fmt, ...)
>>    */
>>   void igt_set_module_param(const char *name, const char *val)
>>   {
>> -	char file_path[PARAM_FILE_PATH_MAX_SZ];
>> -	size_t len = strlen(val);
>> -	int fd;
>> +	const char *path = "/sys/module/i915/parameters";
>> +	int dir;
>>   
>> -	igt_assert_f(strlen(name) < PARAM_NAME_MAX_SZ,
>> -		     "Need to increase PARAM_NAME_MAX_SZ\n");
>> -	strcpy(file_path, MODULE_PARAM_DIR);
>> -	strcpy(file_path + strlen(MODULE_PARAM_DIR), name);
>> +	dir = open(path, O_RDONLY);
>> +	igt_assert(dir >= 0);
>>   
>> -	igt_save_module_param(name, file_path);
>> +	igt_params_save(dir, path, name);
>>   
>> -	fd = open(file_path, O_RDWR);
>> -	igt_assert(write(fd, val, len) == len);
>> -	igt_assert(close(fd) == 0);
>> +	igt_assert(igt_sysfs_set(dir, name, val));
>> +
>> +	igt_assert(close(dir) == 0);
>>   }
>>   
>> +#define PARAM_VALUE_MAX_SZ 16
>> +
> 
> Is this define still needed for something?

Look like it has moved inside igt_aux.c so it's not needed here, I'll 
take it away.

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